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Sample records for infrared spectroscopic ellipsometry

  1. Infrared spectroscopic ellipsometry in semiconductor manufacturing

    NASA Astrophysics Data System (ADS)

    Guittet, Pierre-Yves; Mantz, Ulrich; Weidner, Peter; Stehle, Jean-Louis; Bucchia, Marc; Bourtault, Sophie; Zahorski, Dorian

    2004-05-01

    Infrared spectroscopic ellipsometry (IRSE) metrology is an emerging technology in semiconductor production environment. Infineon Technologies SC300 implemented the first worldwide automated IRSE in a class 1 clean room in 2002. Combining properties of IR light -- large wavelength, low absorption in silicon -- with a short focus optics -- no backside reflection -- which allow model-based analysis, a large number of production applications were developed. Part of Infineon IRSE development roadmap is now focused on depth monitoring for arrays of 3D dry-etched structures. In trench DRAM manufacturing, the areal density is high, and critical dimensions are much lower than mid-IR wavelength. Therefore, extensive use of effective medium theory is made to model 3D structures. IR-SE metrology is not limited by shrinking critical dimensions, as long as the areal density is above a specific cut-off value determined by trenches dimensions, trench-filling and surrounding materials. Two applications for depth monitoring are presented. 1D models were developed and successfully applied to the DRAM trench capacitor structures. Modeling and correlation to reference methods are shown as well as dynamic repeatability and gauge capability results. Limitations of the current tool configuration are reviewed for shallow structures.

  2. Probing the carrier concentration profiles in phosphorus-implanted germanium using infrared spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    D'Costa, Vijay Richard; Yeo, Yee-Chia

    2015-02-01

    Spectroscopic ellipsometry with photon energy in the 0.045-0.65 eV range was used to investigate germanium samples implanted with 30 keV phosphorus ions and annealed at 700 °C. The infrared response of implanted layers is dominated by free carrier absorption which is modeled using a Drude oscillator. The carrier concentration profiles were modeled using an error function, and compared with those obtained by electrochemical capacitance-voltage profiling and secondary ion mass spectrometry. In the flat region of the carrier concentration profile, average carrier concentration and mobility of 1.40 × 1019 cm-3 and 336 cm2V-1s-1, respectively, were obtained. A phosphorus diffusivity of ˜1.2 × 10-13 cm2/s was obtained. The mobility versus carrier concentration relationships obtained for the implanted samples are close to the empirical relationship for bulk Ge.

  3. Probing the carrier concentration profiles in phosphorus-implanted germanium using infrared spectroscopic ellipsometry

    SciTech Connect

    D'Costa, Vijay Richard Yeo, Yee-Chia

    2015-02-21

    Spectroscopic ellipsometry with photon energy in the 0.045–0.65 eV range was used to investigate germanium samples implanted with 30 keV phosphorus ions and annealed at 700 °C. The infrared response of implanted layers is dominated by free carrier absorption which is modeled using a Drude oscillator. The carrier concentration profiles were modeled using an error function, and compared with those obtained by electrochemical capacitance-voltage profiling and secondary ion mass spectrometry. In the flat region of the carrier concentration profile, average carrier concentration and mobility of 1.40 × 10{sup 19} cm{sup −3} and 336 cm{sup 2}V{sup −1}s{sup −1}, respectively, were obtained. A phosphorus diffusivity of ∼1.2 × 10{sup −13} cm{sup 2}/s was obtained. The mobility versus carrier concentration relationships obtained for the implanted samples are close to the empirical relationship for bulk Ge.

  4. Measurement of ionic polarization of SrTiO3 single crystal by far-infrared spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Kanehara, Kazuki; Hoshina, Takuya; Takeda, Hiroaki; Tsurumi, Takaaki

    2014-07-01

    We developed a far-infrared spectroscopic ellipsometer for measuring the complex permittivity of high-permittivity materials in the terahertz (THz) region and demonstrated the dielectric function of SrTiO3 single crystal at 0.75-21 THz. The responses of the Slater, Last, and O6 displacive modes, which are all optical phonon modes of SrTiO3 at room temperature, were clearly observed. The complex permittivity measured by the ellipsometer agreed with the permittivity simulated by a damped harmonic oscillator model. The far-infrared spectroscopic ellipsometry is useful to analyze the phonon modes of high-permittivity materials, which enable us to understand the contribution of the ionic polarizations to the low-frequency permittivity.

  5. Spectroscopic ellipsometry on lamellar gratings

    NASA Astrophysics Data System (ADS)

    Antos, R.; Ohlidal, I.; Mistrik, J.; Murakami, K.; Yamaguchi, T.; Pistora, J.; Horie, M.; Visnovsky, S.

    2005-05-01

    Deep lamellar diffraction gratings fabricated by etching a transparent quartz plate are studied using spectroscopic ellipsometry. The rigorous coupled-wave analysis is used to calculate the optical response of the gratings. Three parameters of the rectangular profile are determined by utilizing the least-square method. Detailed investigation of the spectral dependences demonstrates the uniqueness of the solution. Observing the spectral dependences of Wood anomalies suggests that even complicated profiles can be fitted with high authenticity.

  6. Optical phonons and polariton dispersions of congruent LiNbO3 studied by far-infrared spectroscopic ellipsometry and Raman scattering

    NASA Astrophysics Data System (ADS)

    Kojima, Seiji; Kanehara, Kazuki; Hoshina, Takuya; Tsurumi, Takaaki

    2016-10-01

    IR active optical modes and phonon-polaritons with E(x) and A1(z) symmetries were studied in a ferroelectric congruent lithium niobate crystal. The real and imaginary parts of a dielectric constant along the a- and c-axes were accurately determined by far-infrared spectroscopic ellipsometry (FIRSP) from 40 to 700 cm-1. For the nine transverse optical (TO) modes with E(x) symmetry, it was difficult to observe the 5th E(TO5) mode at 361 cm-1 and the 9th E(TO9) mode at 665 cm-1 by Raman scattering owing to the very low Raman intensity, while these modes were clearly observed by FIRSP. In contrast, the 6th E(TO6) mode at 371 cm-1 was not observed by FIRSP owing to the very weak absorption, while it was clearly observed by Raman scattering. All the four TO modes with A1(z) symmetry were clearly observed independently by FIRSP and Raman scattering. The dispersion relations of phonon-polaritons including the damping of polaritons were determined using the real and imaginary parts of a polariton wavevector calculated from complex dielectric constants. The polariton dispersion of the lowest A1(z) mode at 254 cm-1 is in agreement with the previous forward Raman scattering experiment; however, any anticrossing predicted by the previous impulsive Raman scattering experiment was not observed.

  7. Spectroscopic ellipsometry study of novel nanostructured transparent conducting oxide structures

    NASA Astrophysics Data System (ADS)

    Khosroabadi, Akram A.; Norwood, R. A.

    2013-02-01

    Spectroscopic ellipsometry has been used to find the optical constants, including refractive index, extinction coefficient, thickness and volume fraction of nanostructured transparent conducting oxides including indium tin oxide (ITO) and indium zinc oxide (IZO). We observed sharp features in the ellipsometry data, with the spectral peaks and positions depending on the nanostructure dimensions and material. A superposition of Lorentzian oscillators and the effective medium approximation has been applied to determine the volume ratio of voids and nanopillars, thereby providing the effective optical constants.

  8. Spectroscopic ellipsometry data analysis: Measured vs. calculated quantities

    SciTech Connect

    Jellison, G.E. Jr.

    1997-05-01

    Spectroscopic ellipsometry is a very powerful technique for optical characterization of thin-film and bulk materials, but the technique measures functions of complex reflection coefficients, which are usually not of interest per se. The interesting characteristics such as film thickness, surface roughness thickness, and optical functions can be determined only by modeling the near-surface region of the sample. However, the measured quantities are not equivalent to those determined from the modeling. Ellipsometry measurements determine elements of the sample Mueller matrix, but the usual result of modeling calculations are elements of the sample. Often this difference is academic, but if the sample depolarizes the light, it is not. Ellipsometry calculations also include methods for determining the optical functions of materials. Data for bulk materials are usually accurate for substrates, but are not appropriate for most thin films. Therefore, reasonable parameterizations are quite useful in performing spectroscopic ellipsometry data analysis. Recently, there has been an increased interest in anisotropic materials, both in thin-film and bulk form. A generalized procedure will be presented for calculating the elements of the Jones matrix for any number of layers, any one of which may or may not be uniaxial.

  9. Characterization of semicrystalline polymers after nanoimprint by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Wang, Si; Rond, Johannes; Steinberg, Christian; Papenheim, Marc; Scheer, Hella-Christin

    2016-02-01

    Semicrystalline Reg-P3HT (regio-regular poly-3-hexylthiophene) is a promising material for organic electronics. It features relatively high charge mobility and enables easy preparation because of its solubility. Due to its high optical and electrical anisotropy, the size, number and orientation of the ordered domains are important for applications. To control these properties without limitation from crystalline domains existing after spin coating, thermal nanoimprint is performed beyond the melting point. The state of the art of measurement to analyze the complex morphology is X-ray diffraction (XRD). We address an alternative measurement method to characterize the material by its optical properties, spectroscopic ellipsometry. It provides information on the degree of order from the typical fingerprint absorption spectrum. In addition, when the material is modeled as a uniaxial layer, an anisotropy factor can be derived. The results obtained from spectroscopic ellipsometry are in accordance with those from XRD. In particular, spectroscopic ellipsometry is able to distinguish between order along the backbone and order in π- π stacking direction, which is important with respect to conductivity.

  10. Strain measurements of Ge epilayers on Si by Spectroscopic Ellipsometry

    NASA Astrophysics Data System (ADS)

    Ghosh, A.; Fernando, N.; Medina, A. A.; Nelson, C. M.; Zollner, S.; Xu, S. C.; Menendez, J.; Kouvetakis, J.

    2014-03-01

    Using spectroscopic ellipsometry, we determined the strain of a Ge epilayer grown on a Si (100) substrate. This strain depends on the sample temperature and arises because of the difference in thermal expansion coefficients between Si and Ge. It can be calculated since the thermal expansion coefficients of Si and Ge are known very precisely, if we assume that the Ge epilayer was fully relaxed at the growth temperature, leading to an increase in strain as the temperature decreases. We calculate in-plane tensile strain values of 0.12% at 300 K or 0.19% at 77K for our Ge on Si layer, that compares favorably with an in-plane strain of 0.11% derived from shifts of the Ge lattice reflection at 300 K by x-ray diffraction. This temperature-dependent strain affects the energies of the E1 and E1+Delta1 critical points of the Ge epilayer, which can be measured very precisely using spectroscopic ellipsometry from 77 to 800 K.From the difference in the critical point energies between our Ge epilayers on Si and bulk Ge (up to 20 meV), we can calculate the strain from the known elastic constants and deformation potentials. The strain determined from ellipsometry agrees well with the strain calculated from the temperature-dependent thermal expansion coefficient. This work was supported by AFOSR, Award Number FA9550-13-1-0022.

  11. Rotating compensator spectroscopic ellipsometry for line-width control

    NASA Astrophysics Data System (ADS)

    Lee, Ha-Young; Bang, Kyoung-Yoon; Lee, Jaeho; Bak, Heungin; Sohn, Young-Soo; An, Ilsin

    2002-07-01

    Rotating compensator spectroscopic ellipsometry (RCSE) was applied to the characterization of line-width in deep UV photoresist films. Variation of line-width in few nm was distinguishable by comparing the features in conventional ellipsometry parameters or the degree of polarization spectra obtainable form RCSE. The variations in the former spectra were caused by the density change in patterned PR films. Meanwhile, the variations in latter spectra wee caused by the surface profile of the film. Once the spectral positions of the features were related to the result of CD- SEM, both spectra could be used to estimate the line-width of patterned PR without in-depth analysis. Further, when uniaxial anisotropy was assumed for the film, the line-width could be roughly deduced in the process of extracting the optical properties of film via an effective medium approximation.

  12. Evaluation of the SEI using a multilayer spectroscopic ellipsometry model

    SciTech Connect

    Eric J. Dufek

    2014-08-01

    A multilayer spectroscopic ellipsometry (SE) model has been developed to characterize SEI formation. The model, which consists of two Cauchy layers, is constructed with an inner layer meant to model primarily inorganic compounds adjacent to an electrode and an outer layer which mirrors polymeric, organic constituents on the exterior of the SEI. Comparison of 1:1 EC:EMC and 1:4 EC:EMC with 1.0 M LiPF6 shows distinct differences in the two modeled layers. The data suggest that the thickness of both layers change over a wide potential range. These changes have been linked with other reports on the growth of the SEI.

  13. Evaluation of the SEI using a multilayer spectroscopic ellipsometry model

    DOE PAGESBeta

    Dufek, Eric J.

    2014-08-28

    A multilayer spectroscopic ellipsometry (SE) model has been developed to characterize SEI formation. The model, which consists of two Cauchy layers, is constructed with an inner layer meant to model primarily inorganic compounds adjacent to an electrode and an outer layer which mirrors polymeric, organic constituents on the exterior of the SEI. Comparison of 1:1 EC:EMC and 1:4 EC:EMC with 1.0 M LiPF₆ shows distinct differences in the two modeled layers. The data suggest that the thickness of both layers change over a wide potential range. These changes have been linked with other reports on the growth of the SEI.

  14. The calculation of thin film parameters from spectroscopic ellipsometry data

    SciTech Connect

    Jellison, G.E. Jr.

    1996-02-01

    Spectroscopic ellipsometry (SE) has proven to be a very powerful diagnostic for thin film characterization, but the results of SE experiments must first be compared with calculations to determine thin film parameters such as film thickness and optical functions. This process requires 4 steps: (1) The quantities measured must be specified and the equivalent calculated parameters identified. (2) The film structure must be modeled, where the number of films is specified and certain characteristics of each layer specified, such as whether or not the film is isotropic or anisotropic, homogeneous or graded. (3) The optical functions of each layer must be specified or parameterized. (4) The data must be compared with the calculated spectra, where a quantifiable figure of merit is used for the comparison. The last step is particularly important because without it, no {open_quotes}goodness of fit{close_quotes} parameter is calculated and one does not know whether or not the calculated spectrum fits the data.

  15. Characterization by spectroscopic Ellipsometry, the physical properties of silver nanoparticles.

    NASA Astrophysics Data System (ADS)

    Coanga, Jean-Maurice

    2013-04-01

    Physicists are able to change their minds through their experiments. I think it is time to go kick the curse and go further in research if we want a human future. I work in the Nano-Optics and Plasmonics research. I defined with ellipsomètrie the structure of new type of Nano particles of silver. It's same be act quickly to replace the old dirty leaded electronic-connexion chip and by the other hand to find a new way for the heath care of cancer disease by nanoparticles the next killers of bad cells. Silver nanoparticle layers are obtained by Spark Plasma Sintering are investigated as an alternative to lead alloy based material for solder joint in power mechatronics modules. These layers are characterized by mean of conventional techniques that is the dilatometry technique, the resistivity measurement through the van der Pauw method, and the flash laser technique. Furthermore, the nanoparticles of silver layer are deeply studied by UV-Visible spectroscopic ellipsometry. Spectroscopic angles parameters are determined in function of temperature and dielectric constants are deduced and analyzed through an optical model which takes into account a Drude and a Lorentz component within the Bruggeman effective medium approximation (EMA). The relaxation times and the electrical conductivity are plot in function of temperature. The obtained electrical conductivity give significant result in good agreement to those reported by four points electrical measurement method.

  16. Spectroscopic ellipsometry studies of HF treated Si (100) surfaces

    NASA Astrophysics Data System (ADS)

    Yao, Huade; Woollam, John A.; Alterovitz, Samuel A.

    1993-06-01

    Both ex situ and in situ spectroscopic ellipsometry (SE) measurements were employed to investigate the effect of HF cleaning on Si surfaces. The hydrogen-terminated (H-terminated) Si surface was modeled as an equivalent dielectric layer, and monitored in real time by SE measurements. The SE analyses indicate that, after a 20-sec 9:1 HF dip without rinse, the Si (100) surface was passivated by the hydrogen termination and remained chemically stable. Roughness of the HF-etched bare Si (100) surface was observed, in an ultrahigh vacuum chamber (UHV), and analyzed by the in situ SE. Evidence for desorption of the H-terminated Si surface layer, after being heated to about 550 C in the UHV chamber, is presented and discussed. This is the first use of an ex situ and in situ real-time, nondestructive technique capable of showing state of passivation, the rate of reoxidation, and the surface roughness of the H-terminated Si surfaces.

  17. Spectroscopic ellipsometry studies of HF treated Si (100) surfaces

    NASA Astrophysics Data System (ADS)

    Yao, Huade; Woollam, John A.; Alterovitz, Samuel A.

    1993-08-01

    Both ex situ and in situ spectroscopic ellipsometry (SE) measurements were employed to investigate the effects of HF cleaning on Si surfaces. The hydrogen-terminated (H-terminated) Si surface was modeled as an equivalent dielectric layer, and monitored in real time by SE measurements. The SE analyses indicate that after a 20-s 9:1 HF dip without rinse, the Si(100) surface was passivated by the hydrogen termination and remained chemically stable. Roughness of the HF-etched bare Si(100) surface was observed, in an ultrahigh vacuum (UHV) chamber, and analyzed by the in situ SE. Evidence for desorption of the H-terminated Si surface-layer, after being heated to approximately 550 C in the UHV chamber, is presented and discussed. This is the first use of an ex situ and in situ real-time, nondestructive technique capable of showing state of passivation, the rate of reoxidation, and the surface roughness of the H-terminated Si surfaces.

  18. Imaging spectroscopic ellipsometry of MoS2

    NASA Astrophysics Data System (ADS)

    Funke, S.; Miller, B.; Parzinger, E.; Thiesen, P.; Holleitner, A. W.; Wurstbauer, U.

    2016-09-01

    Micromechanically exfoliated mono- and multilayers of molybdenum disulfide (MoS2) are investigated by spectroscopic imaging ellipsometry. In combination with knife edge illumination, MoS2 flakes can be detected and classified on arbitrary flat and also transparent substrates with a lateral resolution down to 1-2 µm. The complex dielectric functions from mono- and trilayer MoS2 are presented. They are extracted from a multilayer model to fit the measured ellipsometric angles employing an anisotropic and an isotropic fit approach. We find that the energies of the critical points of the optical constants can be treated to be independent of the utilized model, whereas the magnitude of the optical constants varies with the used model. The anisotropic model suggests a maximum absorbance for a MoS2 sheet supported by sapphire of about 14% for monolayer and of 10% for trilayer MoS2. Furthermore, the lateral homogeneity of the complex dielectric function for monolayer MoS2 is investigated with a spatial resolution of 2 µm. Only minor fluctuations are observed. No evidence for strain, for a significant amount of disorder or lattice defects can be found in the wrinkle-free regions of the MoS2 monolayer from complementary µ-Raman spectroscopy measurements. We assume that the minor lateral variation in the optical constants are caused by lateral modification in the van der Waals interaction presumably caused by the preparation using micromechanical exfoliation and viscoelastic stamping.

  19. Imaging spectroscopic ellipsometry of MoS2

    NASA Astrophysics Data System (ADS)

    Funke, S.; Miller, B.; Parzinger, E.; Thiesen, P.; Holleitner, A. W.; Wurstbauer, U.

    2016-09-01

    Micromechanically exfoliated mono- and multilayers of molybdenum disulfide (MoS2) are investigated by spectroscopic imaging ellipsometry. In combination with knife edge illumination, MoS2 flakes can be detected and classified on arbitrary flat and also transparent substrates with a lateral resolution down to 1–2 µm. The complex dielectric functions from mono- and trilayer MoS2 are presented. They are extracted from a multilayer model to fit the measured ellipsometric angles employing an anisotropic and an isotropic fit approach. We find that the energies of the critical points of the optical constants can be treated to be independent of the utilized model, whereas the magnitude of the optical constants varies with the used model. The anisotropic model suggests a maximum absorbance for a MoS2 sheet supported by sapphire of about 14% for monolayer and of 10% for trilayer MoS2. Furthermore, the lateral homogeneity of the complex dielectric function for monolayer MoS2 is investigated with a spatial resolution of 2 µm. Only minor fluctuations are observed. No evidence for strain, for a significant amount of disorder or lattice defects can be found in the wrinkle-free regions of the MoS2 monolayer from complementary µ-Raman spectroscopy measurements. We assume that the minor lateral variation in the optical constants are caused by lateral modification in the van der Waals interaction presumably caused by the preparation using micromechanical exfoliation and viscoelastic stamping.

  20. Imaging spectroscopic ellipsometry of MoS2.

    PubMed

    Funke, S; Miller, B; Parzinger, E; Thiesen, P; Holleitner, A W; Wurstbauer, U

    2016-09-28

    Micromechanically exfoliated mono- and multilayers of molybdenum disulfide (MoS2) are investigated by spectroscopic imaging ellipsometry. In combination with knife edge illumination, MoS2 flakes can be detected and classified on arbitrary flat and also transparent substrates with a lateral resolution down to 1-2 µm. The complex dielectric functions from mono- and trilayer MoS2 are presented. They are extracted from a multilayer model to fit the measured ellipsometric angles employing an anisotropic and an isotropic fit approach. We find that the energies of the critical points of the optical constants can be treated to be independent of the utilized model, whereas the magnitude of the optical constants varies with the used model. The anisotropic model suggests a maximum absorbance for a MoS2 sheet supported by sapphire of about 14% for monolayer and of 10% for trilayer MoS2. Furthermore, the lateral homogeneity of the complex dielectric function for monolayer MoS2 is investigated with a spatial resolution of 2 µm. Only minor fluctuations are observed. No evidence for strain, for a significant amount of disorder or lattice defects can be found in the wrinkle-free regions of the MoS2 monolayer from complementary µ-Raman spectroscopy measurements. We assume that the minor lateral variation in the optical constants are caused by lateral modification in the van der Waals interaction presumably caused by the preparation using micromechanical exfoliation and viscoelastic stamping.

  1. In situ spectroscopic ellipsometry as a surface sensitive tool to probe thin film growth.

    SciTech Connect

    Liu, C.

    1999-02-19

    Sputtered thin film and multilayer x-ray mirrors are made routinely at the Advanced Photon Source (APS) for the APS users. Precise film growth control and characterization are very critical in fabricating high-quality x-ray mirrors. Film thickness calibrations are carried out using in situ and ex situ spectroscopic ellipsometry, interferometry, and x-ray scattering. To better understand the growth and optical properties of different thin film systems, we have carried out a systematic study of sputtered thin films of Au, Rh, Pg Pd, Cu, and Cr, using in situ ellipsometry. Multiple data sets were obtained in situ for each film material with incremental thicknesses and were analyzed with their correlation in mind. We found that in situ spectroscopic ellipsometry as a surface-sensitive tool can also be used to probe the growth and morphology of the thin film system. This application of in situ spectroscopic ellipsometry for metal thin film systems will be discussed.

  2. Application of Fourier transform infrared ellipsometry to assess the concentration of biological molecules.

    PubMed

    Garcia-Caurel, Enric; Drévillon, Bernard; De Martino, Antonello; Schwartz, Laurent

    2002-12-01

    Spectroscopic ellipsometry is a noninvasive optical characterization technique mainly used in the semiconductor field to characterize bare substrates and thin films. In particular, it allows the gathering of information concerning the physical structure of the sample, such as roughness and film thickness, as well as its optical response. In the mid-infrared (IR) range each molecule exhibits a characteristic absorption fingerprint, which makes this technique chemically selective. Phase-modulated IR ellipsometry does not require a baseline correction procedure or suppression of atmospheric CO2 and water-vapor absorption bands, thus greatly reducing the subjectivity in data analysis. We have found that ellipsometric measurements of thin films, such as the solid residuals left on a plane surface after evaporation of a liquid drop containing a given compound in solution, are particularly favorable for dosing purposes because the intensity of IR absorptions shows a linear behavior along a wide range of solution concentrations of the given compound. Our aim is to illustrate with a concrete example and to justify theoretically the linearity experimentally found between radiation absorption and molecule concentration. For the example, we prepared aqueous solutions of glycogen, a molecule of huge biological importance currently tested in biochemical analyses, at concentrations ranging from 1 mg/l to 1 g/l which correspond to those found in physiological conditions. The results of this example are promising for the application of ellipsometry for dosing purposes in biochemistry and biomedicine. PMID:12477127

  3. In situ spectroscopic ellipsometry studies of hydrogen ion bombardment of crystalline silicon

    SciTech Connect

    Hu, Y.Z.; Li, M.; Conrad, K.; Andres, J.W.; Irene, E.A.; Denker, M.; Ray, M.; McGuire, G.

    1992-05-01

    Hydrogen-bombardment induced damage in single crystal silicon as a function of the substrate temperature, ion energy, and ion dose was studied using in situ spectroscopic ellipsometry over the photon energy range 2.0-5.5 eV under high vacuum conditions. The incident hydrogen ion energies were 300 and 1000 eV, and the doses were 10{sup 15}-10{sup 18} ions/cm{sup 2}. In situ spectroscopic ellipsometry results showed that the damage layer thicknesses for the samples bombarded at elevated temperatures are smaller than for samples bombarded at room temperature and subsequently annealed at the same elevated temperature. The diffusion coefficient for hydrogen in silicon of 6 x 10{sup {minus}15} cm{sup {minus}2}/s was obtained from the in situ spectroscopic ellipsometry data. 40 refs., 11 figs., 1 tab.

  4. InGaP grown on Ge (100) by molecular beam epitaxy: a spectroscopic ellipsometry study

    NASA Astrophysics Data System (ADS)

    D'Costa, Vijay Richard; Khai Loke, Wan; Zhou, Qian; Fatt Yoon, Soon; Yeo, Yee-Chia

    2016-03-01

    We investigated the optical properties of disordered In0.52Ga0.48P alloys by spectroscopic ellipsometry in the far-infrared to ultraviolet energy range (0.037-5.1 eV). The alloys were grown on Ge (100) substrate by solid-source molecular beam epitaxy. The far-infrared dielectric function reveals two absorption peaks that can be attributed to InP- and GaP-like vibrational modes. The visible-UV dielectric function of In0.52Ga0.48P alloys nearly lattice-matched to Ge shows the critical points E 0, E 1, and E 2, energies of which are determined using a derivative analysis. A weak transition that can be identified as the E 1 + Δ1 critical point is revealed. The vibrational frequencies and the transition energies in In0.52Ga0.48P are lower relative to In0.49Ga0.51P lattice-matched to GaAs. The downward shifts in E 0 and phonons can be estimated using the compositional dependence of E 0 and phonons of bulk alloys.

  5. Stability of UV exposed RR-P3BT films by spectroscopic ellipsometry

    SciTech Connect

    Diware, Mangesh S.; Byun, J. S.; Hwang, S. Y.; Kim, T. J.; Kim, Y. D.

    2013-02-05

    Stability of regioregular poly(3-butylthiophene) (RR-P3BT) films under irradiation of ultra-violet (UV) light has been studied by spectroscopic ellipsometry at room temperature. Consistent decrease in dielectric function with UV exposure time showed the degree of degradation of polymer. This work suggests that, protective methods are mandatory to use this kind of material in optical devices.

  6. Stability of UV exposed RR-P3BT films by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Diware, Mangesh S.; Byun, J. S.; Hwang, S. Y.; Kim, T. J.; Kim, Y. D.

    2013-02-01

    Stability of regioregular poly(3-butylthiophene) (RR-P3BT) films under irradiation of ultra-violet (UV) light has been studied by spectroscopic ellipsometry at room temperature. Consistent decrease in dielectric function with UV exposure time showed the degree of degradation of polymer. This work suggests that, protective methods are mandatory to use this kind of material in optical devices.

  7. Sensitivity analysis for OMOG and EUV photomasks characterized by UV-NIR spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Heinrich, A.; Dirnstorfer, I.; Bischoff, J.; Meiner, K.; Richter, U.; Mikolajick, T.

    2013-09-01

    We investigated the potentials, applicability and advantages of spectroscopic ellipsometry (SE) for the characterization of high-end photomasks. The SE measurements were done in the ultraviolet-near infrared (UVNIR) wavelength range from 300 nm to 980 nm, at angle of incidences (AOI) between 10 and 70° and with a microspot size of 45 x 10 μm2 (AOI=70°). The measured Ψ and 𝛥 spectra were modeled using the rigorous coupled wave analysis (RCWA) to determine the structural parameters of a periodic array, i.e. the pitch and critical dimension (CD). Two different types of industrial photomasks consisting of line/space structures were evaluated, the reflecting extreme ultraviolet (EUV) and the transmitting opaque MoSi on glass (OMOG) mask. The Ψ and 𝛥 spectra of both masks show characteristic differences, which were related to the Rayleigh singularities and the missing transmission diffraction in the EUV mask. In the second part of the paper, a simulation based sensitivity analysis of the Fourier coefficients α and β is presented, which is used to define the required measurement precision to detect a CD deviation of 1%. This study was done for both mask types to investigate the influence of the stack transmission. It was found that sensitivities to CD variations are comparable for OMOG and EUV masks. For both masks, the highest sensitivities appear close to the Rayleigh singularities and significantly increase at very low AOI. To detect a 1% CD deviation for pitches below 150 nm a measurement precision in the order of 0.01 is required. This measurement precision can be realized with advanced optical hardware. It is concluded that UV-NIR ellipsometry is qualified to characterize photomasks down to the 13 nm technology node in 2020.

  8. In Situ Infrared Ellipsometry for Protein Adsorption Studies on Ultrathin Smart Polymer Brushes in Aqueous Environment

    SciTech Connect

    Kroning, Annika; Furchner, Andreas; Aulich, Dennis; Bittrich, Eva; Rauch, Sebastian; Uhlmann, Petra; Eichhorn, Klaus-Jochen; Seeber, Michael; Luzinov, Igor; Kilbey, S. Michael; Lokitz, Bradley S.; Minko, Sergiy; Hinrichs, Karsten

    2015-02-10

    The protein-adsorbing and -repelling properties of various smart nanometer-thin polymer brushes with high potential for biosensing and biomedical applications are studied by in-situ infrared-spectroscopic ellipsometry (IRSE). IRSE as a highly sensitive non-destructive technique allows us to investigate protein adsorption on polymer brushes in aqueous environment in dependence of external stimuli like temperature and pH. These stimuli are, for instance, relevant in switchable mixed brushes containing poly(N-isopropyl acrylamide) and poly(acrylic acid), respectively. We use such brushes as model surfaces for controlling protein adsorption of human serum albumin and human fibrinogen. IRSE can distinguish between polymer-specific vibrational bands, which yield insights into the hydration state of the brushes, and changes in the protein-specific amide bands, which are related to changes of the protein secondary structure.

  9. In Situ Infrared Ellipsometry for Protein Adsorption Studies on Ultrathin Smart Polymer Brushes in Aqueous Environment

    DOE PAGESBeta

    Kroning, Annika; Furchner, Andreas; Aulich, Dennis; Bittrich, Eva; Rauch, Sebastian; Uhlmann, Petra; Eichhorn, Klaus-Jochen; Seeber, Michael; Luzinov, Igor; Kilbey, S. Michael; et al

    2015-02-10

    The protein-adsorbing and -repelling properties of various smart nanometer-thin polymer brushes with high potential for biosensing and biomedical applications are studied by in-situ infrared-spectroscopic ellipsometry (IRSE). IRSE as a highly sensitive non-destructive technique allows us to investigate protein adsorption on polymer brushes in aqueous environment in dependence of external stimuli like temperature and pH. These stimuli are, for instance, relevant in switchable mixed brushes containing poly(N-isopropyl acrylamide) and poly(acrylic acid), respectively. We use such brushes as model surfaces for controlling protein adsorption of human serum albumin and human fibrinogen. IRSE can distinguish between polymer-specific vibrational bands, which yield insights intomore » the hydration state of the brushes, and changes in the protein-specific amide bands, which are related to changes of the protein secondary structure.« less

  10. Optical properties of As33S67-xSex bulk glasses studied by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Orava, J.; Šik, J.; Wágner, T.; Frumar, M.

    2008-04-01

    Variable angle spectroscopic ellipsometry (VASE) was employed to study the optical properties of As33S67-xSex (x =0, 17, 33.5, 50, and 67at.%) bulk glasses in the UV-vis-NIR (near infrared) spectral region for photon energies from 0.54to4.13eV (photon wavelengths from 2300to300nm). For data analysis, we employed Tauc-Lorentz (TL) dispersion model in the entire measured near bandgap spectral region and standard Cauchy dispersion model in the spectral region below the bandgap. With increasing Se content (x) in the bulk glass, we observed a linear decrease in optical bandgap energy Egopt from 2.52±0.02eV for As33S67 to 1.75±0.01eV for As33Se67 and linear increase in refractive index nTL in the NIR spectral region, e.g., at 0.80eV from 2.327 for As33S67 to 2.758 for As33Se67. The amplitude A decreased with increasing Se content. The peak transition energy E0 and broadening C had a maximum value for x =33.5at.% and systematically decreased for higher S or Se content in glasses. Our study showed that TL model is suitable to describe dielectric functions of studied chalcogenide bulk glasses in the broad spectral region. The bulk glasses had a higher refractive index compared to thin films of corresponding composition. The bulk glasses with high S content had higher value of optical bandgap energy than was previously reported for thin films. The optical bandgap energy of glasses with higher Se content was very similar to the thin films.

  11. Dielectric function of the ferromagnetic semiconductor CdMnCrTe studied by using spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Hwang, Younghun; Um, Youngho

    2014-11-01

    We describe the pseudo-dielectric function of Cd1- x- y Mn x Cr y Te ferromagnetic semiconductor alloys by using spectroscopic ellipsometry in the 1.0 ~ 6.0 eV spectral range at room temperature. The ellipsometry data include structures that can be attributed to the effects of Cr concentration on the E 0, E 1, E 1 + Δ1, and E 2 critical points. Critical-point (CP) parameters were obtained by fitting standard critical point (SCP) model line shapes to the numerically-calculated second- energy derivatives of ɛ( ω) = ɛ 1( ω) + iɛ 2( ω). The E 0, E 1, E 1 + Δ1, and E 2 energies decreased with Cr content y; this phenomenon is related to the hybridization of the valence and the conduction bands in CdTe with the 3 d states of Mn and Cr.

  12. Fundamental study of photoresist dissolution with real time spectroscopic ellipsometry and interferometry

    NASA Astrophysics Data System (ADS)

    Burns, Sean D.; Schmid, Gerard M.; Trinque, Brian C.; Willson, James; Wunderlich, Jennifer; Tsiartas, Pavlos C.; Taylor, James C.; Burns, Ryan L.; Wilson, C. Grant

    2003-06-01

    The use of in situ spectroscopic ellipsometry (SE) is demonstrated as a technique for studying photoresist dissolution. Experiments carried out using a J.A.Woollam M-2000 ellipsometer and a custom built cell designed for in situ film measurements show that bulk dissolution rate measurements using the SE technique agree with dissolution rate data obtained using multiwavelength interferometry. SE is also demonstrated as a method for measuring thin film dissolution rates, water sorption, and films that swell. An additional focus of this work was the topic of interfacial "gel" layer formation during photoresist dissolution. Ellipsometry and interferometry were used to test several photoresist resins, with an emphasis on phenolic polymers. Single and multiple layer models were used to analyze the data, and were compared to model calculations predicting formation of a gel layer. For the materials studied, interfacial gel layer formation in low molecular weight phenolic polymers was not detected, within the resolution of the experimental techniques (< 15 nm).

  13. Observation of Frenkel and charge transfer excitons in pentacene single crystals using spectroscopic generalized ellipsometry

    NASA Astrophysics Data System (ADS)

    Qi, Dongchen; Su, Haibin; Bastjan, M.; Jurchescu, O. D.; Palstra, T. M.; Wee, Andrew T. S.; Rübhausen, M.; Rusydi, A.

    2013-09-01

    We report on the emerging and admixture of Frenkel and charge transfer (CT) excitons near the absorption onset in pentacene single crystals. Using high energy-resolution spectroscopic generalized ellipsometry with in-plane polarization dependence, the excitonic nature of three lowest lying excitations is discussed. Their distinct polarization dependence strongly indicates the presence of both Frenkel and CT types of excitons near the excitation onset. In particular, the peculiar polarization behavior of the second excitation can only be rationalized by taking into account the inherent CT transition dipole moment. This observation has important implications for the pentacene-based optoelectronic devices.

  14. Optical properties of monolayer transition metal dichalcogenides probed by spectroscopic ellipsometry

    SciTech Connect

    Liu, Hsiang-Lin Shen, Chih-Chiang; Su, Sheng-Han; Hsu, Chang-Lung; Li, Ming-Yang; Li, Lain-Jong

    2014-11-17

    Spectroscopic ellipsometry was used to characterize the complex refractive index of chemical-vapor-deposited monolayer transition metal dichalcogenides (TMDs). The extraordinary large value of the refractive index in the visible frequency range is obtained. The absorption response shows a strong correlation between the magnitude of the exciton binding energy and band gap energy. Together with the observed giant spin-orbit splitting, these findings advance the fundamental understanding of their novel electronic structures and the development of monolayer TMDs-based optoelectronic and spintronic devices.

  15. Electronic and structural properties of molybdenum thin films as determined by real-time spectroscopic ellipsometry

    SciTech Connect

    Walker, J. D.; Khatri, H.; Ranjan, V.; Li Jian; Collins, R. W.; Marsillac, S.

    2009-04-06

    Real-time spectroscopic ellipsometry (RTSE) is shown to be an effective contactless probe of radio frequency magnetron sputtered molybdenum thin films used as the back electrode in chalcopyrite [Cu(In,Ga)Se{sub 2}] solar cells. A series of Mo thin films was sputtered onto soda-lime glass substrates at Ar pressures ranging from 4 to 20 mTorr. RTSE measurements reveal how Ar pressure affects the nucleation and growth mechanisms that influence the films' ultimate grain structure and properties. Determinations of the free electron relaxation times at optical frequencies reveal that higher pressures lead to a smaller average grain size and increased void volume fraction.

  16. Optical characterization of the PtSi/Si by using spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Le, Van Long; Kim, Tae Jung; Park, Han Gyeol; Kim, Hwa Seob; Yoo, Chang Hyun; Kim, Hyoung Uk; Kim, Young Dong; Kim, Junsoo; Im, Solyee; Choi, Won Chul; Moon, Seung Eon; Nam, Eun Soo

    2016-08-01

    We report an optical characterization of PtSi films for thermoelectric device applications which was done by using nondestructive spectroscopic ellipsometry (SE). A Pt monolayer and a Pt-Si multilayer which consisted of three pairs of Pt and Si layers were deposited on p-doped-silicon substrates by using sputtering method; then, rapid annealing process was done to form PtSi films through intermixing of Pt and Si atoms at the interface. Pseudodielectric function data < ɛ > = < ɛ 1 > + i < ɛ 2 > for the PtSi/Si samples were obtained from 1.12 to 6.52 eV by using spectroscopic ellipsometry. Employing the Tauc-Lorentz and the Drude models, determined the dielectric function ( ɛ) of the PtSi films. We found that the composition ratio of Pt:Si was nearly 1:1 for the PtSi monolayer and we observed transitions between occupied and unoccupied states in the Pt 5 d states. We also observed the formation of PtSi layers in the Pt-Si multilayer sample. The SE results were confirmed by the transmission electron microscopy and energy dispersive X-ray spectroscopy.

  17. In situ spectroscopic ellipsometry during atomic layer deposition of Pt, Ru and Pd

    NASA Astrophysics Data System (ADS)

    Leick, N.; Weber, J. W.; Mackus, A. J. M.; Weber, M. J.; van de Sanden, M. C. M.; Kessels, W. M. M.

    2016-03-01

    The preparation of ultra-thin platinum-group metal films, such as Pt, Ru and Pd, by atomic layer deposition (ALD) was monitored in situ using spectroscopic ellipsometry in the photon energy range of 0.75-5 eV. The metals’ dielectric function was parametrized using a ‘flexible’ Kramers-Kronig consistent dielectric function because it was able to provide accurate curve shape control over the optical response of the metals. From this dielectric function, it was possible to extract the film thickness values during the ALD process. The important ALD process parameters, such as the nucleation period and growth per cycle of Pt, Ru and Pd could be determined from the thickness evolution. In addition to process parameters, the film resistivity in particular could be extracted from the modeled dielectric function. Spectroscopic ellipsometry thereby revealed itself as a feasible and valuable technique to be used in research and development applications, as well as for process monitoring during ALD.

  18. Mid-infrared spectroscopic investigation

    NASA Technical Reports Server (NTRS)

    Salisbury, John W.; Vergo, Norma; Walter, Louis

    1987-01-01

    Mid-infrared spectroscopic research efforts are discussed. The development of a new instrumentation to permit advanced measurements in the mid-infrared region of the spectrum, the development of a special library of well-characterized mineral and rock specimens for interpretation of remote sensing data, and cooperative measurements of the spectral signatures of analogues of materials that may be present on the surfaces of asteroids, planets or their Moons are discussed.

  19. Role of an Oxidant Mixture as Surface Modifier of Porous Silicon Microstructures Evaluated by Spectroscopic Ellipsometry.

    PubMed

    Montiel-González, Zeuz; Escobar, Salvador; Nava, Rocío; del Río, J Antonio; Tagüeña-Martínez, Julia

    2016-04-21

    Current research on porous silicon includes the construction of complex structures with luminescent and/or photonic properties. However, their preparation with both characteristics is still challenging. Recently, our group reported a possible method to achieve that by adding an oxidant mixture to the electrolyte used to produce porous silicon. This mixture can chemically modify their microstructure by changing the thickness and surface passivation of the pore walls. In this work, we prepared a series of samples (with and without oxidant mixture) and we evaluated the structural differences through their scanning electron micrographs and their optical properties determined by spectroscopic ellipsometry. The results showed that ellipsometry is sensitive to slight variations in the porous silicon structure, caused by changes in their preparation. The fitting process, based on models constructed from the features observed in the micrographs, allowed us to see that the mayor effect of the oxidant mixture is on samples of high porosity, where the surface oxidation strongly contributes to the skeleton thinning during the electrochemical etching. This suggests the existence of a porosity threshold for the action of the oxidant mixture. These results could have a significant impact on the design of complex porous silicon structures for different optoelectronic applications.

  20. Probing initial-stages of ALD growth with dynamic in situ spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Muneshwar, Triratna; Cadien, Ken

    2015-02-01

    The initial stages of ALD surface reactions are probed using dynamic in situ spectroscopic ellipsometry (d-iSE) technique during plasma-enhanced ALD of zirconium nitride (ZrN) thin films in spectral range of 0.73-6.4 eV. The measured change in the ellipsometry parameter Δ, with every precursor (TDMAZr) and reactant (forming gas plasma) exposure is interpreted as the combined effect of film growth and change in surface chemistry during ALD. We present application of Bruggeman's effective-medium approximation (B-EMA) in the analysis of d-iSE data to determine fractional surface coverage (θ) of ALD grown film at the end of every deposition cycle. During the deposition of first few ZrN monolayers, d-iSE datasets are analyzed on the basis of surface diffusion enhanced ALD growth, where the surface adsorbed precursor molecules can diffuse over substrate surface to occupy energetically favorable surface sites. The determined surface coverage of ZrN films highlights the effects of substrate enhanced ALD growth.

  1. Role of an Oxidant Mixture as Surface Modifier of Porous Silicon Microstructures Evaluated by Spectroscopic Ellipsometry

    PubMed Central

    Montiel-González, Zeuz; Escobar, Salvador; Nava, Rocío; del Río, J. Antonio; Tagüeña-Martínez, Julia

    2016-01-01

    Current research on porous silicon includes the construction of complex structures with luminescent and/or photonic properties. However, their preparation with both characteristics is still challenging. Recently, our group reported a possible method to achieve that by adding an oxidant mixture to the electrolyte used to produce porous silicon. This mixture can chemically modify their microstructure by changing the thickness and surface passivation of the pore walls. In this work, we prepared a series of samples (with and without oxidant mixture) and we evaluated the structural differences through their scanning electron micrographs and their optical properties determined by spectroscopic ellipsometry. The results showed that ellipsometry is sensitive to slight variations in the porous silicon structure, caused by changes in their preparation. The fitting process, based on models constructed from the features observed in the micrographs, allowed us to see that the mayor effect of the oxidant mixture is on samples of high porosity, where the surface oxidation strongly contributes to the skeleton thinning during the electrochemical etching. This suggests the existence of a porosity threshold for the action of the oxidant mixture. These results could have a significant impact on the design of complex porous silicon structures for different optoelectronic applications. PMID:27097767

  2. In-situ spectroscopic ellipsometry study of copper selective-area atomic layer deposition on palladium

    SciTech Connect

    Jiang, Xiaoqiang; Wang, Han; Qi, Jie; Willis, Brian G.

    2014-07-01

    Selective area copper atomic layer deposition on palladium seed layers has been investigated with in-situ real-time spectroscopic ellipsometry to probe the adsorption/desorption and reaction characteristics of individual deposition cycles. The reactants are copper bis(2,2,6,6-tetramethyl-3,5-heptanedionate) vapor and hydrogen gas. Self-limiting atomic layer deposition was observed in the temperature range of 135–230 °C in a low pressure reactor. Under optimal conditions, growth occurs selectively on palladium and not on silicon dioxide or silicon nitride layers. Based on in-situ ellipsometry data and supporting experiments, a new mechanism for growth is proposed. In the proposed mechanism, precursor adsorption is reversible, and dissociatively adsorbed hydrogen are the stable surface intermediates between growth cycles. The mechanism is enabled by continuous diffusion of palladium from the seed layer into the deposited copper film and strong H* binding to palladium sites. Less intermixing can be obtained at low growth temperatures and short cycle times by minimizing Cu/Pd inter-diffusion.

  3. Composition Dependence of the Optical Conductivity of NiPt Alloys Determined by Spectroscopic Ellipsometry

    NASA Astrophysics Data System (ADS)

    Abdallah, Lina; Tawalbeh, Tarek; Vasiliev, Igor; Zollner, Stefan; Lavoie, Christian; Ozcan, Ahmet; Raymond, Mark

    2012-10-01

    The complex dielectric function of different Ni-Pt alloys (0% to 25% Pt concentration, 10nm thickness) was determined using spectroscopic ellipsometry over a broad photon energy range from 0.6 to 6.6eV. Data were fitted using basis spline functions as well as Drude-Lorentz oscillators to describe free carrier absorption and interband transitions. We found absorption peaks at 1.5 and 4.7 eV due to interband transitions. Results showed a broadening in the absorption peak of Nickel with increasing the Platinum concentration in the alloy. The experimental results were compared with ab initio density functional theory band structure calculations which showed that adding Platinum enhances the density of states of Nickel especially at low energies. Annealing the metals at 500^o C for 30 s increases the optical conductivity.

  4. Optical detection of melting point depression for silver nanoparticles via in situ real time spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Little, S. A.; Begou, T.; Collins, R. W.; Marsillac, S.

    2012-01-01

    Silver nanoparticle films were deposited by sputtering at room temperature and were annealed while monitoring by real time spectroscopic ellipsometry (SE). The nanoparticle dielectric functions (0.75 eV-6.5 eV) obtained by SE were modeled using Lorentz and generalized oscillators for the nanoparticle plasmon polariton (NPP) and interband transitions, respectively. The nanoparticle melting point could be identified from variations in the oscillator parameters during annealing, and this identification was further confirmed after cooling through significant, irreversible changes in these parameters relative to the as-deposited film. The variation in melting point with physical thickness, and thus average nanoparticle diameter, as measured by SE enables calculation of the surface energy density.

  5. Rapid, non-destructive evaluation of ultrathin WSe{sub 2} using spectroscopic ellipsometry

    SciTech Connect

    Eichfeld, Sarah M.; Lin, Yu-Chuan; Hossain, Lorraine; Eichfeld, Chad M.; Robinson, Joshua A.

    2014-09-01

    The utilization of tungsten diselenide (WSe{sub 2}) in electronic and optoelectronic devices depends on the ability to understand and control the process-property relationship during synthesis. We demonstrate that spectroscopic ellipsometry is an excellent technique for accurate, non-destructive determination of ultra-thin (<30 nm) WSe{sub 2} properties. The refractive index (n) and extinction coefficient (k) were found to be independent of thickness down to 1.3 nm, and were used to determine film thickness, which was confirmed to be within 9% of values found via atomic force microscopy. Finally, the optical bandgap was found to closely correlate with thickness, ranging from 1.2 to 1.55 eV as the WSe{sub 2} is thinned to the equivalent of 2 atomic layers.

  6. Spectroscopic ellipsometry study of Cu{sub 2}ZnSnSe{sub 4} bulk crystals

    SciTech Connect

    León, M. Lopez, N.; Merino, J. M.; Caballero, R.; Levcenko, S.; Gurieva, G.; Serna, R.; Bodnar, I. V.; Nateprov, A.; Guc, M.; Arushanov, E.; Schorr, S.; Perez-Rodriguez, A.

    2014-08-11

    Using spectroscopic ellipsometry we investigated and analyzed the pseudo-optical constants of Cu{sub 2}ZnSnSe{sub 4} bulk crystals, grown by the Bridgman method, over 0.8–4.5 eV photon energy range. The structures found in the spectra of the complex pseudodielectric functions were associated to E{sub 0}, E{sub 1A}, and E{sub 1B} interband transitions and were analyzed in frame of the Adachi's model. The interband transition parameters such as strength, threshold energy, and broadening were evaluated by using the simulated annealing algorithm. In addition, the pseudo-complex refractive index, extinction coefficient, absorption coefficient, and normal-incidence reflectivity were derived over 0.8–4.5 eV photon energy range.

  7. Detection of a MoSe{sub 2} secondary phase layer in CZTSe by spectroscopic ellipsometry

    SciTech Connect

    Demircioğlu, Özden; Riedel, Ingo; Gütay, Levent; Mousel, Marina; Redinger, Alex; Rey, Germain; Weiss, Thomas; Siebentritt, Susanne

    2015-11-14

    We demonstrate the application of Spectroscopic Ellipsometry (SE) for identification of secondary phase MoSe{sub 2} in polycrystalline Cu{sub 2}ZnSnSe{sub 4} (CZTSe) samples. A MoSe{sub 2} reference sample was analyzed, and its optical constants (ε{sub 1} and ε{sub 2}) were extracted by SE analysis. This dataset was implemented into an optical model for analyzing SE data from a glass/Mo/CZTSe sample containing MoSe{sub 2} at the back side of the absorber. We present results on the n and k values of CZTSe and show the extraction of the thickness of the secondary phase MoSe{sub 2} layer. Raman spectroscopy and scanning electron microscopy were applied to confirm the SE results.

  8. Evaluation of Mercaptobenzothiazole Anticorrosive Layer on Cu Surface by Spectroscopic Ellipsometry

    NASA Astrophysics Data System (ADS)

    Nishizawa, Hideaki; Sugiura, Osamu; Matsumura, Yoshiyuki; Kinoshita, Masaharu

    2007-05-01

    Mercaptobenzothiazole (MBT) anticorrosive layer on copper surface prepared in MBT solutions was analyzed by spectroscopic ellipsometry (SE). The results showed that MBT anticorrosive layer was formed on Cu2O layer in the MBT solution at temperatures higher than 50 °C. Additionally, it was confirmed that MBT anticorrosive layer was formed in the MBT solution at room temperature by adding about 20 wt % acetone to the solution. From polishing experiments of MBT anticorrosive layer and benzotriazole (BTA) layer, it was revealed that MBT anticorrosive layer was physically stronger than BTA layer. It is considered that dishing amount in Cu chemical-mechanical polishing (CMP) can be reduced by using MBT. However, MBT anticorrosive layer was not formed in the MBT solution including Hydrogen peroxide (H2O2) suggesting that slurry should be composed without H2O2 in order to use MBT for Cu CMP.

  9. Evolution of optical properties of tin film from solid to liquid studied by spectroscopic ellipsometry and ab initio calculation

    SciTech Connect

    Zhang, D X; Shen, B; Zheng, Y X; Wang, S Y; Zhang, J B; Yang, S D; Zhang, R J; Chen, L Y; Wang, C Z; Ho, K M

    2014-03-24

    The temperature dependent optical properties of tin film from solid to liquid were studied by spectroscopic ellipsometry and ab initio molecular dynamics simulations. The dielectric function of liquid Sn was different from solid, and an interband transition near 1.5 eV was easily observed in solid while it apparently disappeared upon melting. From the evolution of optical properties with temperature, an optical measurement to acquire the melting point by ellipsometry was presented. From first principles calculation, we show that the local structure difference in solid and liquid is responsible for this difference in the optical properties observed in experiment.

  10. Study of the Dielectric Function of Graphene from Spectroscopic Ellipsometry and Electron Energy Loss Spectroscopy

    NASA Astrophysics Data System (ADS)

    Nelson, Florence

    For more than 60 years, semiconductor research has been advancing up the periodic table. The first transistor was made from germanium. This later gave way to silicon-based devices due to the latter's ability to form an excellent interface with thermally-grown oxide. Now for the last ˜8 years, the focus has moved up one more row to carbon for post-CMOS devices in order to comply with the scaling limitations of Moore's law. However, for each of these, the measurements of film properties and dimensions have always been required for technological applications. These measurement methods often incorporate the use of light or electrons in order to take advantage of a wavelength that is on the order of, or smaller than, the feature sizes of interest. This thesis compares the dielectric function of graphene measured by an optical method to that obtained from an electron energy loss method in order to observe the effect of contamination and substrate on the optical properties of graphene exposed to the environment. Whether viewed in terms of how light affects a material (dielectric function) or how a material affects light (refractive index), the optical response is a quantity that may be used to obtain information about a film's thickness, energy structure, and the types of excitations that are responsible for energy loss. The three main experimental methods used in this thesis work are spectroscopic ellipsometry (SE), scanning transmission electron microscopy (STEM), and electron energy loss spectroscopy (EELS). SE is commonly used in clean-room environments for optical measurement over the energy range of ˜0-5 eV. This method is used to study graphene's dielectric function from the ultraviolet (UV) through infrared (IR) regions through use of an oscillator dispersion model. A nearly constant absorbance over the IR and into the visible region is observed due to vertical transitions between graphene's linearly dispersed pi-bands at the Dirac points. An exciton

  11. Characterization of a water-dispersible metal protective coating with Fourier transform infrared spectroscopy, modulated differential scanning calorimetry, and ellipsometry.

    PubMed

    Boyatzis, Stamatis C; Douvas, Antonios M; Argyropoulos, Vassilike; Siatou, Amalia; Vlachopoulou, Marilena

    2012-05-01

    An ethylene-methacrylic acid copolymer, formulated by BASF as a waterborne suspension of its alkylammonium salt and used, among other applications, in art conservation as a temporary protective coating was characterized using Fourier transform infrared (FT-IR) spectroscopy aided by modulated differential scanning calorimetry (MDSC) and ellipsometry. The thermal conversion of thin copolymer films from the freshly applied state, where carboxylic acid and carboxylate ion functional groups co-exist, to a purely acidic working state was spectroscopically followed. Transmission mid-infrared data of the working state showed a 1 : 12 ratio of methacrylic acid towards ethylene units. The glass transition temperature (T(g)) in the same state was found at 45 °C. Copolymer films spin-coated on mechanically polished bronze and iron coupons were characterized with transflection infrared spectroscopy and compared to corresponding transmission mid-infrared spectra of copolymer films spin-coated on silicon wafers. In the case of bronze coupons, evidence for interaction of the carboxylate ion with the copper substrate was obtained. The chemical structure and the thermal behavior of the coating, as well as some implications on its protective capability towards iron and copper alloys, is discussed as this material has received considerable attention in the field of metal conservation and coatings.

  12. Absorption properties of type-II InAs/InAsSb superlattices measured by spectroscopic ellipsometry

    SciTech Connect

    Webster, P. T.; Riordan, N. A.; Liu, S.; Zhang, Y.-H.; Johnson, S. R.; Steenbergen, E. H.

    2015-02-09

    Strain-balanced InAs/InAsSb superlattices offer access to the mid- to long-wavelength infrared region with what is essentially a ternary material system at the GaSb lattice constant. The absorption coefficients of InAs/InAsSb superlattices grown by molecular beam epitaxy on (100)-oriented GaSb substrates are measured at room temperature over the 30 to 800 meV photon energy range using spectroscopic ellipsometry, and the miniband structure of each superlattice is calculated using a Kronig-Penney model. The InAs/InAsSb conduction band offset is used as a fitting parameter to align the calculated superlattice ground state transition energy to the measured absorption onset at room temperature and to the photoluminescence peak energy at low temperature. It is observed that the ground state absorption coefficient and transition strength are proportional to the square of the wavefunction overlap and the ground state absorption coefficient approaches a maximum value of around 5780 cm{sup −1} as the wavefunction overlap approaches 100%. The absorption analysis of these samples indicates that the optical joint density of states is weakly dependent on the period thickness and Sb content of the superlattice, and that wavefunction overlap is the principal design parameter in terms of obtaining strong absorption in these structures.

  13. New method for determination of the photoresist Dill parameters using spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Boher, Pierre; Defranoux, Christophe; Piel, Jean-Philippe; Stehle, Jean-Louis P.

    1999-06-01

    In this paper a new method to determine photoresist DIll parameters is presented. Based on spectroscopic ellipsometry (SE) measurements, this new method is more precise than standard techniques based on transmittance measurements. Indeed, compared to photometry, SE technique is a self calibrated technique which provide directly two independent parameters Tan (Psi) and Cos (Delta) which can be used to extract directly thickness but also optical indices of a layer inside a multilayer structure. Moreover, the wavelength dependence introduces more restrictions for the data analysis since thickness and optical indices can be deduced directly in many cases. We apply this technique to different kinds of photoresist designed for 365nm and 248nm. At each wavelength ellipsometric parameters are simulate directly versus the exposure dose without any assumption on the thickness and on the index of refraction evolution. On 365nm photoresist this new method provides Dill parameters in good agreement with the standard method. On 248nm photoresist we show that the influence of the exposure is more important on the refractive index and on the thickness of the layer than on its absorption.

  14. New method for determination of the photoresist Dill parameters using spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Boher, Pierre; Defranoux, Christophe; Piel, Jean-Philippe; Stehle, Jean-Louis P.

    1999-04-01

    In this paper a new method to determine photoresist Dill parameters is presented. Based on spectroscopic ellipsometry (SE) measurements, this new method is more precise than standard techniques based on transmittance measurements. Indeed, compared to photometry, SE technique is a self calibrated technique which provide directly two independent parameters Tan (Psi) and Cos (Delta) which can be used to extract directly thickness but also optical indices of a layer inside a multilayer structure. Moreover, the wavelength dependence introduces more restrictions for the data analysis since thickness and optical indices can be deduced directly in many cases. We apply this technique to different kinds of photoresist designed for 365nm and 248nm. At each wavelength ellipsometric parameters are simulated directly versus the exposure dose without any assumption on the thickness and on the index of refraction evolution. On 365nm photoresist this new method provides Dill parameters in good agreement with the standard method. On 248nm photoresist we show that the influence of the exposure is more important on the refractive index and on the thickness of the layer than on its absorption.

  15. Kramers-Kronig-consistent optical functions of anisotropic crystals: generalized spectroscopic ellipsometry on pentacene.

    PubMed

    Dressel, M; Gompf, B; Faltermeier, D; Tripathi, A K; Pflaum, J; Schubert, M

    2008-11-24

    The Kramers-Kronig relations between the real and imaginary parts of a response function are widely used in solid-state physics to evaluate the corresponding quantity if only one component is measured. They are among the most fundamental statements since only based on the analytical behavior and causal nature of the material response [Phys. Rev. 104, 1760-1770 (1956)]. Optical losses, for instance, can be obtained from the dispersion of the dielectric constant at all wavelengths, and vice versa [Handbook of optical constants of solids, Vol. 1, p. 35]. Although the general validity was never casted into doubt, it is a longstanding problem that Kramers-Kronig relations cannot simply be applied to anisotropic crystalline materials because contributions from different directions mix in a frequency-dependent way. Here we present a general method to identify frequency-independent principal polarizability directions for which the Kramers-Kronig relations are obeyed even in materials with lowest symmetry. Using generalized spectroscopic ellipsometry on a single crystal surface of triclinic pentacene, as an example, enables us to evaluate the complex dielectric constant and to compare it with band-structure calculations along the crystallographic directions. A general recipe is provided how to proceed from a macroscopic measurement on a low symmetry crystal plane to the microscopic dielectric properties of the unit cell, along whose axes the Kramers-Kronig relations hold.

  16. Spectroscopic ellipsometry as a process control tool for manufacturing cadmium telluride thin film photovoltaic devices

    NASA Astrophysics Data System (ADS)

    Smith, Westcott P.

    In recent decades, there has been concern regarding the sustainability of fossil fuels. One of the more promising alternatives is Cadmium Telluride (CdTe) thin-film photovoltaic (PV) devices. Improved quality measurement techniques may aid in improving this existing technology. Spectroscopic ellipsometry (SE) is a common, non-destructive technique for measuring thin films in the silicon wafer industry. SE results have also been tied to properties believed to play a role in CdTe PV device efficiency. A study assessing the potential of SE for use as a quality measurement tool had not been previously reported. Samples of CdTe devices produced by both laboratory and industrial scale processes were measured by SE and Scanning Electron Microscopy (SEM). Mathematical models of the optical characteristics of the devices were developed and fit to SE data from multiple angles and locations on each sample. Basic statistical analysis was performed on results from the automated fits to provide an initial evaluation of SE as a quantitative quality measurement process. In all cases studied, automated SE models produced average stack thickness values within 10% of the values produced by SEM, and standard deviations for the top bulk layer thickness were less than 1% of the average values.

  17. Spectroscopic ellipsometry of anisotropic materials: application to the optical constants of HgI2.

    PubMed

    En Naciri, A; Johann, L; Kleim, R; Sieskind, M; Amann, M

    1999-02-01

    A variable angle-of-incidence spectroscopic fixed-polarizer, rotating-polarizer, fixed-analyzer ellipsometer (PRPSE) across a spectral range from 300 to 800 nm is used to determine the optical properties of anisotropic uniaxial tetragonal red mercuric iodide (HgI(2)). For the first time, to our knowledge, the bulk crystal HgI(2) surface measured by ellipsometry was not subjected to potassium iodide cutting or etching. Measurements were made at an air-HgI(2) interface with the optic axis parallel to the sample surface. To determine the optical constants, we varied both the angle of incidence and the azimuth of the optic axis with the plane of incidence. The detailed formulas needed for reliable procedures for analyzing the data are presented. The ordinary and extraordinary complex indices of refraction, (n(o)--ik(o)) and (n(e)--ik(e)), respectively, are determined. Good agreement between PRPSE and the prism technique for the refractive index is observed. The surface aging effects of the ellipsometric parameters of HgI(2), during 30 h of exposure to air, were detected by PRPSE. PMID:18305658

  18. Vanadium oxide-carbon nanotube composite films characterized by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    He, Qiong; Xu, Xiangdong; Gu, Yu; Wang, Meng; Yao, Jie; Jiang, Yadong; Sun, Minghui; Ao, Tianhong; Lian, Yuxiang; Wang, Fu; Li, Xinrong

    2016-10-01

    Spectroscopic ellipsometry (SE) is utilized to characterize the vanadium oxide (VO x )-single walled carbon nanotube (SWCNT) composite films prepared by sol-gel. Five Tauc-Lorentz oscillators model is employed to describe the dispersions in the optical responses of VO x and VO x -SWCNT thin films. Results reveal that if the SWCNT concentration in the composite film is increased, the refractive index is decreased, while the extinction coefficient is increased. Moreover, higher SWCNT content leads to lower optical band gap (E g) but larger localized state (E e). Interestingly, both E g and E e values reach saturated at a SWCNT content of ~8 wt%. Particularly, the peak transition energies of the 5 Tauc-Lorentz oscillators have been assigned to the specific transitions according to the band structures of VO x . This work reveals the feasibility of investigating the optical properties and microstructures of VO x -SWCNT composite films by SE. These experimental results will be helpful for better understanding the VO x -SWCNT composite films, and promoting future characterizations of other SWCNT-based composites by SE.

  19. Silicon fin line edge roughness determination and sensitivity analysis by Mueller matrix spectroscopic ellipsometry based scatterometry

    NASA Astrophysics Data System (ADS)

    Dixit, Dhairya; O'Mullane, Samuel; Sunkoju, Sravan; Hosler, Erik R.; Kamineni, Vimal; Preil, Moshe; Keller, Nick; Race, Joseph; Muthinti, Gangadhara Raja; Diebold, Alain C.

    2015-03-01

    Measurement and control of line edge roughness (LER) is one of the most challenging issues facing patterning technology. As the critical dimensions (CD) of patterned structures decrease, LER of only a few nanometers can negatively impact device performance. Here, Mueller matrix spectroscopic ellipsometry (MMSE) based scatterometry is used to determine LER in periodic line-space structures in 28 nm pitch Si fin samples fabricated by directed selfassembly (DSA) patterning. The optical response of the Mueller matrix (MM) elements is influenced by structural parameters like pitch, CD, height, and side-wall angle (SWA), as well as the optical properties of the materials. Evaluation and decoupling MM element response to LER from other structural parameters requires sensitivity analysis using simulations of optical models that include LER. Here, an approach is developed that quantifies Si fin LER by comparing the optical responses generated by systematically varying the grating shape and measurement conditions. Finally, the validity of this approach is established by comparing the results obtained from top down scanning electron microscope (SEM) images and cross-sectional TEM image of the 28 nm pitch Si fins.

  20. Spectroscopic ellipsometry for characterization of InAs/Ga1-xInxSb superlattices

    NASA Astrophysics Data System (ADS)

    Wagner, J.; Schmitz, J.; Herres, N.; Fuchs, F.; Walther, M.

    1998-05-01

    The pseudodielectric function of InAs/Ga1-xInxSb superlattices (SLs) grown by solid-source molecular-beam epitaxy, was measured by spectroscopic ellipsometry (SE) for photon energies ranging from 1.2 to 5 eV. The width of the extrema in the SL pseudodielectric function derived from the E1 and E1+Δ1 interband transitions of the SL constituents InAs and Ga1-xInxSb, was found to depend on the structural quality of the SL. Differences in the SL quality caused by different sequences of InSb- like and GaAs-like interfaces, were easily detected by SE. The formation of the intended interface alternations was verified by Raman spectroscopy. The extrema in the SL pseudodielectric function originating from the E1 and E1+Δ1 interband transitions of Ga1-xInxSb were found to shift to lower energies with increasing In content x. Finally SE has been applied to the analysis of a complete InAs/Ga1-xInxSb SL detector structure.

  1. Neutron reflectometry and spectroscopic ellipsometry studies of cross-linked poly(dimethylsiloxane) after irradiation at 172 nm.

    PubMed

    Graubner, Vera-Maria; Clemens, Daniel; Gutberlet, Thomas; Kötz, Rüdiger; Lippert, Thomas; Nuyken, Oskar; Schnyder, Bernhard; Wokaun, Alexander

    2005-09-13

    Poly(dimethylsiloxane) (PDMS) was irradiated under ambient conditions in air with a Xe2-excimer lamp. The formation of atomic oxygen and ozone during irradiation in air by V-UV photons results in the transformation of PDMS to silicon oxide. The irradiated surfaces were studied by spectroscopic ellipsometry and neutron reflectometry. The measurements revealed the formation of a rough, i.e., between 11 and 20 nm, oxidized surface layer and a decrease of the total layer thickness. The thickness of the oxidized layer decreased for a given PDMS thickness when the polymer was irradiated for longer times and/or higher intensities. The composition of the oxidized layer after irradiation was not uniform through the layer and consisted of a mixture of original polymer and silicon bonded to three or four oxygen atoms (SiOx). The refractive index n determined by ellipsometry reaches a value similar to values reported for SiO2.

  2. Spectroscopic ellipsometry and polarimetry for materials and systems analysis at the nanometer scale: state-of-the-art, potential, and perspectives

    PubMed Central

    Bergmair, Michael; Bruno, Giovanni; Cattelan, Denis; Cobet, Christoph; de Martino, Antonello; Fleischer, Karsten; Dohcevic-Mitrovic, Zorana; Esser, Norbert; Galliet, Melanie; Gajic, Rados; Hemzal, Dušan; Hingerl, Kurt; Humlicek, Josef; Ossikovski, Razvigor; Popovic, Zoran V.; Saxl, Ottilia

    2009-01-01

    This paper discusses the fundamentals, applications, potential, limitations, and future perspectives of polarized light reflection techniques for the characterization of materials and related systems and devices at the nanoscale. These techniques include spectroscopic ellipsometry, polarimetry, and reflectance anisotropy. We give an overview of the various ellipsometry strategies for the measurement and analysis of nanometric films, metal nanoparticles and nanowires, semiconductor nanocrystals, and submicron periodic structures. We show that ellipsometry is capable of more than the determination of thickness and optical properties, and it can be exploited to gain information about process control, geometry factors, anisotropy, defects, and quantum confinement effects of nanostructures. PMID:21170135

  3. Corrosion under argon irradiation of titanium in the low MeV range: A study coupling AFM and Spectroscopic Ellipsometry

    NASA Astrophysics Data System (ADS)

    Do, Ngoc-Long; Garcia-Caurel, Enric; Bérerd, Nicolas; Moncoffre, Nathalie; Gorse-Pomonti, Dominique

    2014-05-01

    This paper reports on a recent study of the corrosion under argon ion irradiation of titanium in the low MeV range (1-9 MeV), associating AFM and Spectroscopic Ellipsometry. Irradiation with MeV Arn+ (n = 1, 3) ions produces damages on the titanium surface. Large craters form on the oxidized titanium surface whose characteristics vary as a function of the argon energy between 2 and 9 MeV. The superficial oxide grows thicker under irradiation over the same energy range, especially near 3 MeV. It is suggested that collisions cascades play a significant role in the overall damage process.

  4. Calibration of Two Difrerent Types of Modulators for an Application in Spectroscopic Phase Modulated Ellipsometry

    NASA Astrophysics Data System (ADS)

    Kouko, S. L.; Llinares, C.

    1995-08-01

    In order to choose a photoelastic modulator for an application in spectroscopic phase modulated ellipsometry a complete calibration of two different types of photoelastic modulators is achieved. First the model that describes the behavior of each of them is accurately determined since the calibration procedure depends on it. Both modulators behave as a static strain model with a phase shift of the form δ = δ_0 + {\\cal A}sin ω t. Using the suitable procedures, the driving voltage V_mod and the static strain δ_0 of both devices are accurately determined as a function of the wavelength from 0.25 μm to 0.75 μm. A method to reduce the errors due to incorrect settings of the modulation voltage and the static birefringence is also proposed. An accuracy check of the calibration done by comparing the indexes of refraction of two silica prisms obtained with our ellipsometer and with the high precision goniometer method shows a very good agreement. Dans le but de choisir un modulateur photoélastique pour une application en ellipsométrie spectroscopique à modulation de phase, le calibrage de deux modulateurs a été réalisé. Dans un premier temps, le modèle décrivant chacun des modulateurs a été déterminé avec précision vu que la procédure de calibrage dépend de celui-ci : les deux modulateurs fonctionnent suivant le modèle avec biréfringence statique ayant un déphasage de la forme δ = δ_0 + {\\cal A}sin ω t. En utilisant les procédures de calibrage appropriées, la tension de pilotage V_mod et la biréfringence statique δ_0 ont été déterminées avec précision en fonction de la longueur d'onde dans la gamme spectrale s'étendant de 0,25 μm à 0,75 μm. Une méthode pour réduire les erreurs dues au calibrage de la tension de modulation et à la biréfringence résiduelle est également proposée. Un test de la précision du calibrage fait en comparant les indices de réfraction de deux prismes de silice obtenus avec notre ellipsomètre et avec

  5. Optical Metrology for Directed Self-assembly Patterning Using Mueller Matrix Spectroscopic Ellipsometry Based Scatterometry

    NASA Astrophysics Data System (ADS)

    Dixit, Dhairya J.

    The semiconductor industry continues to drive patterning solutions that enable devices with higher memory storage capacity, faster computing performance, lower cost per transistors, and higher transistor density. These developments in the field of semiconductor manufacturing along with the overall minimization of the size of transistors require cutting-edge metrology tools for characterization. Directed self-assembly (DSA) patterning process can be used to fabricate nanoscale line-space patterns and contact holes via thermodynamically driven micro-phase separation of block copolymer (BCP) films with boundary constraints from guiding templates. Its main advantages are high pattern resolution (~10 nm), high throughput, no requirement of a high-resolution mask, and compatibility with standard fab-equipment and processes. Although research into DSA patterning has demonstrated a high potential as a nanoscale patterning process, there are critical challenges that must be overcome before transferring DSA into high volume manufacturing, including achievement of low defect density and high process stability. For this, advances in critical dimension (CD) and overlay measurement as well as rapid defect characterization are required. Both scatterometry and critical dimension-scanning electron microscopy (CD-SEM) are routinely used for inline dimensional metrology. CD-SEM inspection is limited, as it does not easily provide detailed line-shape information, whereas scatterometry has the capability of measuring important feature dimensions including: line-width, line-shape, sidewall-angle, and thickness of the patterned samples quickly and non-destructively. The present work describes the application of Mueller matrix spectroscopic ellipsometry (MMSE) based scatterometry to optically characterize DSA patterned line- space grating and contact hole structures fabricated with phase-separated polystyrene-b-polymethylmethacrylate (PS-b-PMMA) at various integration steps of BCP DSA

  6. Temperature dependence of the electronic transitions in BiFeO{sub 3} thin film studied by spectroscopic ellipsometry

    SciTech Connect

    Kang, T. D.; Jeon, B. C.; Moon, S. J.

    2015-04-07

    The temperature dependence of the electronic response of BiFeO{sub 3} thin film grown on a SrTiO{sub 3} substrate is investigated using spectroscopic ellipsometry. By analyzing the pseudodielectric function, we identify two d-d crystal field transitions of Fe{sup 3+} ions in the energy region between 1 and 2 eV. The d-d transitions show abnormal temperature dependence that cannot be attributed to conventional electron-phonon interactions. The origin of the abnormal temperature dependence is discussed in terms of spin-charge coupling. The temperature dependence of the charge transfer transitions located above 2.5 eV is characterized by standard critical point model analysis of the 2nd derivatives of the dielectric function. This analysis provides detailed information of the critical point parameters for charge transfer transitions.

  7. Nucleation and growth of MgO atomic layer deposition: A real-time spectroscopic ellipsometry study

    SciTech Connect

    Wang, Han; Fu, Kan

    2013-11-15

    The atomic layer deposition (ALD) of MgO thin films from bis(cyclopentadienyl) magnesium and H{sub 2}O was studied using in-situ real-time spectroscopic ellipsometry (SE), ex-situ x-ray photoelectron spectroscopy, and grazing-incidence x-ray diffraction. It is found that the initial growth is not linear during the first ten cycles, and magnesium silicate forms spontaneously on the SiO{sub 2}/Si substrates at 250 °C. Submonolayer sensitivity of SE is demonstrated by the analysis of each half-cycle and self-limiting adsorption, revealing characteristic features of hetero- and homo-MgO ALD processes.

  8. Thermal treatment effects imposed on solid DNA cationic lipid complex with hexadecyltrimethylammonium chloride, observed by variable angle spectroscopic ellipsometry

    SciTech Connect

    Nizioł, Jacek

    2014-12-21

    DNA cationic lipid complexes are materials of properties required for applications in organic electronics and optoelectronics. Often, their thermal stability demonstrated by thermogravimetry is cited in the literature as important issue. However, little is known about processes occurring in heated solid DNA cationic lipid complexes. In frame of this work, thin films of Deoxyribonucleic acid-hexadecyltrimethylammonium chloride (DNA-CTMA) were deposited on silicon wafers. Samples were thermally annealed, and simultaneously, their optical functions were measured by spectroscopic ellipsometry. At lower temperatures, thermal expansion coefficient of solid DNA-CTMA was negative, but at higher temperatures positive. Thermally induced modification of absorption spectrum in UV-vis was observed. It occurred at a range of temperatures higher than this of DNA denaturation in solution. The observed phenomenon was irreversible, at least in time scale of the experiment (one day)

  9. Atomic oxygen effects on thin film space coatings studied by spectroscopic ellipsometry, atomic force microscopy, and laser light scattering

    NASA Technical Reports Server (NTRS)

    Synowicki, R. A.; Hale, Jeffrey S.; Woollam, John A.

    1992-01-01

    The University of Nebraska is currently evaluating Low Earth Orbit (LEO) simulation techniques as well as a variety of thin film protective coatings to withstand atomic oxygen (AO) degradation. Both oxygen plasma ashers and an electron cyclotron resonance (ECR) source are being used for LEO simulation. Thin film coatings are characterized by optical techniques including Variable Angle Spectroscopic Ellipsometry, Optical spectrophotometry, and laser light scatterometry. Atomic Force Microscopy (AFM) is also used to characterize surface morphology. Results on diamondlike carbon (DLC) films show that DLC degrades with simulated AO exposure at a rate comparable to Kapton polyimide. Since DLC is not as susceptible to environmental factors such as moisture absorption, it could potentially provide more accurate measurements of AO fluence on short space flights.

  10. Effect of Ta concentration on the refractive index of TiO2:Ta studied by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Nurfani, Eka; Kurniawan, Robi; Muhammady, Shibghatullah; Marlina, Resti; Sutjahja, Inge M.; Winata, Toto; Rusydi, Andrivo; Darma, Yudi

    2016-04-01

    We have investigated optical properties of Ta-doped TiO2 thin film on LaAlO3 (LAO) substrate using Spectroscopic Ellipsometry (SE) at room temperature. Amplitude ratio Ψ and phase difference L1 between p- and s- polarized light waves are obtained by multiple incident angles measurement (60°, 70°, and 80°) at energy range of 0.5 - 6.5 eV. In order to obtain optical properties for every Ta concentrations (0.01, 0.4, and 5 at. %), multilayer modelling was performed simultaneously by using Drude-Lorentz model. Refractive index and optical dispersion parameters were determined by Wemple-DiDomenico relation. In general, refractive index at zero photon energy n(0) increases by increasing Ta concentration. Furthermore, optical band gap shows a significant increasing due to presence of Ta dopant. In addition, other optical constants are discussed as well.

  11. Water Vapor Uptake of Ultrathin Films of Biologically Derived Nanocrystals: Quantitative Assessment with Quartz Crystal Microbalance and Spectroscopic Ellipsometry.

    PubMed

    Niinivaara, Elina; Faustini, Marco; Tammelin, Tekla; Kontturi, Eero

    2015-11-10

    Despite the relevance of water interactions, explicit analysis of vapor adsorption on biologically derived surfaces is often difficult. Here, a system was introduced to study the vapor uptake on a native polysaccharide surface; namely, cellulose nanocrystal (CNC) ultrathin films were examined with a quartz crystal microbalance with dissipation monitoring (QCM-D) and spectroscopic ellipsometry (SE). A significant mass uptake of water vapor by the CNC films was detected using the QCM-D upon increasing relative humidity. In addition, thickness changes proportional to changes in relative humidity were detected using SE. Quantitative analysis of the results attained indicated that in preference to being soaked by water at the point of hydration each individual CNC in the film became enveloped by a 1 nm thick layer of adsorbed water vapor, resulting in the detected thickness response. PMID:26461931

  12. Chemical and structural changes in a pH-responsive mixed polyelectrolyte brush studied by infrared ellipsometry.

    PubMed

    Hinrichs, Karsten; Aulich, Dennis; Ionov, Leonid; Esser, Norbert; Eichhorn, Klaus-Jochen; Motornov, Mikhail; Stamm, Manfred; Minko, Sergiy

    2009-09-15

    This work provides direct chemical and structural insight into pH-dependent changes of an ultrathin (d=12 nm) mixed polyelectrolyte brush. In-situ infrared spectroscopic ellipsometry was used for the first time to study the gradual pH-responsive behavior of the brush, constituted of weak anionic and cationic polyelectrolytes, poly(acrylic acid) (PAA) and poly(2-vinylpyridine) (P2VP), respectively. The pH-dependent infrared fingerprints in the mid-infrared spectral range were analyzed as a function of chemical and structural changes in the mixed brush caused by pH changes. Thereby, the IR spectra were directly correlated to different chemical states of the brush, giving previously not accessible new information on the ionization of the thin film. In contrast to other techniques (e.g., classical attenuated total reflection IR spectroscopy) we used almost plane Si-substrates for the IR ellipsometric approach with application of a single reflection mode. The optical path through Si is of minimal length, which makes a large spectral range accessible. For the most pronounced bands of the carboxyl group at 1718 cm(-1) and the carboxylate ion at 1565 cm(-1), the band amplitudes were correlated with the degree of ionization of the carboxylic groups. Interpretation of the pH-dependent changes in the spectral signature reveals gradual changes of the chemical structures of the mixed brush between three distinct switchable states: strongly ionized PAA at pH 10, strongly ionized P2VP at pH 2, and mainly nonionized functional groups in a "dry" PAA-P2VP polyelectrolyte complex in the range from pH=4 to pH=7. At intermediate pH, the IR spectra confirm the previously made hypothesis of the formation of a polyelectrolyte complex between P2VP and PAA in the mixed brush. From IR spectra it is also concluded that the polyelectrolyte complex is formed as a result of a small fraction of ionized functional groups. PMID:19572506

  13. Spectroscopic ellipsometry of homoepitaxial diamond multilayers and delta-doped structures

    SciTech Connect

    Bousquet, J.; Chicot, G.; Eon, D.; Bustarret, E.

    2014-01-13

    The optimization of diamond-based unipolar electronic devices such as pseudo-vertical Schottky diodes or delta-doped field effect transistors relies in part on the sequential growth of nominally undoped (p{sup –}) and heavily boron doped (p{sup ++}) layers with well-controlled thicknesses and steep interfaces. Optical ellipsometry offers a swift and contactless method to characterize the thickness, roughness, and electronic properties of semiconducting and metallic diamond layers. We report ellipsometric studies carried out on delta-doped structures and other epitaxial multilayers with various boron concentrations and thicknesses (down to the nanometer range). The results are compared with Secondary Ion Mass Spectroscopy and transport measurements.

  14. Investigating organic multilayers by spectroscopic ellipsometry: specific and non-specific interactions of polyhistidine with NTA self-assembled monolayers

    PubMed Central

    Solano, Ilaria; Parisse, Pietro; Gramazio, Federico; Casalis, Loredana; Canepa, Maurizio

    2016-01-01

    Summary Background: A versatile strategy for protein–surface coupling in biochips exploits the affinity for polyhistidine of the nitrilotriacetic acid (NTA) group loaded with Ni(II). Methods based on optical reflectivity measurements such as spectroscopic ellipsometry (SE) allow for label-free, non-invasive monitoring of molecule adsorption/desorption at surfaces. Results: This paper describes a SE study about the interaction of hexahistidine (His6) on gold substrates functionalized with a thiolate self-assembled monolayer bearing the NTA end group. By systematically applying the difference spectra method, which emphasizes the small changes of the ellipsometry spectral response upon the nanoscale thickening/thinning of the molecular film, we characterized different steps of the process such as the NTA-functionalization of Au, the adsorption of the His6 layer and its eventual displacement after reaction with competitive ligands. The films were investigated in liquid, and ex situ in ambient air. The SE investigation has been complemented by AFM measurements based on nanolithography methods (nanografting mode). Conclusion: Our approach to the SE data, exploiting the full spectroscopic potential of the method and basic optical models, was able to provide a picture of the variation of the film thickness along the process. The combination of δΔi +1 ,i(λ), δΨi +1 ,i(λ) (layer-addition mode) and δΔ† i ', i +1(λ), δΨ† i ', i +1(λ) (layer-removal mode) difference spectra allowed us to clearly disentangle the adsorption of His6 on the Ni-free NTA layer, due to non specific interactions, from the formation of a neatly thicker His6 film induced by the Ni(II)-loading of the NTA SAM. PMID:27335745

  15. In-situ spectroscopic ellipsometry and structural study of HfO{sub 2} thin films deposited by radio frequency magnetron sputtering

    SciTech Connect

    Cantas, Ayten; Aygun, Gulnur; Basa, Deepak Kumar

    2014-08-28

    We have investigated the reduction of unwanted interfacial SiO{sub 2} layer at HfO{sub 2}/Si interface brought about by the deposition of thin Hf metal buffer layer on Si substrate prior to the deposition of HfO{sub 2} thin films for possible direct contact between HfO{sub 2} thin film and Si substrate, necessary for the future generation devices based on high-κ HfO{sub 2} gate dielectrics. Reactive rf magnetron sputtering system along with the attached in-situ spectroscopic ellipsometry (SE) was used to predeposit Hf metal buffer layer as well as to grow HfO{sub 2} thin films and also to undertake the in-situ characterization of the high-κ HfO{sub 2} thin films deposited on n-type 〈100〉 crystalline silicon substrate. The formation of the unwanted interfacial SiO{sub 2} layer and its reduction due to the predeposited Hf metal buffer layer as well as the depth profiling and also structure of HfO{sub 2} thin films were investigated by in-situ SE, Fourier Transform Infrared spectroscopy, and Grazing Incidence X-ray Diffraction. The study demonstrates that the predeposited Hf metal buffer layer has played a crucial role in eliminating the formation of unwanted interfacial layer and that the deposited high-κ HfO{sub 2} thin films are crystalline although they were deposited at room temperature.

  16. In-situ Spectroscopic Ellipsometry of the Cu Deposition Process from Supercritical Fluids: Evidence of an Abnormal Surface Layer Formation

    NASA Astrophysics Data System (ADS)

    Sasaki, Takuya; Tamegai, Yukihiro; Ueno, Takahiro; Watanabe, Mitsuhiro; Jin, Lianhua; Kondoh, Eiichi

    2012-05-01

    In this paper, we report in-situ spectroscopic ellipsometry of Cu deposition from supercritical carbon dioxide fluids. The motivations of this work were 1) to perform a detailed observation of Cu growth with precision optical metrology, 2) to study substrate dependence on Cu growth, particularly for Ru and TiN substrates in the present case, and 3) to demonstrate the possibility and usefulness of ellipsometry for diagnosing supercritical fluid processing. The Cu deposition was carried out through hydrogen reduction of a Cu β-diketonate precursor at 160-180 °C. During growth, a very large deviation of ellipsometric parameters (Ψ and Δ) from a single-layer model prediction was observed; this deviation was much larger than that expected from island formation which has been frequently reported in in-situ ellipsometric observation of the vapor growth of thin films. From model analyses, it was found that an abnormal dielectric layer having a high refractive index and a thickness of 10-50 nm is present on the growing Cu surface. The refractive index of this layer was (1.5-2) + (0.2-0.3)i and from this, we concluded that this layer is the condensed precursor. The condensed layer develops prior to Cu nucleation. As for the substrate dependence on Cu growth, both layers develop faster on Ru than on TiN. This corresponds to the fact that chemisorption occurs more easily on Ru. The deposition kinetics under the presence of the condensed layer are also discussed.

  17. Infrared spectroscopic measurements and analysis

    NASA Technical Reports Server (NTRS)

    Birnbaum, G.

    1976-01-01

    The collision induced spectrum in equilibrium H2(eH2) and in equilibrium H2-He mixtures have been determined at densities below 120 amagat in the region 500 to 900 cm/1 at 293, 195, and 77K. The collision induced spectrum of normal H2 at 77K in the region 25 to 490 cm/1 has also been determined. The details of the experiment, experimental results, and comparison with previous results are presented. A report dealing with a new theory of the shape of pressure induced spectra with an application to the far infrared spectrum of eH2 at 77K is appended.

  18. Spectroscopic Ellipsometry Studies of Ag and ZnO Thin Films and Their Interfaces for Thin Film Photovoltaics

    NASA Astrophysics Data System (ADS)

    Sainju, Deepak

    Many modern optical and electronic devices, including photovoltaic devices, consist of multilayered thin film structures. Spectroscopic ellipsometry (SE) is a critically important characterization technique for such multilayers. SE can be applied to measure key parameters related to the structural, optical, and electrical properties of the components of multilayers with high accuracy and precision. One of the key advantages of this non-destructive technique is its capability of monitoring the growth dynamics of thin films in-situ and in real time with monolayer level precision. In this dissertation, the techniques of SE have been applied to study the component layer materials and structures used as back-reflectors and as the transparent contact layers in thin film photovoltaic technologies, including hydrogenated silicon (Si:H), copper indium-gallium diselenide (CIGS), and cadmium telluride (CdTe). The component layer materials, including silver and both intrinsic and doped zinc oxide, are fabricated on crystalline silicon and glass substrates using magnetron sputtering techniques. These thin films are measured in-situ and in real time as well as ex-situ by spectroscopic ellipsometry in order to extract parameters related to the structural properties, such as bulk layer thickness and surface roughness layer thickness and their time evolution, the latter information specific to real time measurements. The index of refraction and extinction coefficient or complex dielectric function of a single unknown layer can also be obtained from the measurement versus photon energy. Applying analytical expressions for these optical properties versus photon energy, parameters that describe electronic transport, such as electrical resistivity and electron scattering time, can be extracted. The SE technique is also performed as the sample is heated in order to derive the effects of annealing on the optical properties and derived electrical transport parameters, as well as the

  19. Investigation of PTFE transfer films by infrared emission spectroscopy and phase-locked ellipsometry

    NASA Technical Reports Server (NTRS)

    Lauer, James L.; Bunting, Bruce G.; Jones, William R., Jr.

    1987-01-01

    When a PTFE sheet was rubbed unidirectionally over a smooth surface of stainless steel an essentially monomolecular transfer film was formed. By ellipsometric and emission infrared spectroscopic techniques it was shown that the film was 10 to 15 A thick and birefringent. From the intensity differences of infrared bands obtained with a polarizer passing radiation polarized in mutually perpendicular planes, it was possible to deduce transfer film orientation with the direction of rubbing. After standing in air for several weeks the transfer films apparently increased in thickness by as much as threefold. At the same time both the index of refraction and the absorption index decreased. Examination of the surfaces by optical and electron microscopies showed that the films had become porous and flaky. These observations were consistent with previous tribological measurements. The coefficients of friction decreased with the formation of the transfer film but increased again as the film developed breaks. The applicability of the ellipsometric and polarized infrared emission techniques to the identification of monomolecular tribological transfer films of polymers such as PTFE has been demonstrated.

  20. Using spectroscopic ellipsometry for quick prediction of number density of nanoparticles bound to non-transparent solid surfaces

    NASA Astrophysics Data System (ADS)

    Bhat, Rajendra R.; Genzer, Jan

    2005-12-01

    We report on the use of spectroscopic ellipsometry (SE) in predicting number density of nanoparticles bound to the surfaces decorated with either organic monolayers or surface-grafted polymers. Two systems are considered that comprise citrate-stabilized gold nanoparticles adsorbed on: (1) 3-aminopropyltriethoxysilane (APTES) self-assembled monolayer (SAM), and (2) surface-tethered polyacrylamide (PAAm). Number density of gold nanoparticles on the surface is varied systematically by gradually increasing either the concentration of APTES molecules in the SAM or molecular weight of grafted PAAm. The adsorption of gold nanoparticles on APTES gradient surfaces is monitored via atomic force microscopy (AFM), near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, and SE. The partition of gold nanoparticles on PAAm gradient assemblies is characterized by AFM, ultraviolet-visible (UV-vis) spectroscopy, and SE. By correlating the results obtained from the various techniques on nanoparticle coatings, we derive an empirical linear relationship between the number density of nanoparticles on surfaces and cos ( Δ) parameter measured in SE. Excellent agreement between nanoparticle number density determined experimentally from AFM scans and that predicted by SE proves the potential of SE as a quick, predictive technique to estimate number density of nanoparticles bound to solid, non-transparent substrates.

  1. Interplay of electron correlations and localization in disordered β-tantalum films: Evidence from dc transport and spectroscopic ellipsometry study

    SciTech Connect

    Kovaleva, N. N.; Chvostova, D.; Dejneka, A.; Bagdinov, A. V.; Petrova, M. G.; Demikhov, E. I.; Pudonin, F. A.

    2015-02-02

    We report the dc transport (5 K ≲ T ≲ 380 K) and spectroscopic ellipsometry (0.8 eV ≤ hν ≤ 8.5 eV, T ≃ 300 K) study of β-Ta films prepared by rf sputtering deposition as a function of their thickness in the range 2.5 nm ≲ d ≲ 200 nm. The dc transport of the β-Ta films with a thickness d ≳ 25 nm is characterized by negative temperature coefficient of resistivity (TCR) caused by localization effects peculiar of highly disordered metals. Their dielectric function spectra display non-metallic-like behavior due to the presence of the pronounced band at 2 eV. We found that with increasing TCR absolute value, specifying elevated degree disorder, the optical spectral weight (SW) of free charge carriers decreases. The associated SW is recovered in the range of Mott-Hubbard transitions, indicating the mechanism of localization enhancement by electronic correlations in disordered metals.

  2. A view of the implanted SiC damage by Rutherford backscattering spectroscopy, spectroscopic ellipsometry, and transmission electron microscopy

    SciTech Connect

    Battistig, G.; Khanh, N. Q.; Petrik, P.; Lohner, T.; Dobos, L.; Pecz, B.; Garcia Lopez, J.; Morilla, Y.

    2006-11-01

    4H-SiC single crystalline substrates were implanted at room temperature with 150 keV Al{sup +} ions using fluences of 4x10{sup 14}, 1x10{sup 15}, and 2x10{sup 15} cm{sup -2} with current density of 2.5 {mu}A cm{sup -2}. The samples were subsequently annealed at 1100 deg. C in N{sub 2} for 1 h in order to analyze their structural recovery. The disorder induced in both sublattices by the Al{sup +} ions was studied by backscattering spectrometry in channeling geometry with a 3.5 MeV He{sup 2+} beam. The results were compared with the optical properties of the samples measured by spectroscopic ellipsometry. In a previous work, we concluded that during the postimplantation annealing of a highly damaged SiC crystalline material the short distance order can be recovered, while the long distance disorder remains. We also presented the possibility to have grains of different polytypes oriented faraway from the original direction. Now, this alternative is confirmed by the cross-sectional transmission and high resolution electron microscopy studies, carried out to obtain information about the crystal structure.

  3. Etching of a-Si:H thin films by hydrogen plasma: A view from in situ spectroscopic ellipsometry

    SciTech Connect

    Hadjadj, Aomar Larbi, Fadila; Gilliot, Mickaël; Roca i Cabarrocas, Pere

    2014-08-28

    When atomic hydrogen interacts with hydrogenated amorphous silicon (a-Si:H), the induced modifications are of crucial importance during a-Si:H based devices manufacturing or processing. In the case of hydrogen plasma, the depth of the modified zone depends not only on the plasma processing parameters but also on the material. In this work, we exposed a-Si:H thin films to H{sub 2} plasma just after their deposition. In situ UV-visible spectroscopic ellipsometry measurements were performed to track the H-induced changes in the material. The competition between hydrogen insertion and silicon etching leads to first order kinetics in the time-evolution of the thickness of the H-modified zone. We analyzed the correlation between the steady state structural parameters of the H-modified layer and the main levers that control the plasma-surface interaction. In comparison with a simple doped layer, exposure of a-Si:H based junctions to the same plasma treatment leads to a thinner H-rich subsurface layer, suggesting a possible charged state of hydrogen diffusing.

  4. Characterization of Si (sub X)Ge (sub 1-x)/Si Heterostructures for Device Applications Using Spectroscopic Ellipsometry

    NASA Technical Reports Server (NTRS)

    Sieg, R. M.; Alterovitz, S. A.; Croke, E. T.; Harrell, M. J.; Tanner, M.; Wang, K. L.; Mena, R. A.; Young, P. G.

    1993-01-01

    Spectroscopic ellipsometry (SE) characterization of several complex Si (sub X)Ge (sub 1-x)/Si heterostructures prepared for device fabrication, including structures for heterojunction bipolar transistors (HBT), p-type and n-type heterostructure modulation doped field effect transistors, has been performed. We have shown that SE can simultaneously determine all active layer thicknesses, Si (sub X)Ge (sub 1-x) compositions, and the oxide overlayer thickness, with only a general knowledge of the structure topology needed a priori. The characterization of HBT material included the SE analysis of a Si (sub X)Ge (sub 1-x) layer deeply buried (600 nanometers) under the silicon emitter and cap layers. In the SE analysis of n-type heterostructures, we examined for the first time a silicon layer under tensile strain. We found that an excellent fit can be obtained using optical constants of unstrained silicon to represent the strained silicon conduction layer. We also used SE to measure lateral sample homogeneity, providing quantitative identification of the inhomogeneous layer. Surface overlayers resulting from prior sample processing were also detected and measured quantitatively. These results should allow SE to be used extensively as a non-destructive means of characterizing Si (sub X)Ge (sub 1-x)/Si heterostructures prior to device fabrication and testing.

  5. Determination of the optical properties and size dispersion of Si nanoparticles within a dielectric matrix by spectroscopic ellipsometry

    SciTech Connect

    Keita, A.-S.; Naciri, A. En Battie, Y.; Delachat, F.; Carrada, M.; Ferblantier, G.; Slaoui, A.

    2014-09-14

    We report on a comparative study between dielectric functions of Si nanoparticles (Si-NPs) obtained from Bruggeman effective medium approximation (BEMA), Maxwell-Garnett (MG), and a modified Maxwell-Garnett (MMG) models. Unlike BEMA and MG, a size-distribution dependent dielectric function of Si-NPs is considered in the introduced MMG model. We show that the standard deviation σ of a size distribution can be evaluated by analyzing the imaginary part of the dielectric functions of Si-NPs extracted from BEMA and MMG. In order to demonstrate this, several samples composed of Si-NPs embedded in silicon-rich silicon nitride are investigated by spectroscopic ellipsometry over the photon energy range varying between 2 and 4 eV. Assuming a lognormal size distribution of the Si nanoparticles, it is evidenced that the parameter σ ranges between 1.15 and 1.35. The values of size dispersion deduced by this methodology are in good agreement with TEM observations.

  6. Quantifying protein adsorption on combinatorially sputtered Al-, Nb-, Ta- and Ti-containing films with electron microprobe and spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Byrne, T. M.; Lohstreter, L.; Filiaggi, M. J.; Bai, Zhijun; Dahn, J. R.

    2009-04-01

    Although metallic biomaterials are widely used, systematic studies of protein adsorption onto such materials are generally lacking. Combinatorial binary libraries of Al 1-xNb x, Al 1-xTa x, Al 1-xTi x, Nb 1-xTa x, Nb 1-xTi x, and Ta 1-xTi x (0 ⩽ x ⩽ 1) and a ternary library of Al 1-xTi xTa y (0 ⩽ x ⩽ 1 and 0 ⩽ y ⩽ 0.7), along with their corresponding pure element films were sputtered onto glass substrates using a unique magnetron sputtering technique. Films were characterized with wavelength-dispersive spectroscopy (WDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Fibrinogen and albumin adsorption amounts were measured by wavelength-dispersive spectroscopy (WDS) and spectroscopic ellipsometry (SE) equipment, both high throughput techniques with automated motion stage capabilities. Protein adsorption onto these films was found to be closely correlated to the alumina surface fraction, with high alumina content at the surface leading to low amounts of adsorbed fibrinogen and albumin. Protein adsorption amounts obtained with WDS and SE were in good agreement for all films.

  7. Temperature-dependent adsorption of tellurium and mercury species on cadmium telluride studied by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Badano, Giacomo

    In this study, a subsonic molecular beam of Hg was directed on CdTe surfaces and the absorption spectra were measured for the first time by ellipsometry. We analyze the optical spectra of Hg adsorbed on CdTe surfaces, over the range 1.6--4.5 eV, for a variety of temperatures and Hg fluxes. When a CdTe(211)B surface is subjected to a Hg flux, various effects can occur. Hg will be present on and just beneath the surface in a variety of forms: chemisorbed on the Te sites or on excess Te (forming a 2D surface, 1D chains or isolated atoms or clusters), physisorbed as a 2D liquid, or diffused into the CdTe bulk. In our analysis of the change in the pseudo dielectric function, we made several approximations. We treated the different constituents as separate layers, which is strictly speaking not true, because the various Hg forms are probably mixed. Second, we used the 3D form of the Hg1- xCdxTe e(□; x) dielectric function to mimic chemisorbed Hg on the surface. Also, we used a Drude function to model the presence of physisorbed Hg, although that is probably a good approximation. Third, we fit only the imaginary part of the dielectric function, , because it has a more direct physical meaning, and unlike the real part does not depend on the presence of out-of-range critical points. In addition, the limited resolution of the M88 ellipsometer prevented us from using a critical point analysis to interpret the data. These limitations notwithstanding, our analysis gives surprisingly good results, in that it reproduces the expected dependence of the thickness of the chemisorbed and physisorbed components correctly as a function of temperature and pressure and gives reasonable values for the composition of the Hg1-xCd xTe. Although we do not at present believe the absolute numbers that the analysis provides, we believe that this approach confirms our general ideas regarding the nature of the CdTe(211) surface under Hg, and is valuable at least technologically, to

  8. General approach to the analysis of plasmonic structures using spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Verre, R.; Modreanu, M.; Ualibek, O.; Fox, D.; Fleischer, K.; Smith, C.; Zhang, H.; Pemble, M.; McGilp, J. F.; Shvets, I. V.

    2013-06-01

    In this article a route to analyze the full optical response of plasmonic structures is developed. First, the simple case of an anisotropic thin plasmonic layer supported on a transparent substrate is analyzed by introducing a quantity named anisotropic surface excess function (ASEF). The spectral features are analyzed in terms of effective dielectric function, demonstrating a more direct relation with the plasmonic response of the layer. The formalism is then generalized using a transfer matrix method. The formalism developed is supported by experimental evidence obtained by measuring the response of anisotropic nanoparticle arrays grown at a glancing angle. The agreement between theory and experiment is clear, suggesting that SE can be conveniently employed to measure the spectroscopic response of plasmonic structures. It is also demonstrated that the figure of merit of the plasmonic resonance for refractive index sensing can be greatly improved, with optimized measurement configurations, using polarized spectroscopy.

  9. Influence of annealing temperature and Sn doping on the optical properties of hematite thin films determined by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    de Souza, Lígia P.; Chaves, Rodrigo O. G.; Malachias, Angelo; Paniago, Roberto; Ferreira, Sukarno O.; Ferlauto, Andre S.

    2016-06-01

    Hematite (α-Fe2O3) thin films were prepared by sol-gel route and investigated for application in H2 generation by photo-assisted water splitting. The photoelectrochemical (PEC) performance was shown to increase significantly for films deposited on SnO2:F/glass subjected to high temperature (T) annealing (>750 °C). Strong correlation was found between photogenerated current, donor concentration, and Sn concentration as determined by Mott-Schottky analysis and X-ray photoelectron spectroscopy. The effects of thermal annealing and Sn addition in the resulting microstructure and optical properties of hematite films deposited on fused silica substrates were determined by a combination of structural characterization techniques and spectroscopic ellipsometry. Thermal annealing (>600 °C) induces a higher optical absorption that is associated directly to film densification and grain growth; however, it promotes no changes in the energy positions of the main Fe2O3 electronic transitions. The band gap energy was found to be 2.21 eV and independent of microstructure and of Sn concentration for all studied films. On the other hand, Sn can be incorporated in the Fe2O3 lattice for concentration up to Sn/Fe ˜2%, leading to an increase in energy split of the main absorption peak, attributed to a distortion of the Fe2O3 lattice. For higher concentrations, Sn incorporation leads to a reduction in absorption, associated with higher porosity and the formation of a secondary Sn-rich phase. In summary, the variation in the optical properties induced by thermal annealing and Sn addition cannot account for the order of magnitude increase of the current density generated by photoanodes annealed at high T (>750 °C); thus, it is concluded that the major contribution for the enhanced PEC performance comes from improved electronic properties induced by the n-type doping caused by Sn diffusion from the SnO2:F substrate.

  10. Dielectric function and magneto-optical Voigt constant of Cu2O: A combined spectroscopic ellipsometry and polar magneto-optical Kerr spectroscopy study

    NASA Astrophysics Data System (ADS)

    Haidu, Francisc; Fronk, Michael; Gordan, Ovidiu D.; Scarlat, Camelia; Salvan, Georgeta; Zahn, Dietrich R. T.

    2011-11-01

    Cuprous oxide is a highly interesting material for the emerging field of transparent oxide electronics. In this work the energy dispersion of the dielectric function of Cu2O bulk material is revised by spectroscopic ellipsometry measurements in an extended spectral range from 0.73 to 10 eV. For the first time, the magneto-optical Kerr effect was measured in the spectral range from 1.7 to 5.5 eV and the magneto-optical Voigt constant of Cu2O was obtained by numerical calculations from the magneto-optical Kerr effect spectra and the dielectric function.

  11. Infrared Spectroscopic Imaging: The Next Generation

    PubMed Central

    Bhargava, Rohit

    2013-01-01

    Infrared (IR) spectroscopic imaging seemingly matured as a technology in the mid-2000s, with commercially successful instrumentation and reports in numerous applications. Recent developments, however, have transformed our understanding of the recorded data, provided capability for new instrumentation, and greatly enhanced the ability to extract more useful information in less time. These developments are summarized here in three broad areas— data recording, interpretation of recorded data, and information extraction—and their critical review is employed to project emerging trends. Overall, the convergence of selected components from hardware, theory, algorithms, and applications is one trend. Instead of similar, general-purpose instrumentation, another trend is likely to be diverse and application-targeted designs of instrumentation driven by emerging component technologies. The recent renaissance in both fundamental science and instrumentation will likely spur investigations at the confluence of conventional spectroscopic analyses and optical physics for improved data interpretation. While chemometrics has dominated data processing, a trend will likely lie in the development of signal processing algorithms to optimally extract spectral and spatial information prior to conventional chemometric analyses. Finally, the sum of these recent advances is likely to provide unprecedented capability in measurement and scientific insight, which will present new opportunities for the applied spectroscopist. PMID:23031693

  12. High-Definition Infrared Spectroscopic Imaging

    PubMed Central

    Reddy, Rohith K.; Walsh, Michael J.; Schulmerich, Matthew V.; Carney, P. Scott; Bhargava, Rohit

    2013-01-01

    The quality of images from an infrared (IR) microscope has traditionally been limited by considerations of throughput and signal-to-noise ratio (SNR). An understanding of the achievable quality as a function of instrument parameters, from first principals is needed for improved instrument design. Here, we first present a model for light propagation through an IR spectroscopic imaging system based on scalar wave theory. The model analytically describes the propagation of light along the entire beam path from the source to the detector. The effect of various optical elements and the sample in the microscope is understood in terms of the accessible spatial frequencies by using a Fourier optics approach and simulations are conducted to gain insights into spectroscopic image formation. The optimal pixel size at the sample plane is calculated and shown much smaller than that in current mid-IR microscopy systems. A commercial imaging system is modified, and experimental data are presented to demonstrate the validity of the developed model. Building on this validated theoretical foundation, an optimal sampling configuration is set up. Acquired data were of high spatial quality but, as expected, of poorer SNR. Signal processing approaches were implemented to improve the spectral SNR. The resulting data demonstrated the ability to perform high-definition IR imaging in the laboratory by using minimally-modified commercial instruments. PMID:23317676

  13. Dielectric functions and carrier concentrations of Hg{sub 1−x}Cd{sub x}Se films determined by spectroscopic ellipsometry

    SciTech Connect

    Lee, A. J.; Peiris, F. C.; Brill, G.; Doyle, K.; Myers, T. H.

    2015-08-17

    Spectroscopic ellipsometry, ranging from 35 meV to 6 eV, was used to determine the dielectric functions of a series of molecular beam epitaxy-grown Hg{sub 1−x}Cd{sub x}Se thin films deposited on both ZnTe/Si(112) and GaSb(112) substrates. The fundamental band gap as well as two higher-order electronic transitions blue-shift with increasing Cd composition in Hg{sub 1−x}Cd{sub x}Se, as expected. Representing the free carrier absorption with a Drude oscillator, we found that the effective masses of Hg{sub 1−x}Cd{sub x}Se (grown on ZnTe/Si) vary between 0.028 and 0.050 times the free electron mass, calculated using the values of carrier concentration and the mobility obtained through Hall measurements. Using these effective masses, we determined the carrier concentrations of Hg{sub 1−x}Cd{sub x}Se samples grown on GaSb, which is of significance as films grown on such doped-substrates posit ambiguous results when measured by conventional Hall experiments. These models can serve as a basis for monitoring Cd-composition during sample growth through in-situ spectroscopic ellipsometry.

  14. Investigation of Bovine Serum Albumin (BSA) Attachment onto Self-Assembled Monolayers (SAMs) Using Combinatorial Quartz Crystal Microbalance with Dissipation (QCM-D) and Spectroscopic Ellipsometry (SE)

    PubMed Central

    Phan, Hanh T. M.; Bartelt-Hunt, Shannon; Rodenhausen, Keith B.; Schubert, Mathias; Bartz, Jason C.

    2015-01-01

    Understanding protein adsorption kinetics to surfaces is of importance for various environmental and biomedical applications. Adsorption of bovine serum albumin to various self-assembled monolayer surfaces including neutral and charged hydrophilic and hydrophobic surfaces was investigated using in-situ combinatorial quartz crystal microbalance with dissipation and spectroscopic ellipsometry. Adsorption of bovine serum albumin varied as a function of surface properties, bovine serum albumin concentration and pH value. Charged surfaces exhibited a greater quantity of bovine serum albumin adsorption, a larger bovine serum albumin layer thickness, and increased density of bovine serum albumin protein compared to neutral surfaces at neutral pH value. The quantity of adsorbed bovine serum albumin protein increased with increasing bovine serum albumin concentration. After equilibrium sorption was reached at pH 7.0, desorption of bovine serum albumin occurred when pH was lowered to 2.0, which is below the isoelectric point of bovine serum albumin. Our data provide further evidence that combinatorial quartz crystal microbalance with dissipation and spectroscopic ellipsometry is a sensitive analytical tool to evaluate attachment and detachment of adsorbed proteins in systems with environmental implications. PMID:26505481

  15. Infrared laser spectroscopic trace gas sensing

    NASA Astrophysics Data System (ADS)

    Sigrist, Markus

    2016-04-01

    Chemical sensing and analyses of gas samples by laser spectroscopic methods are attractive owing to several advantages such as high sensitivity and specificity, large dynamic range, multi-component capability, and lack of pretreatment or preconcentration procedures. The preferred wavelength range comprises the fundamental molecular absorption range in the mid-infared between 3 and 15 μm, whereas the near-infrared range covers the (10-100 times weaker) higher harmonics and combination bands. The availability of near-infrared and, particularly, of broadly tunable mid-infrared sources like external cavity quantum cascade lasers (EC-QCLs), interband cascade lasers (ICLs), difference frequency generation (DFG), optical parametric oscillators (OPOs), recent developments of diode-pumped lead salt semiconductor lasers, of supercontinuum sources or of frequency combs have eased the implementation of laser-based sensing devices. Sensitive techniques for molecular absorption measurements include multipass absorption, various configurations of cavity-enhanced techniques such as cavity ringdown (CRD), or of photoacoustic spectroscopy (PAS) including quartz-enhanced (QEPAS) or cantilever-enhanced (CEPAS) techniques. The application requirements finally determine the optimum selection of laser source and detection scheme. In this tutorial talk I shall discuss the basic principles, present various experimental setups and illustrate the performance of selected systems for chemical sensing of selected key atmospheric species. Applications include an early example of continuous vehicle emission measurements with a mobile CO2-laser PAS system [1]. The fast analysis of C1-C4 alkanes at sub-ppm concentrations in gas mixtures is of great interest for the petrochemical industry and was recently achieved with a new type of mid-infrared diode-pumped piezoelectrically tuned lead salt vertical external cavity surface emitting laser (VECSEL) [2]. Another example concerns measurements on short

  16. New infrared spectroscopic database for bromine nitrate

    NASA Astrophysics Data System (ADS)

    Wagner, Georg; Birk, Manfred

    2016-08-01

    Fourier transform infrared measurements of bromine nitrate have been performed in the spectral region 675-1400 cm-1 at 0.014 cm-1 spectral resolution. Absorption cross sections were derived from 38 spectra covering the temperature range from 203 to 296 K and air pressure range from 0 to 190 mbar. For line-by-line analysis, further spectra were recorded at 0.00094 cm-1 spectral resolution at 223 and 293 K. The sample was synthesized from ClONO2 and Br2. Band strengths of the bands ν3 around 803 cm-1 and ν2 around 1286 cm-1 were determined from three pure BrONO2 measurements at different temperatures and pressures. Number densities in the absorption cell were derived from pressure measurements of the purified sample taking into account small amounts of impurities determined spectroscopically. Resulting band strengths are Sν3 = 2.872(52) × 10-17 cm2 molec-1 cm-1 and Sν2 = 3.63(15) × 10-17 cm2 molec-1 cm-1. Absorption cross sections of all measurements were scaled to these band strengths. Further data reduction was achieved with an interpolation scheme based on two-dimensional polynomials in ln(pressure) and temperature. The database is well-suited for remote-sensing application and should reduce the atmospheric bromine nitrate error budget substantially.

  17. Measurement of InAsSb bandgap energy and InAs/InAsSb band edge positions using spectroscopic ellipsometry and photoluminescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Webster, P. T.; Riordan, N. A.; Liu, S.; Steenbergen, E. H.; Synowicki, R. A.; Zhang, Y.-H.; Johnson, S. R.

    2015-12-01

    The structural and optical properties of lattice-matched InAs0.911Sb0.089 bulk layers and strain-balanced InAs/InAs1-xSbx (x ˜ 0.1-0.4) superlattices grown on (100)-oriented GaSb substrates by molecular beam epitaxy are examined using X-ray diffraction, spectroscopic ellipsometry, and temperature dependent photoluminescence spectroscopy. The photoluminescence and ellipsometry measurements determine the ground state bandgap energy and the X-ray diffraction measurements determine the layer thickness and mole fraction of the structures studied. Detailed modeling of the X-ray diffraction data is employed to quantify unintentional incorporation of approximately 1% Sb into the InAs layers of the superlattices. A Kronig-Penney model of the superlattice miniband structure is used to analyze the valence band offset between InAs and InAsSb, and hence the InAsSb band edge positions at each mole fraction. The resulting composition dependence of the bandgap energy and band edge positions of InAsSb are described using the bandgap bowing model; the respective low and room temperature bowing parameters for bulk InAsSb are 938 and 750 meV for the bandgap, 558 and 383 meV for the conduction band, and -380 and -367 meV for the valence band.

  18. Measurement of InAsSb bandgap energy and InAs/InAsSb band edge positions using spectroscopic ellipsometry and photoluminescence spectroscopy

    SciTech Connect

    Webster, P. T.; Riordan, N. A.; Liu, S.; Zhang, Y.-H.; Johnson, S. R.; Steenbergen, E. H.

    2015-12-28

    The structural and optical properties of lattice-matched InAs{sub 0.911}Sb{sub 0.089} bulk layers and strain-balanced InAs/InAs{sub 1−x}Sb{sub x} (x ∼ 0.1–0.4) superlattices grown on (100)-oriented GaSb substrates by molecular beam epitaxy are examined using X-ray diffraction, spectroscopic ellipsometry, and temperature dependent photoluminescence spectroscopy. The photoluminescence and ellipsometry measurements determine the ground state bandgap energy and the X-ray diffraction measurements determine the layer thickness and mole fraction of the structures studied. Detailed modeling of the X-ray diffraction data is employed to quantify unintentional incorporation of approximately 1% Sb into the InAs layers of the superlattices. A Kronig-Penney model of the superlattice miniband structure is used to analyze the valence band offset between InAs and InAsSb, and hence the InAsSb band edge positions at each mole fraction. The resulting composition dependence of the bandgap energy and band edge positions of InAsSb are described using the bandgap bowing model; the respective low and room temperature bowing parameters for bulk InAsSb are 938 and 750 meV for the bandgap, 558 and 383 meV for the conduction band, and −380 and −367 meV for the valence band.

  19. Spectroscopic ellipsometry on Si/SiO{sub 2}/graphene tri-layer system exposed to downstream hydrogen plasma: Effects of hydrogenation and chemical sputtering

    SciTech Connect

    Eren, Baran; Fu, Wangyang; Marot, Laurent Calame, Michel; Steiner, Roland; Meyer, Ernst

    2015-01-05

    In this work, the optical response of graphene to hydrogen plasma treatment is investigated with spectroscopic ellipsometry measurements. Although the electronic transport properties and Raman spectrum of graphene change after plasma hydrogenation, ellipsometric parameters of the Si/SiO2/graphene tri-layer system do not change. This is attributed to plasma hydrogenated graphene still being electrically conductive, since the light absorption of conducting 2D materials does not depend on the electronic band structure. A change in the light transmission can only be observed when higher energy hydrogen ions (30 eV) are employed, which chemically sputter the graphene layer. An optical contrast is still apparent after sputtering due to the remaining traces of graphene and hydrocarbons on the surface. In brief, plasma treatment does not change the light transmission of graphene; and when it does, this is actually due to plasma damage rather than plasma hydrogenation.

  20. I Situ and Real Time Spectroscopic Ellipsometry Studies of the Processing and Fabrication of Hydrogenated Amorphous Silicon Carbon Alloy Thin Films and Devices.

    NASA Astrophysics Data System (ADS)

    Lu, Yi-Wei

    1995-01-01

    Real time spectroscopic ellipsometry (RTSE) is used to monitor the growth of plasma-enhanced chemical vapor-deposited (PECVD) hydrogenated amorphous silicon carbon alloy thin films and the fabrication of glass/SnO _2/p-i-n/Cr amorphous silicon heterojunction solar cells in a single-chamber system. RTSE has the capability of measuring 128-point spectra from 1.5 to 4.8 eV in acquisition and repetition times as short as 16 ms and 32 ms, respectively. With the spectroscopic capability as well as the ultra fast repetition and acquisition times, we can determine not only the evolution of the microstructure of the individual films of the solar cell, including the surface roughness thickness, the bulk film thickness, and void density, but also the photo-electronic properties of the films including the complex dielectric function and the optical gap. The interfacial reactions that occur between the SnO _2 and p-layer, and the contamination that occurs between the p-layer and i-layer during the preparation of the solar cells were also identified by RTSE. With the information provided by RTSE, the relationships between the processing conditions and both the properties of films and the performance of the cells can be better understood. Thus, an interface treatment technique and optimized process strategies have been designed, and films and cells of better properties and performance have been achieved with the guidance provided by RTSE.

  1. Determination of thermo-optic properties of atomic layer deposited thin TiO2 films for athermal resonant waveguide gratings by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Saleem, Muhammad Rizwan; Ali, Rizwan; Honkanen, Seppo; Turunen, Jari

    2014-05-01

    We report on variation in the refractive index of amorphous and isotropic TiO2 thin films grown by Atomic Layer Deposition (ALD) in nano optical devices. ALD-TiO2 films of thicknesses <= 200 nm exhibiting negative thermo-optic coefficient (TOC) due to decrease in refractive index with temperature, owing to inherent hydrophilic nature. While ALD-TiO2 films with thicknesses > 200 nm show positive TOC due to the predominance of TiO2 thickness over the very thin surface porosity region. The negative TOC of thin TiO2 films was controlled by depositing thin ALD-Al2O3 diffusion barrier films that showed impermeable behavior to block the evaporation of adsorbed water molecules on TiO2 surfaces in thermal environments. This approach turns negative sign of TOC of TiO2 thin films to positive one which is necessary to stabilize the central resonance peak of a guided mode resonance filter (GMRF). The ALD-TiO2 and ALDAl2O3 bi-layer stack was modeled by VASE analysis of spectroscopic ellipsometry using Cauchy Model to extract refractive indices at various temperatures, measured at two different angle of incidence (65° and 75°), covering a wide spectral range 380 <= λ <= 1800. The temperature dependent index and density of TiO2 films were calculated from ellipsometric measured data using Lorentz-Lorenz relation.

  2. Spectroscopic ellipsometry and UV-vis studies at room temperature of the novel organic-inorganic hybrid of salt Bis (4-acetylanilinium) tetrachlorocadmiate

    NASA Astrophysics Data System (ADS)

    Jellibi, A.; Chaabane, I.; Guidara, K.

    2016-05-01

    The optical properties of Bis (4-acetylanilinium) tetrachlorocadmiate compound were studied using phase modulated spectroscopic ellipsometry (PMSE) and ultraviolet-visible (UV-Vis) spectroscopy in the range 200-800 nm. The optical absorbance were measured in order to deduce the absorption coefficient α and optical band gap Eg, thus the Tauc model was used to determine the optical gap energy of the synthesized (C8H10NO)2CdCl4 compound. The analysis of the data revealed the existence of optical allowed direct transition mechanisms with the band gap energy equal to 3.17 eV. On the other hand the single-effective-oscillator model was used to fit the calculated data to the experimental ellipsometric spectra. Thus the values of the dispersion energy and single-oscillator strength are determined. Also, the extinction coefficient, refractive index, dispersion parameter and both the real εr and imaginary parts εi of the dielectric permittivity of Bis (4-acetylanilinium) tetrachlorocadmiate compound were calculated and the results are discussed.

  3. A high throughput approach to quantify protein adsorption on combinatorial metal/metal oxide surfaces using electron microprobe and spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Byrne, T.; Lohstreter, L.; Filiaggi, M. J.; Bai, Zhijun; Dahn, J. R.

    2008-09-01

    Although metallic biomaterials are widely used, systematic studies of protein adsorption onto such materials are generally lacking. Combinatorial binary films of Al 1-xTi x and Al 1-xNb x (0 ⩽ x ⩽ 1) and corresponding pure element films were produced on glass substrates using a unique magnetron sputtering technique. Fibrinogen and albumin adsorption amounts were measured by wavelength-dispersive spectroscopy (WDS) and spectroscopic ellipsometry (SE) equipment, both high throughput techniques with automated motion stage capabilities. X-ray diffraction revealed that the binary films have crystalline phases present near the ends of the compositional gradient with an amorphous region throughout the interior of the gradient. X-ray photoelectron spectroscopy provided the surface chemistry along the binary films and showed that Al 2O 3 preferentially formed at the surface. Protein adsorption onto these films was found to be closely correlated to the alumina surface fraction, with high alumina content at the surface leading to low amounts of adsorbed fibrinogen and albumin. Protein adsorption amounts obtained with WDS and SE were in excellent agreement for all films. This suggests that this combinatorial materials approach combined with these state-of-the-art, automated high throughput instruments provides a novel way to accurately monitor protein adsorption taking place at the surfaces of these metal/metal oxide materials.

  4. Characterization of excimer laser annealed polycrystalline Si1-xGex alloy thin films by x-ray diffraction and spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Yu, Guolin; Krishna, Kalaga Murali; Shao, Chunlin; Umeno, Masayoshi; Soga, Tetsuo; Watanabe, Junji; Jimbo, Takashi

    1998-01-01

    Thin films of Si1-xGex alloys of different compositions x have been deposited, on single-crystal Si (100) surface and glass substrates, by simple ion beam sputtering, at room temperature. Crystallization of these films has been done using excimer laser annealing. Structural and optical properties of as-deposited and annealed Si1-xGex alloy films are characterized by x-ray diffraction (XRD), uv-visible spectrophotometry, spectroscopic ellipsometry (SE), and Auger electron spectroscopy (AES). The as-deposited films, both on Si and glass, have been found to be amorphous by XRD. Polycrystalline nature of laser-annealed samples has been evidenced by both x-ray and SE measurements. The results of x-ray, uv-visible, AES, and SE are compared and discussed. The poly-Si1-xGex films were oriented predominantly to (111) and the grain sizes were determined from half-width of x-ray peaks. The compositions x of Si1-xGex films have been evaluated from the SE dielectric function ɛ(ω) data, using the second-derivative technique, and are found to be 0.23 and 0.36 for two different compositions. A detailed analysis of ɛ(ω) with the effective-medium theory has demonstrated the volume fraction of crystalline Si1-xGex increases with the increasing energy of laser irradiation.

  5. Effects of oxygen partial pressure, deposition temperature, and annealing on the optical response of CdS:O thin films as studied by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Junda, Maxwell M.; Grice, Corey R.; Subedi, Indra; Yan, Yanfa; Podraza, Nikolas J.

    2016-07-01

    Ex-situ spectroscopic ellipsometry measurements are made on radio frequency magnetron sputtered oxygenated cadmium sulfide (CdS:O) thin films. Films are deposited onto glass substrates at room temperature and at 270 °C with varying oxygen to total gas flow ratios in the sputtering ambient. Ellipsometric spectra from 0.74 to 5.89 eV are collected before and after annealing at 607 °C to simulate the thermal processes during close-space sublimation of overlying cadmium telluride in that solar cell configuration. Complex dielectric function (ɛ = ɛ1 + iɛ2) spectra are extracted for films as a function of oxygen gas flow ratio, deposition temperature, and post-deposition annealing using a parametric model accounting for critical point transitions and an Urbach tail for sub-band gap absorption. The results suggest an inverse relationship between degree of crystallinity and oxygen gas flow ratio, whereas annealing is shown to increase crystallinity in all samples. Direct band gap energies are determined from the parametric modeling of ɛ and linear extrapolations of the square of the absorption coefficient. As-deposited samples feature a range of band gap energies whereas annealing is shown to result in gap energies ranging only from 2.40 to 2.45 eV, which is close to typical band gaps for pure cadmium sulfide.

  6. Nucleation and initial growth of atomic layer deposited titanium oxide determined by spectroscopic ellipsometry and the effect of pretreatment by surface barrier discharge

    NASA Astrophysics Data System (ADS)

    Cameron, David C.; Krumpolec, Richard; Ivanova, Tatiana V.; Homola, Tomáš; Černák, Mirko

    2015-08-01

    This paper reports on the use of spectroscopic ellipsometry to characterise the initial nucleation stage of the atomic layer deposition of the anatase phase of titanium dioxide on silicon substrates. Careful control and analysis of the ellipsometric measurements enables the determination of the evolution of crystallite diameter and surface density in the nucleation stage before a continuous film is formed. This growth behaviour is in line with atomic force microscopy measurements of the crystallite size. The crystallite diameter is a linear function of the number of ALD cycles with a slope of approximately 1.7 Å cycle-1 which is equivalent to a layer growth rate of 0.85 Å cycle-1 consistent with a ripening process which increases the crystallite size while reducing their density. The crystallite density decreases from ∼3 × 1017 m-3 in the initial nucleation stages to ∼3 × 1015 m-3 before the film becomes continuous. The effect of exposing the substrate to a diffuse coplanar surface barrier discharge in an air atmosphere before deposition was measured and only small differences were found: the plasma treated samples were slightly rougher in the initial stages and required a greater number of cycles to form a continuous film (∼80) compared to the untreated films (∼50). A thicker layer of native oxide was found after plasma treatment.

  7. Sensitivity analysis and line edge roughness determination of 28-nm pitch silicon fins using Mueller matrix spectroscopic ellipsometry-based optical critical dimension metrology

    NASA Astrophysics Data System (ADS)

    Dixit, Dhairya; O'Mullane, Samuel; Sunkoju, Sravan; Gottipati, Abhishek; Hosler, Erik R.; Kamineni, Vimal; Preil, Moshe; Keller, Nick; Race, Joseph; Muthinti, Gangadhara Raja; Diebold, Alain C.

    2015-07-01

    Measurement and control of line edge roughness (LER) is one of the most challenging issues facing patterning technology. As the critical dimensions (CDs) of patterned structures decrease, an LER of only a few nanometers negatively impacts device performance. Here, Mueller matrix (MM) spectroscopic ellipsometry-based scatterometry is used to characterize LER in periodic line-space structures in 28-nm pitch Si fin samples fabricated by directed self-assembly patterning. The optical response of the MM elements is influenced by structural parameters like pitch, CDs, height, and side-wall angle, as well as the optical properties of the materials. Evaluation and decoupling MM element response to LER from other structural parameters requires sensitivity analysis using scatterometry models that include LER. Here, an approach is developed that can be used to characterize LER in Si fins by comparing the optical responses generated by systematically varying the grating shape and measurement conditions. Finally, the validity of this approach is established by comparing the results obtained from power spectral density analysis of top down scanning electron microscope images and cross-sectional transmission electron microscope image of the 28-nm pitch Si fins.

  8. Spectroscopic ellipsometry meets AFM nanolithography: about hydration of bio-inert oligo(ethylene glycol)-terminated self assembled monolayers on gold.

    PubMed

    Solano, Ilaria; Parisse, Pietro; Gramazio, Federico; Cavalleri, Ornella; Bracco, Gianangelo; Castronovo, Matteo; Casalis, Loredana; Canepa, Maurizio

    2015-11-21

    For the first time, to our knowledge, spectroscopic ellipsometry (SE) has been combined with state-of-the-art AFM differential height measurements conducted after shaving nano-lithography of ultrathin, soft-matter films for thickness determination. We investigated self-assembled monolayers of SH-(CH2)11-EGn-OH molecules on gold, where EG is ethylene glycol units and n = 3 and 6, a prototypical non-fouling system. We performed SE measurements (245-1200 nm) focusing on the changes induced by the formation of the film (difference spectra). SE measurements, analysed by simple models, confirm the formation of the S-Au interface, transparency of the SAMs and provide a sharp picture of the ability of the EG functionality to protect the surface from unspecific adsorption of proteins. A quantitative assessment of the film thickness by SE was carried out ex situ, thanks to the optical contrast between the film and the ambient, and by AFM in liquid. The cross-check between SE and AFM height measurements combined with the comparison between in-liquid and ex situ SE measurements allowed obtaining non-perturbative information about the vertical density profile of the SAM. The in-liquid SE measurements indicate a refractive index matching between the aqueous medium and the outer part of the SAM, consistent with a disordered configuration of OEG and/or the penetration of water amid the OEG strands. A critical discussion provides a detailed insight into the subtle issues and pitfalls related to the thickness determination of soft-matter films to the monolayer limit. PMID:26445913

  9. Spectroscopic ellipsometry determination of the optical constants of titanium-doped WO{sub 3} films made by co-sputter deposition

    SciTech Connect

    Vargas, M.; Rubio, E. J.; Gutierrez, A.; Ramana, C. V.

    2014-04-07

    Titanium (Ti) doped tungsten oxide (WO{sub 3}) thin films were grown by co-sputter deposition of W and Ti metal targets. The sputtering powers to the W and Ti were kept constant at 100 W and 50 W, respectively, while varying the growth temperature (T{sub s}) in the range of 25–400 °C. The structural quality of Ti-doped WO{sub 3} films is dependent on T{sub s}. Ti-doped WO{sub 3} films grown at T{sub s} < 400 °C were amorphous. A temperature of 400 °C is critical to promote the structural order and formation of monoclinic, nanocrystalline films. The optical constants and their dispersion profiles determined from spectroscopic ellipsometry indicate that there is no significant inter-diffusion at the film-substrate interface for W-Ti oxide film growth of ∼40 nm. The index refraction (n) at λ = 550 nm varies in the range of 2.15–2.40 with a gradual increase in T{sub s}. Lorentz-Lorenz analysis (n{sub (λ)} = 550 nm) of the data indicates the gradual improvement in the packing density coupled with structural transformation accounts for the observed optical quality of the Ti-doped WO{sub 3} films as a function of T{sub s}. A correlation between the growth conditions and optical constants is discussed.

  10. Quartz crystal microbalance with dissipation monitoring and spectroscopic ellipsometry measurements of the phospholipid bilayer anchoring stability and kinetics of hydrophobically modified DNA oligonucleotides.

    PubMed

    van der Meulen, Stef A J; Dubacheva, Galina V; Dogterom, Marileen; Richter, Ralf P; Leunissen, Mirjam E

    2014-06-10

    Decorating lipid bilayers with oligonucleotides has great potential for both fundamental studies and applications, taking advantage of the membrane properties and the specific Watson-Crick base pairing. Here, we systematically studied the binding of DNA oligonucleotides with the frequently used hydrophobic anchors cholesterol, stearyl, and distearyl to supported lipid bilayers made of dioleoylphosphatidylcholine (DOPC) by quartz crystal microbalance with dissipation monitoring and spectroscopic ellipsometry (SE). All three anchors were found to incorporate well into DOPC lipid membranes, yet only the distearyl-based anchor remained stable in the bilayer when it was rinsed. The unstable anchoring of the cholesterol- and stearyl-based oligonucleotides can, however, be stabilized by hybridization of the oligonucleotides to complementary DNA modified with a second hydrophobic anchor of the same type. In all cases, the incorporation into the lipid bilayer was found to be limited by mass transport, although micelle formation likely reduced the effective concentration of available oligonucleotides in some samples, leading to substantial differences in binding rates. Using a viscoelastic model to determine the thickness of the DNA layer and elucidating the surface coverage by SE, we found that at equal bulk concentrations double-stranded DNA constructs attached to the lipid bilayer establish a layer that is thicker than that of single-stranded oligonucleotides, whereas the DNA surface densities are similar. Shortening the length of the oligonucleotides, on the other hand, does alter both the thickness and surface density of the DNA layer. This indicates that at the bulk oligonucleotide concentrations employed in our experiments, the packing of the oligonucleotides is not affected by the anchor type, but rather by the length of the DNA. The results are useful for material and biomedical applications that require efficient linking of oligonucleotides to lipid membranes. PMID

  11. Optical properties of silicon nanocrystals embedded in Si3N4 matrix measured by spectroscopic ellipsometry and UV-Vis-NIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Barbé, J.; Despax, B.; Perraud, S.; Makasheva, K.

    2014-04-01

    In this paper, we report a spectroscopic ellipsometry study of the optical properties of silicon nanocrystals (Si-ncs) embedded in silicon nitride matrix. The nanocomposite thin-films were elaborated by radiofrequency plasma enhanced chemical vapor deposition from ammonia and silane precursors, followed by high temperature annealing. Bruggeman effective medium approximation combined with the Tauc-Lorentz dispersion law was found to be an appropriate model in describing the ellipsometric data, and provided a fine determination of the dielectric functions or complex permittivity of Si-ncs embedded in silicon nitride. It is shown that the dielectric functions of Si-ncs undergo a large reduction in amplitude and broadening compared to the dielectric function of the bulk crystalline Si. Consequently to the disappearance of direct transition energy E 1 and E 2, the imaginary part ɛ 2 of the dielectric function of Si-ncs exhibits a single line shape centered between E 1 and E 2. With decreasing Si-ncs size, we observe a red-shift of ɛ 2 which cannot be attributed to bandgap expansion, but is better explained by electron-phonon interactions in the case of a Si3N4 matrix with high Young modulus. According to Tauc-Lorentz dispersion law, the obtained bandgap values of Si-ncs are between 1.58 eV and 1.67 eV for Si-ncs with diameters from 4.6 nm to 3.8 nm, which is in good agreement with measurements from UV-Vis-NIR spectroscopy.

  12. Ultrafast dynamic ellipsometry and spectroscopy of laser shocked materials

    SciTech Connect

    Bolme, Cynthia A; Mc Grane, Shawn D; Dang, Nhan C; Whitley, Von H; Moore, David S.

    2011-01-20

    Ultrafast dynamic ellipsometry is used to measure the material motion and changes in the optical refractive index of laser shock compressed materials. This diagnostic has shown us that the ultrafast laser driven shocks are the same as shocks on longer timescales and larger length scales. We have added spectroscopic diagnostics of infrared absorption, ultra-violet - visible transient absorption, and femtosecond stimulated Raman scattering to begin probing the initiation chemistry that occurs in shock reactive materials. We have also used the femtosecond stimulated Raman scattering to measure the vibrational temperature of materials using the Stokes gain to anti-Stokes loss ratio.

  13. AKARI INFRARED CAMERA SURVEY OF THE LARGE MAGELLANIC CLOUD. II. THE NEAR-INFRARED SPECTROSCOPIC CATALOG

    SciTech Connect

    Shimonishi, Takashi; Onaka, Takashi; Kato, Daisuke; Sakon, Itsuki; Ita, Yoshifusa; Kawamura, Akiko; Kaneda, Hidehiro

    2013-02-01

    We performed a near-infrared spectroscopic survey toward an area of {approx}10 deg{sup 2} of the Large Magellanic Cloud (LMC) with the infrared satellite AKARI. Observations were carried out as part of the AKARI Large-area Survey of the Large Magellanic Cloud (LSLMC). The slitless multi-object spectroscopic capability of the AKARI/IRC enabled us to obtain low-resolution (R {approx} 20) spectra in 2-5 {mu}m for a large number of point sources in the LMC. As a result of the survey, we extracted about 2000 infrared spectra of point sources. The data are organized as a near-infrared spectroscopic catalog. The catalog includes various infrared objects such as young stellar objects (YSOs), asymptotic giant branch (AGB) stars, supergiants, and so on. It is shown that 97% of the catalog sources have corresponding photometric data in the wavelength range from 1.2 to 11 {mu}m, and 67% of the sources also have photometric data up to 24 {mu}m. The catalog allows us to investigate near-infrared spectral features of sources by comparison with their infrared spectral energy distributions. In addition, it is estimated that about 10% of the catalog sources are observed at more than two different epochs. This enables us to study a spectroscopic variability of sources by using the present catalog. Initial results of source classifications for the LSLMC samples are presented. We classified 659 LSLMC spectra based on their near-infrared spectral features by visual inspection. As a result, it is shown that the present catalog includes 7 YSOs, 160 C-rich AGBs, 8 C-rich AGB candidates, 85 O-rich AGBs, 122 blue and yellow supergiants, 150 red super giants, and 128 unclassified sources. Distributions of the classified sources on the color-color and color-magnitude diagrams are discussed in the text. Continuous wavelength coverage and high spectroscopic sensitivity in 2-5 {mu}m can only be achieved by space observations. This is an unprecedented large-scale spectroscopic survey toward the

  14. [Terahertz and Infrared Spectroscopic Investigation of Cellulose].

    PubMed

    Qiu, Guo-hua; Zhang, Le; Shentu, Nan-ying

    2016-03-01

    To investigate the Terahertz's application prospect, corn, wheat husk and reed were used to detect their Terahertz Time Domain Spectroscopy, and be compared with that of cellulose powder. The experimental results show that all of their absorption peaks exist at 1.75, 1.62, 1.1, and 0.7 THz. Absorption intensity of cellulose powder, corn, wheat husk and reed were compared in some frequencies points. It finds that corn, wheat husk and reed have higher absorption intensity than cellulose powder in early frequency domain. However, absorption intensity of cellulose powder is the strongest at 1.62 THz. Cellulose content in corn, wheat husk and reed were detected by using the method of chemical analysis. The peaks of absorption coefficient are related to their cellulose content at this frequency. It shows that plant cellulose occur lattice vibration in the frequency. Deformation, bending, flexing, and other changes appear to their functional keys. Quantum chemical calculation was carried out by using density functional theory to cellulose and the structure diagram of cellulose molecular formula was obtained. It also finds some absorption peaks exist at 0.7, 1.1, and 1.75 THz. Characterization of cellulose clusters mainly includes CH2, OH, CH, and so on. Glucose hydroxyl radical on the ring is active in the cellulose chain. Where hydroxyl related chemical reaction can occur, Hydroxyl can also be integrated into the intermolecular and intramolecular hydrogen bond. Terahertz wave can promote hydrogen bond vibration. This kind of vibration is weak in the intermolecular interaction. The vibration and rotating happen in dipole transition. The crystal lattice rotates and is absorptive in low frequency, and large molecular skeleton vibrates. All of them can show different intensity and position of the absorption peak in the terahertz band. Corn and cellulose were analyzed by infrared spectrum. The reverse and vibration mode of cellulose was discussed. The absorption peak is

  15. [Terahertz and Infrared Spectroscopic Investigation of Cellulose].

    PubMed

    Qiu, Guo-hua; Zhang, Le; Shentu, Nan-ying

    2016-03-01

    To investigate the Terahertz's application prospect, corn, wheat husk and reed were used to detect their Terahertz Time Domain Spectroscopy, and be compared with that of cellulose powder. The experimental results show that all of their absorption peaks exist at 1.75, 1.62, 1.1, and 0.7 THz. Absorption intensity of cellulose powder, corn, wheat husk and reed were compared in some frequencies points. It finds that corn, wheat husk and reed have higher absorption intensity than cellulose powder in early frequency domain. However, absorption intensity of cellulose powder is the strongest at 1.62 THz. Cellulose content in corn, wheat husk and reed were detected by using the method of chemical analysis. The peaks of absorption coefficient are related to their cellulose content at this frequency. It shows that plant cellulose occur lattice vibration in the frequency. Deformation, bending, flexing, and other changes appear to their functional keys. Quantum chemical calculation was carried out by using density functional theory to cellulose and the structure diagram of cellulose molecular formula was obtained. It also finds some absorption peaks exist at 0.7, 1.1, and 1.75 THz. Characterization of cellulose clusters mainly includes CH2, OH, CH, and so on. Glucose hydroxyl radical on the ring is active in the cellulose chain. Where hydroxyl related chemical reaction can occur, Hydroxyl can also be integrated into the intermolecular and intramolecular hydrogen bond. Terahertz wave can promote hydrogen bond vibration. This kind of vibration is weak in the intermolecular interaction. The vibration and rotating happen in dipole transition. The crystal lattice rotates and is absorptive in low frequency, and large molecular skeleton vibrates. All of them can show different intensity and position of the absorption peak in the terahertz band. Corn and cellulose were analyzed by infrared spectrum. The reverse and vibration mode of cellulose was discussed. The absorption peak is

  16. Infrared-spectroscopic nanoimaging with a thermal source

    NASA Astrophysics Data System (ADS)

    Huth, F.; Schnell, M.; Wittborn, J.; Ocelic, N.; Hillenbrand, R.

    2011-05-01

    Fourier-transform infrared (FTIR) spectroscopy is a widely used analytical tool for chemical identification of inorganic, organic and biomedical materials, as well as for exploring conduction phenomena. Because of the diffraction limit, however, conventional FTIR cannot be applied for nanoscale imaging. Here we demonstrate a novel FTIR system that allows for infrared-spectroscopic nanoimaging of dielectric properties (nano-FTIR). Based on superfocusing of thermal radiation with an infrared antenna, detection of the scattered light, and strong signal enhancement employing an asymmetric FTIR spectrometer, we improve the spatial resolution of conventional infrared spectroscopy by more than two orders of magnitude. By mapping a semiconductor device, we demonstrate spectroscopic identification of silicon oxides and quantification of the free-carrier concentration in doped Si regions with a spatial resolution better than 100 nm. We envisage nano-FTIR becoming a powerful tool for chemical identification of nanomaterials, as well as for quantitative and contact-free measurement of the local free-carrier concentration and mobility in doped nanostructures.

  17. Wide Integral Field Infrared Spectroscopic Survey of Nearby Galaxies

    NASA Astrophysics Data System (ADS)

    Sivanandam, Suresh; Moon, Dae-Sik; Zaritsky, Dennis F.; Chou, Richard; Meyer, Elliot; Ma, Ke; Jarvis, Miranda; Eisner, Joshua A.

    2015-01-01

    We are constructing a novel infrared integral field spectrograph with a large field of view (~50'x20') that will be available on the Kitt Peak 90' Bok telescope this spring. This wide integral field infrared spectrograph (WIFIS) operates over two wavelength ranges, zJ-band (0.9-1.35 microns) and H-band (1.5-1.8 microns), and has moderate spectral resolving power, 3,000 in zJ-band and 2,200 in H-band, respectively. WIFIS' field-of-view is comparable to current optical integral field spectrographs that are carrying out large galaxy surveys, e.g. SAMI, CALIFA, and MaNGA. We are designing a large nearby galaxy survey to complement the data already been taken by these optical integral field spectroscopic surveys. The near-infrared window provides a sensitive probe of the initial mass functions of stellar populations, the OB stellar fractions in massive star forming regions, and the kinematics of and obscured star formation within merging systems. This will be the first large scale infrared integral field spectroscopic survey of nearby galaxies.

  18. Fundamental developments in infrared spectroscopic imaging for biomedical applications.

    PubMed

    Pilling, Michael; Gardner, Peter

    2016-04-01

    Infrared chemical imaging is a rapidly emerging field with new advances in instrumentation, data acquisition and data analysis. These developments have had significant impact in biomedical applications and numerous studies have now shown that this technology offers great promise for the improved diagnosis of the diseased state. Relying on purely biochemical signatures rather than contrast from exogenous dyes and stains, infrared chemical imaging has the potential to revolutionise histopathology for improved disease diagnosis. In this review we discuss the recent advances in infrared spectroscopic imaging specifically related to spectral histopathology (SHP) and consider the current state of the field. Finally we consider the practical application of SHP for disease diagnosis and consider potential barriers to clinical translation highlighting current directions and the future outlook. PMID:26996636

  19. Phonon and free-charge carrier properties in group-III nitride heterostructures investigated by spectroscopic ellipsometry and optical Hall effect

    NASA Astrophysics Data System (ADS)

    Schoeche, Stefan

    The material class of group-III nitrides gained tremendous technological importance for optoelectronic and high-power/high-frequency amplification devices. Tunability of the direct band gap from 0.65 eV (InN) to 6.2 eV (AlN) by alloying, high breakthrough voltages and intrinsic mobilities, as well as the formation of highly mobile 2d electron gases (2DEG) at heterointerfaces make these compounds ideal for many applications. GaN and Ga-rich alloys are well studied and current research is mainly device-oriented. For example, choice and quality of the gate dielectric significantly influence device performance in high-electron mobility transistors (HEMT) which utilize highly mobile 2DEGs at heterointerfaces. Experimental access to the 2DEG channel properties without influence from parasitic currents or contact properties are desirable. In- and Al-rich ternary alloys are less explored than Ga-rich compounds. For InN and In-rich alloys, while many material parameters such as stiffness constants or effective mass values are largely unknown, reliable p-type doping is a major challenge, also because p-type conducting channels are buried within highly conductive n-type material formed at the surface and interfaces preventing electrical characterization. For AlN and high-Al content alloys, doping mechanisms are not understood and reliable fabrication of material with high free-charge carrier (FCC) concentrations was achieved just recently. Difficulties to form ohmic contacts impair electrical measurements and optical characterization is impeded by lack of high-energy excitation sources. In this work, spectroscopic ellipsometry over the wide spectral range from the THz to VUV in combination with optical Hall effect (generalized ellipsometry with applied magnetic field) from THz to MIR are applied in order to investigate the phonon modes and FCC properties in group-III nitride heterostructures. Adequate model descriptions and analysis strategies are introduced which allow

  20. Synchrotron radiation-based far-infrared spectroscopic ellipsometer with full Mueller-matrix capability

    SciTech Connect

    Stanislavchuk, T. N.; Kang, T. D.; Rogers, P. D.; Standard, E. C.; Basistyy, R.; Nita, G.; Zhou, T.; Sirenko, A. A.; Kotelyanskii, A. M.; Carr, G. L.; Kotelyanskii, M.

    2013-02-15

    We developed far-IR spectroscopic ellipsometer at the U4IR beamline of the National Synchrotron Light Source in Brookhaven National Laboratory. This ellipsometer is able to measure both, rotating analyzer and full-Mueller matrix spectra using rotating retarders, and wire-grid linear polarizers. We utilize exceptional brightness of synchrotron radiation in the broad spectral range between about 20 and 4000 cm{sup -1}. Fourier-transform infrared (FT-IR) spectrometer is used for multi-wavelength data acquisition. The sample stage has temperature variation between 4.2 and 450 K, wide range of {theta}-2{theta} angular rotation, {chi} tilt angle adjustment, and X-Y-Z translation. A LabVIEW-based software controls the motors, sample temperature, and FT-IR spectrometer and also allows to run fully automated experiments with pre-programmed measurement schedules. Data analysis is based on Berreman's 4 Multiplication-Sign 4 propagation matrix formalism to calculate the Mueller matrix parameters of anisotropic samples with magnetic permeability {mu}{ne} 1. A nonlinear regression of the rotating analyzer ellipsometry and/or Mueller matrix (MM) spectra, which are usually acquired at variable angles of incidence and sample crystallographic orientations, allows extraction of dielectric constant and magnetic permeability tensors for bulk and thin-film samples. Applications of this ellipsometer setup for multiferroic and ferrimagnetic materials with {mu}{ne} 1 are illustrated with experimental results and simulations for TbMnO{sub 3} and Dy{sub 3}Fe{sub 5}O{sub 12} single crystals. We demonstrate how magnetic and electric dipoles, such as magnons and phonons, can be distinguished from a single MM measurement without adducing any modeling arguments. The parameters of magnetoelectric components of electromagnon excitations are determined using MM spectra of TbMnO{sub 3}.

  1. Infrared Imaging, Spectroscopic, and Photometric Studies of Comets

    NASA Technical Reports Server (NTRS)

    Gehrz, Robert D.

    1997-01-01

    We have continued our program of infrared (IR) photometric, imaging, spectroscopic, and polarimetric temporal observations of comets to study the properties of comet dust and comet nuclei. During the first two years we digitized our IR data base on P/Halley and other recent comets to facilitate further analysis and comparison with other data bases, and found compelling evidence for the emission of a burst of small grains from P/Halley's nucleus at perihelion. We reported imaging and photometric observations of Comets Austin 1990 V and Swift-Tuttle 1992. The Swift-Tuttle 1992t observations included IR photometry, several 7-14 micron long-slit spectra of the coma and a time-sequence of more than 150 10 micron broadband images of the coma. An analysis of near-IR images of the inner coma of P/Halley obtained on three consecutive nights in 1986 March showed sunwardjets. We completed our analysis of IR imaging spectrosco-photometric data on comets. We also obtained observations of Comets Hyakutake 1996 B2 and Hale/Bopp 1995 01. We obtained infrared imaging, photometric, spectroscopic and polarimetric temporal observations of bright comets using a network of five telescopes, with emphasis on simultaneous observations of comets at many wavelengths with different instruments. Our program offers several unique advantages: 1) rapid observational response to new comets with dedicated infrared telescopes; 2) observations within a few degrees of the sun when comets are near perihelion and 3) access to advanced infrared array imagers and spectrometers. In particular, reduction, analysis, publication and archiving of our Jupiter/sl-9 and Comet Hyakutake infrared data received special emphasis. Instrumentation development included installation of the latest version of the innovative FORTH telescope control and a data acquisition system that enables us to control three telescopes remotely by telephone from anywhere in the world for comet observations in broad daylight. We have

  2. Optical properties and London dispersion interaction of amorphous and crystalline SiO2 determined by vacuum ultraviolet spectroscopy and spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Tan, G. L.; Lemon, M. F.; Jones, D. J.; French, R. H.

    2005-11-01

    The interband optical properties of crystalline (quartz) and amorphous SiO2 in the vacuum ultraviolet (VUV) region have been investigated using combined spectroscopic ellipsometry and VUV spectroscopy. Over the range of 1.5-42 eV the optical properties exhibit similar exciton and interband transitions, with crystalline SiO2 exhibiting larger transition strengths and index of refraction. Crystalline SiO2 has more sharp features in the interband transition strength spectrum than amorphous SiO2 , the energy of the absorption edge for crystalline SiO2 is about 1 eV higher than that for amorphous SiO2 , and the direct band-gap energies for X -cut and Z -cut quartz are 8.30 and 8.29 eV within the absorption coefficient range 2-20cm-1 . In crystalline SiO2 we report different interband transition peaks at 16.2, 20.1, 21, 22.6, and 27.5 eV, which are in addition to those lower energy transitions previously reported at 10.4, 11.6, 14, and 17.1 eV. We find the bulk plasmon energy in X - and Z -cut crystalline quartz and amorphous SiO2 to be at 24.6, 25.2, and 23.7 eV, respectively. The oscillator strength (f) sum rules of the interband transitions for crystalline SiO2 is 10-10.8 electrons per formula unit for transition energies up to 45 eV. These differences in the electronic structure and optical properties, and the physical densities of crystalline and amorphous SiO2 , can be attributed to differences in the intermediate-range order (IRO) and long-range order (LRO) of the different forms of SiO2 . The intimate relationship between the electronic structure and optical properties and the London dispersion interaction has attracted increased interest recently, and the role of amorphous silica and other structural glass formers as a fluid in high-temperature wetting and materials processes means a detailed knowledge of the optical properties and London dispersion interaction in SiO2 is important. Hamaker constants for the London dispersion interaction of the configuration of

  3. Predicting Future Space-Based Slitless Spectroscopic Surveys Using the WFC3 Infrared Spectroscopic Parallels (WISP)

    NASA Astrophysics Data System (ADS)

    Colbert, James W.; Teplitz, H.; Malkan, M.; Atek, H.; Ross, N.; Siana, B.; Henry, A.; McCarthy, P.; Bunker, A.; Scarlata, C.

    2012-01-01

    Future space telescopes are likely to make extensive use of slitless grism spectroscopy in the near-IR over large areas of sky. Both ESA's recently selected Euclid mission and the WFIRST mission being studied by NASA plan slitless spectroscopic surveys to obtain redshifts over thousands of square degrees. The HST WFC3 camera has two near-infrared grisms, G102 and G141, covering 0.8-1.6 microns, making it perfect the perfect laboratory for predicting what these future missions will find. We present results from the WFC3 Infrared Spectroscopic Parallels (WISP) program, which has been taking deep WFC3 observations using both grisms at random locations across the sky in parallel with primary COS observations. The WISP survey presently consists of more than 150 fields, covering 700 square arcminutes, reaching fluxes of 5 x 10-17 ergs/s/cm2. We will present completeness corrected number counts, luminosity functions, and predicted counts for the proposed future missions. We will also discuss the issue of line identification of the emission lines, particularly H-alpha and [OIII]5007 which often have similar fluxes and equivalent widths.

  4. Analysis of Forensic Casework Utilizing Infrared Spectroscopic Imaging.

    PubMed

    Lanzarotta, Adam

    2016-01-01

    A search of the current scientific literature yields a limited number of studies that describe the use of Fourier transform infrared (FT-IR) spectroscopic imaging for the analysis of forensic casework, which is likely due to the fact that these instruments are fairly new commodities to the field of analytical chemistry and are therefore not yet commonplace in forensic laboratories. This report describes recent forensic case studies that have used the technique for determining the composition of a wide variety of multi-component sample types, including animal tissue sections for toxic inclusions, drugs/dietary supplements, an antibiotic with an active pharmaceutical ingredient (API) present as several different salt forms, an adulterated bulk API, unknown trace powders for illicit drugs and an ophthalmic solution suspected of being adulterated with bleach.

  5. Infrared and Raman spectroscopic features of plant cuticles: a review

    PubMed Central

    Heredia-Guerrero, José A.; Benítez, José J.; Domínguez, Eva; Bayer, Ilker S.; Cingolani, Roberto; Athanassiou, Athanassia; Heredia, Antonio

    2014-01-01

    The cuticle is one of the most important plant barriers. It is an external and continuous lipid membrane that covers the surface of epidermal cells and whose main function is to prevent the massive loss of water. The spectroscopic characterization of the plant cuticle and its components (cutin, cutan, waxes, polysaccharides and phenolics) by infrared and Raman spectroscopies has provided significant advances in the knowledge of the functional groups present in the cuticular matrix and on their structural role, interaction and macromolecular arrangement. Additionally, these spectroscopies have been used in the study of cuticle interaction with exogenous molecules, degradation, distribution of components within the cuticle matrix, changes during growth and development and characterization of fossil plants. PMID:25009549

  6. Analysis of Forensic Casework Utilizing Infrared Spectroscopic Imaging †

    PubMed Central

    Lanzarotta, Adam

    2016-01-01

    A search of the current scientific literature yields a limited number of studies that describe the use of Fourier transform infrared (FT-IR) spectroscopic imaging for the analysis of forensic casework, which is likely due to the fact that these instruments are fairly new commodities to the field of analytical chemistry and are therefore not yet commonplace in forensic laboratories. This report describes recent forensic case studies that have used the technique for determining the composition of a wide variety of multi-component sample types, including animal tissue sections for toxic inclusions, drugs/dietary supplements, an antibiotic with an active pharmaceutical ingredient (API) present as several different salt forms, an adulterated bulk API, unknown trace powders for illicit drugs and an ophthalmic solution suspected of being adulterated with bleach. PMID:26927101

  7. High Definition Infrared Spectroscopic Imaging for Lymph Node Histopathology

    PubMed Central

    Leslie, L. Suzanne; Wrobel, Tomasz P.; Mayerich, David; Bindra, Snehal; Emmadi, Rajyasree; Bhargava, Rohit

    2015-01-01

    Chemical imaging is a rapidly emerging field in which molecular information within samples can be used to predict biological function and recognize disease without the use of stains or manual identification. In Fourier transform infrared (FT-IR) spectroscopic imaging, molecular absorption contrast provides a large signal relative to noise. Due to the long mid-IR wavelengths and sub-optimal instrument design, however, pixel sizes have historically been much larger than cells. This limits both the accuracy of the technique in identifying small regions, as well as the ability to visualize single cells. Here we obtain data with micron-sized sampling using a tabletop FT-IR instrument, and demonstrate that the high-definition (HD) data lead to accurate identification of multiple cells in lymph nodes that was not previously possible. Highly accurate recognition of eight distinct classes - naïve and memory B cells, T cells, erythrocytes, connective tissue, fibrovascular network, smooth muscle, and light and dark zone activated B cells was achieved in healthy, reactive, and malignant lymph node biopsies using a random forest classifier. The results demonstrate that cells currently identifiable only through immunohistochemical stains and cumbersome manual recognition of optical microscopy images can now be distinguished to a similar level through a single IR spectroscopic image from a lymph node biopsy. PMID:26039216

  8. The molecular structure of chloritoid: a mid-infrared and near-infrared spectroscopic study.

    PubMed

    Li, Kuo; Liu, Qinfu; Cheng, Hongfei; Deng, Yutao; Frost, Ray L

    2015-06-15

    The mineral chloritoid collected from the argillite in the bottom of Yaopo Formation of Western Beijing was characterized by mid-infrared (MIR) and near-infrared (NIR) spectroscopy. The MIR spectra showed all fundamental vibrations including the hydroxyl units, basic aluminosilicate framework and the influence of iron on the chloritoid structure. The NIR spectrum of the chloritoid showed combination (ν+δ)OH bands with the fundamental stretching (ν) and bending (δ) vibrations. Based on the chemical component data and the analysis result from the MIR and NIR spectra, the crystal structure of chloritoid from western hills of Beijing, China, can be illustrated. Therefore, the application of the technique across the entire infrared region is expected to become more routine and extend its usefulness, and the reproducibility of measurement and richness of qualitative information should be simultaneously considered for proper selection of a spectroscopic method for the unit cell structural analysis.

  9. Time-resolved infrared spectroscopic techniques as applied to channelrhodopsin

    PubMed Central

    Ritter, Eglof; Puskar, Ljiljana; Bartl, Franz J.; Aziz, Emad F.; Hegemann, Peter; Schade, Ulrich

    2015-01-01

    Among optogenetic tools, channelrhodopsins, the light gated ion channels of the plasma membrane from green algae, play the most important role. Properties like channel selectivity, timing parameters or color can be influenced by the exchange of selected amino acids. Although widely used, in the field of neurosciences for example, there is still little known about their photocycles and the mechanism of ion channel gating and conductance. One of the preferred methods for these studies is infrared spectroscopy since it allows observation of proteins and their function at a molecular level and in near-native environment. The absorption of a photon in channelrhodopsin leads to retinal isomerization within femtoseconds, the conductive states are reached in the microsecond time scale and the return into the fully dark-adapted state may take more than minutes. To be able to cover all these time regimes, a range of different spectroscopical approaches are necessary. This mini-review focuses on time-resolved applications of the infrared technique to study channelrhodopsins and other light triggered proteins. We will discuss the approaches with respect to their suitability to the investigation of channelrhodopsin and related proteins. PMID:26217670

  10. Temperature-dependent dielectric functions and interband critical points of relaxor lead hafnate-modified PbSc1/2Ta1/2O3 ferroelectric ceramics by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Duan, Z. H.; Hu, Z. G.; Jiang, K.; Li, Y. W.; Wang, G. S.; Dong, X. L.; Chu, J. H.

    2013-04-01

    The electronic band structures and dielectric functions of (1-x)PbSc1/2Ta1/2O3-xPbHfO3 ceramics with different composition have been investigated by variable-temperature spectroscopic ellipsometry. Using the standard critical-point (SCP) model, three typical interband transitions can be observed from the second derivative of dielectric functions. The CP transitions, which are sensitive to B-site order degree, show a redshift trend with the temperature due to the electron-phonon interactions and lattice thermal expansion. The linear temperature coefficients are varied with oxygen vacancy, B-atom (Sc, Ta, Hf) arrangement, and Pb-O bonds owing to addition of PbHfO3.

  11. Raman and ellipsometry spectroscopic analysis of graphene films grown directly on Si substrate via CVD technique for estimating the graphene atomic planes number

    NASA Astrophysics Data System (ADS)

    Al-Hazmi, F. S.; Beall, Gary W.; Al-Ghamdi, A. A.; Alshahrie, Ahmed; Shokr, F. S.; Mahmoud, Waleed E.

    2016-08-01

    Two reliable approaches for estimating the number of atomic planes of graphene films grown on Si substrate were demonstrated by Raman and ellipsometry spectroscopies. The first approach depends on the measurement of the ratio of the integrated Raman scattering intensity of the graphene G band to the optical phonon band of Si substrate (IG/ISi). The second approach belongs to ellipsometry measurement of the ratio of the amplitude of the reflected polarized light from the surface of the graphene films to the amplitude of reflected polarized light from the surface of the Si substrate (ΨG/ΨSi). These two approaches could efficiently recognize the number of atomic planes in the graphene films (1 ≤ n ≤ 10). The results were compared with atomic force microscopy (AFM) measurement and showed a linear regression with slope of 0.36 ± 0.01 nm/graphene layer. The Two approaches will open a new avenue to efficiently count the number of graphene layers during the preparation process.

  12. Mass Assembly In The WFC3 Infrared Spectroscopic Parallels Survey

    NASA Astrophysics Data System (ADS)

    Colbert, James; Teplitz, Harry; Scarlata, Claudia; Siana, Brian; Malkan, Matt; McCarthy, Patrick; Henry, Alaina; Atek, Hakim; Fosbury, Robert; Ross, Nathanial; Hathi, Nimish; Bridge, Carrie; Bunker, Andrew; Dressler, Alan; Shim, Hyunjin; Bedregal, Alejandro; Dominguez, Alberto; Rafelski, Marc; Masters, Dan; Martin, Crystal

    2013-10-01

    The WFC3 Infrared Spectroscopic Parallel (WISP) Survey uses over 1300 HST orbits to study galaxy evolution over a majority of cosmic history. Its slitless grism spectroscopy over a wide, continuous spectral range (0.8-1.7 micron) provides an unbiased selection of thousands of emission line galaxies over 0.5 < z < 2.5. Hundreds of these galaxies are detected in multiple emission lines, allowing for important diagnostics of metallicity and dust extinction. We propose deep 3.6 micron imaging (5 sigma, 0.9 micro-Jy) of 40 of the deepest WISP fields observed with the combination of G102+G141 grisms, in order to detect emission-line galaxies down to 0.1 L*. Combined with our HST optical and near-IR photometry, these IRAC data will be critical to determining accurate stellar masses for both passive and active galaxies in our survey. We will determine the evolution of the faint end slope of the stellar mass function and the mass-metallicity relation down to low-mass galaxies, including measurement of a possible mass-metallicity-SFR fundamental plane. The addition of the IRAC photometry will also provide much stronger constraints on dust extinction and star formation history, especially when combined with information available from the emission lines themselves.

  13. The Garfield and Uley nontronites--an infrared spectroscopic comparison.

    PubMed

    Frost, Ray L; Kloprogge, J Theo; Ding, Zhe

    2002-07-01

    FTIR and Infrared emission spectroscopy (IES) has been used to characterise the Uley (Australian) and Garfield nontronites. These clay minerals are characterised by a strong emission band at 3570 cm(-1) attributed to the FeFeOH unit. Dehydroxylation is followed by the loss of intensity of this band as a function of temperature. Dehydroxylation is also followed by the loss of intensity of the FeFeOH deformation vibration at 843 cm(-1). IES shows that the dehydroxylation occurs as a continuous process in comparison to DTA/TGA studies where the dehydroxylation occurs abruptly at 425 degrees C. Water in these high iron bearing smectites have been observed through the stretching mode at 3430 cm(-1) and the bending mode at 1630 cm(-1). Different types of water are identified in the nontronite structure by the analysis of the band profile in the 1590-1680 cm(-1) region. Low frequency vibrations show that the Uley green nontronite is similar to the Garfield nontronite. The brown Uley nontronite is closer to the Hohen-Hagen nontronite. The Uley nontronites may, therefore, be used spectroscopically to replace other nontronites as a reference clay mineral. PMID:12164487

  14. THE WFC3 INFRARED SPECTROSCOPIC PARALLEL (WISP) SURVEY

    SciTech Connect

    Atek, H.; Scarlata, C.; Colbert, J. W.; Shim, H.; Malkan, M.; Ross, N. R.; McCarthy, P.; Dressler, A.; Teplitz, H. I.; Siana, B.; Bridge, C.; Henry, A.; Martin, C.; Bunker, A. J.; Fosbury, R. A. E.

    2010-11-01

    We present the WFC3 Infrared Spectroscopic Parallel (WISP) Survey. WISP is obtaining slitless, near-infrared grism spectroscopy of {approx}90 independent, high-latitude fields by observing in the pure-parallel mode with the Wide Field Camera Three on the Hubble Space Telescope for a total of {approx}250 orbits. Spectra are obtained with the G{sub 102} ({lambda} = 0.8-1.17 {mu}m, R {approx}210) and G{sub 141} grisms ({lambda} = 1.11-1.67 {mu}m, R {approx}130), together with direct imaging in the J and H bands (F110W and F140W, respectively). In the present paper, we present the first results from 19 WISP fields, covering approximately 63 arcmin{sup 2}. For typical exposure times ({approx}6400 s in G{sub 102} and {approx}2700 s in G{sub 141}), we reach 5{sigma} detection limits for emission lines of f {approx} 5 x 10{sup -17} erg s{sup -1} cm{sup -2} for compact objects. Typical direct imaging 5{sigma} limits are 26.3 and 26.1 mag. (AB) in F110W and F140W, respectively. Restricting ourselves to the lines measured with the highest confidence, we present a list of 328 emission lines, in 229 objects, in a redshift range 0.3 < z < 3. The single-line emitters are likely to be a mix of H{alpha} and [O III]5007,4959 A, with H{alpha} predominating. The overall surface density of high-confidence emission-line objects in our sample is approximately 4 per arcmin{sup 2}. These first fields show high equivalent width sources, active galactic nucleus, and post-starburst galaxies. The median observed star formation rate (SFR) of our H{alpha}-selected sample is 4 M{sub sun} yr{sup -1}. At intermediate redshifts, we detect emission lines in galaxies as faint as H{sub 140} {approx} 25, or M{sub R} < -19, and are sensitive to SFRs down to less than 1 M{sub sun} yr{sup -1}. The slitless grisms on WFC3 provide a unique opportunity to study the spectral properties of galaxies much fainter than L* at the peak of the galaxy assembly epoch.

  15. The Cassini mission: Infrared and microwave spectroscopic measurements

    NASA Technical Reports Server (NTRS)

    Kunde, V. G.

    1989-01-01

    The Cassini Orbiter and Titan Probe model payloads include a number of infrared and microwave instruments. This document describes: (1) the fundamental scientific objectives for Saturn and Titan which can be addressed by infrared and microwave instrumentation, (2) the instrument requirements and the accompanying instruments, and (3) the synergism resulting from the comprehensive coverage of the total infrared and microwave spectrum by the complement of individual instruments. The baseline consists of four instruments on the orbiter and two on the Titan probe. The orbiter infrared instruments are: (1) a microwave spectrometer and radiometer; (2) a far to mid-infrared spectrometer; (3) a pressure modulation gas correlation spectrometer, and (4) a near-infrared grating spectrometer. The two Titan probe infrared instruments are: (1) a near-infrared instrument, and (2) a tunable diode laser infrared absorption spectrometer and nephelometer.

  16. Near infrared spectroscopic imaging assessment of cartilage composition: Validation with mid infrared imaging spectroscopy.

    PubMed

    Palukuru, Uday P; Hanifi, Arash; McGoverin, Cushla M; Devlin, Sean; Lelkes, Peter I; Pleshko, Nancy

    2016-07-01

    Disease or injury to articular cartilage results in loss of extracellular matrix components which can lead to the development of osteoarthritis (OA). To better understand the process of disease development, there is a need for evaluation of changes in cartilage composition without the requirement of extensive sample preparation. Near infrared (NIR) spectroscopy is a chemical investigative technique based on molecular vibrations that is increasingly used as an assessment tool for studying cartilage composition. However, the assignment of specific molecular vibrations to absorbance bands in the NIR spectrum of cartilage, which arise from overtones and combinations of primary absorbances in the mid infrared (MIR) spectral region, has been challenging. In contrast, MIR spectroscopic assessment of cartilage is well-established, with many studies validating the assignment of specific bands present in MIR spectra to specific molecular vibrations. In the current study, NIR imaging spectroscopic data were obtained for compositional analysis of tissues that served as an in vitro model of OA. MIR spectroscopic data obtained from the identical tissue regions were used as the gold-standard for collagen and proteoglycan (PG) content. MIR spectroscopy in transmittance mode typically requires a much shorter pathlength through the sample (≤10 microns thick) compared to NIR spectroscopy (millimeters). Thus, this study first addressed the linearity of small absorbance bands in the MIR region with increasing tissue thickness, suitable for obtaining a signal in both the MIR and NIR regions. It was found that the linearity of specific, small MIR absorbance bands attributable to the collagen and PG components of cartilage (at 1336 and 856 cm(-1), respectively) are maintained through a thickness of 60 μm, which was also suitable for NIR data collection. MIR and NIR spectral data were then collected from 60 μm thick samples of cartilage degraded with chondroitinase ABC as a model

  17. Near infrared spectroscopic imaging assessment of cartilage composition: Validation with mid infrared imaging spectroscopy.

    PubMed

    Palukuru, Uday P; Hanifi, Arash; McGoverin, Cushla M; Devlin, Sean; Lelkes, Peter I; Pleshko, Nancy

    2016-07-01

    Disease or injury to articular cartilage results in loss of extracellular matrix components which can lead to the development of osteoarthritis (OA). To better understand the process of disease development, there is a need for evaluation of changes in cartilage composition without the requirement of extensive sample preparation. Near infrared (NIR) spectroscopy is a chemical investigative technique based on molecular vibrations that is increasingly used as an assessment tool for studying cartilage composition. However, the assignment of specific molecular vibrations to absorbance bands in the NIR spectrum of cartilage, which arise from overtones and combinations of primary absorbances in the mid infrared (MIR) spectral region, has been challenging. In contrast, MIR spectroscopic assessment of cartilage is well-established, with many studies validating the assignment of specific bands present in MIR spectra to specific molecular vibrations. In the current study, NIR imaging spectroscopic data were obtained for compositional analysis of tissues that served as an in vitro model of OA. MIR spectroscopic data obtained from the identical tissue regions were used as the gold-standard for collagen and proteoglycan (PG) content. MIR spectroscopy in transmittance mode typically requires a much shorter pathlength through the sample (≤10 microns thick) compared to NIR spectroscopy (millimeters). Thus, this study first addressed the linearity of small absorbance bands in the MIR region with increasing tissue thickness, suitable for obtaining a signal in both the MIR and NIR regions. It was found that the linearity of specific, small MIR absorbance bands attributable to the collagen and PG components of cartilage (at 1336 and 856 cm(-1), respectively) are maintained through a thickness of 60 μm, which was also suitable for NIR data collection. MIR and NIR spectral data were then collected from 60 μm thick samples of cartilage degraded with chondroitinase ABC as a model

  18. Generalized Ellipsometry in Unusual Configurations

    SciTech Connect

    Jellison Jr, Gerald Earle; Holcomb, David Eugene; Hunn, John D; Rouleau, Christopher M; Wright, Gomez W

    2006-01-01

    Most ellipsometry experiments are performed by shining polarized light onto a sample at a large angle of incidence, and the results are interpreted in terms of thin film thicknesses and isotropic optical functions of the film or substrate. However, it is possible to alter the geometrical arrangement, either by observing the sample in transmission or at normal-incidence reflection. In both cases, the experiment is fundamentally the same, but the interpretation of the results is considerably different. Both configurations can be used in conjunction with microscope optics, allowing for images to be made of the sample. The results of three examples of these different configurations using the two-modulator generalized ellipsometer (2-MGE) are reported: (1) spectroscopic birefringence measurements of ZnO, (2) electric field-induced birefringence (Pockels effect) in GaAs, and (3) normal-incidence reflection anisotropy of highly oriented pyrolytic graphite (HOPG).

  19. Simulating Future Near-Infrared Grism Spectroscopy Using The WFC3 Infrared Spectroscopic Parallels (WISP)

    NASA Astrophysics Data System (ADS)

    Colbert, James W.; Teplitz, H. I.; Atek, H.; Bunker, A. J.; Rafelski, M.; Scarlata, C.; Ross, N.; Malkan, M. A.; Bedregal, A.; Dominguez, A.; Dressler, A.; Henry, A. L.; Martin, C. L.; Masters, D.; McCarthy, P. J.; Siana, B. D.

    2014-01-01

    We present near-infrared emission line counts and luminosity functions from the HST WFC3 Infrared Spectroscopic Parallels (WISP) program for 29 fields observed using both the G102 and G141 grism. Using these derived emission line counts we make predictions for future space missions, like WFIRST, that will make extensive use of slitless grism spectroscopy in the near-IR over large areas of sky. The WISP survey is sensitive to fainter flux levels (3-5x10^-17 ergs/s/cm2) than the near-infrared grism missions aimed at baryonic acoustic oscillation cosmology (1-4x10^-16 ergs/s/cm2), allowing us to both investigate the fainter emission lines the large area surveys will be missing and make count predictions for the deeper grism pointings that are likely to be done over smaller areas. Cumulative number counts of 0.7infrared grism surveys will probe; our survey finds no galaxies with H-alpha/[OIII < 0.95 that have H-alpha flux greater than 3x10^-16 ergs/s/cm2. We find good agreement between our derived luminosity functions and those from narrow band H-alpha surveys, like those of HiZELS (Sobral et al. 2013) and New Halpha (Ly et. 2011). The evolution in both the H-alpha luminosity function from z=0.3-1.5 and the [OIII] luminosity function from z=0.7-2.3 is almost entirely in the L* parameter, which steadily increases with redshift over those ranges. We will also present simulations of future large area near-infrared grism spectroscopy, based on the observed distributions of emission line fluxes, galaxy sizes, redshifts, H-alpha/[OIII] ratios, and equivalent widths seen in the WISP survey.

  20. Study of CuPt-type ordering and dopant effect of In{sub 0.5}Ga{sub 0.5}P/GaAs using spectroscopic ellipsometry

    SciTech Connect

    Lee, H. |; Klein, M.V.; Olson, J.M.; Hsieh, K.C.

    1994-09-01

    The CuPt-type ordering and dopant effects of In{sub 0.5}Ga{sub 0.5}P/GaAs epitaxial layers have been studied using spectroscopic ellipsometry and transmission electron microscopy. The degree of ordering was estimated by both transmission electron diffraction and direct band edge, E{sub 0}. Conventional lineshape fitting of E{sub 1}, E{sub 1}+{Delta}{sub 1}, and E{sub 2} gaps using the second derivative of pseudo dielectric functions shows that the peak position and oscillator strength of the E{sub 1} gap are basically a function of CuPt-type ordering whereas their broadening and phase depend mainly on carrier concentration. The decrease of E{sub 1} gap is explained in terms of CuPt-type ordering. In contrast to the E{sub 1} gap, all the lineshape parameters of the E{sub 2} gap depend mainly on CuPt-type ordering. This difference is discussed in terms of apparent {open_quotes}CuAu-type ordering{close_quotes} or Y2 structure which was observed by transmission electron diffraction.

  1. Raman and infrared spectroscopic study of turquoise minerals.

    PubMed

    Čejka, Jiří; Sejkora, Jiří; Macek, Ivo; Malíková, Radana; Wang, Lina; Scholz, Ricardo; Xi, Yunfei; Frost, Ray L

    2015-10-01

    Raman and infrared spectra of three well-defined turquoise samples, CuAl6(PO4)4(OH)8·4H2O, from Lavender Pit, Bisbee, Cochise county, Arizona; Kouroudaiko mine, Faleme river, Senegal and Lynch Station, Virginia were studied, interpreted and compared. Observed Raman and infrared bands were assigned to the stretching and bending vibrations of phosphate tetrahedra, water molecules and hydroxyl ions. Approximate O-H⋯O hydrogen bond lengths were inferred from the Raman and infrared spectra. No Raman and infrared bands attributable to the stretching and bending vibrations of (PO3OH)(2-) units were observed. PMID:25956330

  2. Raman and infrared spectroscopic study of turquoise minerals

    NASA Astrophysics Data System (ADS)

    Čejka, Jiří; Sejkora, Jiří; Macek, Ivo; Malíková, Radana; Wang, Lina; Scholz, Ricardo; Xi, Yunfei; Frost, Ray L.

    2015-10-01

    Raman and infrared spectra of three well-defined turquoise samples, CuAl6(PO4)4(OH)8·4H2O, from Lavender Pit, Bisbee, Cochise county, Arizona; Kouroudaiko mine, Faleme river, Senegal and Lynch Station, Virginia were studied, interpreted and compared. Observed Raman and infrared bands were assigned to the stretching and bending vibrations of phosphate tetrahedra, water molecules and hydroxyl ions. Approximate O-H⋯O hydrogen bond lengths were inferred from the Raman and infrared spectra. No Raman and infrared bands attributable to the stretching and bending vibrations of (PO3OH)2- units were observed.

  3. Raman and infrared spectroscopic study of turquoise minerals.

    PubMed

    Čejka, Jiří; Sejkora, Jiří; Macek, Ivo; Malíková, Radana; Wang, Lina; Scholz, Ricardo; Xi, Yunfei; Frost, Ray L

    2015-10-01

    Raman and infrared spectra of three well-defined turquoise samples, CuAl6(PO4)4(OH)8·4H2O, from Lavender Pit, Bisbee, Cochise county, Arizona; Kouroudaiko mine, Faleme river, Senegal and Lynch Station, Virginia were studied, interpreted and compared. Observed Raman and infrared bands were assigned to the stretching and bending vibrations of phosphate tetrahedra, water molecules and hydroxyl ions. Approximate O-H⋯O hydrogen bond lengths were inferred from the Raman and infrared spectra. No Raman and infrared bands attributable to the stretching and bending vibrations of (PO3OH)(2-) units were observed.

  4. Optical properties of amorphous and crystalline Sb-doped SnO2 thin films studied with spectroscopic ellipsometry: Optical gap energy and effective mass

    NASA Astrophysics Data System (ADS)

    So, Hyeon Seob; Park, Jun-Woo; Jung, Dae Ho; Ko, Kun Hee; Lee, Hosun

    2015-08-01

    We investigated the optical properties of amorphous and crystalline antimony (Sb)-doped tin dioxide (SnO2) thin films grown using the co-sputtering deposition method at room temperature. We used undoped and Sb-doped (8 wt. %) SnO2 targets. Varying the relative power ratio of the two targets, we controlled the Sb-composition of the SnO2:Sb thin films up to 2.3 at. % of Sb contents. Through annealing, the as-grown amorphous SnO2:Sb thin films were transformed to crystalline thin films. Dielectric functions were obtained from the measured ellipsometry angles, Ψ and Δ, using the Drude and parametric optical constant models. We determined the absorption coefficients and optical gap energies of the SnO2:Sb thin films from the dielectric functions. We found increasing optical gap energy with increasing Sb composition. Increases in the Drude tail amplitudes, a signature of free carrier concentrations, were found in annealed, crystalline thin films with increasing Sb composition. The increase in the optical gap energy with increasing Sb composition was mainly attributed to the Burstein-Moss effect. Using Hall effect measurements, we obtained Hall carrier concentrations (NHall) and electron Hall mobilities (μHall). The carrier concentrations and mobilities increased from 2.6 × 1019 cm-3 and 1.0 cm2/(V s) to 2.0 × 1020 cm-1 and 7.2 cm2/(V s), respectively, with increasing Sb contents. This result suggests that the nominally undoped SnO2 films are unintentionally n-type doped. Assuming that the NHall and optical carrier concentrations (Nopt) were the same, we obtained the effective masses of the SnO2:Sb thin films with increasing Sb compositions. The effective masses of the SnO2:Sb thin films increased from 0.245 m0 to 0.4 m0 with increasing Sb doping contents, and the nonparabolicity of the conduction band was estimated. We discussed the relation between the optical (μopt) and Hall (μHall) mobilities as a function of Sb contents and grain sizes.

  5. Optical properties of amorphous and crystalline Sb-doped SnO{sub 2} thin films studied with spectroscopic ellipsometry: Optical gap energy and effective mass

    SciTech Connect

    So, Hyeon Seob; Park, Jun-Woo; Jung, Dae Ho; Ko, Kun Hee; Lee, Hosun

    2015-08-28

    We investigated the optical properties of amorphous and crystalline antimony (Sb)-doped tin dioxide (SnO{sub 2}) thin films grown using the co-sputtering deposition method at room temperature. We used undoped and Sb-doped (8 wt. %) SnO{sub 2} targets. Varying the relative power ratio of the two targets, we controlled the Sb-composition of the SnO{sub 2}:Sb thin films up to 2.3 at. % of Sb contents. Through annealing, the as-grown amorphous SnO{sub 2}:Sb thin films were transformed to crystalline thin films. Dielectric functions were obtained from the measured ellipsometry angles, Ψ and Δ, using the Drude and parametric optical constant models. We determined the absorption coefficients and optical gap energies of the SnO{sub 2}:Sb thin films from the dielectric functions. We found increasing optical gap energy with increasing Sb composition. Increases in the Drude tail amplitudes, a signature of free carrier concentrations, were found in annealed, crystalline thin films with increasing Sb composition. The increase in the optical gap energy with increasing Sb composition was mainly attributed to the Burstein-Moss effect. Using Hall effect measurements, we obtained Hall carrier concentrations (N{sub Hall}) and electron Hall mobilities (μ{sub Hall}). The carrier concentrations and mobilities increased from 2.6 × 10{sup 19 }cm{sup −3} and 1.0 cm{sup 2}/(V s) to 2.0 × 10{sup 20 }cm{sup −1} and 7.2 cm{sup 2}/(V s), respectively, with increasing Sb contents. This result suggests that the nominally undoped SnO{sub 2} films are unintentionally n-type doped. Assuming that the N{sub Hall} and optical carrier concentrations (N{sub opt}) were the same, we obtained the effective masses of the SnO{sub 2}:Sb thin films with increasing Sb compositions. The effective masses of the SnO{sub 2}:Sb thin films increased from 0.245 m{sub 0} to 0.4 m{sub 0} with increasing Sb doping contents, and the nonparabolicity of the conduction band was estimated. We

  6. Near-infrared spectroscopic tissue imaging for medical applications

    DOEpatents

    Demos, Stavros; Staggs, Michael C.

    2006-12-12

    Near infrared imaging using elastic light scattering and tissue autofluorescence are explored for medical applications. The approach involves imaging using cross-polarized elastic light scattering and tissue autofluorescence in the Near Infra-Red (NIR) coupled with image processing and inter-image operations to differentiate human tissue components.

  7. Near-infrared spectroscopic tissue imaging for medical applications

    DOEpatents

    Demos; Stavros , Staggs; Michael C.

    2006-03-21

    Near infrared imaging using elastic light scattering and tissue autofluorescence are explored for medical applications. The approach involves imaging using cross-polarized elastic light scattering and tissue autofluorescence in the Near Infra-Red (NIR) coupled with image processing and inter-image operations to differentiate human tissue components.

  8. The optical constants of plutonium metal between .7 and 4.3 eV measured by spectroscopic ellipsometry using a double-windowed experimental chamber.

    SciTech Connect

    Mookerji, B; Stratman, M; Wall, M; Siekhaus, W

    2006-07-06

    A double-windowed vacuum-tight experimental chamber was developed, and calibrated on the spectroscopic ellipsometer over the energy range from .7 to 4.5 eV using a silicon wafer with approximately 25 nm oxide thickness to remove the multiple-window effects from measurements. The ellipsometric measurements were done such that incident and exit beam were at 65 degree from surface normal. The plutonium sample (3 mm diameter, .1 mm thick) was electro-polished and mounted into the sample chamber in a glove box having a nitrogen atmosphere with less than 100ppm moisture and oxygen content. The index of refraction n and the extinction coefficient k decrease from 3.7 to 1 and 5.5 to 1.1 respectively as the photon energy increases from .7 to 4.3 eV.

  9. Monitoring the composition of the Cd{sub 1-} {sub z}Zn{sub z}Te heteroepitaxial layers by spectroscopic ellipsometry

    SciTech Connect

    Yakushev, M. V. Shvets, V. A.; Azarov, I. A.; Rykhlytski, S. V.; Sidorov, Yu. G.; Spesivtsev, E. V.; Shamirzaev, T. S.

    2010-01-15

    A hardware-software complex based on a spectroscopic ellipsometer integrated into a molecular beam epitaxy installation and destined to monitor the composition of the Cd{sub 1} {sub -z}Zn{sub z}Te alloy at small values of z is described. Methodical features of determination of the composition of growing layers by the spectra of ellipsometric parameters are considered. The procedure of determination of the composition by the absorption edge that allows measuring this parameter accurate to 1.2% is developed. Problems are considered the solutions of which will allow one to increase the resolution by the composition. In particular, maintaining a stable temperature during growth is required for this purpose.

  10. Mid-infrared vibrational spectroscopic characterization of 5,6-dihydroxyindole and eumelanin derived from it

    NASA Astrophysics Data System (ADS)

    Hyogo, Ryosuke; Nakamura, Atsushi; Okuda, Hidekazu; Wakamatsu, Kazumasa; Ito, Shosuke; Sota, Takayuki

    2011-12-01

    Mid-infrared vibrational spectroscopic study has been made on 5,6-dihydroxyindole (DHI) and DHI-derived eumelanin. It has been revealed for DHI monomer that measured infrared absorption spectrum is well reproduced by that predicted from ab initio calculations. Thus, vibrational modes of DHI monomer causing dominant absorption bands have been successfully assigned. It has been also reconfirmed that DHI-derived eumelanin includes indolequinone and/or quinone methide units in addition to DHI units.

  11. Fourier transform infrared spectroscopic analysis of cell differentiation

    NASA Astrophysics Data System (ADS)

    Ishii, Katsunori; Kimura, Akinori; Kushibiki, Toshihiro; Awazu, Kunio

    2007-02-01

    Stem cells and its differentiations have got a lot of attentions in regenerative medicine. The process of differentiations, the formation of tissues, has become better understood by the study using a lot of cell types progressively. These studies of cells and tissue dynamics at molecular levels are carried out through various approaches like histochemical methods, application of molecular biology and immunology. However, in case of using regenerative sources (cells, tissues and biomaterials etc.) clinically, they are measured and quality-controlled by non-invasive methods from the view point of safety. Recently, the use of Fourier Transform Infrared spectroscopy (FT-IR) has been used to monitor biochemical changes in cells, and has gained considerable importance. The objective of this study is to establish the infrared spectroscopy of cell differentiation as a quality control of cell sources for regenerative medicine. In the present study, as a basic study, we examined the adipose differentiation kinetics of preadipocyte (3T3-L1) and the osteoblast differentiation kinetics of bone marrow mesenchymal stem cells (Kusa-A1) to analyze the infrared absorption spectra. As a result, we achieved to analyze the adipose differentiation kinetics using the infrared absorption peak at 1739 cm-1 derived from ester bonds of triglyceride and osteoblast differentiation kinetics using the infrared absorption peak at 1030 cm-1 derived from phosphate groups of calcium phosphate.

  12. Infrared Spectroscopic Investigation on CH Bond Acidity in Cationic Alkanes

    NASA Astrophysics Data System (ADS)

    Matsuda, Yoshiyuki; Xie, Min; Fujii, Asuka

    2016-06-01

    We have demonstrated large enhancements of CH bond acidities in alcohol, ether, and amine cations through infrared predissociation spectroscopy based on the vacuum ultraviolet photoionization detection. In this study, we investigate for the cationic alkanes (pentane, hexane, and heptane) with different alkyl chain lengths. The σ electrons are ejected in the ionization of alkanes, while nonbonding electrons are ejected in ionization of alcohols, ethers, and amines. Nevertheless, the acidity enhancements of CH in these cationic alkanes have also been demonstrated by infrared spectroscopy. The correlations of their CH bond acidities with the alkyl chain lengths as well as the mechanisms of their acidity enhancements will be discussed by comparison of infrared spectra and theoretical calculations.

  13. Infrared Spectroscopic Study for the Hydrated Clusters of Pentane Cation

    NASA Astrophysics Data System (ADS)

    Endo, Tomoya; Matsuda, Yoshiyuki; Fujii, Asuka

    2016-06-01

    We performed infrared predissociation spectroscopy of size-selected pentane-water cluster cations, [pentane-(H2O)n]+, n=1-3, generated through the vacuum-ultraviolet photoionization. In the infrared spectra of the di- and tri-hydrated clusters, there appear broad features which spread to the lower frequency region from 2800 cm-1. These broad features are assigned to vibrations of a proton, which is transferred from CH of the pentane cation to the water molecules. These results indicate that the pentane cation has high proton donor ability. We will discuss these results based on theoretical conputations.

  14. Mid-infrared laser-spectroscopic sensing of chemical species

    PubMed Central

    Sigrist, Markus W.

    2014-01-01

    This letter reports on mid-infrared laser-based detection and analysis of chemical species. Emphasis is put on broadly tunable laser sources and sensitive detection schemes. Selected examples from our lab illustrate the performance and potential of such systems in various areas including environmental and medical sensing. PMID:26257952

  15. Palm-size wide-field Fourier spectroscopic imager with uncooled infrared microbolometer arrays for smartphone

    NASA Astrophysics Data System (ADS)

    Kawashima, Natsumi; Suzuki, Yo; Qi, Wei; Hosono, Satsuki; Saito, Tsubasa; Ogawa, Satoshi; Sato, Shun; Fujiwara, Masaru; Nishiyama, Akira; Wada, Kenji; Tanaka, Naotaka; Ishimaru, Ichiro

    2015-03-01

    We proposed the imaging-type 2-dimensional Fourier spectroscopy that is a near-common-path interferometer with strong robustness against mechanical vibrations. We introduced the miniature uncooled infrared microbolometer arrays for smartphone (e.g. product name: FILR ONE price: around 400USD). And we constructed the phase-shifter with the piezo impact drive mechanism (maker: Technohands.co.Ltd., stroke: 4.5mm, resolution: 0.01μm, size: 20mm, price: around 800USD). Thus, we realized the palm-size mid-infrared spectroscopic imager [size: L56mm×W69mm×H43mm weight: 500g]. And by using wide-angle lens as objective lens, the proposed method can obtain the wide-field 2- dimensional middle-infrared (wavelength: 7.5-13.5[μm]) spectroscopic imaging of radiation lights emitted from human bodies itself

  16. A Near-infrared Spectroscopic Survey of Class I Protostars

    NASA Astrophysics Data System (ADS)

    Connelley, Michael S.; Greene, Thomas P.

    2010-11-01

    We present the results of a near-IR spectroscopic survey of 110 Class I protostars observed from 0.80 μm to 2.43 μm at a spectroscopic resolution of R = 1200. This survey is unique in its selection of targets from the whole sky, its sample size, wavelength coverage, depth, and sample selection. We find that Class I objects exhibit a wide range of lines and the continuum spectroscopic features. Eighty-five percent of Class I protostars exhibit features indicative of mass accretion, and we found that the veiling excess, CO emission, and Br γ emission are closely related. We modeled the spectra to estimate the veiling excess (rk ) and extinction to each target. We also used near-IR colors and emission line ratios, when available, to also estimate extinction. In the course of this survey, we observed the spectra of 10 FU Orionis-like objects, including 2 new ones, as well as 3 Herbig Ae-type stars among our Class I young stellar objects. We used photospheric absorption lines, when available, to estimate the spectral type of each target. Although most targets are late-type stars, there are several A- and F-type stars in our sample. Notably, we found no A or F class stars in the Taurus-Auriga or Perseus star-forming regions. There are several cases where the observed CO and/or water absorption bands are deeper than expected from the photospheric spectral type. We find a correlation between the appearance of the reflection nebula, which traces the distribution of material on very large scales, and the near-IR spectrum, which probes smaller scales. All of the FU Orionis-like objects are associated with reflection nebulae. The spectra of the components of spatially resolved protostellar binaries tend to be very similar. In particular both components tend to have similar veiling and H2 emission, inconsistent with random selection from the sample as a whole. There is a strong correlation between [Fe II] and H2 emission, supporting previous results showing that H2 emission

  17. [Infrared spectroscopic analysis of Guilin watermelon frost products].

    PubMed

    Huang, Dong-lan; Chen, Xiao-kang; Xu, Yong-qun; Sun, Su-qin; Zhou, Qun; Lu, Wen-guan

    2012-08-01

    The objective of the present study is to analyze different products of Guilin watermelon frost by Fourier transform infrared spectroscopy (FTIR), second derivative infrared spectroscopy and two-dimensional correlation spectroscopy (2D-IR) under thermal perturbation. The structural information of the samples indicates that samples from the same factory but of different brands had some dissimilarities in the IR spectra, and the type and content of accessories of them were different compared with conventional IR spectra of samples, peaks at 638 and 616 cm(-1) all arise from anhydrous sodium sulfate in watermelon frost spray and watermelon frost capsule; the characteristic absorption peaks of the sucrose, dextrin or other accessories can be seen clearly in the spectra of watermelon frost throat-clearing buccal tablets, watermelon frost throat tablets and watermelon frost lozenge. And the IR spectra of watermelon frost lozenge is very similar to the IR spectra of sucrose, so it can be easily proved that the content of sucrose in watermelon frost lozenge is high. In the 2D-IR correlation spectra, the samples presented the differences in the position, number and relative intensity of autopeaks and correlation peak clusters. Consequently, the macroscopical fingerprint characters of FTIR, second derivative infrared spectra and 2D-IR spectra can not only provide the information about main chemical constituents in medical materials, but also analyze and identify the type and content of accessories in Guilin watermelon frost. In conclusion, the multi-steps IR macro-fingerprint method is rapid, effective, visual and accurate for pharmaceutical research. PMID:23156761

  18. [Infrared spectroscopic analysis of Guilin watermelon frost products].

    PubMed

    Huang, Dong-lan; Chen, Xiao-kang; Xu, Yong-qun; Sun, Su-qin; Zhou, Qun; Lu, Wen-guan

    2012-08-01

    The objective of the present study is to analyze different products of Guilin watermelon frost by Fourier transform infrared spectroscopy (FTIR), second derivative infrared spectroscopy and two-dimensional correlation spectroscopy (2D-IR) under thermal perturbation. The structural information of the samples indicates that samples from the same factory but of different brands had some dissimilarities in the IR spectra, and the type and content of accessories of them were different compared with conventional IR spectra of samples, peaks at 638 and 616 cm(-1) all arise from anhydrous sodium sulfate in watermelon frost spray and watermelon frost capsule; the characteristic absorption peaks of the sucrose, dextrin or other accessories can be seen clearly in the spectra of watermelon frost throat-clearing buccal tablets, watermelon frost throat tablets and watermelon frost lozenge. And the IR spectra of watermelon frost lozenge is very similar to the IR spectra of sucrose, so it can be easily proved that the content of sucrose in watermelon frost lozenge is high. In the 2D-IR correlation spectra, the samples presented the differences in the position, number and relative intensity of autopeaks and correlation peak clusters. Consequently, the macroscopical fingerprint characters of FTIR, second derivative infrared spectra and 2D-IR spectra can not only provide the information about main chemical constituents in medical materials, but also analyze and identify the type and content of accessories in Guilin watermelon frost. In conclusion, the multi-steps IR macro-fingerprint method is rapid, effective, visual and accurate for pharmaceutical research.

  19. Infrared spectroscopic investigations of the compensatoin effect in ceramic materials

    SciTech Connect

    Vanina, E.A.; Kostyukov, N.S.

    1995-09-01

    The objective in this paper was to investigate by means of infrared spectroscopy samples of M-23 electrical porcelain ceramic after irradiation in a BOR-60 reactor with a neutron fluence of 6.5 x 10(exp 21)/square centimeter and isothermal annealing at 700 C and 1000 C for 10 hours. The work was performed on an IKS-29 spectrophotometer using samples in the form of a suspension in vasoline oil and pressed tablets with Potassium Bromide. The investigations were performed after the irradiated samples were allowed to stand for 7 years. It was found that partial amorphization of the quartz occurred.

  20. Infrared spectroscopic investigations of cationic ethanol, propanol, and butanol

    NASA Astrophysics Data System (ADS)

    Matsuda, Yoshiyuki; Harigaya, Hiroyuki; Xie, Min; Takahashi, Kaito; Fujii, Asuka

    2015-11-01

    Infrared spectroscopy of the alcohol cations of ethanol, propanol, and butanol was performed to investigate their structures and hyperconjugation mechanisms. In the ethanol cation, the Csbnd C bond hyperconjugates with the singly occupied molecular orbital (SOMO) at the oxygen atom, so that the Csbnd C bond weakens and the bond length elongates. Multiple hyperconjugations among SOMO, the Csbnd C bond, and the end Csbnd H bond occur in the propanol cation and enhance the acidity of the Csbnd H bond through the delocalization of its bonding σ electron. The butanol cation forms the oxonium-type structure through the proton transfer from the terminal CH bond.

  1. Infrared spectroscopic probing of dimethylamine clusters in an Ar matrix.

    PubMed

    Li, Siyang; Kjaergaard, Henrik G; Du, Lin

    2016-02-01

    Amines have many atmospheric sources and their clusters play an important role in aerosol nucleation processes. Clusters of a typical amine, dimethylamine (DMA), of different sizes were measured with matrix isolation IR (infrared) and NIR (near infrared) spectroscopy. The NIR vibrations are more separated and therefore it is easier to distinguish different sizes of clusters in this region. The DMA clusters, up to DMA tetramer, have been optimized using density functional methods, and the geometries, binding energies and thermodynamic properties of DMA clusters were obtained. The computed frequencies and intensities of NH-stretching vibrations in the DMA clusters were used to interpret the experimental spectra. We have identified the fundamental transitions of the bonded NH-stretching vibration and the first overtone transitions of the bonded and free NH-stretching vibration in the DMA clusters. Based on the changes in vibrational intensities during the annealing processes, the growth of clusters was clearly observed. The results of annealing processes indicate that DMA molecules tend to form larger clusters with lower energies under matrix temperatures, which is also supported by the calculated reaction energies of cluster formation. PMID:26969545

  2. Spitzer mid-infrared spectroscopic observations of planetary nebulae

    NASA Astrophysics Data System (ADS)

    Mata, H.; Ramos-Larios, G.; Guerrero, M. A.; Nigoche-Netro, A.; Toalá, J. A.; Fang, X.; Rubio, G.; Kemp, S. N.; Navarro, S. G.; Corral, L. J.

    2016-06-01

    We present Spitzer Space Telescope archival mid-infrared (mid-IR) spectroscopy of a sample of 11 planetary nebulae (PNe). The observations, acquired with the Spitzer Infrared Spectrograph (IRS), cover the spectral range 5.2-14.5 μm that includes the H2 0-0 S(2) to S(7) rotational emission lines. This wavelength coverage has allowed us to derive the Boltzmann distribution and calculate the H2 rotational excitation temperature (Tex). The derived excitation temperatures have consistent values ≃900 ± 70 K for different sources despite their different structural components. We also report the detection of mid-IR ionic lines of [Ar III], [S IV], and [Ne II] in most objects, and polycyclic aromatic hydrocarbon features in a few cases. The decline of the [Ar III]/[Ne II] line ratio with the stellar effective temperature can be explained either by a true neon enrichment or by high density circumstellar regions of PNe that presumably descend from higher mass progenitor stars.

  3. Infrared spectroscopic characteristics of normal and malignant colonic epithelium

    NASA Astrophysics Data System (ADS)

    Krupnik, Eduardo; Jackson, Michael; Bird, Ranjana P.; Smith, Ian C. P.; Mantsch, Henry H.

    1998-04-01

    IR spectroscopy is being widely used to study the biochemical changes associated with cancer. In particular, based upon the hypothesis that biochemical changes associated with cancer precede morphological manifestations of the disease, IR spectroscopy is being evaluated as a potential early diagnostic and prognostic tool. In the current study, IR spectroscopy was applied to the study of colon tissue from rats treated with the specific colon carcinogen azoxymethane, to determine whether tumor induction was associated with identifiable spectroscopic changes in the colon. Characteristic spectra were found for each layer of the colon. Spectra of normal-appearing mucosa and tumors form treated animals then compared to spectra of control mucosa. Differences between tumors and control mucosa were apparent, indicating changes in cellular biochemistry associated with tumor development. In particular, differences in absorptions attributed to nucleic acids were seen, indicating alterations in the structure of cellular DNA in malignant and carcinogen treated tissues. Interestingly, spectra of carcinogen treated rates exhibit characteristics intermediate between those of normal mucosa and tumors. Application of multivariate analysis allowed non-subjective classification of the spectra into three distinct classes with and accuracy of 86.7 percent. The separate classification of control and treated mucosa suggests that IR spectroscopy, when combined with the appropriate classifier, can indeed detect biochemical changes in tissue before physical manifestation of the disease process.

  4. Raman and infrared spectroscopic study of kamphaugite-(Y)

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; López, Andrés; Scholz, Ricardo

    2015-05-01

    We have studied the carbonate mineral kamphaugite-(Y)(CaY(CO3)2(OH)·H2O), a mineral which contains yttrium and specific rare earth elements. Chemical analysis shows the presence of Ca, Y and C. Back scattering SEM appears to indicate a single pure phase. The vibrational spectroscopy of kamphaugite-(Y) was obtained using a combination of Raman and infrared spectroscopy. Two distinct Raman bands observed at 1078 and 1088 cm-1 provide evidence for the non-equivalence of the carbonate anion in the kamphaugite-(Y) structure. Such a concept is supported by the number of bands assigned to the carbonate antisymmetric stretching mode. Multiple bands in the ν4 region offers further support for the non-equivalence of carbonate anions in the structure. Vibrational spectroscopy enables aspects of the structure of the mineral kamphaugite-(Y) to be assessed.

  5. Spectroscopic research on infrared emittance of coal ash deposits

    SciTech Connect

    Saljnikov, Aleksandar; Komatina, Mirko; Gojak, Milan; Vucicevic, Biljana; Goricanec, Darko; Stevanovic, Zoran

    2009-11-15

    This paper deals with thermal radiation characteristics of ash deposits on a pulverized coal combustion boiler of an electric power plant. Normal emittance spectra in the near to medium infrared (2.5-25 {mu}m) region and total normal emittances were measured on four kinds of ground ash deposits. Measurements were conducted in the 570-1460 K temperature range which is common for boiler furnaces, by both heating and cooling the ash samples, with the aim to study the effect of their thermal history. Dependence of emittance on wavelength, temperature and chemical composition was studied, too. Samples were tested for transparency (opacity) to verify the accuracy of results. It was determined that the thicknesses used for the ash powders are opaque for infrared radiation for thicknesses in the order of a millimeter. Tests have shown that spectral emittance increases with an increase of wavelength with a characteristic pattern common for all samples. Spectral normal emittance increases strongly with temperature at shorter wavelengths and remains high and unchanged at longer ones. Emittance spectra are not very sensitive to chemical composition of ashes especially beyond {lambda} {approx} 5 {mu}m. With an increase of temperature, total emittance of the powdered sample decreases to a minimum value around 1200 K. Further temperature rise induces an increase of total emittance due to sintering in the ash. On cooling, the emittance increases monotonically following the hysteresis. Quantitative directions for evaluating thermal radiation characteristics of ash deposits for the merits of the safety design of boiler furnaces were proposed. That comprises correlating the experimentally obtained emittance spectra with curves of simple analytical form, i.e., a continuous function of minimum emittance vs. wavelength. The proposed method can be extended to other specimens from the same furnace and used to determine correlations for thermal calculation of old and design of new furnaces

  6. High-definition Fourier transform infrared spectroscopic imaging of breast tissue

    NASA Astrophysics Data System (ADS)

    Leslie, L. Suzanne; Kadjacsy-Balla, Andre; Bhargava, Rohit

    2015-03-01

    Breast cancer diagnosis relies on staining serial sections of a biopsy in a process that can be time intensive and costly. Fourier transform infrared imaging (FT-IR) is a non-destructive, label-free chemical imaging technique that uses the vibrational structure of the biological molecules of the sample to provide contrast for images at any absorption peak in the mid-infrared. The full potential of spectroscopic imaging has been limited by the spatial resolution provided by most commercial instruments. By increasing the magnification and numerical aperture of the microscope, image pixel sizes on the order of 1.1 micron can be achieved, allowing HD FT-IR spectroscopic imaging to provide high quality images that could aid in histopathology, diagnosis, and studies of breast cancer progression.

  7. Interband electronic transitions and phase transformation of multiferroic Bi{sub 1−x}La{sub x}Fe{sub 1−y}Ti{sub y}O{sub 3} ceramics revealed by temperature-dependent spectroscopic ellipsometry

    SciTech Connect

    Xu, L. P.; Jiang, P. P.; Duan, Z. H.; Hu, Z. G. Zhu, Z. Q.; Chu, J. H.; Zhang, L. L.; Yu, J.

    2013-12-21

    Optical properties and phase transition of Bi{sub 1−x}La{sub x}Fe{sub 1−y}Ti{sub y}O{sub 3} (BLFTO) ceramics with different composition (0.02 ≤ x ≤ 0.10, 0.01 ≤ y ≤ 0.06) have been investigated by spectroscopic ellipsometry (SE) in the temperature range of −70–450 °C. The real part of the complex dielectric function ε{sub 1} increases with the temperature. Meanwhile, the imaginary part ε{sub 2} in the low-energy region decreases with the temperature and has an opposite trend in the high-energy side. Four typical interband transitions (E{sub a} ∼ 2.50 eV, E{sub b} ∼ 2.70 eV, E{sub c} ∼ 3.60 eV, and E{sub d} ∼ 4.25 eV) can be observed from the second derivative of the complex dielectric functions with aid of the standard critical point model. The critical point (CP) transition becomes broadening and shifts to a lower energy side as La and Ti compositions increase. Moreover, the CP transition energies show a red-shift trend with increasing the temperature until 320 °C, due to the lattice thermal expansion and electron-phonon interaction. The typical interband transitions and partial spectral weight present anomalies in the proximity of antiferromagnetic transition owing to the coupling between magnetic and ferroelectric order parameters and spin-lattice coupling for BLFTO multiferroic materials. It was found that the Néel temperature of BLFTO ceramics decreases from 364 to 349 °C with increasing doping composition of La and Ti elements. These phenomena can be attributed to the modification of electronic structure and magnetic order because the differences of electronegativity and ionic radii between Bi and La, Fe and Ti induce the variations on the bond angle and bond length between cations and anions. Moreover, the substitution for magnetic Fe{sup 3+} ions with nonmagnetic Ti{sup 4+} ions can reduce the exchange interaction between adjacent magnetic moments. Therefore, SE technique can be sensitive for

  8. Dynamics of ion bombardment-induced modifications of Si(001) at the radio-frequency-biased electrode in low-pressure oxygen plasmas: In situ spectroscopic ellipsometry and Monte Carlo study

    SciTech Connect

    Amassian, A.; Svec, M.; Desjardins, P.; Martinu, L.

    2006-09-15

    Low-pressure O{sub 2} plasma exposures were performed on c-Si(001) at a radio frequency (rf)-powered electrode in the presence of substrate self-biasing (V{sub B}) from V{sub B}=-60 to -600 V, in order to evaluate ion-surface interactions at the growth surface under ion bombardment conditions suitable for the fabrication of high quality optical coatings. The plasma-surface interactions were monitored in situ using real-time spectroscopic ellipsometry (RTSE), which reveals time- and ion-fluence-resolved information about depth-dependent modifications, such as damage and oxidation below the c-Si substrate surface. RTSE analysis indicates almost immediate damage formation (<<1 s) to a depth of a few nanometers below the surface after exposure to a low oxygen ion fluence ({approx}5x10{sup 14} O cm{sup -2}). Oxide growth is detected at intermediate fluence ({approx}10{sup 15}-10{sup 16} O cm{sup -2}) and is attributed to O subplantation (shallow implantation); it forms near the surface of the target on top of an O-deficient interfacial damage layer (DL). Both layers experience a self-limiting growth behavior at high fluence (>10{sup 17} cm{sup -2}) as oxide and DL thicknesses reach bias-dependent steady-state values, determined by the maximum ion penetration depth, which increases from {approx}3.6 to 9.5 nm for V{sub B}=-60 to -600 V. The in situ experimental study was complemented by Monte Carlo TRIDYN simulations based on the binary collision approximation, which were modified to calculate dynamic changes in the composition of a target exposed to a broad-energy ion source (rf plasma source) at high fluence. Simulation results are found to agree exceptionally well with experiment. In addition, they reveal that the 1.2-3.5-nm-thick DL formed in the steady-state regime is a result of (1) damage formation due to the presence of a small number of high energy O{sup +} ions in the plasma environment, capable of penetrating and damaging up to 3 nm deeper than the majority ion

  9. Ion-surface interactions on c-Si(001) at the radiofrequency-powered electrode in low-pressure plasmas: Ex situ spectroscopic ellipsometry and Monte Carlo simulation study

    SciTech Connect

    Amassian, A.; Desjardins, P.; Martinu, L.

    2006-01-15

    We use variable-angle spectroscopic ellipsometry (VASE) to investigate oxide and interface formation during plasma-oxidation of monocrystalline Si(001) at the radiofrequency (rf) powered electrode of a plasma-enhanced chemical vapor deposition reactor. HF-etched c-Si(001) wafers were exposed to an oxygen plasma under conditions similar to those used in optical coatings deposition in order to ascertain the effects of plasma-bulk interactions, and to gauge to what depth O{sub 2}{sup +} and O{sup +} ions interact with and alter the structure and composition of the target in the presence of negative self-bias, V{sub B}. From VASE analyses, modifications are best described using a two-layer model: A top layer consisting of SiO{sub 2} and a defective interfacial layer (DL) composed of a mixture of c-Si, a-Si, and SiO{sub 2}. The saturation value of the modification depth (oxide and DL thickness) increases from 3.4{+-}0.4 to 9.6{+-}0.4 nm, for V{sub B} ranging from -60 to -600 V, respectively, and scales with E{sub max}{sup 1/2}, where E{sub max} is the maximum energy of ions from an rf discharge. These results are in agreement with nuclear ion-bulk interactions leading to atomic displacements and defect accumulation. The interfacial layer broadens with increasing verttical bar V{sub B} vertical bar while the fraction of a-Si detected increases from {approx}1% up to {approx}55% over the investigated V{sub B} range, indicative of ballistic and thus depth-dependent oxygen transport to the SiO{sub 2}-Si interface. Monte Carlo simulations in the binary collision approximation predict significant surface recession due to sputtering, therefore resulting in an apparent self-limiting oxidation mechanism. The surface layers reach their steady-state thicknesses within the first 2 min of plasma exposure and subsequently move into the bulk of the c-Si substrate as a result of oxide sputtering and oxygen transport.

  10. Fourier Transform Microwave and Infrared Spectroscopic Investigation of Propiolactone

    NASA Astrophysics Data System (ADS)

    Chen, Ziqiu; van Wijngaarden, Jennifer

    2009-06-01

    The pure rotational spectrum of the four-membered ester ring propiolactone (C{_3}H{_4}O{_2}) has been measured in a supersonic jet between 7 and 22 GHz using Fourier transform microwave (FTMW) spectroscopy. For the normal isotopologue, a total of 19 a- and b-type transitions have been recorded. Fifteen transitions due to three different ^{13}C isotopologues have also been observed. The microwave spectrum was analyzed to obtain an improved set of ground state rotational constants in comparison to earlier microwave experiments. The new set of rotational parameters was used to predict the rovibrational band structure of the lowest frequency modes of propiolactone. A total of 12 vibrational band origins have been observed between 400 and 1500 cm^{-1} using the far infrared beamline of the Canadian Light Source coupled to a Bruker IFS125HR spectrometer. The spectra were recorded with a resolution of 0.000969 cm^{-1} and although the intensities of the bands vary, 9 bands are of sufficient quality for complete rovibrational assignment. The progress of the assignment of this rich spectrum will be discussed. D. W. Boone, C O. Britt and J. E. Boggs J. Chem. Phys. 43 (1190), 1965.

  11. Near Infrared Spectroscopic Evaluation Of Water In Hyaline Cartilage

    PubMed Central

    Padalkar, MV; Spencer, RG; Pleshko, N

    2013-01-01

    In diseased conditions of cartilage such as osteoarthritis, there is typically an increase in water content from the average normal of 60–85% to greater than 90%. As cartilage has very little capability for self-repair, methods of early detection of degeneration are required, and assessment of water could prove to be a useful diagnostic method. Current assessment methods are either destructive, time consuming or have limited sensitivity. Here, we investigated the hypotheses that non-destructive near infrared spectroscopy (NIRS) of articular cartilage can be used to differentiate between free and bound water, and to quantitatively assess water content. The absorbances centered at 5200 cm−1 and 6890 cm−1 were attributed to a combination of free and bound water, and to free water only, respectively. The integrated areas of both absorbance bands were found to correlate linearly with the absolute water content (R=0.87 and R= 0.86) and with percent water content (R=0.97 and R=0.96) of the tissue. Partial least square models were also successfully developed and were used to predict water content, and percent free water. These data demonstrate that NIRS can be utilized to quantitatively determine water content in articular cartilage, and may aid in early detection of degenerative tissue changes in a laboratory setting, and with additional validations, possibly in a clinical setting. PMID:23824216

  12. Raman and infrared spectroscopic study of boussingaultite and nickelboussingaultite

    NASA Astrophysics Data System (ADS)

    Culka, Adam; Jehlička, Jan; Němec, Ivan

    2009-08-01

    The Raman and infrared spectra of two secondary sulphate minerals, boussingaultite [(NH 4) 2Mg(SO 4) 2·6H 2O] and nickelboussingaultite [(NH 4) 2Ni,Mg(SO 4) 2·6H 2O] have been collected. Two bands observed at 983 and 990 cm -1 were attributed to the ν1(SO 42-) symmetric stretching vibration. The bands at 1133, 1096 and 1063 cm -1 in boussingaultite spectra and bands at 1149, 1093 and 1063 cm -1 in nickelboussingaultite spectra were attributed to the ν3(SO 42-) antisymmetric stretching vibration. The splitting of the ν4(SO 42-) bending vibration produced bands at 625 and 615 cm -1 in the boussingaultite spectra and 652, 624 and 602 cm -1 in the nickelboussingaultite spectra. Similarly, in the case of the ν2(SO 4) bending vibration, the bands were observed at 454 cm -1 in the boussingaultite spectra and 482, 457 and 440 cm -1 in the nickelboussingaultite spectra. The splitting of bands is the result of lowered symmetry of sulphate ions and possibly a result of substitution of Mg ions by Ni ions in nickelboussingaultite. The bands in the NH 4+ bending vibration region were observed at 1705 and 1678 cm -1 ( ν2), 1460 and 1438 cm -1 ( ν4) for the mineral boussingaultite. In the high wavenumber region the bands arising from the OH (bands above 3000 cm -1) and the NH 4+ (2940, 2918 and 2845 cm -1) stretching vibrations were identified.

  13. NEAR-INFRARED SPECTROSCOPIC STUDY OF V1647 ORI

    SciTech Connect

    Brittain, Sean D.; Liskowsky, Joseph; Rettig, Terrence W.; Simon, Theodore; Gibb, Erika L.

    2010-01-01

    We present new high-resolution infrared echelle spectra of V1647 Ori, the young star that illuminates McNeil's nebula. From the start, V1647 Ori has been an enigmatic source that has defied classification, in some ways resembling eruptive stars of the FUor class and in other respects the EXor variables. V1647 Ori underwent an outburst in 2003 before fading back to its pre-outburst brightness in 2006. In 2008, it underwent a new outburst. In this paper, we present high-resolution K-band and M-band spectra from the W. M. Keck Observatory that were acquired during the 2008 outburst. We compare the spectra to spectra acquired during the previous outburst and quiescent phases. We find that the luminosity and full width at half maximum power of Br gamma increased as the star has brightened and decreased when the star faded, indicating that these phases are driven by variations in the accretion rate. We also show that the temperature of the CO emission has varied with the stellar accretion rate, confirming suggestions from modeling of the heating mechanisms of the inner disk. Finally, we find that the lowest energy blueshifted CO absorption lines originally reported in 2007 are no longer detected. The absence of these lines confirms the short-lived nature of the outflow launched at the start of the quiescent phase in 2006.

  14. Fourier transform infrared spectroscopic study of intact cells of the nitrogen-fixing bacterium Azospirillum brasilense

    NASA Astrophysics Data System (ADS)

    Kamnev, A. A.; Ristić, M.; Antonyuk, L. P.; Chernyshev, A. V.; Ignatov, V. V.

    1997-06-01

    The data of Fourier transform infrared (FTIR) spectroscopic measurements performed on intact cells of the soil nitrogen-fixing bacterium Azospirillum brasilense grown in a standard medium and under the conditions of an increased metal uptake are compared and discussed. The structural FTIR information obtained is considered together with atomic absorption spectrometry (AAS) data on the content of metal cations in the bacterial cells. Some methodological aspects concerning preparation of bacterial cell samples for FTIR measurements are also discussed.

  15. Near-infrared spectroscopic evaluation of lyophilized viral vaccine formulations.

    PubMed

    Hansen, Laurent; Beer, Thomas De; Pieters, Sigrid; Heyden, Yvan Vander; Vervaet, Chris; Remon, Jean Paul; Montenez, Jean-Pierre; Daoussi, Rim

    2013-01-01

    This article examines the applicability of near-infrared spectroscopy (NIRS) to evaluate the virus state in a freeze-dried live, attenuated vaccine formulation. Therefore, this formulation was freeze-dried using different virus volumes and after applying different pre-freeze-drying virus treatments (resulting in different virus states): (i) as used in the commercial formulation; (ii) without antigen (placebo); (iii) concentrated via a centrifugal filter device; and (iv) stressed by 96 h exposure to room temperature. Each freeze-dried product was measured directly after freeze-drying with NIR spectroscopy and the spectra were analyzed using principal component analysis (PCA). Herewith, two NIR spectral regions were evaluated: (i) the 7300-4000 cm(-1) region containing the amide A/II band which might reflect information on the coated proteins of freeze-dried live, attenuated viruses; and (ii) the C-H vibration overtone regions (10,000-7500 and 6340-5500 cm(-1) ) which might supply information on the lipid layer surrounding the freeze-dried live, attenuated viruses. The different pre-freeze-drying treated live, attenuated virus formulations (different virus states and virus volumes) resulted in different clusters in the scores plots resulting from the PCA of the collected NIR spectra. Secondly, partial least squares discriminant analysis models (PLS-DA) were developed and evaluated, allowing classification of the freeze-dried formulations according to virus pretreatment. The results of this study suggest the applicability of NIR spectroscopy for evaluating live, attenuated vaccine formulations with respect to their virus pretreatment and virus volume. PMID:24014045

  16. Mid - infrared solid state lasers for spectroscopic applications

    NASA Astrophysics Data System (ADS)

    Terekhov, Yuri

    This work is devoted to study of novel high power middle-infrared (Mid-IR) laser sources enabling development of portable platform for sensing of organic molecules with the use of recently discovered Quartz Enhanced Photo Acoustic Spectroscopy (QEPAS). The ability to detect small concentrations is beneficial to monitor atmosphere pollution as well for biomedical applications such as analysis of human breath to detect earlier stages of cancer or virus activities. A QEPAS technique using a quartz tuning fork (QTF) as a detector enables a strong enhancement of measured signal when pump laser is modulated with a frequency coinciding with a natural frequency of a QTF. It is known that the detectability of acousto-optics based sensors is proportional to the square root of the laser intensity used for detection of analyte. That is the reason why commercially available semiconductor Mid-IR lasers having small output power limit sensitivity of modern QEPAS based sensors. The lack of high power broadly tunable lasers operating with a modulation frequency of quartz forks (~ 32.768 kHz) is the major motivation of this study. Commercially available Mid-IR (2-3.3 microm), single frequency, continuous wave (CW) fiber pumped lasers based on transition metal doped chalcogenides (e.g. Cr:ZnSe) prove to be efficient laser sources for organic molecules detection. However, their direct modulation is limited to several kHz, and cannot be directly used in combination with QEPAS. Hence, one objective of this work is to study and develop fiber laser pumped Ho:YAG (Er:YAG)/Cr:ZnSe tandem laser system/s. Ho (Holmium) and/or Er (Erbium) ions having long radiation lifetime (~ 10 ms) can effectively accumulate population inversion under CW fiber laser excitation. Utilization of acousto-optic (AO) modulators in the cavity of Ho:YAG (Er:YAG) laser will enable effective Q-Switching with repetition rate easily reaching the resonance frequency of a QTF. It is expected that utilization of Ho:YAG (Er

  17. [Tri-Level Infrared Spectroscopic Identification of Hot Melting Reflective Road Marking Paint].

    PubMed

    Li, Hao; Ma, Fang; Sun, Su-qin

    2015-12-01

    In order to detect the road marking paint from the trace evidence in traffic accident scene, and to differentiate their brands, we use Tri-level infrared spectroscopic identification, which employs the Fourier transform infrared spectroscopy (FTIR), the second derivative infrared spectroscopy(SD-IR), two-dimensional correlation infrared spectroscopy(2D-IR) to identify three different domestic brands of hot melting reflective road marking paints and their raw materials in formula we Selected. The experimental results show that three labels coatings in ATR and FTIR spectrograms are very similar in shape, only have different absorption peak wave numbers, they have wide and strong absorption peaks near 1435 cm⁻¹, and strong absorption peak near 879, 2955, 2919, 2870 cm⁻¹. After enlarging the partial areas of spectrograms and comparing them with each kind of raw material of formula spectrograms, we can distinguish them. In the region 700-970 and 1370-1 660 cm⁻¹ the spectrograms mainly reflect the different relative content of heavy calcium carbonate of three brands of the paints, and that of polyethylene wax (PE wax), ethylene vinyl acetate resin (EVA), dioctyl phthalate (DOP) in the region 2800-2960 cm⁻¹. The SD-IR not only verify the result of the FTIR analysis, but also further expand the microcosmic differences and reflect the different relative content of quartz sand in the 512-799 cm-1 region. Within the scope of the 1351 to 1525 cm⁻¹, 2D-IR have more significant differences in positions and numbers of automatically peaks. Therefore, the Tri-level infrared spectroscopic identification is a fast and effective method to distinguish the hot melting road marking paints with a gradually improvement in apparent resolution.

  18. [Tri-Level Infrared Spectroscopic Identification of Hot Melting Reflective Road Marking Paint].

    PubMed

    Li, Hao; Ma, Fang; Sun, Su-qin

    2015-12-01

    In order to detect the road marking paint from the trace evidence in traffic accident scene, and to differentiate their brands, we use Tri-level infrared spectroscopic identification, which employs the Fourier transform infrared spectroscopy (FTIR), the second derivative infrared spectroscopy(SD-IR), two-dimensional correlation infrared spectroscopy(2D-IR) to identify three different domestic brands of hot melting reflective road marking paints and their raw materials in formula we Selected. The experimental results show that three labels coatings in ATR and FTIR spectrograms are very similar in shape, only have different absorption peak wave numbers, they have wide and strong absorption peaks near 1435 cm⁻¹, and strong absorption peak near 879, 2955, 2919, 2870 cm⁻¹. After enlarging the partial areas of spectrograms and comparing them with each kind of raw material of formula spectrograms, we can distinguish them. In the region 700-970 and 1370-1 660 cm⁻¹ the spectrograms mainly reflect the different relative content of heavy calcium carbonate of three brands of the paints, and that of polyethylene wax (PE wax), ethylene vinyl acetate resin (EVA), dioctyl phthalate (DOP) in the region 2800-2960 cm⁻¹. The SD-IR not only verify the result of the FTIR analysis, but also further expand the microcosmic differences and reflect the different relative content of quartz sand in the 512-799 cm-1 region. Within the scope of the 1351 to 1525 cm⁻¹, 2D-IR have more significant differences in positions and numbers of automatically peaks. Therefore, the Tri-level infrared spectroscopic identification is a fast and effective method to distinguish the hot melting road marking paints with a gradually improvement in apparent resolution. PMID:26964206

  19. MASSIVE YOUNG STELLAR OBJECTS IN THE GALACTIC CENTER. I. SPECTROSCOPIC IDENTIFICATION FROM SPITZER INFRARED SPECTROGRAPH OBSERVATIONS

    SciTech Connect

    An, Deokkeun; RamIrez, Solange V.; Boogert, A. C. Adwin; Sellgren, Kris; Arendt, Richard G.; Schultheis, Mathias; Cotera, Angela S.; Stolovy, Susan R.

    2011-08-01

    We present results from our spectroscopic study, using the Infrared Spectrograph (IRS) on board the Spitzer Space Telescope, designed to identify massive young stellar objects (YSOs) in the Galactic center (GC). Our sample of 107 YSO candidates was selected based on Infrared Array Camera (IRAC) colors from the high spatial resolution, high sensitivity Spitzer/IRAC images in the Central Molecular Zone, which spans the central {approx}300 pc region of the Milky Way. We obtained IRS spectra over 5-35 {mu}m using both high- and low-resolution IRS modules. We spectroscopically identify massive YSOs by the presence of a 15.4 {mu}m shoulder on the absorption profile of 15 {mu}m CO{sub 2} ice, suggestive of CO{sub 2} ice mixed with CH{sub 3}OH ice on grains. This 15.4 {mu}m shoulder is clearly observed in 16 sources and possibly observed in an additional 19 sources. We show that nine massive YSOs also reveal molecular gas-phase absorption from CO{sub 2}, C{sub 2}H{sub 2}, and/or HCN, which traces warm and dense gas in YSOs. Our results provide the first spectroscopic census of the massive YSO population in the GC. We fit YSO models to the observed spectral energy distributions and find YSO masses of 8-23 M{sub sun}, which generally agree with the masses derived from observed radio continuum emission. We find that about 50% of photometrically identified YSOs are confirmed with our spectroscopic study. This implies a preliminary star formation rate of {approx}0.07 M{sub sun} yr{sup -1} at the GC.

  20. Heterogeneously integrated silicon photonics for the mid-infrared and spectroscopic sensing.

    PubMed

    Chen, Yu; Lin, Hongtao; Hu, Juejun; Li, Mo

    2014-07-22

    Besides being the foundational material for microelectronics, crystalline silicon has long been used for the production of infrared lenses and mirrors. More recently, silicon has become the key material to achieve large-scale integration of photonic devices for on-chip optical interconnect and signal processing. For optics, silicon has significant advantages: it offers a very high refractive index and is highly transparent in the spectral range from 1.2 to 8 μm. To fully exploit silicon’s superior performance in a remarkably broad range and to enable new optoelectronic functionalities, here we describe a general method to integrate silicon photonic devices on arbitrary foreign substrates. In particular, we apply the technique to integrate silicon microring resonators on mid-infrared compatible substrates for operation in the mid-infrared. These high-performance mid-infrared optical resonators are utilized to demonstrate, for the first time, on-chip cavity-enhanced mid-infrared spectroscopic analysis of organic chemicals with a limit of detection of less than 0.1 ng.

  1. Raman, infrared and near-infrared spectroscopic characterization of the herderite-hydroxylherderite mineral series

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; Scholz, Ricardo; López, Andrés; Xi, Yunfei; Queiroz, Camila de Siqueira; Belotti, Fernanda M.; Filho, Mauro Cândido

    2014-01-01

    Natural single-crystal specimens of the herderite-hydroxylherderite series from Brazil, with general formula CaBePO4(F,OH), were investigated by electron microprobe, Raman, infrared and near-infrared spectroscopies. The minerals occur as secondary products in granitic pegmatites. Herderite and hydroxylherderite minerals show extensive solid solution formation. The Raman spectra of hydroxylherderite are characterized by bands at around 985 and 998 cm-1, assigned to ν1 symmetric stretching mode of the HOPO33- and PO43- units. Raman bands at around 1085, 1128 and 1138 cm-1 are attributed to both the HOP and PO antisymmetric stretching vibrations. The set of Raman bands observed at 563, 568, 577, 598, 616 and 633 cm-1 are assigned to the ν4 out of plane bending modes of the PO4 and H2PO4 units. The OH Raman stretching vibrations of hydroxylherderite were observed ranging from 3626 cm-1 to 3609 cm-1. The infrared stretching vibrations of hydroxylherderites were observed between 3606 cm-1 and 3599 cm-1. By using a Libowitzky type function, hydrogen bond distances based upon the OH stretching bands were calculated. Characteristic NIR bands at around 6961 and 7054 cm-1 were assigned to the first overtone of the fundamental, whilst NIR bands at 10,194 and 10,329 cm-1 are assigned to the second overtone of the fundamental OH stretching vibration. Insight into the structure of the herderite-hydroxylherderite series is assessed by vibrational spectroscopy.

  2. Breast histopathology using random decision forests-based classification of infrared spectroscopic imaging data

    NASA Astrophysics Data System (ADS)

    Mayerich, David M.; Walsh, Michael; Kadjacsy-Balla, Andre; Mittal, Shachi; Bhargava, Rohit

    2014-03-01

    Current methods for cancer detection rely on clinical stains, often using immunohistochemistry techniques. Pathologists then evaluate the stained tissue in order to determine cancer stage treatment options. These methods are commonly used, however they are non-quantitative and it is difficult to control for staining quality. In this paper, we propose the use of mid-infrared spectroscopic imaging to classify tissue types in tumor biopsy samples. Our goal is to augment the data available to pathologists by providing them with quantitative chemical information to aid diagnostic activities in clinical and research activities related to breast cancer.

  3. Thermal Physical, and Infrared Spectroscopic Studies on Glasses Prepared by Microwave Route

    SciTech Connect

    Jagadeesha, N.; Gowda, V. C. Veeranna; Chakradhar, R. P. S.; Reddy, C. Narayana

    2011-07-15

    This paper describes thermal, physical and spectroscopic properties of glasses prepared by a novel micro wave method. These studies exhibited a strong compositional dependent trend and existence of characteristic boro-vanadate groups in these glasses. The scheme of modification of borate and vanadate groups is controlled by Sanderson's electronegativity principle. Analysis of density and glass transition temperatures suggests the presence of characteristic four coordinated borate and diboro - vanadate groups in these glasses. The presence of [BO{sub 4/2}]{sup -} and [B{sub 2}V{sub 2}O{sub 9}]{sup 2-}) groups are confirmed by Infrared Spectroscopy of investigated glasses.

  4. Infrared spectroscopic imaging detects chemical modifications in liver fibrosis due to diabetes and disease

    PubMed Central

    Sreedhar, Hari; Varma, Vishal K.; Gambacorta, Francesca V.; Guzman, Grace; Walsh, Michael J.

    2016-01-01

    The importance of stroma as a rich diagnostic region in tissue biopsies is growing as there is an increasing understanding that disease processes in multiple organs can affect the composition of adjacent connective tissue regions. This may be especially true in the liver, since this organ’s central metabolic role exposes it to multiple disease processes. We use quantum cascade laser infrared spectroscopic imaging to study changes in the chemical status of hepatocytes and fibrotic regions of liver tissue that result from the progression of liver cirrhosis to hepatocellular carcinoma and the potentially confounding effects of diabetes mellitus. PMID:27375956

  5. Infrared spectroscopic imaging detects chemical modifications in liver fibrosis due to diabetes and disease.

    PubMed

    Sreedhar, Hari; Varma, Vishal K; Gambacorta, Francesca V; Guzman, Grace; Walsh, Michael J

    2016-06-01

    The importance of stroma as a rich diagnostic region in tissue biopsies is growing as there is an increasing understanding that disease processes in multiple organs can affect the composition of adjacent connective tissue regions. This may be especially true in the liver, since this organ's central metabolic role exposes it to multiple disease processes. We use quantum cascade laser infrared spectroscopic imaging to study changes in the chemical status of hepatocytes and fibrotic regions of liver tissue that result from the progression of liver cirrhosis to hepatocellular carcinoma and the potentially confounding effects of diabetes mellitus.

  6. Infrared spectroscopic imaging detects chemical modifications in liver fibrosis due to diabetes and disease.

    PubMed

    Sreedhar, Hari; Varma, Vishal K; Gambacorta, Francesca V; Guzman, Grace; Walsh, Michael J

    2016-06-01

    The importance of stroma as a rich diagnostic region in tissue biopsies is growing as there is an increasing understanding that disease processes in multiple organs can affect the composition of adjacent connective tissue regions. This may be especially true in the liver, since this organ's central metabolic role exposes it to multiple disease processes. We use quantum cascade laser infrared spectroscopic imaging to study changes in the chemical status of hepatocytes and fibrotic regions of liver tissue that result from the progression of liver cirrhosis to hepatocellular carcinoma and the potentially confounding effects of diabetes mellitus. PMID:27375956

  7. Spectral histology of breast tissue using mid-infrared spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Pounder, F. Nell; Bhargava, Rohit

    2009-02-01

    Histopathologic recognition is the gold standard in breast cancer diagnoses and is a primary determinant tool for cancer research. Unfortunately, the manual nature of histopathologic recognition leads to low throughput analysis, delays in decision-making and errors. Here, we present an automated means to accurate histologic recognition using mid-infrared molecular spectroscopy. Fourier transform infrared (FT-IR) spectroscopic imaging is combined with statistical pattern recognition and high throughput sampling to provide automated tissue segmentation into constituent cell types. The method does not need dyes or probes and dispenses with human input. Results demonstrate that the technique is capable of accurate histologic segmentation that can potentially become competitive with that attained by conventional immunohistochemical analyses.

  8. Raman, infrared and near-infrared spectroscopic characterization of the herderite-hydroxylherderite mineral series.

    PubMed

    Frost, Ray L; Scholz, Ricardo; López, Andrés; Xi, Yunfei; Queiroz, Camila de Siqueira; Belotti, Fernanda M; Cândido Filho, Mauro

    2014-01-24

    Natural single-crystal specimens of the herderite-hydroxylherderite series from Brazil, with general formula CaBePO4(F,OH), were investigated by electron microprobe, Raman, infrared and near-infrared spectroscopies. The minerals occur as secondary products in granitic pegmatites. Herderite and hydroxylherderite minerals show extensive solid solution formation. The Raman spectra of hydroxylherderite are characterized by bands at around 985 and 998 cm(-1), assigned to ν1 symmetric stretching mode of the HOPO3(3-) and PO4(3-) units. Raman bands at around 1085, 1128 and 1138 cm(-1) are attributed to both the HOP and PO antisymmetric stretching vibrations. The set of Raman bands observed at 563, 568, 577, 598, 616 and 633 cm(-1) are assigned to the ν4 out of plane bending modes of the PO4 and H2PO4 units. The OH Raman stretching vibrations of hydroxylherderite were observed ranging from 3626 cm(-1) to 3609 cm(-1). The infrared stretching vibrations of hydroxylherderites were observed between 3606 cm(-1) and 3599 cm(-1). By using a Libowitzky type function, hydrogen bond distances based upon the OH stretching bands were calculated. Characteristic NIR bands at around 6961 and 7054 cm(-1) were assigned to the first overtone of the fundamental, whilst NIR bands at 10,194 and 10,329 cm(-1) are assigned to the second overtone of the fundamental OH stretching vibration. Insight into the structure of the herderite-hydroxylherderite series is assessed by vibrational spectroscopy.

  9. Raman, infrared and near-infrared spectroscopic characterization of the herderite-hydroxylherderite mineral series.

    PubMed

    Frost, Ray L; Scholz, Ricardo; López, Andrés; Xi, Yunfei; Queiroz, Camila de Siqueira; Belotti, Fernanda M; Cândido Filho, Mauro

    2014-01-24

    Natural single-crystal specimens of the herderite-hydroxylherderite series from Brazil, with general formula CaBePO4(F,OH), were investigated by electron microprobe, Raman, infrared and near-infrared spectroscopies. The minerals occur as secondary products in granitic pegmatites. Herderite and hydroxylherderite minerals show extensive solid solution formation. The Raman spectra of hydroxylherderite are characterized by bands at around 985 and 998 cm(-1), assigned to ν1 symmetric stretching mode of the HOPO3(3-) and PO4(3-) units. Raman bands at around 1085, 1128 and 1138 cm(-1) are attributed to both the HOP and PO antisymmetric stretching vibrations. The set of Raman bands observed at 563, 568, 577, 598, 616 and 633 cm(-1) are assigned to the ν4 out of plane bending modes of the PO4 and H2PO4 units. The OH Raman stretching vibrations of hydroxylherderite were observed ranging from 3626 cm(-1) to 3609 cm(-1). The infrared stretching vibrations of hydroxylherderites were observed between 3606 cm(-1) and 3599 cm(-1). By using a Libowitzky type function, hydrogen bond distances based upon the OH stretching bands were calculated. Characteristic NIR bands at around 6961 and 7054 cm(-1) were assigned to the first overtone of the fundamental, whilst NIR bands at 10,194 and 10,329 cm(-1) are assigned to the second overtone of the fundamental OH stretching vibration. Insight into the structure of the herderite-hydroxylherderite series is assessed by vibrational spectroscopy. PMID:24076459

  10. The Far Infrared Spectroscopic Explorer (FIRSPEX): probing the lifecycle of the ISM in the universe

    NASA Astrophysics Data System (ADS)

    Rigopoulou, D.; Caldwell, M.; Ellison, B.; Pearson, C.; Caux, E.; Cooray, A.; Gallego, J. D.; Gerin, M.; Goicoechea, J. R.; Goldsmith, P.; Kramer, C.; Lis, D. C.; Molinari, S.; Ossenkopf-Okada, V.; Savini, G.; Tan, B. K.; Tielens, X.; Viti, S.; Wiedner, M.; Yassin, G.

    2016-07-01

    The Far Infrared Spectroscopic Explorer (FIRSPEX) is a novel European-led astronomy mission concept developed to enable large area ultra high spectroscopic resolution surveys in the THz regime. FIRSPEX opens up a relatively unexplored spectral and spatial parameter space that will produce an enormously significant scientific legacy by focusing on the properties of the multi-phase ISM, the assembly of molecular clouds in our Galaxy and the onset of star formation; topics which are fundamental to our understanding of galaxy evolution. The mission uses a heterodyne instrument and a ~1.2 m primary antenna to scan large areas of the sky in a number of discreet spectroscopic channels from L2. The FIRSPEX bands centered at [CI] 809 GHz, [NII]1460 GHz, [CII]1900 GHz and [OI]4700 GHz have been carefully selected to target key atomic and ionic fine structure transitions difficult or impossible to access from the ground but fundamental to the study of the multi-phase ISM in the Universe. The need for state-of-the-art sensitivity dictates the use of superconducting mixers configured either as tunnel junctions or hot electron bolometers. This technology requires cooling to low temperatures, approaching 4K, in order to operate. The receivers will operate in double sideband configuration providing a total of 7 pixels on the sky. FIRSPEX will operate from L2 in both survey and pointed mode enabling velocity resolved spectroscopy of large areas of sky as well as targeted observations.

  11. Studies on Nephrite and Jadeite Jades by Fourier Transform Infrared (ftir) and Raman Spectroscopic Techniques

    NASA Astrophysics Data System (ADS)

    Tan, T. L.; Ng, L. L.; Lim, L. C.

    2013-10-01

    The mineralogical properties of black nephrite jade from Western Australia are studied by Fourier transform infrared (FTIR) spectroscopy using both transmission and specular reflectance techniques in the 4000-400 cm-1 wavenumber region. The infrared absorption peaks in the 3700-3600 cm-1 region which are due to the O-H stretching mode provides a quantitative analysis of the Fe/(Fe+Mg) ratio in the mineral composition of jade samples. The Fe/(Fe+Mg) percentage in black nephrite is found to be higher than that in green nephrite, but comparable to that of actinolite (iron-rich nephrite). This implies that the mineralogy of black nephrite is closer to actinolite than tremolite. The jade is also characterized using Raman spectroscopy in the 1200-200 cm-1 region. Results from FTIR and Raman spectroscopic data of black nephrite jade are compared with those of green nephrite jade from New Zealand and jadeite jade from Myanmar. Black nephrite appears to have a slightly different chemical composition from green nephrite. Spectra from FTIR and Raman spectroscopic techniques were found to be useful in differentiating black nephrite, green nephrite, and green jadeite jades. Furthermore, data on refractive index, specific gravity, and hardness of black nephrite jade are measured and compared with those of green nephrite and of jadeite jade.

  12. Infrared Spectroscopic Imaging Survey (emph{IRSIS}) payload for an Indian satellite

    NASA Astrophysics Data System (ADS)

    Ghosh, S. K.

    The Infrared Spectroscopic Imaging Survey (IRSIS) experiment, targeted for the Small Satellite Mission of the Indian Space Research Organization (ISRO), will carry out spectroscopic measurements in the wavelength range 1.7 to 6.4 μm seamlessly for the first time, covering a large fraction (˜ 50%) of the sky (including the Galactic Plane), with a reasonable sensitivity (completeness at 2.2 μm, K = 14 mag.). The planned Spectral Resolution is ˜ 100. Primary science goals include : (i) Discovery & classification of Brown Dwarfs, M-L-T Dwarfs (faint end of Initial Mass Function); (ii) Large scale mapping in emission features; e.g. Polycyclic Aromatic Hydrocarbon (PAH) at 3.3 μm, 6.2 μm, etc. (Galactic Plane survey); (iii) Minor bodies of Solar System : Asteroids, Comets, Inter- Planetary Dust; Origin, evolution & types of Organics; History of Solar System; and (iv) Asymptotic Giant Branch (AGB), Red-Super-Giant (RSG), Carbon-rich stars; (Galactic Bulge survey). In addition, it will support studies of time critical phenomena like novae, comets etc, under Targets of Opportunity (ToO) observations. The IRSIS database is expected to provide better understanding of energetics and composition of the ISM, infrared characterisation of stars, and various types of Solar system bodies.

  13. FRIENDS OF HOT JUPITERS. III. AN INFRARED SPECTROSCOPIC SEARCH FOR LOW-MASS STELLAR COMPANIONS

    SciTech Connect

    Piskorz, Danielle; Knutson, Heather A.; Ngo, Henry; Batygin, Konstantin; Muirhead, Philip S.; Crepp, Justin R.; Hinkley, Sasha; Morton, Timothy D.

    2015-12-01

    Surveys of nearby field stars indicate that stellar binaries are common, yet little is known about the effects that these companions may have on planet formation and evolution. The Friends of Hot Jupiters project uses three complementary techniques to search for stellar companions to known planet-hosting stars: radial velocity monitoring, adaptive optics imaging, and near-infrared spectroscopy. In this paper, we examine high-resolution K band infrared spectra of fifty stars hosting gas giant planets on short-period orbits. We use spectral fitting to search for blended lines due to the presence of cool stellar companions in the spectra of our target stars, where we are sensitive to companions with temperatures between 3500 and 5000 K and projected separations less than 100 AU in most systems. We identify eight systems with candidate low-mass companions, including one companion that was independently detected in our AO imaging survey. For systems with radial velocity accelerations, a spectroscopic non-detection rules out scenarios involving a stellar companion in a high inclination orbit. We use these data to place an upper limit on the stellar binary fraction at small projected separations, and show that the observed population of candidate companions is consistent with that of field stars and also with the population of wide-separation companions detected in our previous AO survey. We find no evidence that spectroscopic stellar companions are preferentially located in systems with short-period gas giant planets on eccentric and/or misaligned orbits.

  14. Skin hydration by spectroscopic imaging using multiple near-infrared bands

    NASA Astrophysics Data System (ADS)

    Attas, E. Michael; Sowa, Michael G.; Posthumus, Trevor B.; Schattka, Bernhard J.; Mantsch, Henry H.; Zhang, Shuliang L.

    2002-03-01

    Near-infrared spectroscopic methods have been developed to determine the degree of hydration of human skin in vivo. Reflectance spectroscopic imaging was used to investigate the distribution of skin moisture as a function of location. A human study in a clinical setting has generated quantitative data showing the effects of a drying agent and a moisturizer on delineated regions of the forearms of eight volunteers. Two digital imaging systems equipped with liquid-crystal tunable filters were used to collect stacks of monochromatic images at 10-nm intervals over the wavelength bands 650-1050 nm and 960-1700 nm. Images generated from measurements of water absorption-band areas at three different near-IR wavelengths (970, 1200, and 1450 nm) showed obvious differences in the apparent distribution of water in skin. Changes resulting from the skin treatments were much more evident in the 1200-nm and 1450-nm images than in the 970-nm ones. The variable sensitivity of the method at different wavelengths has been interpreted as being the result of different penetration depths of the infrared light used in the reflectance studies. Ex-vivo experiments with pigskin have provided evidence supporting the relationship between wavelength and penetration depth. Combining the hydration results from several near-IR water bands allows additional information on hydration depth to be obtained.

  15. Spectroscopic Infrared Extinction Mapping as a Probe of Grain Growth in IRDCs

    NASA Astrophysics Data System (ADS)

    Lim, Wanggi; Carey, Sean J.; Tan, Jonathan C.

    2015-11-01

    We present spectroscopic tests of MIR to FIR extinction laws in IRDC G028.36+00.07, a potential site of massive star and star cluster formation. Lim & Tan developed methods of FIR extinction mapping of this source using Spitzer-MIPS 24 μm and Herschel-PACS 70 μm images, and by comparing to MIR Spitzer-IRAC 3-8 μm extinction maps, found tentative evidence for grain growth in the highest mass surface density regions. Here we present results of spectroscopic infrared extinction mapping using Spitzer-IRS (14-38 μm) data of the same Infrared dark cloud (IRDC). These methods allow us to first measure the SED of the diffuse Galactic interstellar medium that is in the foreground of the IRDC. We then carry out our primary investigation of measuring the MIR to FIR opacity law and searching for potential variations as a function of mass surface density within the IRDC. We find relatively flat, featureless MIR-FIR opacity laws that lack the ˜12 and ˜35 μm features associated with the thick water ice mantle models of Ossenkopf & Henning. Their thin ice mantle models and the coagulating aggregate dust models of Ormel et al. are a generally better match to the observed opacity laws. We also find evidence for generally flatter MIR to FIR extinction laws as mass surface density increases, strengthening the evidence for grain and ice mantle growth in higher density regions.

  16. SPECTROSCOPIC INFRARED EXTINCTION MAPPING AS A PROBE OF GRAIN GROWTH IN IRDCs

    SciTech Connect

    Lim, Wanggi; Carey, Sean J.; Tan, Jonathan C.

    2015-11-20

    We present spectroscopic tests of MIR to FIR extinction laws in IRDC G028.36+00.07, a potential site of massive star and star cluster formation. Lim and Tan developed methods of FIR extinction mapping of this source using Spitzer-MIPS 24 μm and Herschel-PACS 70 μm images, and by comparing to MIR Spitzer-IRAC 3–8 μm extinction maps, found tentative evidence for grain growth in the highest mass surface density regions. Here we present results of spectroscopic infrared extinction mapping using Spitzer-IRS (14–38 μm) data of the same Infrared dark cloud (IRDC). These methods allow us to first measure the SED of the diffuse Galactic interstellar medium that is in the foreground of the IRDC. We then carry out our primary investigation of measuring the MIR to FIR opacity law and searching for potential variations as a function of mass surface density within the IRDC. We find relatively flat, featureless MIR–FIR opacity laws that lack the ∼12 and ∼35 μm features associated with the thick water ice mantle models of Ossenkopf and Henning. Their thin ice mantle models and the coagulating aggregate dust models of Ormel et al. are a generally better match to the observed opacity laws. We also find evidence for generally flatter MIR to FIR extinction laws as mass surface density increases, strengthening the evidence for grain and ice mantle growth in higher density regions.

  17. Chemometric evaluation of near infrared, fourier transform infrared, and Raman spectroscopic models for the prediction of nimodipine polymorphs.

    PubMed

    Siddiqui, Akhtar; Rahman, Ziyaur; Sayeed, Vilayat A; Khan, Mansoor A

    2013-11-01

    The objective of this study was to assess the performance of the chemometric model to predict the proportion of the recrystallized polymorphs of nimodipine from the cosolvent formulations. Ranging from 100% to 0% (w/w) of polymorph I, the two polymorphs mixtures were prepared and characterized spectroscopically using Fourier transformed infrared spectroscopy (FTIR), near-infrared spectroscopy (NIR), and Raman spectroscopy. Instrumental responses were treated to construct multivariate calibration model using principal component regression (PCR) and partial least square regression approaches. Treated data showed better model fitting than without treatment, which demonstrated higher correlation coefficient (R(2) ) and lower root mean square of standard error (RMSE) and standard error (SE). Multiple scattering correction and standard normal variate exhibited higher R(2) and lower RMSE and SE values than second derivative. Goodness of fit for FTIR and NIR (R(2) ∼ 0.99) data was better than Raman (R(2) ∼ 0.95). Furthermore, the models were applied on the recrystallized polymorphs obtained by storing nimodipine-cosolvent formulations at selected stability conditions. The relative composition of the polymorphs differed with storage conditions. NIR-chemical imaging on recrystallized sample of nimodipine at 15°C qualitatively corroborated the model-based prediction of the two polymorphs. Therefore, these studies strongly suggest the importance of the potential utility of the chemometric model in predicting nimodipine polymorphs.

  18. A far-infrared spectroscopic survey of intermediate redshift (ultra) luminous infrared galaxies

    SciTech Connect

    Magdis, Georgios E.; Rigopoulou, D.; Hopwood, R.; Clements, D.; Huang, J.-S.; Farrah, D.; Pearson, C.; Alonso-Herrero, Almudena; Bock, J. J.; Cooray, A.; Griffin, M. J.; Oliver, S.; Perez Fournon, I.; Riechers, D.; Swinyard, B. M.; Thatte, N.; Scott, D.; Valtchanov, I.; Vaccari, M.

    2014-11-20

    We present Herschel far-IR photometry and spectroscopy as well as ground-based CO observations of an intermediate redshift (0.21 ≤ z ≤ 0.88) sample of Herschel-selected (ultra)-luminous infrared galaxies (L {sub IR} > 10{sup 11.5} L {sub ☉}). With these measurements, we trace the dust continuum, far-IR atomic line emission, in particular [C II] 157.7 μm, as well as the molecular gas of z ∼ 0.3 luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) and perform a detailed investigation of the interstellar medium of the population. We find that the majority of Herschel-selected intermediate redshift (U)LIRGs have L {sub C} {sub II}/L {sub FIR} ratios that are a factor of about 10 higher than that of local ULIRGs and comparable to that of local normal and high-z star-forming galaxies. Using our sample to bridge local and high-z [C II] observations, we find that the majority of galaxies at all redshifts and all luminosities follow an L {sub C} {sub II}–L {sub FIR} relation with a slope of unity, from which local ULIRGs and high- z active-galactic-nucleus-dominated sources are clear outliers. We also confirm that the strong anti-correlation between the L {sub C} {sub II}/L {sub FIR} ratio and the far-IR color L {sub 60}/L {sub 100} observed in the local universe holds over a broad range of redshifts and luminosities, in the sense that warmer sources exhibit lower L {sub C} {sub II}/L {sub FIR} at any epoch. Intermediate redshift ULIRGs are also characterized by large molecular gas reservoirs and by lower star formation efficiencies compared to that of local ULIRGs. The high L {sub C} {sub II}/L {sub FIR} ratios, the moderate star formation efficiencies (L {sub IR}/L{sub CO}{sup ′} or L {sub IR}/M{sub H{sub 2}}), and the relatively low dust temperatures of our sample (which are also common characteristics of high-z star-forming galaxies with ULIRG-like luminosities) indicate that the evolution of the physical properties of (U)LIRGs between the

  19. Fourier Transform Infrared Spectroscopic Studies Of Wheat In The Mid Infrared

    NASA Astrophysics Data System (ADS)

    Olinger, Jill M.; Griffiths, Peter R.

    1989-12-01

    Official grain standards of the United States state that wheat may be divided into seven classes which are: Durum, Red Durum, Hard Red Spring, Hard Red Winter, Soft Red Winter, White, and Mixed.1 Most end uses of wheat involve converting the grain into flour through one of a variety of grinding methods. The quality of wheat-based products is often very dependent upon the type or class of wheat which was used to make the flour. Pasta products, for example, are made almost exclusively from the flour of durum wheats, which are the hardest of the wheats listed above. The highest quality breads are produced using flour from wheats classed as hard, whereas cakes, cookies and pastries are considered best when flour from wheats classed as soft are used. It is obvious then that the capability of determining the class of a particular wheat, especially with respect to hardness, is of economic importance to growers, processors, and merchants of wheat and wheat products. Hardness has been measured in many different ways 2-5 but, as of yet, no one method has become the method of choice. This paper reports on the use of principal components analysis (PCA) of mid infrared diffuse reflectance (DR) spectra of diluted ground wheats to aid in the classification of those wheats with respect to their hardness. The theory and mathematics involved in a principal component analysis have been described elsewhere.9

  20. Recognizing brain activities by functional near-infrared spectroscope signal analysis

    PubMed Central

    Khoa, Truong Quang Dang; Nakagawa, Masahiro

    2008-01-01

    Background Functional Near-Infrared Spectroscope (fNIRs) is one of the latest technologies which utilize light in the near-infrared range to determine brain activities. Near-infrared technology allows design of safe, portable, wearable, non-invasive and wireless qualities monitoring systems. This indicates that fNIRs signal monitoring of brain hemodynamics can be value in helping to understand brain tasks. In this paper, we present results of fNIRs signal analysis to show that there exist distinct patterns of hemodynamic responses which recognize brain tasks toward developing a Brain-Computer interface. Results We applied Higuchi's fractal dimension algorithms to analyse irregular and complex characteristics of fNIRs signals, and then Wavelets transform is used to analysis for preprocessing as signal filters and feature extractions and Neural networks is a module for cognition brain tasks. Conclusion Throughout two experiments, we have demonstrated the feasibility of fNIRs analysis to recognize human brain activities. PMID:18590571

  1. Quantitative infrared spectroscopic method for the study of the hydration of ions in aqueous solutions

    SciTech Connect

    Kristiansson, O.; Lindgren, J.; de Villepin, J.

    1988-05-05

    An infrared spectroscopic method for the study of the hydration of ions in aqueous solutions has been developed. OD stretching bands of isotopically dilute HDO molecules in the first hydration sphere of ions are obtained when the absorption from H/sub 2/O molecules and HDO molecules in the bulk water are removed by a double difference technique. The method is applied to aqueous solutions of Ni(ClO/sub 4/)/sub 2/, Ni(BF/sub 4/)/sub 2/, and Ni(PF/sub 6/)/sub 2/. Coordination numbers of 4.6 +/- 0.8 for the ClO/sub 4//sup -/ anion and 3.9 +/- 0.8 for the BF/sub 4//sup -/ anion are obtained. A systematic study of the influence of different salt and HDO concentrations has been undertaken. It is found that Lambert-Beer's law is valid in the concentration ranges studied.

  2. THE NASA AMES POLYCYCLIC AROMATIC HYDROCARBON INFRARED SPECTROSCOPIC DATABASE: THE COMPUTED SPECTRA

    SciTech Connect

    Bauschlicher, C. W.; Ricca, A.; Boersma, C.; Mattioda, A. L.; Cami, J.; Peeters, E.; Allamandola, L. J.; Sanchez de Armas, F.; Puerta Saborido, G.; Hudgins, D. M.

    2010-08-15

    The astronomical emission features, formerly known as the unidentified infrared bands, are now commonly ascribed to polycyclic aromatic hydrocarbons (PAHs). The laboratory experiments and computational modeling done at the NASA Ames Research Center to create a collection of PAH IR spectra relevant to test and refine the PAH hypothesis have been assembled into a spectroscopic database. This database now contains over 800 PAH spectra spanning 2-2000 {mu}m (5000-5 cm{sup -1}). These data are now available on the World Wide Web at www.astrochem.org/pahdb. This paper presents an overview of the computational spectra in the database and the tools developed to analyze and interpret astronomical spectra using the database. A description of the online and offline user tools available on the Web site is also presented.

  3. SEM, EDX, Infrared and Raman spectroscopic characterization of the silicate mineral yuksporite

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; López, Andrés; Scholz, Ricardo; Theiss, Frederick L.; Romano, Antônio Wilson

    2015-02-01

    The mineral yuksporite (K,Ba)NaCa2(Si,Ti)4O11(F,OH)ṡH2O has been studied using the combination of SEM with EDX and vibrational spectroscopic techniques of Raman and infrared spectroscopy. Scanning electron microscopy shows a single pure phase with cleavage fragment up to 1.0 mm. Chemical analysis gave Si, Al, K, Na and Ti as the as major elements with small amounts of Mn, Ca, Fe and REE. Raman bands are observed at 808, 871, 930, 954, 980 and 1087 cm-1 and are typical bands for a natural zeolite. Intense Raman bands are observed at 514, 643 and 668 cm-1. A very sharp band is observed at 3668 cm-1 and is attributed to the OH stretching vibration of OH units associated with Si and Ti. Raman bands resolved at 3298, 3460, 3562 and 3628 cm-1 are assigned to water stretching vibrations.

  4. Pectin functionalised by fatty acids: Diffuse reflectance infrared Fourier transform (DRIFT) spectroscopic characterisation

    NASA Astrophysics Data System (ADS)

    Kamnev, Alexander A.; Calce, Enrica; Tarantilis, Petros A.; Tugarova, Anna V.; De Luca, Stefania

    2015-01-01

    Chemically modified pectin derivatives obtained by partial esterification of its hydroxyl moieties with fatty acids (FA; oleic, linoleic and palmitic acids), as well as the initial apple peel pectin were comparatively characterised using diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. Characteristic changes observed in DRIFT spectra in going from pectin to its FA esters are related to the corresponding chemical modifications. Comparing the DRIFT spectra with some reported data on FTIR spectra of the same materials measured in KBr or NaCl matrices has revealed noticeable shifts of several polar functional groups both in pectin and in its FA-esterified products induced by the halide salts. The results obtained have implications for careful structural analyses of biopolymers with hydrophilic functional groups by means of different FTIR spectroscopic methodologies.

  5. Infrared spectroscopic measurement of skin hydration and sebum levels and comparison to corneometer and sebumeter

    NASA Astrophysics Data System (ADS)

    Ezerskaia, Anna; Pereira, S. F.; Urbach, H. P.; Varghese, Babu

    2016-05-01

    Skin health characterized by a system of water and lipids in Stratum Corneum provide protection from harmful external elements and prevent trans-epidermal water loss. Skin hydration (moisture) and sebum (skin surface lipids) are considered to be important factors in skin health; a right balance between these components is an indication of skin health and plays a central role in protecting and preserving skin integrity. In this manuscript we present an infrared spectroscopic method for simultaneous and quantitative measurement of skin hydration and sebum levels utilizing differential detection with three wavelengths 1720, 1750, and 1770 nm, corresponding to the lipid vibrational bands that lie "in between" the prominent water absorption bands. The skin sebum and hydration values on the forehead under natural conditions and its variations to external stimuli were measured using our experimental set-up. The experimental results obtained with the optical set-up show good correlation with the results obtained with the commercially available instruments Corneometer and Sebumeter.

  6. High-definition Fourier transform infrared spectroscopic imaging of prostate tissue

    NASA Astrophysics Data System (ADS)

    Wrobel, Tomasz P.; Kwak, Jin Tae; Kadjacsy-Balla, Andre; Bhargava, Rohit

    2016-03-01

    Histopathology forms the gold standard for cancer diagnosis and therapy, and generally relies on manual examination of microscopic structural morphology within tissue. Fourier-Transform Infrared (FT-IR) imaging is an emerging vibrational spectroscopic imaging technique, especially in a High-Definition (HD) format, that provides the spatial specificity of microscopy at magnifications used in diagnostic surgical pathology. While it has been shown for standard imaging that IR absorption by tissue creates a strong signal where the spectrum at each pixel is a quantitative "fingerprint" of the molecular composition of the sample, here we show that this fingerprint also enables direct digital pathology without the need for stains or dyes for HD imaging. An assessment of the potential of HD imaging to improve diagnostic pathology accuracy is presented.

  7. Development of an ultrahigh-performance infrared detector platform for advanced spectroscopic sensing systems

    NASA Astrophysics Data System (ADS)

    Jain, Manish; Wicks, Gary; Marshall, Andrew; Craig, Adam; Golding, Terry; Hossain, Khalid; McEwan, Ken; Howle, Chris

    2014-05-01

    Laser-based stand-off sensing of threat agents (e.g. explosives, toxic industrial chemicals or chemical warfare agents), by detection of distinct infrared spectral absorption signature of these materials, has made significant advances recently. This is due in part to the availability of infrared and terahertz laser sources with significantly improved power and tunability. However, there is a pressing need for a versatile, high performance infrared sensor that can complement and enhance the recent advances achieved in laser technology. This work presents new, high performance infrared detectors based on III-V barrier diodes. Unipolar barrier diodes, such as the nBn, have been very successful in the MWIR using InAs(Sb)-based materials, and in the MWIR and LWIR using type-II InAsSb/InAs superlattice-based materials. This work addresses the extension of the barrier diode architecture into the SWIR region, using GaSb-based and InAs-based materials. The program has resulted in detectors with unmatched performance in the 2-3 μm spectral range. Temperature dependent characterization has shown dark currents to be diffusion limited and equal to, or within a factor of 5, of the Rule 07 expression for Auger-limited HgCdTe detectors. Furthermore, D* values are superior to those of existing detectors in the 2-3 μm band. Of particular significance to spectroscopic sensing systems is the ability to have near-background limited performance at operation temperatures compatible with robust and reliable solid state thermoelectric coolers.

  8. Mercury And The Moon: Mid-infrared Spectroscopic Measurements Of The Surface

    NASA Astrophysics Data System (ADS)

    Donaldson Hanna, Kerri L.; Sprague, A. L.; Kozlowski, R. W.; Boccafolo, K.; Helbert, J.; Maturilli, A.; Warell, J.

    2006-09-01

    Spectroscopic observations (7.5 - 13 μm) of Mercury and the Moon obtained with MIRSI (Mid-Infrared Spectrometer and Imager) at the NASA Infrared Telescope Facility (IRTF) are presented. The spectra were acquired at mercurian W. longitudes 172 - 282° covering north polar to south polar latitudes. Also acquired were lunar surface measurements of the Apollo 16 landing site and Grimaldi basin and highlands. Mercury measurements covered Caloris Basin, Basin S, and other regions on the side not imaged by Mariner 10. Lunar locations were chosen for their known surface compositions determined from near-infrared spectral telescopic observations and Apollo return samples. Spectra for both bodies were reduced with the same calibration star to minimize reduction differences. Spectral differences between the mercurian locations indicate a heterogeneous composition and differences between Mercury and lunar spectra indicate compositional differences between the two bodies. All collected spectra from Mercury and the Moon show distinct and recognizable features including the Christiansen emissivity maximum and one or more transmission minima. Other features have yet to be identified. True emission spectra of rock and mineral powders with varying grain sizes will be presented for comparison with the data. Acknowledgements: The authors of this paper were Visiting Astronomers at the Infrared Telescope Facility, which is operated by the University of Hawaii under Cooperative Agreement no. NCC 5-538 with the National Aeronautics and Space Administration, Science Mission Directorate, Planetary Astronomy Program. We are especially grateful to Alan Tokunaga and Eric Tollestrup for useful engineering time on the telescope and Don Hunten for helpful discussions. This work was supported by NSF grant AST-0406796.

  9. Infrared and Raman spectroscopic studies on alkali borate glasses: evidence of mixed alkali effect.

    PubMed

    Padmaja, G; Kistaiah, P

    2009-03-19

    A lithium-potassium-borate glass system containing manganese and iron cations has been thoroughly investigated in order to obtain information about the mixed alkali effect and the structural role of both the manganese and iron in such glass hosts. Mixed alkali borate glasses of the (30 - x)Li(2)O - xK(2)O - 10CdO/ZnO - 59B(2)O(3) (x = 0, 10, 15, 20, and 30) doped with 1MnO(2)/1Fe(2)O(3) system were prepared by a melt quench technique. The amorphous phase of the prepared glass samples was confirmed from their X-ray diffraction. The spectroscopic properties of glass samples were studied using infrared (IR) and Raman spectroscopic techniques. The density of all the prepared glasses was measured using Archimedes principle. Molar volumes were estimated from the density data. IR spectra of these glasses revealed a dramatic variation of three- and four-coordinated boron structures as a function of mixed alkali concentration. The vibrations due to Li-O, K-O, and MnO(4)/FeO(4) arrangements are consistent in all the compositions and show a nonlinear variation in the intensity with alkali content. Raman spectra of different alkali combinations with CdO and ZnO present drastic changes in the intensity of various Raman bands. The observation of disappearance and reappearance of IR and Raman bands as a function of various alkali concentrations is an important result pertaining to the mixed alkali effect in borate glasses. Acting as complementary spectroscopic techniques, both types of measurements, IR and Raman, revealed that the network structure of the studied glasses is mainly based on BO(3) and BO(4) units placed in different structural groups, the BO(3) units being dominant. The measured IR and Raman spectra of different glasses are used to clarify the optical properties of the present glasses correlating them with their structure and composition. PMID:19235995

  10. Discovery of Three Distant, Cold Brown Dwarfs in the WFC3 Infrared Spectroscopic Parallels Survey

    NASA Astrophysics Data System (ADS)

    Masters, D.; McCarthy, P.; Burgasser, A. J.; Hathi, N. P.; Malkan, M.; Ross, N. R.; Siana, B.; Scarlata, C.; Henry, A.; Colbert, J.; Atek, H.; Rafelski, M.; Teplitz, H.; Bunker, A.; Dressler, A.

    2012-06-01

    We present the discovery of three late-type (>=T4.5) brown dwarfs, including a probable Y dwarf, in the WFC3 Infrared Spectroscopic Parallels (WISP) survey. We use the G141 grism spectra to determine the spectral types of the dwarfs and derive distance estimates based on a comparison with nearby T dwarfs with known parallaxes. These are the most distant spectroscopically confirmed T/Y dwarfs, with the farthest at an estimated distance of ~400 pc. We compare the number of cold dwarfs found in the WISP survey with simulations of the brown dwarf mass function. The number found is generally consistent with an initial stellar mass function dN/dMvpropM -α with α = 0.0-0.5, although the identification of a Y dwarf is somewhat surprising and may be indicative of either a flatter absolute magnitude/spectral-type relation than previously reported or an upturn in the number of very-late-type brown dwarfs in the observed volume.

  11. DISCOVERY OF THREE DISTANT, COLD BROWN DWARFS IN THE WFC3 INFRARED SPECTROSCOPIC PARALLELS SURVEY

    SciTech Connect

    Masters, D.; Siana, B.; McCarthy, P.; Hathi, N. P.; Dressler, A.; Burgasser, A. J.; Malkan, M.; Ross, N. R.; Scarlata, C.; Henry, A.; Colbert, J.; Atek, H.; Rafelski, M.; Teplitz, H.; Bunker, A.

    2012-06-10

    We present the discovery of three late-type ({>=}T4.5) brown dwarfs, including a probable Y dwarf, in the WFC3 Infrared Spectroscopic Parallels (WISP) survey. We use the G141 grism spectra to determine the spectral types of the dwarfs and derive distance estimates based on a comparison with nearby T dwarfs with known parallaxes. These are the most distant spectroscopically confirmed T/Y dwarfs, with the farthest at an estimated distance of {approx}400 pc. We compare the number of cold dwarfs found in the WISP survey with simulations of the brown dwarf mass function. The number found is generally consistent with an initial stellar mass function dN/dM{proportional_to}M{sup -{alpha}} with {alpha} = 0.0-0.5, although the identification of a Y dwarf is somewhat surprising and may be indicative of either a flatter absolute magnitude/spectral-type relation than previously reported or an upturn in the number of very-late-type brown dwarfs in the observed volume.

  12. A NEAR-INFRARED SPECTROSCOPIC STUDY OF YOUNG FIELD ULTRACOOL DWARFS

    SciTech Connect

    Allers, K. N.; Liu, Michael C.

    2013-08-01

    We present a near-infrared (0.9-2.4 {mu}m) spectroscopic study of 73 field ultracool dwarfs having spectroscopic and/or kinematic evidence of youth ( Almost-Equal-To 10-300 Myr). Our sample is composed of 48 low-resolution (R Almost-Equal-To 100) spectra and 41 moderate-resolution spectra (R {approx}> 750-2000). First, we establish a method for spectral typing M5-L7 dwarfs at near-IR wavelengths that is independent of gravity. We find that both visual and index-based classification in the near-IR provides consistent spectral types with optical spectral types, though with a small systematic offset in the case of visual classification at J and K band. Second, we examine features in the spectra of {approx}10 Myr ultracool dwarfs to define a set of gravity-sensitive indices based on FeH, VO, K I, Na I, and H-band continuum shape. We then create an index-based method for classifying the gravities of M6-L5 dwarfs that provides consistent results with gravity classifications from optical spectroscopy. Our index-based classification can distinguish between young and dusty objects. Guided by the resulting classifications, we propose a set of low-gravity spectral standards for the near-IR. Finally, we estimate the ages corresponding to our gravity classifications.

  13. Electronic Time-Gated and Spectroscopic Near-Infrared Imaging of Lesions in Human Tissues*

    NASA Astrophysics Data System (ADS)

    Gayen, S. K.; Alrubaiee, M.; Alfano, R. R.; Koutcher, J.; Savage, H.

    2000-03-01

    Near-infrared (NIR) transillumination imaging is used to investigate normal and cancerous tissues of human breast, thyroid, and parotid gland. The time-sliced imaging arrangement uses 130-fs, 1 kHz repetition-rate, 800 nm pulses from a Ti:sapphire laser and amplifier system for sample illumination and a CCD camera coupled to a gated image intensifier for recording two-dimensional (2D) images. Images recorded with earlier temporal slices of transmitted light highlight cancerous tissues while those recorded with later slices accentuate normal fibrous tissues. The spectroscopic imaging arrangement uses 1210-1300 nm tunable output of a Cr:forsterite laser for sample illumination, a Fourier space gate to discriminate against multiple-scattered light, and a NIR area camera to record 2D images. When light is tuned to a known absorption resonance of a particular tissue type, a marked enhancement in image contrast is observed which is indicative of the diagnostic potential of spectroscopic imaging.

  14. Near infrared spectroscopic analysis of single malt Scotch whisky on an optofluidic chip.

    PubMed

    Ashok, Praveen C; Praveen, Bavishna B; Dholakia, K

    2011-11-01

    Standardization and quality monitoring of alcoholic beverages is an important issue in the liquor production industry. Various spectroscopic techniques have proved useful for tackling this problem. An ideal sensing device for alcoholic beverages should be able to detect the quality of alcohol with a small amount of sample at a low acquisition time using a portable and easy to use device. We propose the use of near infra-red spectroscopy on an optofluidic chip for quality monitoring of single malt Scotch whisky. This is chip upon which we have previously realized waveguide confined Raman spectroscopy. Analysis on this alignment-free, portable chip may be performed in only 2 seconds with a sample volume of only 20 µl. Using a partial least square (PLS) calibration, we demonstrate that the alcohol content in the beverage may be predicted to within a 1% prediction error. Principal component analysis (PCA) was employed for successful classification of whiskies based upon their age, type and cask. The prospect of implementing an optofluidic analogue of a conventional fiber based spectroscopic probe allows a rapid analysis of alcoholic beverages with dramatically reduced sample volumes.

  15. An in situ infrared spectroscopic investigation of the pyrolysis of ethylene glycol encapsulated in silica sodalite.

    SciTech Connect

    Maroni, V. A.; Epperson, S. J.; Chemical Engineering; Univ. of Tulsa

    2001-11-29

    The thermal stability and pyrolysis of ethylene glycol (EG) encapsulated in the sodalite cages of all-silica sodalite were studied by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and transmission infrared spectroscopy. Evidence for the presence of encapsulated CO2 formed as a result of partial decomposition of EG molecules was observed starting at about 600 K. Complete, irreversible pyrolysis of the EG occurred between 675 and 775 K. After treatment at 775 K, the CO2 remained encapsulated in the sodalite framework, even though there were spectroscopic indications that the pyrolysis caused a disordering of the sodalite framework. There appeared to be a temperature dependence of the conformational interactions of the EG O---H groups up to 600 K, which was mainly manifested as a weakening of intramolecular hydrogen bonding. The only detectable encapsulated products of the EG decomposition in an inert (N2 or Ar) environment were CO2 and a carbonaceous (coke- or soot-like) residue. There was no evidence of other encapsulated products, such as CO, H2, H2O, or light hydrocarbons.

  16. An amorphous monolayer: Infrared spectroscopic and theoretical studies of SO2 on NaCl (100)

    NASA Astrophysics Data System (ADS)

    Berg, Otto; Ewing, George E.; Meredith, Andrew W.; Stone, Anthony J.

    1996-05-01

    At temperatures between 100 and 110 K, exposing the (100) face of NaCl to unsaturated SO2 gas yields a stable adlayer. Infrared spectra of adsorbed SO2 contain complex resonances near the origins of the molecular symmetric and asymmetric stretching vibrations. On photometric grounds the absolute coverage of the surface is found to be one molecule per exposed Na+Cl- ion pair. The spectra of this monolayer consist of several sharp lines overlapping one broad feature for each molecular mode. By comparison to vibrational excitons in simpler systems, the coexistence of crystalline and amorphous adlayer structures is strongly indicated. This partial ordering is pressure dependent, and develops spontaneously on a time scale of minutes. The disordered component, in contrast, is never in equilibrium with the gas phase. Computational simulations have detailed the microscopic basis of this behavior. Accurate ab initio models of the SO2 molecule and NaCl(100) surface were used in a Monte Carlo simulation of the experimental conditions. At both half and full coverage, an amorphous two-dimensional condensate developed. This is minimally consistent with the polarized infrared photometry. Seemingly equilibrated Monte Carlo runs retained some memory of the initial molecular configuration, again consistent with hysteresis observed in the spectroscopic experiments. No structural order developed in the simulations, but the energetic state of affairs was clarified: the potential driving adsorption and condensation is deep in comparison to available thermal energy, but relatively insensitive to molecular orientation.

  17. Spectroscopic Study of Terahertz Generation in Mid-Infrared Quantum Cascade Lasers.

    PubMed

    Jiang, Yifan; Vijayraghavan, Karun; Jung, Seungyong; Jiang, Aiting; Kim, Jae Hyun; Demmerle, Frederic; Boehm, Gerhard; Amann, Markus C; Belkin, Mikhail A

    2016-02-16

    Terahertz quantum cascade laser sources based on intra-cavity difference-frequency generation are currently the only room-temperature mass-producible diode-laser-like emitters of coherent 1-6 THz radiation. Device performance has improved dramatically over the past few years to reach milliwatt-level power output and broad tuning from 1.2 to 5.9 THz, all at room-temperature. Terahertz output in these sources originates from intersubband optical nonlinearity in the laser active region. Here we report the first comprehensive spectroscopic study of the optical nonlinearity and investigate its dependence on the mid-infrared pump frequencies. Our work shows that the terahertz generation efficiency can vary by a factor of 2 or greater depending on the spectral position of the mid-infrared pumps for a fixed THz difference-frequency. We have also measured for the first time the linewidth for transitions between the lower quantum cascade laser states, which is critical for determining terahertz nonlinearity and predicting optical loss in quantum cascade laser waveguides.

  18. Fourier transform infrared spectroscopic imaging of cardiac tissue to detect collagen deposition after myocardial infarction

    NASA Astrophysics Data System (ADS)

    Cheheltani, Rabee; Rosano, Jenna M.; Wang, Bin; Sabri, Abdel Karim; Pleshko, Nancy; Kiani, Mohammad F.

    2012-05-01

    Myocardial infarction often leads to an increase in deposition of fibrillar collagen. Detection and characterization of this cardiac fibrosis is of great interest to investigators and clinicians. Motivated by the significant limitations of conventional staining techniques to visualize collagen deposition in cardiac tissue sections, we have developed a Fourier transform infrared imaging spectroscopy (FT-IRIS) methodology for collagen assessment. The infrared absorbance band centered at 1338 cm-1, which arises from collagen amino acid side chain vibrations, was used to map collagen deposition across heart tissue sections of a rat model of myocardial infarction, and was compared to conventional staining techniques. Comparison of the size of the collagen scar in heart tissue sections as measured with this methodology and that of trichrome staining showed a strong correlation (R=0.93). A Pearson correlation model between local intensity values in FT-IRIS and immuno-histochemical staining of collagen type I also showed a strong correlation (R=0.86). We demonstrate that FT-IRIS methodology can be utilized to visualize cardiac collagen deposition. In addition, given that vibrational spectroscopic data on proteins reflect molecular features, it also has the potential to provide additional information about the molecular structure of cardiac extracellular matrix proteins and their alterations.

  19. Spectroscopic technique with wide range of wavelength information improves near-infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Eda, Hideo; Aoki, Hiromichi; Eura, Shigeru; Ebe, Kazutoshi

    2009-02-01

    Near-infrared spectroscopy (NIRS) calculates hemoglobin parameters, such as oxygenated hemoglobin (oxyHb) and deoxygenated hemoglobin (deoxyHb) using the near-infrared light around the wavelength of 800nm. This is based on the modified-Lambert-Beer's law that changes in absorbance are proportional to changes in hemoglobin parameters. Many conventional measurement methods uses only a few wavelengths, however, in this research, basic examination of NIRS measurement was approached by acquiring wide range of wavelength information. Venous occlusion test was performed by using the blood pressure cuff around the upper arm. Pressure of 100mmHg was then applied for about 3 minutes. During the venous occlusion, the spectrum of the lower arm muscles was measured every 15 seconds, within the range of 600 to 1100nm. It was found that other wavelength bands hold information correlating to this venous occlusion task. Technique of improving the performance of NIRS measurement using the Spectroscopic Method is very important for Brain science.

  20. Spectroscopic Study of Terahertz Generation in Mid-Infrared Quantum Cascade Lasers

    PubMed Central

    Jiang, Yifan; Vijayraghavan, Karun; Jung, Seungyong; Jiang, Aiting; Kim, Jae Hyun; Demmerle, Frederic; Boehm, Gerhard; Amann, Markus C.; Belkin, Mikhail A.

    2016-01-01

    Terahertz quantum cascade laser sources based on intra-cavity difference-frequency generation are currently the only room-temperature mass-producible diode-laser-like emitters of coherent 1–6 THz radiation. Device performance has improved dramatically over the past few years to reach milliwatt-level power output and broad tuning from 1.2 to 5.9 THz, all at room-temperature. Terahertz output in these sources originates from intersubband optical nonlinearity in the laser active region. Here we report the first comprehensive spectroscopic study of the optical nonlinearity and investigate its dependence on the mid-infrared pump frequencies. Our work shows that the terahertz generation efficiency can vary by a factor of 2 or greater depending on the spectral position of the mid-infrared pumps for a fixed THz difference-frequency. We have also measured for the first time the linewidth for transitions between the lower quantum cascade laser states, which is critical for determining terahertz nonlinearity and predicting optical loss in quantum cascade laser waveguides. PMID:26879901

  1. Near infrared spectroscopic calibration models for real time monitoring of powder density.

    PubMed

    Román-Ospino, Andrés D; Singh, Ravendra; Ierapetritou, Marianthi; Ramachandran, Rohit; Méndez, Rafael; Ortega-Zuñiga, Carlos; Muzzio, Fernando J; Romañach, Rodolfo J

    2016-10-15

    Near infrared spectroscopic (NIRS) calibration models for real time prediction of powder density (tap, bulk and consolidated) were developed for a pharmaceutical formulation. Powder density is a critical property in the manufacturing of solid oral dosages, related to critical quality attributes such as tablet mass, hardness and dissolution. The establishment of calibration techniques for powder density is highly desired towards the development of control strategies. Three techniques were evaluated to obtain the required variation in powder density for calibration sets: 1) different tap density levels (for a single component), 2) generating different strain levels in powders blends (and as consequence powder density), through a modified shear Couette Cell, and 3) applying normal forces during a compressibility test with a powder rheometer to a pharmaceutical blend. For each variation in powder density, near infrared spectra were acquired to develop partial least squares (PLS) calibration models. Test samples were predicted with a relative standard error of prediction of 0.38%, 7.65% and 0.93% for tap density (single component), shear and rheometer respectively. Spectra obtained in real time in a continuous manufacturing (CM) plant were compared to the spectra from the three approaches used to vary powder density. The calibration based on the application of different strain levels showed the greatest similarity with the blends produced in the CM plant.

  2. Predicting future space near-IR grism surveys using the WFC3 infrared spectroscopic parallels survey

    SciTech Connect

    Colbert, James W.; Atek, Hakim; Teplitz, Harry; Rafelski, Marc; Bunker, Andrew; Ross, Nathaniel; Malkan, Matt; Scarlata, Claudia; Bedregal, Alejandro G.; Dominguez, Alberto; Masters, Dan; Siana, Brian; Dressler, Alan; McCarthy, Patrick; Henry, Alaina; Martin, Crystal L.

    2013-12-10

    We present near-infrared emission line counts and luminosity functions from the Hubble Space Telescope Wide Field Camera 3 Infrared Spectroscopic Parallels (WISP) program for 29 fields (0.037 deg{sup 2}) observed using both the G102 and G141 grism. Altogether we identify 1048 emission line galaxies with observed equivalent widths greater than 40 Å, 467 of which have multiple detected emission lines. We use simulations to correct for significant (>20%) incompleteness introduced in part by the non-dithered, non-rotated nature of the grism parallels. The WISP survey is sensitive to fainter flux levels ((3-5) × 10{sup –17} erg s{sup –1} cm{sup –2}) than the future space near-infrared grism missions aimed at baryonic acoustic oscillation cosmology ((1-4) × 10{sup –16} erg s{sup –1} cm{sup –2}), allowing us to probe the fainter emission line galaxies that the shallower future surveys may miss. Cumulative number counts of 0.7 < z < 1.5 galaxies reach 10,000 deg{sup –2} above an Hα flux of 2 × 10{sup –16} erg s{sup –1} cm{sup –2}. Hα-emitting galaxies with comparable [O III] flux are roughly five times less common than galaxies with just Hα emission at those flux levels. Galaxies with low Hα/[O III] ratios are very rare at the brighter fluxes that future near-infrared grism surveys will probe; our survey finds no galaxies with Hα/[O III] < 0.95 that have Hα flux greater than 3 × 10{sup –16} erg s{sup –1} cm{sup –2}. Our Hα luminosity function contains a comparable number density of faint line emitters to that found by the Near IR Camera and Multi-Object Spectrometer near-infrared grism surveys, but significantly fewer (factors of 3-4 less) high-luminosity emitters. We also find that our high-redshift (z = 0.9-1.5) counts are in agreement with the high-redshift (z = 1.47) narrowband Hα survey of HiZELS (Sobral et al.), while our lower redshift luminosity function (z = 0.3-0.9) falls slightly below their z = 0.84 result. The evolution

  3. Predicting Future Space Near-IR Grism Surveys Using the WFC3 Infrared Spectroscopic Parallels Survey

    NASA Astrophysics Data System (ADS)

    Colbert, James W.; Teplitz, Harry; Atek, Hakim; Bunker, Andrew; Rafelski, Marc; Ross, Nathaniel; Scarlata, Claudia; Bedregal, Alejandro G.; Dominguez, Alberto; Dressler, Alan; Henry, Alaina; Malkan, Matt; Martin, Crystal L.; Masters, Dan; McCarthy, Patrick; Siana, Brian

    2013-12-01

    We present near-infrared emission line counts and luminosity functions from the Hubble Space Telescope Wide Field Camera 3 Infrared Spectroscopic Parallels (WISP) program for 29 fields (0.037 deg2) observed using both the G102 and G141 grism. Altogether we identify 1048 emission line galaxies with observed equivalent widths greater than 40 Å, 467 of which have multiple detected emission lines. We use simulations to correct for significant (>20%) incompleteness introduced in part by the non-dithered, non-rotated nature of the grism parallels. The WISP survey is sensitive to fainter flux levels ((3-5) × 10-17 erg s-1 cm-2) than the future space near-infrared grism missions aimed at baryonic acoustic oscillation cosmology ((1-4) × 10-16 erg s-1 cm-2), allowing us to probe the fainter emission line galaxies that the shallower future surveys may miss. Cumulative number counts of 0.7 < z < 1.5 galaxies reach 10,000 deg-2 above an Hα flux of 2 × 10-16 erg s-1 cm-2. Hα-emitting galaxies with comparable [O III] flux are roughly five times less common than galaxies with just Hα emission at those flux levels. Galaxies with low Hα/[O III] ratios are very rare at the brighter fluxes that future near-infrared grism surveys will probe; our survey finds no galaxies with Hα/[O III] < 0.95 that have Hα flux greater than 3 × 10-16 erg s-1 cm-2. Our Hα luminosity function contains a comparable number density of faint line emitters to that found by the Near IR Camera and Multi-Object Spectrometer near-infrared grism surveys, but significantly fewer (factors of 3-4 less) high-luminosity emitters. We also find that our high-redshift (z = 0.9-1.5) counts are in agreement with the high-redshift (z = 1.47) narrowband Hα survey of HiZELS (Sobral et al.), while our lower redshift luminosity function (z = 0.3-0.9) falls slightly below their z = 0.84 result. The evolution in both the Hα luminosity function from z = 0.3-1.5 and the [O III] luminosity function from z = 0.7-2.3 is

  4. Ultra-Trace Chemical Sensing with Long-Wave Infrared Cavity-Enhanced Spectroscopic Sensors

    SciTech Connect

    Taubman, Matthew S.; Myers, Tanya L.; Cannon, Bret D.; Williams, Richard M.; Schultz, John F.

    2003-02-20

    The infrared sensors task of Pacific Northwest National Laboratory's (PNNL's) Remote Spectroscopy Project (Task B of Project PL211) is focused on the science and technology of remote and in-situ spectroscopic chemical sensors for detecting proliferation and coun-tering terrorism. Missions to be addressed by remote chemical sensor development in-clude detecting proliferation of nuclear or chemical weapons, and providing warning of terrorist use of chemical weapons. Missions to be addressed by in-situ chemical sensor development include countering terrorism by screening luggage, personnel, and shipping containers for explosives, firearms, narcotics, chemical weapons, or chemical weapons residues, and mapping contaminated areas. The science and technology is also relevant to chemical weapons defense, air operations support, monitoring emissions from chemi-cal weapons destruction or industrial activities, law enforcement, medical diagnostics, and other applications. Sensors for most of these missions will require extreme chemical sensitivity and selectiv-ity because the signature chemicals of importance are expected to be present in low con-centrations or have low vapor pressures, and the ambient air is likely to contain pollutants or other chemicals with interfering spectra. Cavity-enhanced chemical sensors (CES) that draw air samples into optical cavities for laser-based interrogation of their chemical content promise real-time, in-situ chemical detection with extreme sensitivity to specified target molecules and superb immunity to spectral interference and other sources of noise. PNNL is developing CES based on quantum cascade (QC) lasers that operate in the mid-wave infrared (MWIR - 3 to 5 microns) and long-wave infrared (LWIR - 8 to 14 mi-crons), and CES based on telecommunications lasers operating in the short-wave infrared (SWIR - 1 to 2 microns). All three spectral regions are promising because smaller mo-lecular absorption cross sections in the SWIR are offset

  5. Diffuse reflectance infrared spectroscopic identification of dispersant/particle bonding mechanisms in functional inks.

    PubMed

    Deiner, L Jay; Farjami, Elaheh

    2015-05-08

    In additive manufacturing, or 3D printing, material is deposited drop by drop, to create micron to macroscale layers. A typical inkjet ink is a colloidal dispersion containing approximately ten components including solvent, the nano to micron scale particles which will comprise the printed layer, polymeric dispersants to stabilize the particles, and polymers to tune layer strength, surface tension and viscosity. To rationally and efficiently formulate such an ink, it is crucial to know how the components interact. Specifically, which polymers bond to the particle surfaces and how are they attached? Answering this question requires an experimental procedure that discriminates between polymer adsorbed on the particles and free polymer. Further, the method must provide details about how the functional groups of the polymer interact with the particle. In this protocol, we show how to employ centrifugation to separate particles with adsorbed polymer from the rest of the ink, prepare the separated samples for spectroscopic measurement, and use Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS) for accurate determination of dispersant/particle bonding mechanisms. A significant advantage of this methodology is that it provides high level mechanistic detail using only simple, commonly available laboratory equipment. This makes crucial data available to almost any formulation laboratory. The method is most useful for inks composed of metal, ceramic, and metal oxide particles in the range of 100 nm or greater. Because of the density and particle size of these inks, they are readily separable with centrifugation. Further, the spectroscopic signatures of such particles are easy to distinguish from absorbed polymer. The primary limitation of this technique is that the spectroscopy is performed ex-situ on the separated and dried particles as opposed to the particles in dispersion. However, results from attenuated total reflectance spectra of the wet separated

  6. Diffuse reflectance infrared spectroscopic identification of dispersant/particle bonding mechanisms in functional inks.

    PubMed

    Deiner, L Jay; Farjami, Elaheh

    2015-01-01

    In additive manufacturing, or 3D printing, material is deposited drop by drop, to create micron to macroscale layers. A typical inkjet ink is a colloidal dispersion containing approximately ten components including solvent, the nano to micron scale particles which will comprise the printed layer, polymeric dispersants to stabilize the particles, and polymers to tune layer strength, surface tension and viscosity. To rationally and efficiently formulate such an ink, it is crucial to know how the components interact. Specifically, which polymers bond to the particle surfaces and how are they attached? Answering this question requires an experimental procedure that discriminates between polymer adsorbed on the particles and free polymer. Further, the method must provide details about how the functional groups of the polymer interact with the particle. In this protocol, we show how to employ centrifugation to separate particles with adsorbed polymer from the rest of the ink, prepare the separated samples for spectroscopic measurement, and use Diffuse Reflectance Fourier Transform Infrared Spectroscopy (DRIFTS) for accurate determination of dispersant/particle bonding mechanisms. A significant advantage of this methodology is that it provides high level mechanistic detail using only simple, commonly available laboratory equipment. This makes crucial data available to almost any formulation laboratory. The method is most useful for inks composed of metal, ceramic, and metal oxide particles in the range of 100 nm or greater. Because of the density and particle size of these inks, they are readily separable with centrifugation. Further, the spectroscopic signatures of such particles are easy to distinguish from absorbed polymer. The primary limitation of this technique is that the spectroscopy is performed ex-situ on the separated and dried particles as opposed to the particles in dispersion. However, results from attenuated total reflectance spectra of the wet separated

  7. AKARI NEAR-INFRARED SPECTROSCOPIC SURVEY FOR CO{sub 2} IN 18 COMETS

    SciTech Connect

    Ootsubo, Takafumi; Kawakita, Hideyo; Hamada, Saki; Kobayashi, Hitomi; Yamaguchi, Mitsuru; Usui, Fumihiko; Nakagawa, Takao; Ueno, Munetaka; Ishiguro, Masateru; Sekiguchi, Tomohiko; Watanabe, Jun-ichi; Sakon, Itsuki; Shimonishi, Takashi; Onaka, Takashi

    2012-06-10

    We conducted a spectroscopic survey of cometary volatiles with the Infrared Camera on board the Japanese infrared satellite AKARI in the wavelength range from 2.5 to 5 {mu}m. In our survey, 18 comets, including both the Oort cloud comets and the Jupiter-family comets, were observed in the period from 2008 June to 2010 January, most of which were observed at least twice. The prominent emission bands in the observed spectra are the fundamental vibrational bands of water (H{sub 2}O) at 2.7 {mu}m and carbon dioxide (CO{sub 2}) at 4.3 {mu}m. The fundamental vibrational band of carbon monoxide (CO) around 4.7 {mu}m and the broad emission feature, probably related to carbon-hydrogen-bearing molecules, can also be recognized around the 3.3-3.5-{mu}m region in some of the comets. With respect to H{sub 2}O, gas production rate ratios of CO{sub 2} have been derived in 17 comets, except for the comet 29P/Schwassmann-Wachmann 1. Our data set provides the largest homogeneous database of CO{sub 2}/H{sub 2}O production rate ratios in comets obtained so far. The CO{sub 2}/H{sub 2}O production rate ratios are considered to reflect the composition of cometary ice when a comet is observed at a heliocentric distance within {approx}2.5 AU, since H{sub 2}O ice fully sublimates there. The CO{sub 2}/H{sub 2}O ratio in cometary ice spans from several to {approx}30% among the comets observed at <2.5 AU (13 out of the 17 comets). Alternatively, the ratio of CO/CO{sub 2} in the comets seems to be smaller than unity based on our observations, although we only obtain upper limits for CO in most of the comets.

  8. Progress Towards a High-Precision Infrared Spectroscopic Survey of the H_3^+ Ion

    NASA Astrophysics Data System (ADS)

    Perry, Adam J.; Hodges, James N.; Markus, Charles R.; Kocheril, G. Stephen; Jenkins, Paul A., II; McCall, Benjamin J.

    2015-06-01

    The trihydrogen cation, H_3^+, represents one of the most important and fundamental molecular systems. Having only two electrons and three nuclei, H_3^+ is the simplest polyatomic system and is a key testing ground for the development of new techniques for calculating potential energy surfaces and predicting molecular spectra. Corrections that go beyond the Born-Oppenheimer approximation, including adiabatic, non-adiabatic, relativistic, and quantum electrodynamic corrections are becoming more feasible to calculate. As a result, experimental measurements performed on the H_3^+ ion serve as important benchmarks which are used to test the predictive power of new computational methods. By measuring many infrared transitions with precision at the sub-MHz level it is possible to construct a list of the most highly precise experimental rovibrational energy levels for this molecule. Until recently, only a select handful of infrared transitions of this molecule have been measured with high precision (˜ 1 MHz). Using the technique of Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy, we are aiming to produce the largest high-precision spectroscopic dataset for this molecule to date. Presented here are the current results from our survey along with a discussion of the combination differences analysis used to extract the experimentally determined rovibrational energy levels. O. Polyansky, et al., Phil. Trans. R. Soc. A (2012), 370, 5014. M. Pavanello, et al., J. Chem. Phys. (2012), 136, 184303. L. Diniz, et al., Phys. Rev. A (2013), 88, 032506. L. Lodi, et al., Phys. Rev. A (2014), 89, 032505. J. Hodges, et al., J. Chem. Phys (2013), 139, 164201.

  9. Matrix isolation infrared spectroscopic study of the vapor species over heated ReO{sub 3}

    SciTech Connect

    Almond, M.J.; Orrin, R.H.; Ogden, J.S.

    1996-02-01

    The vapor phase species over ReO{sub 3} heated in vacuo to approx 400C have been trapped in argon or nitrogen matrices at approx 12 K. The only species within such matrices detected by infrared spectroscopy is Re{sub 2}O{sub 7}. The bands of matrix-isolated Re{sub 2}O{sub 7} have been assigned by comparison with the spectrum of the gaseous compound. Most of the isolated Re{sub 2}O{sub 7} is shown to be in the monomeric form; thus, an infrared absorption at 916.5 cm{sup {minus}1} (N{sub 2} matrix), which had previously been assigned to an aggregate of Re{sub 2}O{sub 7} may, on the basis of annealing experiments, be attributed to the monomer. The solid remaining in the sample tube following heating of the ReO{sub 3} sample consists of ReO{sub 2} in both the monoclinic and orthorhombic crystal forms alongside some unreacted cubic ReO{sub 3} and a small amount of orthorhombic Re{sub 2}O{sub 7}. Thus, it is found that thermal decomposition of ReO{sub 3} in vacuo at 400 C follows the expected disproportionation route. The authors find no spectroscopic evidence for the existence of other species, such as ReO{sub 3} or HReO{sub 4}, in the vapor above heated ReO{sub 3}. This finding is in contrast to the results of earlier mass spectrometric studies that suggested that molecular ReO{sub 3} was present in the vapor together with Re{sub 2}O{sub 7}.

  10. On the importance of image formation optics in the design of infrared spectroscopic imaging systems.

    PubMed

    Mayerich, David; van Dijk, Thomas; Walsh, Michael J; Schulmerich, Matthew V; Carney, P Scott; Bhargava, Rohit

    2014-08-21

    Infrared spectroscopic imaging provides micron-scale spatial resolution with molecular contrast. While recent work demonstrates that sample morphology affects the recorded spectrum, considerably less attention has been focused on the effects of the optics, including the condenser and objective. This analysis is extremely important, since it will be possible to understand effects on recorded data and provides insight for reducing optical effects through rigorous microscope design. Here, we present a theoretical description and experimental results that demonstrate the effects of commonly-employed cassegranian optics on recorded spectra. We first combine an explicit model of image formation and a method for quantifying and visualizing the deviations in recorded spectra as a function of microscope optics. We then verify these simulations with measurements obtained from spatially heterogeneous samples. The deviation of the computed spectrum from the ideal case is quantified via a map which we call a deviation map. The deviation map is obtained as a function of optical elements by systematic simulations. Examination of deviation maps demonstrates that the optimal optical configuration for minimal deviation is contrary to prevailing practice in which throughput is maximized for an instrument without a sample. This report should be helpful for understanding recorded spectra as a function of the optics, the analytical limits of recorded data determined by the optical design, and potential routes for optimization of imaging systems.

  11. Low Mass Galaxy Evolution In The WFC3 Infrared Spectroscopic Parallels Survey

    NASA Astrophysics Data System (ADS)

    Colbert, James; Teplitz, Harry; Scarlata, Claudia; Siana, Brian; Malkan, Matt; McCarthy, Patrick; Henry, Alaina; Atek, Hakim; Fosbury, Robert; Ross, Nathanial; Hathi, Nimish; Bridge, Carrie; Bunker, Andrew; Dressler, Alan; Shim, Hyunjin; Bedregal, Alejandro; Dominguez, Alberto; Rafelski, Marc; Masters, Dan

    2012-12-01

    The WFC3 Infrared Spectroscopic Parallel (WISP) Survey uses nearly 1000 HST orbits to study the epoch of peak star formation. Its slitless grism spectroscopy over a wide, continuous spectral range (0.8-1.7 micron) provides an unbiased selection of thousands of emission line galaxies over 0.5 < z < 2.5. Hundreds of these galaxies are detected in multiple emission lines, allowing for important diagnostics of metallicity and dust extinction. We propose deep 3.6 micron imaging (5 sigma, 0.9 micro-Jy) of 39 of the deepest WISP fields observed with the combination of G102+G141 grisms, in order to detect emission-line galaxies down to 0.1 L*. Combined with our HST optical and near-IR photometry, these IRAC data will be critical to determining accurate stellar masses for both passive and active galaxies in our survey. We will determine the evolution of the faint end slope of the stellar mass function and the mass-metallicity relation down to low-mass galaxies, including measurement of a possible mass-metallicity-SFR fundamental plane. The addition of the IRAC photometry will also provide much stronger constraints on dust extinction and star formation history, especially when combined with information available from the emission lines themselves.

  12. Measuring Low Mass Galaxies In The WFC3 Infrared Spectroscopic Parallels Survey

    NASA Astrophysics Data System (ADS)

    Colbert, James; Teplitz, Harry; Scarlata, Claudia; Siana, Brian; Malkan, Matt; McCarthy, Patrick; Henry, Alaina; Atek, Hakim; Fosbury, Robert; Ross, Nathanial; Hathi, Nimish; Bridge, Carrie; Bunker, Andrew; Dressler, Alan; Shim, Hyunjin; Bedregal, Alejandro; Dominguez, Alberto; Rafelski, Marc; Masters, Dan; Martin, Crystal; Dai, Sophia

    2015-10-01

    The WFC3 Infrared Spectroscopic Parallel (WISP) Survey uses over 1800 HST orbits to study galaxy evolution over a majority of cosmic history. Its slitless grism spectroscopy over a wide, continuous spectral range (0.8-1.7 micron) provides an unbiased selection of thousands of emission line galaxies over 0.5 < z < 2.5. Hundreds of these galaxies are detected in multiple emission lines, allowing for important diagnostics of metallicity and dust extinction. We propose deep 3.6 micron imaging (5 sigma, 0.9 micro-Jy) of 60 of the deepest WISP fields observed with the combination of G102+G141 grisms, in order to detect emission-line galaxies down to 0.1 L* and masses below 10^8 Mo. Combined with our HST optical and near-IR photometry, these IRAC data will be critical to determining accurate stellar masses for both passive and active galaxies in our survey. We will determine the evolution of the faint end slope of the stellar mass function and the mass-metallicity relation down to low-mass galaxies. The addition of the IRAC photometry will also provide much stronger constraints on dust extinction and star formation history, especially when combined with information available from the emission lines themselves.

  13. Real-time near-infrared spectroscopic inspection system for adulterated sesame oil

    NASA Astrophysics Data System (ADS)

    Kang, Sukwon; Lee, Kang-jin; Son, Jaeryong; Kim, Moon S.

    2010-04-01

    Sesame seed oil is popular and expensive in Korea and has been often mixed with other less expensive vegetable oils. The objective of this research is to develop an economical and rapid adulteration determination system for sesame seed oil mixed with other vegetable oils. A recently developed inspection system consists of a light source, a measuring unit, a spectrophotometer, fiber optics, and a data acquisition module. A near-infrared transmittance spectroscopic method was used to develop the prediction model using Partial Least Square (PLS). Sesame seed oil mixed with a range of concentrations of corn, or perilla, or soybean oil was measured in 8 mm diameter glass tubes. For the model development, a correlation coefficient value of 0.98 was observed for corn, perilla, and soybean oil mixtures with standard errors of correlation of 6.32%, 6.16%, and 5.67%, respectively. From the prediction model, the correlation coefficients of corn oil, perilla oil, and soybean oil were 0.98, 0.97 and 0.98, respectively. The Standard Error of Prediction (SEP) for corn oil, perilla oil, and soybean oil were 6.52%, 6.89% and 5.88%, respectively. The results indicated that this system can potentially be used as a rapid non-destructive adulteration analysis tool for sesame seed oil mixed with other vegetable oils.

  14. Practical protocols for fast histopathology by Fourier transform infrared spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Keith, Frances N.; Reddy, Rohith K.; Bhargava, Rohit

    2008-02-01

    Fourier transform infrared (FT-IR) spectroscopic imaging is an emerging technique that combines the molecular selectivity of spectroscopy with the spatial specificity of optical microscopy. We demonstrate a new concept in obtaining high fidelity data using commercial array detectors coupled to a microscope and Michelson interferometer. Next, we apply the developed technique to rapidly provide automated histopathologic information for breast cancer. Traditionally, disease diagnoses are based on optical examinations of stained tissue and involve a skilled recognition of morphological patterns of specific cell types (histopathology). Consequently, histopathologic determinations are a time consuming, subjective process with innate intra- and inter-operator variability. Utilizing endogenous molecular contrast inherent in vibrational spectra, specially designed tissue microarrays and pattern recognition of specific biochemical features, we report an integrated algorithm for automated classifications. The developed protocol is objective, statistically significant and, being compatible with current tissue processing procedures, holds potential for routine clinical diagnoses. We first demonstrate that the classification of tissue type (histology) can be accomplished in a manner that is robust and rigorous. Since data quality and classifier performance are linked, we quantify the relationship through our analysis model. Last, we demonstrate the application of the minimum noise fraction (MNF) transform to improve tissue segmentation.

  15. Near-infrared spectroscopic determination of salinity and internal pressure of fluid inclusions in minerals.

    PubMed

    Kagi, Hiroyuki; Kiyasu, Akiko; Akagi, Tasuku; Nara, Masayuki; Sawaki, Takayuki

    2006-04-01

    A near-infrared (NIR) spectroscopic method is proposed to achieve the simultaneous determination of salinity and internal pressure of fluid inclusions in natural minerals. A combination band between the anti-symmetric stretching and bending vibrations of molecular water at approximately 5180 cm-1 was observed for standard salt solutions and natural minerals containing fluid inclusions with known salinities. A curve-fitting procedure was used to analyze the change in the band shape of the combination. Justification of the calibration was confirmed by observation of fluid inclusions in natural minerals whose salinities had already been determined using microthermometry. The detection limit of the present method is 1 NaCl-eq wt. %. The minimum size of fluid inclusions that produced well-resolved spectra was approximately 30 microm. This method was applied to assess micro fluid inclusions in a natural diamond with cubic growth habit (cuboid). The salinity and residual pressure of those fluid inclusions were estimated respectively as 4.4 wt. % NaCl-eq and 0.6-0.8 GPa. The present method is complementary to Raman microscopy and microthermometry for the determination of salinity in fluid inclusions of geological samples. PMID:16613640

  16. Spectroscopic analysis of bladder cancer tissues using Fourier transform infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Al-Muslet, Nafie A.; Ali, Essam E.

    2012-03-01

    Bladder cancer is one of the most common cancers in Africa. It takes several days to reach a diagnosis using histological examinations of specimens obtained by endoscope, which increases the medical expense. Recently, spectroscopic analysis of bladder cancer tissues has received considerable attention as a diagnosis technique due to its sensitivity to biochemical variations in the samples. This study investigated the use of Fourier transform infrared (FTIR) spectroscopy to analyze a number of bladder cancer tissues. Twenty-two samples were collected from 11 patients diagnosed with bladder cancer from different hospitals without any pretreatment. From each patient two samples were collected, one normal and another cancerous. FTIR spectrometer was used to differentiate between normal and cancerous bladder tissues via changes in spectra of these samples. The investigations detected obvious changes in the bands of proteins (1650, 1550 cm-1), lipids (2925, 2850 cm-1), and nucleic acid (1080, 1236 cm-1). The results show that FTIR spectroscopy is promising as a rapid, accurate, nondestructive, and easy to use alternative method for identification and diagnosis of bladder cancer tissues.

  17. Infrared Spectroscopic Study For Structural Investigation Of Lithium Lead Silicate Glasses

    SciTech Connect

    Ahlawat, Navneet; Aghamkar, Praveen; Ahlawat, Neetu; Agarwal, Ashish; Monica

    2011-12-12

    Lithium lead silicate glasses with composition 30Li{sub 2}O{center_dot}(70-x)PbO{center_dot}xSiO{sub 2}(where, x = 10, 20, 30, 40, 50 mol %)(LPS glasses) were prepared by normal melt quench technique at 1373 K for half an hour in air to understand their structure. Compositional dependence of density, molar volume and glass transition temperature of these glasses indicates more compactness of the glass structure with increasing SiO{sub 2} content. Fourier transform infrared (FTIR) spectroscopic data obtained for these glasses was used to investigate the changes induced in the local structure of samples as the ratio between PbO and SiO{sub 2} content changes from 6.0 to 0.4. The observed absorption band around 450-510 cm{sup -1} in IR spectra of these glasses indicates the presence of network forming PbO{sub 4} tetrahedral units in glass structure. The increase in intensity with increasing SiO{sub 2} content (upto x = 30 mol %) suggests superposition of Pb-O and Si-O bond vibrations in absorption band around 450-510 cm{sup -1}. The values of optical basicity in these glasses were found to be dependent directly on PbO/SiO{sub 2} ratio.

  18. Optimization of near-infrared spectroscopic process monitoring at low signal-to-noise ratio.

    PubMed

    Schneider, Hendrik; Reich, Gabriele

    2011-03-15

    An approach for the optimization of near-infrared (NIR) spectroscopic process monitoring at low signal-to-noise ratio is presented. It compromises the combined adjustment of different measurement variables and data pretreatments considering the prediction error, economic aspects of the application, and process constraints. The integration time, light intensity, and number of averaged spectra were varied; their mutual influence on the prediction error of partial least squares (PLS) models (i.e., root-mean-square error of cross-validation (RMSECV)) was evaluated in the laboratory. At low signal levels, the spectral uncertainty had a strong impact on the prediction error. It leveled off with increasing values of all three parameters and was finally dominated by other sources of uncertainty. The experimental findings could be characterized and explained by a mathematical equation, which was deduced from theoretical principles. The knowledge about the interaction of the measurement variables allowed their combined adjustment resulting in a reduced impact of spectral uncertainty on the prediction error (i.e., root-mean-square error of prediction (RMSEP)) without additional costs or process modifications. Moreover, a convenient procedure to compensate the stray light caused by strongly absorbing windows was developed. The whole approach was successfully applied to a challenging process, namely, the NIR inline monitoring of the liquid content of two model substances in a rotating suspension dryer.

  19. Early detection of ozone-induced hydroperoxides in epithelial cells by a novel infrared spectroscopic method.

    PubMed

    Hemmingsen, A; Allen, J T; Zhang, S; Mortensen, J; Spiteri, M A

    1999-11-01

    In the lower atmosphere ozone is a toxic and an unwanted oxidising pollutant causing injury to the airway epithelial cells by lipid peroxidation to yield products such as phospholipid hydroperoxides (PLHP). Measurements of PLHP, which are primary oxidation products, may reflect an early susceptibility of the target cell to oxidative stress. Biphasic cultures of bronchial epithelial cells (BEAS-2B) were exposed to ozone at environmentally relevant concentrations (0.1-1.0 ppm) for 4 and 12 h. Detection of PLHP was made using a novel technique based on fourier transform infrared spectroscopy (FTIR) in combination with high performance thin-layer chromatography (HPTLC). Six phospholipids were identified on the HPTLC plate; lysophosphatidylcholine (LPC), sphingomyelin (SM), phosphatidylcholine (PC), lysophosphatidylethanolamine (LPE), phosphatidylinositol (PI), and phosphatidylethanolamine (PE). From the FTIR spectra, O-O stretching of hydroperoxides was identified in the range 890-820cm(-1). Multivariate data analysis revealed a positive correlation (r = 0.99 for 4 h exposure and r = 0.98 for 12h exposure) between ozone exposure levels and the region of the FTIR-spectrum comprising the main wavelengths for hydroperoxides. These data support this alternative, versatile and novel spectroscopic approach for the early detection of ozone-mediated damage in human airway epithelial cells.

  20. On the importance of image formation optics in the design of infrared spectroscopic imaging systems

    PubMed Central

    Mayerich, David; van Dijk, Thomas; Walsh, Michael; Schulmerich, Matthew; Carney, P. Scott

    2014-01-01

    Infrared spectroscopic imaging provides micron-scale spatial resolution with molecular contrast. While recent work demonstrates that sample morphology affects the recorded spectrum, considerably less attention has been focused on the effects of the optics, including the condenser and objective. This analysis is extremely important, since it will be possible to understand effects on recorded data and provides insight for reducing optical effects through rigorous microscope design. Here, we present a theoretical description and experimental results that demonstrate the effects of commonly-employed cassegranian optics on recorded spectra. We first combine an explicit model of image formation and a method for quantifying and visualizing the deviations in recorded spectra as a function of microscope optics. We then verify these simulations with measurements obtained from spatially heterogeneous samples. The deviation of the computed spectrum from the ideal case is quantified via a map which we call a deviation map. The deviation map is obtained as a function of optical elements by systematic simulations. Examination of deviation maps demonstrates that the optimal optical configuration for minimal deviation is contrary to prevailing practice in which throughput is maximized for an instrument without a sample. This report should be helpful for understanding recorded spectra as a function of the optics, the analytical limits of recorded data determined by the optical design, and potential routes for optimization of imaging systems. PMID:24936526

  1. Near infrared photometric and optical spectroscopic study of 22 low mass star clusters embedded in nebulae

    NASA Astrophysics Data System (ADS)

    Soares, J. B.; Bica, E.; Ahumada, A. V.; Clariá, J. J.

    2008-02-01

    Aims:Among the star clusters in the Galaxy, those embedded in nebulae represent the youngest group, which has only recently been explored. The analysis of a sample of 22 candidate embedded stellar systems in reflection nebulae and/or HII environments is presented. Methods: We employed optical spectroscopic observations of stars in the directions of the clusters carried out at CASLEO (Argentina) together with near infrared photometry from the 2MASS catalogue. Our analysis is based on source surface density, colour-colour diagrams and on theoretical pre-main sequence isochrones. We take into account the field star contamination by carrying out a statistical subtraction. Results: The studied objects have the characteristics of low mass systems. We derive their fundamental parameters. Most of the cluster ages are younger than 2 Myr. The studied embedded stellar systems in reflection nebulae and/or HII region complexes do not have stars of spectral types earlier than B. The total stellar masses locked in the clusters are in the range 20-220 M⊙. They are found to be gravitationally unstable and are expected to dissolve in a timescale of a few Myr. Based on observations made at Complejo Astronómico El Leoncito, which is operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the National Universities of La Plata, Córdoba and San Juan, Argentina.

  2. Fourier Transform Infrared Spectroscopic Imaging of Fracture Healing in the Normal Mouse

    PubMed Central

    Gollwitzer, Hans; Yang, Xu; Spevak, Lyudmila; Lukashova, Lyudmila; Nocon, Allina; Fields, Kara; Pleshko, Nancy; Courtland, Hayden William; Bostrom, Mathias P.; Boskey, Adele L.

    2015-01-01

    Fourier transform infrared spectroscopic imaging (FTIRI) was used to study bone healing with spatial analysis of various callus tissues in wild type mice. Femoral fractures were produced in 28 male C57BL mice by osteotomy. Animals were sacrificed at 1, 2, 4, and 8 weeks to obtain callus tissue at well-defined healing stages. Following microcomputerized tomography, bone samples were cut in consecutive sections for FTIRI and histology, allowing for spatial correlation of both imaging methods in different callus areas (early calcified cartilage, woven bone, areas of intramembranous and endochondral bone formation). Based on FTIRI, mineral/matrix ratio increased significantly during the first 4 weeks of fracture healing in all callus areas and correlated with bone mineral density measured by micro-CT. Carbonate/phosphate ratio was elevated in newly formed calcified tissue and at week 2 attained values comparable to cortical bone. Collagen maturity and mineral crystallinity increased during weeks 1–8 in most tissues while acid phosphate substitution decreased. Temporal and callus area dependent changes were detected throughout the healing period. These data assert the usefulness of FTIRI for evaluation of fracture healing in the mouse and its potential to evaluate pathologic fracture healing and the effects of therapeutic interventions. PMID:26034749

  3. Mineralogical and spectroscopic investigation of enstatite chondrites by X-ray diffraction and infrared reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Izawa, M. R.; King, P. L.; Flemming, R. L.; Peterson, R. C.; McCausland, P. J.

    2009-05-01

    Reflectance spectroscopy of well-characterized meteorites provides an important means of linking meteorites to potential parent objects; an important objective in meteoritics research. There is a lack of such sample- correlated spectroscopic and mineralogical data sets in the literature to date. In an effort to improve this situation, the bulk mineralogy and infrared reflectance spectra of 13 enstatite chondrite meteorite finds, spanning the full range of textural alteration grades in both EL and EH classes have been investigated, including eleven recovered from the Antarctic and one from Northwest Africa. Rietveld refinement of high- resolution powder X-ray diffraction (XRD) data was used to identify the major mineral phases and quantify their modal abundances. The mineralogy and modes agree well with those of well-documented enstatite chondrites. Terrestrial weathering products such as Fe-oxyhydroxides, gypsum, and carbonates also occur in most of the meteorites from Antarctica. The mineral abundances determined via Rietveld refinement have been used to calculate model grain densities for each meteorite (i.e. density of the solid phases). Bulk magnetic susceptibility measurements combined with modal mineralogy reveal that as terrestrial weathering increases, both grain density and bulk susceptibility decrease. Sample-correlated thermal infrared (400-4500 cm-1, 2-25 μm) biconical (Diffuse) Reflectance Infrared Fourier Transform Spectroscopy data were collected for each meteorite to facilitate comparison with remote sensing data. The meteorite spectra are dominated by features corresponding to enstatite. Terrestrial weathering manifests itself as a broad, asymmetric H2O band centered near ~3400 cm-1, analogous to the "3 μm water of hydration feature" recognized in asteroid spectra, particularly from the enigmatic W-type asteroids. Additional sharp features superimposed on this band, as well as the sharpness of an asymmetric feature related to bound molecular

  4. Versatile transmission ellipsometry to study linear ferrofluid magneto-optics.

    PubMed

    Kooij, E S; Gâlcă, A C; Poelsema, B

    2006-12-01

    Linear birefringence and dichroism of magnetite ferrofluids are studied simultaneously using spectroscopic ellipsometry in transmission mode. It is shown that this versatile technique enables highly accurate characterisation of magneto-optical phenomena. Magnetic field-dependent linear birefringence and dichroism as well as the spectral dependence are shown to be in line with previous results. Despite the qualitative agreement with established models for magneto-optical phenomena, these fail to provide an accurate, quantitative description of our experimental results using the bulk dielectric function of magnetite. We discuss the results in relation to these models, and indicate how the modified dielectric function of the magnetite nanoparticles can be obtained. PMID:16997315

  5. The usefulness of subtraction ictal SPECT and ictal near-infrared spectroscopic topography in patients with West syndrome.

    PubMed

    Haginoya, Kazuhiro; Uematsu, Mitsugu; Munakata, Mitsutoshi; Kakisaka, Yosuke; Kikuchi, Atsuo; Nakayama, Tojo; Hino-Fukuyo, Naomi; Tsuburaya, Rie; Kitamura, Taro; Sato-Shirai, Ikuko; Abe, Yu; Matsumoto, Yoko; Wakusawa, Keisuke; Kobayashi, Tomoko; Ishitobi, Mamiko; Togashi, Noriko; Iwasaki, Masaki; Nakasato, Nobukazu; Iinuma, Kazuie

    2013-11-01

    The recent findings on subtraction ictal SPECT and ictal near-infrared spectroscopic topography in patients with West syndrome were summarized and its availability for presurgical evaluation was discussed. The subtraction ictal SPECT study in patients with West syndrome demonstrated the cortical epileptic region and subcortical involvement, which may consist of epilepsy networks related to the spasms. Moreover, subtraction ictal SPECT may have predictive power for short-term seizure outcome. Patients with a symmetric hyperperfusion pattern are predicted to have a better seizure outcome, whereas patients with asymmetric hyperperfusion pattern may develop poor seizure control. Importantly, asymmetric MRI findings had no predictive power for seizure outcome. Multichannel near-infrared spectroscopic topography applied to the patients with West syndrome detected an increase in regional cerebral blood volume in multiple areas which were activated either simultaneously or sequentially during spasms. Topographic changes in cerebral blood volume were closely correlated with spasm phenotype, suggesting that the cortex is involved in the generation of spasms. In conclusion, subtraction ictal SPECT may be considered as a useful tool for presurgical evaluation of patients with West syndrome and investigation of the pathophysiology of spasms. The ictal near-infrared spectroscopic topography should be more investigated to see if this is useful tool for presurgical evaluation.

  6. Multi-steps infrared spectroscopic characterization of the effect of flowering on medicinal value of Cistanche tubulosa

    NASA Astrophysics Data System (ADS)

    Lai, Zuliang; Xu, Peng; Wu, Peiyi

    2009-01-01

    Multi-steps infrared spectroscopic methods, including conventional Fourier transform infrared spectroscopy (FT-IR), second derivative spectroscopy and two-dimensional infrared (2D-IR) correlation spectroscopy, have been proved to be effective methods to examine complicated mixture system such as Chinese herbal medicine. The focus of this paper is the investigation on the effect of flowering on the pharmaceutical components of Cistanche tubulosa by using the Multi-steps infrared spectroscopic method. Power-spectrum analysis is applied to improve the resolution of 2D-IR contour maps and much more details of overlapped peaks are detected. According to the results of FT-IR and second derivative spectra, the peak at 1732 cm -1 assigned to C dbnd O is stronger before flowering than that after flowering in the stem, while more C dbnd O groups are found in the top after flowering. The spectra of root change a lot in the process of flowering for the reason that many peaks shift and disappear after flowering. Seven peaks in the spectra of stem, which are assigned to different kinds of glycoside components, are distinguished by Power-spectra in the range of 900-1200 cm -1. The results provide a scientific explanation to the traditional experience that flowering consumes the pharmaceutical components in stem and the seeds absorb some nutrients of stem after flowering. In conclusion, the Multi-steps infrared spectroscopic method combined with Power-spectra is a promising method to investigate the flowering process of C. tubulosa and discriminate various parts of the herbal medicine.

  7. Infrared external reflection spectroscopic studies of phase transitions in Langmuir monolayers of stearyl alcohol

    NASA Astrophysics Data System (ADS)

    Buontempo, Joseph T.; Rice, Stuart A.

    1993-11-01

    There is a steadily growing body of evidence that much of the information available concerning the properties of Langmuir monolayers concerns systems which are not in a state of equilibrium. What are now known to be unrelaxed monolayers of stearyl alcohol exhibit a high surface pressure phase transition whose signature in the isotherm changes from a ``kink'' (0-8 °C), to a small nearly flat region (8-15 °C), and finally to another kink (at higher temperatures). We have carried out external reflection infrared spectroscopic studies of relaxed monolayers of stearyl alcohol along a representative isotherm from each of the mentioned temperature regions. The results of our studies indicate that in each region the surfactant hydrocarbon chain becomes more ordered (i.e., has fewer gauche conformations) as the surface pressure is increased. We find that (i) at 5 °C, throughout the surface pressure range where the change in intramolecular chain order occurs, the collective tilt of the hydrocarbon chains remains nearly constant. For this isotherm the kink signals the point at which the hydrocarbon chains have achieved a very high degree of intramolecular order, perhaps the all-trans limit. (ii) In the 11 °C monolayer, in the phase often referred to as ``superfluid'', the intramolecular disorder in the hydrocarbon chains is measurably greater than in the equivalent phases in the higher and lower temperature regions. We also show that in the relaxed monolayer the nearly flat portion of the isotherm observed in the unrelaxed monolayer is almost totally absent, leaving only a kink very similar to those observed at higher and lower temperatures. (iii) At 25 °C, although the hydrocarbon chains in the relaxed monolayer attain a relatively high degree of intramolecular order, the high surface pressure phase transition is not observed. Instead, the surface pressure levels off at a value below that at which the transition is expected, and below the equilibrium spreading pressure

  8. WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time

    NASA Astrophysics Data System (ADS)

    Malkan, Matthew

    2013-10-01

    Our WFC3 Infrared Spectroscopic Parallels (WISPs) have shown the power of slitless spectroscopy to probe galaxy evolution from 0.51 to low masses, with the support of our ongoing ground-based follow-up. (3) Examine the role of metal-poor dwarfs and extreme starbursts in galaxy assembly. (4) Use the Balmer break and D4000 diagnostics to find and determine the ages of absorption-line galaxies down to J=24-25. (5) Search for rare objects such as Lya emitters at z>6, reddened AGN, close physical pairs of galaxies, T- and Y-dwarf stars (of which we have already found three).The WISP value-added public data release is likely to be one of Hubble's major legacies of 0.8--1.7 um spectroscopy.

  9. WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time

    NASA Astrophysics Data System (ADS)

    Malkan, Matthew

    2012-10-01

    Our WFC3 Infrared Spectroscopic Parallels {WISPs} have shown the power of slitless spectroscopy to probe galaxy evolution from 0.51 to low masses, with the support of our ongoing ground-based follow-up. {3} Examine the role of metal-poor dwarf galaxies in galaxy assembly. {4} Use the Balmer break and D4000 diagnostics to find and determine the ages of absorption-line galaxies down to J=25. {5} Search for rare objects such as Lya emitters at z>5.5, reddened AGN, close physical pairs of galaxies, and L- and T-dwarf stars {of which we have already found three}.The WISP value-added public data release is likely to be Hubble's principal legacy of 0.8-1.7 um spectroscopy.

  10. WFC3 Infrared Spectroscopic Parallel Survey WISP: A Survey of Star Formation Across Cosmic Time

    NASA Astrophysics Data System (ADS)

    Malkan, Matthew

    2013-10-01

    Our WFC3 Infrared Spectroscopic Parallels {WISPs} have shown the power of slitless spectroscopy to probe galaxy evolution from 0.51 to low masses, with the support of our ongoing ground-based follow-up. {3} Examine the role of metal-poor dwarfs and extreme starbursts in galaxy assembly. {4} Use the Balmer break and D4000 diagnostics to find and determine the ages of absorption-line galaxies down to J=24-25. {5} Search for rare objects such as Lya emitters at z>6, reddened AGN, close physical pairs of galaxies, T- and Y-dwarf stars {of which we have already found three}.The WISP value-added public data release is likely to be one of Hubble's major legacies of 0.8-1.7 um spectroscopy.

  11. Fourier transform infrared spectroscopic imaging parameters describing acid phosphate substitution in biologic hydroxyapatite.

    PubMed

    Spevak, Lyudmila; Flach, Carol R; Hunter, Tracey; Mendelsohn, Richard; Boskey, Adele

    2013-05-01

    Acid phosphate substitution into mineralized tissues is an important determinant of their mechanical properties and their response to treatment. This study identifies and validates Fourier transform infrared spectroscopic imaging (FTIRI) spectral parameters that provide information on the acid phosphate (HPO4) substitution into hydroxyapatite in developing mineralized tissues. Curve fitting and Fourier self-deconvolution were used to identify subband positions in model compounds (with and without HPO4). The intensity of subbands at 1127 and 1110 cm(-1) correlated with the acid phosphate content in these models. Peak height ratios of these subbands to the ν3 vibration at 1096 cm(-1) found in stoichiometric apatite were evaluated in the model compounds and mixtures thereof. FTIRI spectra of bones and teeth at different developmental ages were analyzed using these spectral parameters. Factor analysis (a chemometric technique) was also conducted on the tissue samples and resulted in factor loadings with spectral features corresponding to the HPO4 vibrations described above. Images of both factor correlation coefficients and the peak height ratios 1127/1096 and 1112/1096 cm(-1) demonstrated higher acid phosphate content in younger vs. more mature regions in the same specimen. Maps of the distribution of acid phosphate content will be useful for characterizing the extent of new bone formation, the areas of potential decreased strength, and the effects of therapies such as those used in metabolic bone diseases (osteoporosis, chronic kidney disease) on mineral composition. Because of the wider range of values obtained with the 1127/1096 cm(-1) parameter compared to the 1110/1096 cm(-1) parameter and the smaller scatter in the slope, it is suggested that this ratio should be the parameter of choice.

  12. Fourier transform infrared spectroscopic imaging identifies early biochemical markers of tissue damage

    NASA Astrophysics Data System (ADS)

    Varma, Vishal K.; Ohlander, Samuel; Nguyen, Peter; Vendryes, Christopher; Parthiban, Sujeeth; Hamilton, Blake; Wallis, M. Chad; Kajdacsy-Balla, Andre; Hannaford, Blake; Lendvay, Thomas; Hotaling, James M.; Walsh, Michael J.

    2014-03-01

    Fourier Transform Infrared (FT-IR) spectroscopic imaging can allow for the rapid imaging of tissue biochemistry in a label-free and non-perturbing fashion. With the rapid adoption of new minimally invasive surgery (MIS) technologies over the last 20 years, adequate skill to safely and effectively use these technologies may not be achieved and risk of undue physical pressure being placed on tissues is a concern. Previous work has demonstrated that a number of histological stains can detect tissue damage, however, this process requires the initiation and progression of a signaling cascade that results in the epitope of interest being expressed. We proposed to identify the early biochemical markers associated with physical tissue damage from applied forces, thus not requiring transcriptional and translational protein synthesis as traditional immunohistochemistry does. To demonstrate that FT-IR can measure biochemical changes in tissues that have undergone physical force, we took ex-vivo lamb's liver that had been freshly excised and applied varying levels of physical pressure (0kPa to 30kPa). Tissues were then formalin-fixed, paraffin-embedded, and sectioned on to glass for H and E staining to identify damage and on to an IR slide for FT-IR imaging. Regions of interest containing hepatocytes were identified and average FT-IR spectra were extracted from the damaged and undamaged livers. FT-IR spectra showed clear biochemical changes associated with tissue damage. In addition, chemical changes could be observed proceeding histological changes observed when using conventional staining approaches.

  13. Near-infrared spectroscopic studies of self-forming lipids and nanovesicles

    NASA Astrophysics Data System (ADS)

    Bista, Rajan K.; Bruch, Reinhard F.

    2009-02-01

    Lipids and liposomes have remained an active research topic for several decades due to their significance as membrane model. Several vibrational spectroscopic techniques have been developed and employed to study the properties of lipids and liposomes. In this study, near-infrared (NIR) spectroscopy has been used to analyze a suite of synthesized PEGylated lipids trademarked as QuSomesTM. The three amphiphiles used in this study, differ in their apolar hydrophobic chain length and contain various units of polar polyethylene glycol (PEG) head groups. In contrast to conventional phospholipids, this new kind of lipids forms liposomes spontaneously upon hydration, without the supply of external activation energy. Whilst the NIR spectra of QuSomesTM show a common pattern, differences in the spectra are observed which enable the lipids to be distinguished. NIR absorption spectra of these new artificial lipids have been recorded in the spectral range of 4800-9000 cm-1 (~2100-1100 nm) by using a new miniaturized spectrometer based on micro-optical-electro-mechanical systems (MOEMS) technology. In particular, we have established specific band structures as "molecular fingerprints" corresponding to overtones and combinations vibrational modes involving mainly C-H and O-H functional groups for sample analysis of QuSomesTM. Moreover, we have demonstrated that the nanovesicles formed by such lipids in polar solvents show high stability and obey Beer's law at low concentration. The results reported in this study may find applications in various field including the development of lipids based drug delivery systems.

  14. Adulteration screening of botanical materials by a sensitive and model-free approach using infrared spectroscopic imaging and two-dimensional correlation infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Chen, Jian-bo; Zhou, Qun; Sun, Su-qin

    2016-11-01

    Infrared (IR) spectroscopy is often used as a simple, fast, and green method for the adulteration screening of botanical materials for foods and herbs. However, the overlapping of absorption signals of various substances significantly decrease the sensitivity and specificity of IR spectroscopy in the detection of adulterated samples. In this research, a model-free approach is proposed for the sensitive and non-targeted screening of botanical materials adulterated by adding other plant materials. First, the spectra of the entities in the test sample are collected by near-infrared spectroscopic imaging and clustered by unsupervised pattern recognition methods. The sample may be adulterated if there are two or more clusters of the entities. Next, the entities of different clusters are characterized by mid-infrared spectroscopy to interpret the chemical compositions to determine the clustering is caused whether by adulteration or other reasons. Second derivative spectroscopy and two-dimensional correlation spectroscopy are often needed to resolve the overlapped bands mathematically or experimentally to find the characteristic signals to identify the authentic and adulterant entities. The feasibility of this approach was proved by the simulated adulterated sample of saffron. In conclusion, botanical materials adulterated by adding other plant materials can be detected by a simple, fast, sensitive, and green screening approach using IR spectroscopic imaging, two-dimensional correlation spectroscopy, and necessary chemometrics techniques.

  15. Noninvasive, near infrared spectroscopic-measured muscle pH and PO2 indicate tissue perfusion for cardiac surgical patients undergoing cardiopulmonary bypass

    NASA Technical Reports Server (NTRS)

    Soller, Babs R.; Idwasi, Patrick O.; Balaguer, Jorge; Levin, Steven; Simsir, Sinan A.; Vander Salm, Thomas J.; Collette, Helen; Heard, Stephen O.

    2003-01-01

    OBJECTIVE: To determine whether near infrared spectroscopic measurement of tissue pH and Po2 has sufficient accuracy to assess variation in tissue perfusion resulting from changes in blood pressure and metabolic demand during cardiopulmonary bypass. DESIGN: Prospective clinical study. SETTING: Academic medical center. SUBJECTS: Eighteen elective cardiac surgical patients. INTERVENTION: Cardiac surgery under cardiopulmonary bypass. MEASUREMENTS AND MAIN RESULTS: A near infrared spectroscopic fiber optic probe was placed over the hypothenar eminence. Reference Po2 and pH sensors were inserted in the abductor digiti minimi (V). Data were collected every 30 secs during surgery and for 6 hrs following cardiopulmonary bypass. Calibration equations developed from one third of the data were used with the remaining data to investigate sensitivity of the near infrared spectroscopic measurement to physiologic changes resulting from cardiopulmonary bypass. Near infrared spectroscopic and reference pH and Po2 measurements were compared for each subject using standard error of prediction. Near infrared spectroscopic pH and Po2 at baseline were compared with values during cardiopulmonary bypass just before rewarming commenced (hypotensive, hypothermic), after rewarming (hypotensive, normothermic) just before discontinuation of cardiopulmonary bypass, and at 6 hrs following cardiopulmonary bypass (normotensive, normothermic) using mixed-model analysis of variance. Near infrared spectroscopic pH and Po2 were well correlated with the invasive measurement of pH (R2 =.84) and Po2 (R 2 =.66) with an average standard error of prediction of 0.022 +/- 0.008 pH units and 6 +/- 3 mm Hg, respectively. The average difference between the invasive and near infrared spectroscopic measurement was near zero for both the pH and Po2 measurements. Near infrared spectroscopic Po2 significantly decreased 50% on initiation of cardiopulmonary bypass and remained depressed throughout the bypass and

  16. Infrared Spectroscopic Analyses of Sulfate, Nitrate, and Carbonate-bearing Atacama Desert Soils: Analogs for the Interpretation of Infrared Spectra from the Martian Surface

    NASA Technical Reports Server (NTRS)

    Dalton, J. B.; Dalton, J. B.; Ewing, S. A.; Amundson, R.; McKay, C. P.

    2005-01-01

    The Atacama Desert of northern Chile is the driest desert on Earth, receiving only a few mm of rain per decade. The Mars climate may, in the past, have been punctuated by short-lived episodes of aqueous activity. The paleo-Martian environment may have had aqueous conditions similar to the current conditions that exist in the Atacama, and Mars soils may have formed with soil chemistry and mineralogy similar to those found in the Atacama. Remote and in-situ analysis of the Martian surface using infrared technology has a long heritage. Future investigations of the subsurface mineralogy are likely to build upon this heritage, and will benefit from real life lessons to be learned from terrestrial analog studies. To that end, preliminary results from a near- and mid-infrared spectroscopic study of Atacama soil profiled at a range of depths are presented.

  17. Book Review: Reiner Salzer and Heinz W. Siesler (Eds.): Infrared and Raman spectroscopic imaging, 2nd ed.

    SciTech Connect

    Moore, David Steven

    2015-05-10

    This second edition of "Infrared and Raman Spectroscopic Imaging" propels practitioners in that wide-ranging field, as well as other readers, to the current state of the art in a well-produced and full-color, completely revised and updated, volume. This new edition chronicles the expanded application of vibrational spectroscopic imaging from yesterday's time-consuming point-by-point buildup of a hyperspectral image cube, through the improvements afforded by the addition of focal plane arrays and line scan imaging, to methods applicable beyond the diffraction limit, instructs the reader on the improved instrumentation and image and data analysis methods, and expounds on their application to fundamental biomedical knowledge, food and agricultural surveys, materials science, process and quality control, and many others.

  18. Book Review: Reiner Salzer and Heinz W. Siesler (Eds.): Infrared and Raman spectroscopic imaging, 2nd ed.

    DOE PAGESBeta

    Moore, David Steven

    2015-05-10

    This second edition of "Infrared and Raman Spectroscopic Imaging" propels practitioners in that wide-ranging field, as well as other readers, to the current state of the art in a well-produced and full-color, completely revised and updated, volume. This new edition chronicles the expanded application of vibrational spectroscopic imaging from yesterday's time-consuming point-by-point buildup of a hyperspectral image cube, through the improvements afforded by the addition of focal plane arrays and line scan imaging, to methods applicable beyond the diffraction limit, instructs the reader on the improved instrumentation and image and data analysis methods, and expounds on their application to fundamentalmore » biomedical knowledge, food and agricultural surveys, materials science, process and quality control, and many others.« less

  19. Continuous statistical modelling for rapid detection of adulteration of extra virgin olive oil using mid infrared and Raman spectroscopic data.

    PubMed

    Georgouli, Konstantia; Martinez Del Rincon, Jesus; Koidis, Anastasios

    2017-02-15

    The main objective of this work was to develop a novel dimensionality reduction technique as a part of an integrated pattern recognition solution capable of identifying adulterants such as hazelnut oil in extra virgin olive oil at low percentages based on spectroscopic chemical fingerprints. A novel Continuous Locality Preserving Projections (CLPP) technique is proposed which allows the modelling of the continuous nature of the produced in-house admixtures as data series instead of discrete points. The maintenance of the continuous structure of the data manifold enables the better visualisation of this examined classification problem and facilitates the more accurate utilisation of the manifold for detecting the adulterants. The performance of the proposed technique is validated with two different spectroscopic techniques (Raman and Fourier transform infrared, FT-IR). In all cases studied, CLPP accompanied by k-Nearest Neighbors (kNN) algorithm was found to outperform any other state-of-the-art pattern recognition techniques. PMID:27664692

  20. Towards a wearable near infrared spectroscopic probe for monitoring concentrations of multiple chromophores in biological tissue in vivo

    PubMed Central

    Chitnis, Danial; Airantzis, Dimitrios; Highton, David; Williams, Rhys; Phan, Phong; Giagka, Vasiliki; Powell, Samuel; Cooper, Robert J.; Tachtsidis, Ilias; Smith, Martin; Elwell, Clare E.; Hebden, Jeremy C.; Everdell, Nicholas

    2016-01-01

    The first wearable multi-wavelength technology for functional near-infrared spectroscopy has been developed, based on a custom-built 8-wavelength light emitting diode (LED) source. A light-weight fibreless probe is designed to monitor changes in the concentrations of multiple absorbers (chromophores) in biological tissue, the most dominant of which at near-infrared wavelengths are oxyhemoglobin and deoxyhemoglobin. The use of multiple wavelengths enables signals due to the less dominant chromophores to be more easily distinguished from those due to hemoglobin and thus provides more complete and accurate information about tissue oxygenation, hemodynamics, and metabolism. The spectroscopic probe employs four photodiode detectors coupled to a four-channel charge-to-digital converter which includes a charge integration amplifier and an analogue-to-digital converter (ADC). Use of two parallel charge integrators per detector enables one to accumulate charge while the other is being read out by the ADC, thus facilitating continuous operation without dead time. The detector system has a dynamic range of about 80 dB. The customized source consists of eight LED dies attached to a 2 mm × 2 mm substrate and encapsulated in UV-cured epoxy resin. Switching between dies is performed every 20 ms, synchronized to the detector integration period to within 100 ns. The spectroscopic probe has been designed to be fully compatible with simultaneous electroencephalography measurements. Results are presented from measurements on a phantom and a functional brain activation study on an adult volunteer, and the performance of the spectroscopic probe is shown to be very similar to that of a benchtop broadband spectroscopy system. The multi-wavelength capabilities and portability of this spectroscopic probe will create significant opportunities for in vivo studies in a range of clinical and life science applications. PMID:27370501

  1. Towards a wearable near infrared spectroscopic probe for monitoring concentrations of multiple chromophores in biological tissue in vivo

    NASA Astrophysics Data System (ADS)

    Chitnis, Danial; Airantzis, Dimitrios; Highton, David; Williams, Rhys; Phan, Phong; Giagka, Vasiliki; Powell, Samuel; Cooper, Robert J.; Tachtsidis, Ilias; Smith, Martin; Elwell, Clare E.; Hebden, Jeremy C.; Everdell, Nicholas

    2016-06-01

    The first wearable multi-wavelength technology for functional near-infrared spectroscopy has been developed, based on a custom-built 8-wavelength light emitting diode (LED) source. A lightweight fibreless probe is designed to monitor changes in the concentrations of multiple absorbers (chromophores) in biological tissue, the most dominant of which at near-infrared wavelengths are oxyhemoglobin and deoxyhemoglobin. The use of multiple wavelengths enables signals due to the less dominant chromophores to be more easily distinguished from those due to hemoglobin and thus provides more complete and accurate information about tissue oxygenation, hemodynamics, and metabolism. The spectroscopic probe employs four photodiode detectors coupled to a four-channel charge-to-digital converter which includes a charge integration amplifier and an analogue-to-digital converter (ADC). Use of two parallel charge integrators per detector enables one to accumulate charge while the other is being read out by the ADC, thus facilitating continuous operation without dead time. The detector system has a dynamic range of about 80 dB. The customized source consists of eight LED dies attached to a 2 mm × 2 mm substrate and encapsulated in UV-cured epoxy resin. Switching between dies is performed every 20 ms, synchronized to the detector integration period to within 100 ns. The spectroscopic probe has been designed to be fully compatible with simultaneous electroencephalography measurements. Results are presented from measurements on a phantom and a functional brain activation study on an adult volunteer, and the performance of the spectroscopic probe is shown to be very similar to that of a benchtop broadband spectroscopy system. The multi-wavelength capabilities and portability of this spectroscopic probe will create significant opportunities for in vivo studies in a range of clinical and life science applications.

  2. Assessing the Compositional Diversity of Intrusive Rocks on the Moon Using Near-Infrared Spectroscopic Data

    NASA Astrophysics Data System (ADS)

    Klima, R. L.

    2016-05-01

    Near-infrared, gamma-ray and neutron, and thermal-infrared observations have advanced our understanding of the compositional diversity, including minor components such as thorium and hydroxyl, of intrusive lithologies exposed on the lunar surface.

  3. QUANTITATIVE FOURIER TRANSFORM INFRARED SPECTROSCOPIC INVESTIGATION OF HUMIC SUBSTANCE FUNCTIONAL GROUP COMPOSITION

    EPA Science Inventory

    Infrared (IR) spectroscopy has been widely used for the structural investigation of humic substances. Although Fourier Transform Infrared (FTIR) instrumentation has been available for sometime, relatively little work with these instruments has been reported for humic substances,...

  4. The GTC mid-infrared spectroscopic program of primitive outer-belt asteroids

    NASA Astrophysics Data System (ADS)

    Licandro, J.; Alvarez-Iglesias, C. Carlos; Cabrera-Lavers, A.; Ali-Lagoa, V.; Pinilla-Alonso, N.; Campins, H.; de Leon, J.; Kelley, M.

    2014-07-01

    Asteroids in the outer edge of the asteroid belt (Cybeles, Hildas, and Jupiter Trojans) may provide a number of clues to the origin and evolution of the asteroid belt and the formation of our planetary system. They have a pristine composition, experienced little heating and may contain a significant fraction of ice in their interiors. The origin of these populations is still under debate. Levison et al. (2009) suggested that a large fraction of these bodies are transneptunian objects (TNOs) moved to these resonances in an early epoch of the Solar System called the ''Late Heavy Bombardment'' (LHB). To compare the physical properties of these asteroid populations with TNOs and comets is thus a strong test of dynamical models. In mid 2013, we started a mid-infrared photometric and spectroscopic program in the N-band using the CANARICAM camera-spectrograph at the 10.4-m GTC telescope at the ''Roque de los Muchachos'' Obserbatory (Canary Islands, Spain). We aim to study the surface composition and key properties such as radius, albedo, and thermal inertia based on their low-resolution 8--13-micron spectra and N-band photometry. We already obtained the spectra of 5 objects, that of (225) Henrieta is shown as an example in the Figure. The three published spectra of Trojan asteroids (Emery et al. 2006) and of (65) Cybele (Licandro et al. 2011) exhibit clear emissivity features from which the compositional and physical properties can be inferred. The spectra of these objects strongly resemble one another, presenting an emission plateau due to silicates at about 9.1-11.5 microns (the Si-O stretch fundamental). Fine-grained silicates in a very porous (fairly castle) structure, and no other mineral group (Emery et al. 2006, Vernazza et al. 2012), reproduce the major features of the Trojans and Cybele asteroid spectra. In this work, we present the preliminary results of our observational program including the N-band spectra, size, and albedo of the already observed 5 asteroids

  5. Infrared Spectroscopic Evidence of Surface Speciation of Amino Acids on Titanium Dioxide

    NASA Astrophysics Data System (ADS)

    Jonsson, C. M.; Jonsson, C. L.; Parikh, S. J.; Sverjensky, D. A.; Cleaves, H. J.; Hazen, R. M.

    2008-12-01

    Interactions that occur at the interface between molecules and mineral surfaces in the presence of water are integral to many chemical and physical processes, including the behavior of pollutants in the environment, metal implants in the human body, and perhaps the origin of life. During the emergence of life, mineral surfaces may have played a role in the selection of amino acids, leading to the formation of proteins that are essential building blocks of life. To investigate this hypothesis, we are studying two amino acids, glutamic (Glu) and aspartic (Asp) acid, and their adsorption to the rutile form of titanium dioxide as a function of pH and surface coverage in electrolyte solutions. The objective is to get a fundamental understanding of the speciation and coordination chemistry of these amino acids at the rutile surface. We used attenuated total reflectance (ATR) Fourier transform infrared (FTIR) spectroscopy to investigate the adsorption of Glu on rutile, and a previously published ATR-FTIR study [1] of Asp and Glu adsorption on an amorphous titanium dioxide film was used as a guide to peak assignment and interpretation of our FTIR spectra. Binding of Glu to both surfaces occurs primarily through one or both of the carboxyl groups, implying that at least two types of surface complexes are formed in a proportion presumably dependent on surface coverage and pH. The interpretation of our results suggests that Glu binds to rutile in a mixed chelating-monodentate fashion involving both carboxyl groups (Glu lying down at the surface), and in a chelating fashion involving only the gamma carboxyl group (Glu standing up at the surface). FTIR results also show that the intensity of the amine peak increases with sorption, which is possibly a consequence of the amine group being brought closer to the surface but not binding directly to it. Glu adsorption on rutile is favored at low pH, based on results from batch adsorption experiments. We have commenced a systematic

  6. A monitoring campaign for Luhman 16AB. I. Detection of resolved near-infrared spectroscopic variability

    SciTech Connect

    Burgasser, Adam J.; Gillon, Michaël; Jehin, E.; Delrez, L.; Opitom, C.; Faherty, Jacqueline K.; Radigan, Jacqueline; Triaud, Amaury H. M. J.; Plavchan, Peter

    2014-04-10

    We report resolved near-infrared spectroscopic monitoring of the nearby L dwarf/T dwarf binary WISE J104915.57–531906.1AB (Luhman 16AB), as part of a broader campaign to characterize the spectral energy distribution and temporal variability of this system. A continuous 45 minute sequence of low-resolution IRTF/SpeX data spanning 0.8-2.4 μm were obtained, concurrent with combined-light optical photometry with ESO/TRAPPIST. Our spectral observations confirm the flux reversal of this binary, and we detect a wavelength-dependent decline in the relative spectral fluxes of the two components coincident with a decline in the combined-light optical brightness of the system over the course of the observation. These data are successfully modeled as a combination of achromatic (brightness) and chromatic (color) variability in the T0.5 Luhman 16B, consistent with variations in overall cloud opacity; and no significant variability was found in L7.5 Luhman 16A, consistent with recent resolved photometric monitoring. We estimate a peak-to-peak amplitude of 13.5% at 1.25 μm over the full light curve. Using a simple two-spot brightness temperature model for Luhman 16B, we infer an average cold covering fraction of ≈30%-55%, varying by 15%-30% over a rotation period assuming a ≈200-400 K difference between hot and cold regions. We interpret these variations as changes in the covering fraction of a high cloud deck and corresponding 'holes' which expose deeper, hotter cloud layers, although other physical interpretations are possible. A Rhines scale interpretation for the size of the variable features explains an apparent correlation between period and amplitude for Luhman 16B and the variable T dwarfs SIMP 0136+0933 and 2MASS J2139+0220, and predicts relatively fast winds (1-3 km s{sup –1}) for Luhman 16B consistent with light curve evolution on an advective time scale (1-3 rotation periods). The strong variability observed in this flux reversal brown dwarf pair supports

  7. One- and two-dimensional infrared spectroscopic studies of solution-phase homogeneous catalysis and spin-forbidden reactions

    SciTech Connect

    Sawyer, Karma Rae

    2008-12-01

    Understanding chemical reactions requires the knowledge of the elementary steps of breaking and making bonds, and often a variety of experimental techniques are needed to achieve this goal. The initial steps occur on the femto- through picosecond time-scales, requiring the use of ultrafast spectroscopic methods, while the rate-limiting steps often occur more slowly, requiring alternative techniques. Ultrafast one and two-dimensional infrared and step-scan FTIR spectroscopies are used to investigate the photochemical reactions of four organometallic complexes. The analysis leads to a detailed understanding of mechanisms that are general in nature and may be applicable to a variety of reactions.

  8. Investigation of infrared spectra of atmospheric gases to support stratospheric spectroscopic investigations

    NASA Technical Reports Server (NTRS)

    Shaw, J. H.

    1980-01-01

    Spectroscopic instrumentation and the absorption characteristics of atmospheric gases are discussed in relation to the requirements of spectroscopic stratospheric experiments. Improvement in the spectral resolution, accuracy of the line parameters, and the ranges of atmospheric conditions over which information is to be obtained are among the factors considered. Methods of simultaneously analyzing entire bands containing many lines were developed and applied to the analysis of bands of N20 and CO2. Progress in this analysis is reported.

  9. Spectroscopic-ellipsometric study of native oxide removal by liquid phase HF process

    NASA Astrophysics Data System (ADS)

    Kurhekar, Anil Sudhakar; Apte, Prakash R.

    2013-02-01

    Ex situ spectroscopic ellipsometry (SE) measurements have been employed to investigate the effect of liquid-phase hydrofluoric acid (HF) cleaning on Si<100> surfaces for microelectromechanical systems application. The hydrogen terminated (H-terminated) Si surface was realized as an equivalent dielectric layer, and SE measurements are performed. The SE analyses indicate that after a 20-s 100:5 HF dip with rinse, the Si (100) surface was passivated by the hydrogen termination and remained chemically stable. Roughness of the HF-etched bare Si (100) surface was observed and analyzed by the ex-situ SE. Evidence for desorption of the H-terminated Si surface layer is studied using Fourier transform infrared spectroscopy and ellipsometry, and discussed. This piece of work explains the usage of an ex situ, non-destructive technique capable of showing state of passivation, the H-termination of Si<100> surfaces.

  10. Spectroscopic-ellipsometric study of native oxide removal by liquid phase HF process

    PubMed Central

    Kurhekar, Anil Sudhakar; Apte, Prakash R

    2014-01-01

    Ex situ spectroscopic ellipsometry (SE) measurements have been employed to investigate the effect of liquid-phase hydrofluoric acid (HF) cleaning on Si<100> surfaces for microelectromechanical systems application. The hydrogen terminated (H-terminated) Si surface was realized as an equivalent dielectric layer, and SE measurements are performed. The SE analyses indicate that after a 20-s 100:5 HF dip with rinse, the Si (100) surface was passivated by the hydrogen termination and remained chemically stable. Roughness of the HF-etched bare Si (100) surface was observed and analyzed by the ex-situ SE. Evidence for desorption of the H-terminated Si surface layer is studied using Fourier transform infrared spectroscopy and ellipsometry, and discussed. This piece of work explains the usage of an ex situ, non-destructive technique capable of showing state of passivation, the H-termination of Si<100> surfaces. PMID:24619506

  11. Far-Infrared and Microwave Spectroscopic Examination of Weakly Bound Molecular Complexes: Potential Energy Surfaces and Internal Dynamics

    NASA Astrophysics Data System (ADS)

    Reeve, Scott Wayne

    1992-01-01

    High resolution far infrared gas phase absorption experiments on both the Ar-HX (X = F, Cl, Br) and the Ar -NH_3 systems are described. All of the spectroscopic measurements were obtained with a tunable far infrared difference frequency sideband (TuFIRS) spectrometer which was coupled to a continuous free jet expansion. In each system the low frequency bending and stretching vibrations, corresponding to the van der Waals coordinates, were observed and measured. The experimental measurements allow basic physical properties (e.g., rotational and centrifugal distortion constants) for these systems to be determined which are sensitive to the global topology of the intermolecular potential energy surface, and thus, provide critical tests for the physical models used to construct potential energy surfaces. A high resolution rotational spectroscopic study of the gas phase complex HCN-BF_3, done as a collaborative effort with scientists at the National Institute for Standards and Technology (NIST), is also described. Here, a Fourier transform microwave spectrometer is used to determine the molecular structure and basic physical properties of the HCN-BF_3 complex. We find the molecular structure to be that of an incipiently bonded molecule. In addition, we interpret the molecular structure, and the other measured molecular properties, within the generalized reaction path framework for BF_3 + nitrogen adducts discussed previously by Dvorak, et. al.^1 ftn^1M. A. Dvorak, R. S. Ford, R. D. Suenram, F. J. Lovas, and K. R. Leopold, J. Amer. Chem. Soc., 114, 108 (1992).

  12. Near-infrared spectroscopic photoacoustic microscopy using a multi-color fiber laser source

    PubMed Central

    Buma, Takashi; Wilkinson, Benjamin C.; Sheehan, Timothy C.

    2015-01-01

    We demonstrate a simple multi-wavelength optical source suitable for spectroscopic optical resolution photoacoustic microscopy (OR-PAM) of lipid-rich tissue. 1064 nm laser pulses are converted to multiple wavelengths beyond 1300 nm via nonlinear optical propagation in a birefringent optical fiber. OR-PAM experiments with lipid phantoms clearly show the expected absorption peak near 1210 nm. We believe this simple multi-color technique is a promising cost-effective approach to spectroscopic OR-PAM of lipid-rich tissue. PMID:26309746

  13. Comparison of refractive indices measured by m-lines and ellipsometry: application to polymer blend and ceramic thin films for gas sensors

    NASA Astrophysics Data System (ADS)

    Wood, Thomas; Le Rouzo, Judikaël.; Flory, François; Coudray, Paul; Mastelaro, Valmor R.; Pelissari, Pedro; Zilio, Sérgio

    2012-10-01

    Two optical techniques, "m-lines" and spectroscopic ellipsometry, are compared for their suitability for obtaining the wavelength and temperature dispersion of the refractive index of thin film layers used in gas detector devices. Two types of materials often integrated into gas sensors are studied: a polymer organic-inorganic blend deposited by spin-coating typically used in near infra-red waveguides and the ceramic semiconductor SrTi1-xFexO3 (strontium titanate) doped with iron at concentrations x = 0.075 and 0.1 deposited by electron beam deposition. In this paper, we will compare the refractive index dispersion obtained by m-lines and ellipsometry, and comment on the differences between the measured parameters for the two materials. The chromatic dispersion will be represented by a three term Cauchy law. An intuitive method of verifying the measured indices using an integrating sphere and reflexion coefficient modelling techniques will also be demonstrated. Thermo-optic coefficients of the order of -1×10-4/K for both materials are reported, and very low chromatic dispersions are also measured thanks to the high sensitivity of the m-lines technique.

  14. A Multiwavelength Study of Cygnus X-1: The First Mid-infrared Spectroscopic Detection of Compact Jets

    NASA Astrophysics Data System (ADS)

    Rahoui, Farid; Lee, Julia C.; Heinz, Sebastian; Hines, Dean C.; Pottschmidt, Katja; Wilms, Jörn; Grinberg, Victoria

    2011-07-01

    We report on a Spitzer/InfraRed Spectrograph (mid-infrared), RXTE/PCA+HEXTE (X-ray), and Ryle (radio) simultaneous multiwavelength study of the microquasar Cygnus X-1, which aimed at an investigation of the origin of its mid-infrared emission. Compact jets were present in two out of three observations, and we show that they strongly contribute to the mid-infrared continuum. During the first observation, we detect the spectral break—where the transition from the optically thick to the optically thin regime takes place—at about 2.9 × 1013 Hz. We then show that the jet's optically thin synchrotron emission accounts for Cygnus X-1's emission beyond 400 keV, although it cannot alone explain its 3-200 keV continuum. A compact jet was also present during the second observation, but we do not detect the break, since it has likely shifted to higher frequencies. In contrast, the compact jet was absent during the last observation, and we show that the 5-30 μm mid-infrared continuum of Cygnus X-1 stems from the blue supergiant companion star HD 226868. Indeed, the emission can then be understood as the combination of the photospheric Rayleigh-Jeans tail and the bremsstrahlung from the expanding stellar wind. Moreover, the stellar wind is found to be clumpy, with a filling factor f ∞ ≈ 0.09-0.10. Its bremsstrahlung emission is likely anti-correlated to the soft X-ray emission, suggesting an anti-correlation between the mass-loss and mass-accretion rates. Nevertheless, we do not detect any mid-infrared spectroscopic evidence of interaction between the jets and Cygnus X-1's environment and/or the companion star's stellar wind.

  15. A Precise Determination of the Mid-infrared Interstellar Extinction Law Based on the APOGEE Spectroscopic Survey

    NASA Astrophysics Data System (ADS)

    Xue, Mengyao; Jiang, B. W.; Gao, Jian; Liu, Jiaming; Wang, Shu; Li, Aigen

    2016-06-01

    A precise measure of the mid-infrared interstellar extinction law is crucial for investigating the properties of interstellar dust, especially larger-sized grains. Based on the stellar parameters derived from the SDSS-III/Apache Point Observatory Galaxy Evolution Experiment (APOGEE) spectroscopic survey, we select a large sample of G-type and K-type giants as the tracers of the Galactic mid-infrared extinction. We calculate the intrinsic stellar color excesses from the stellar effective temperatures and use them to determine the mid-infrared extinction for a given line of sight. For the entire sky of the Milky Way surveyed by APOGEE, we derive the extinctions (relative to {A}{{{K}}{{S}}}, the K S-band extinction at wavelength λ = 2.16 μm) for the four Wide-field Infrared Survey Explorer (WISE) bands at 3.4, 4.6, 12, and 22 μm, the four Spitzer/Infrared Array Camera bands at 3.6, 4.5, 5.8, and 8 μm, the Spitzer/MIPS24 band at 23.7 μm, and, for the first time, the AKARI/S9W band at 8.23 μm. Our results agree with previous works in that the extinction curve is flat in the ˜3-8 μm wavelength range and is generally consistent with the {R}V = 5.5 model curve, except our determination exceeds the model prediction in the WISE/W4 band. Although some previous works found that the mid-IR extinction law appears to vary with the extinction depth {A}{{{K}}{{S}}}, no noticeable variation has been found in this work. The uncertainties are analyzed in terms of the bootstrap resampling method and Monte-Carlo simulation and are found to be rather small.

  16. A MULTIWAVELENGTH STUDY OF CYGNUS X-1: THE FIRST MID-INFRARED SPECTROSCOPIC DETECTION OF COMPACT JETS

    SciTech Connect

    Rahoui, Farid; Lee, Julia C.; Heinz, Sebastian; Hines, Dean C.; Pottschmidt, Katja; Wilms, Joern; Grinberg, Victoria E-mail: jclee@cfa.harvard.edu E-mail: hines@stsci.edu E-mail: joern.wilms@sternwarte.uni-erlangen.de

    2011-07-20

    We report on a Spitzer/InfraRed Spectrograph (mid-infrared), RXTE/PCA+HEXTE (X-ray), and Ryle (radio) simultaneous multiwavelength study of the microquasar Cygnus X-1, which aimed at an investigation of the origin of its mid-infrared emission. Compact jets were present in two out of three observations, and we show that they strongly contribute to the mid-infrared continuum. During the first observation, we detect the spectral break-where the transition from the optically thick to the optically thin regime takes place-at about 2.9 x 10{sup 13} Hz. We then show that the jet's optically thin synchrotron emission accounts for Cygnus X-1's emission beyond 400 keV, although it cannot alone explain its 3-200 keV continuum. A compact jet was also present during the second observation, but we do not detect the break, since it has likely shifted to higher frequencies. In contrast, the compact jet was absent during the last observation, and we show that the 5-30 {mu}m mid-infrared continuum of Cygnus X-1 stems from the blue supergiant companion star HD 226868. Indeed, the emission can then be understood as the combination of the photospheric Rayleigh-Jeans tail and the bremsstrahlung from the expanding stellar wind. Moreover, the stellar wind is found to be clumpy, with a filling factor f{sub {infinity}} {approx} 0.09-0.10. Its bremsstrahlung emission is likely anti-correlated to the soft X-ray emission, suggesting an anti-correlation between the mass-loss and mass-accretion rates. Nevertheless, we do not detect any mid-infrared spectroscopic evidence of interaction between the jets and Cygnus X-1's environment and/or the companion star's stellar wind.

  17. A Multiwavelength Study of Cygnus X-1: The First Mid-Infrared Spectroscopic Detection of Compact Jets

    NASA Technical Reports Server (NTRS)

    Rahoui, Farid; Lee, Julia C.; Heinz, Sebastian; Hines, Dean C.; Pottschmidt, Katja; Wilms, Joern

    2011-01-01

    We report on a Spitzer/IRS (mid-infrared), RXTE /PCA+HEXTE (X-ray), and Ryle (radio) simultaneous multi-wavelength study of the micro quasar Cygnus X-I, which aimed at an investigation of the origin of its mid-infrared emission. Compact jets were present in two out of three observations, and we show that they strongly contribute to the mid-infrared continuum. During the first observation, we detect the spectral break - where the transition from the optically thick to the optically thin regime takes place - at about 2.9 x 10(exp 13) Hz. We then show that the jet's optically thin synchrotron emission accounts for the Cygnus X-1's emission beyond 400 keY, although it cannot alone explain its 3-200 keV continuum. A compact jet was also present during the second observation, but we do not detect the break, since it has likely shifted to higher frequencies. In contrast, the compact jet was absent during the last observation, and we show that the 5-30 micron mid-infrared continuum of Cygnus X-I stems from the blue supergiant companion star HD 226868. Indeed, the emission can then be understood as the combination of the photospheric Raleigh-Jeans tail and the bremsstrahlung from the expanding stellar wind. Moreover, the stellar wind is found to be clumpy, with a filling factor f(sub infinity) approx.= 0.09-0.10. Its bremsstrahlung emission is likely anti-correlated to the soft X-ray emission, suggesting an anticorrelation between the mass-loss and mass-accretion rates. Nevertheless, we do not detect any mid-infrared spectroscopic evidence of interaction between the jets and the Cygnus X-1's environment and/or companion star's stellar wind.

  18. Infrared optical properties and AFM of spin-cast chitosan films chemically modified with 1,2 Epoxy-3-phenoxy-propane.

    PubMed

    Nosal, W H; Thompson, D W; Yan, L; Sarkar, S; Subramanian, A; Woollam, J A

    2005-11-25

    Chemical modification of spin-cast chitosan films has been performed. This modification involves the attachment of 1,2 Epoxy-3-phenoxy-propane, commonly known as glycidyl phenyl ether (GPE), to the amine group of the chitosan molecule. Optical properties of modified films have been determined in the infrared region of the spectrum using spectroscopic ellipsometry, and are reported in this paper. Special attention is paid to the infrared region where the index of refraction and extinction coefficients from 750 to 4000 cm(-1) were determined. Difference plots of IR optical data before and after chemical modification were generated to confirm that modification had occurred. Optical modeling of infrared spectroscopic ellipsometry (IRSE) data with respect to chemical bond vibrations has also been performed. This modeling involved curve fitting of resonant chemical bond absorptions using Lorentz oscillators. These oscillator models allow for comparison of modified chitosan to unmodified chitosan. The purpose of this research was to determine infrared optical constants of chemically modified chitosan films This work shows that surface chemistry of biomaterials can be studied quite sensitively with spectroscopy ellipsometry, detecting as little as 100 ng/cm(2) of GPE.

  19. High-definition Fourier Transform Infrared (FT-IR) spectroscopic imaging of human tissue sections towards improving pathology.

    PubMed

    Sreedhar, Hari; Varma, Vishal K; Nguyen, Peter L; Davidson, Bennett; Akkina, Sanjeev; Guzman, Grace; Setty, Suman; Kajdacsy-Balla, Andre; Walsh, Michael J

    2015-01-01

    High-definition Fourier Transform Infrared (FT-IR) spectroscopic imaging is an emerging approach to obtain detailed images that have associated biochemical information. FT-IR imaging of tissue is based on the principle that different regions of the mid-infrared are absorbed by different chemical bonds (e.g., C=O, C-H, N-H) within cells or tissue that can then be related to the presence and composition of biomolecules (e.g., lipids, DNA, glycogen, protein, collagen). In an FT-IR image, every pixel within the image comprises an entire Infrared (IR) spectrum that can give information on the biochemical status of the cells that can then be exploited for cell-type or disease-type classification. In this paper, we show: how to obtain IR images from human tissues using an FT-IR system, how to modify existing instrumentation to allow for high-definition imaging capabilities, and how to visualize FT-IR images. We then present some applications of FT-IR for pathology using the liver and kidney as examples. FT-IR imaging holds exciting applications in providing a novel route to obtain biochemical information from cells and tissue in an entirely label-free non-perturbing route towards giving new insight into biomolecular changes as part of disease processes. Additionally, this biochemical information can potentially allow for objective and automated analysis of certain aspects of disease diagnosis.

  20. Infrared and Raman spectroscopical studies of salicylic and salicylate derivatives in aqueous solution

    NASA Astrophysics Data System (ADS)

    Humbert, B.; Alnot, M.; Quilès, F.

    1998-03-01

    The assignment of vibrations of salicylic acid, salicylate monoanion and salicylate bianion in aqueous solution are discussed with the help of Raman spectroscopy, of attenuated total reflection infrared spectroscopy and of the computational density functional theory (DFT) approach.

  1. Adsorption of water on porous Vycor glass studied by ellipsometry.

    PubMed

    Alvarez-Herrero, A; Heredero, R L; Bernabeu, E; Levy, D

    2001-02-01

    The variation of the optical properties of porous Vycor glass (Corning, Model 7930) under different relative-humidity conditions was studied. The adsorption of water into the glass pores was investigated with spectroscopic ellipsometry. The change of the refractive index was Deltan approximately 0.04 between 5% and 90% relative humidity. A linear relation between the ellipsometer parameter tan Psi, the amount of water adsorbed in the glass pores, and information about the pore-size distributions was established. The results are in accord with the values obtained from N2 isotherms, transmission electron microscope micrographs, and the manufacturer's specifications (radius of approximately 20 A). The possibility of using this material as a transducer for implementation in a fiber-optic sensor to measure humidity was evaluated. PMID:18357027

  2. Instrumentation considerations in multichannel ellipsometry for real-time spectroscopy

    NASA Astrophysics Data System (ADS)

    An, Ilsin; Cong, Yue; Nguyen, N. V.; Pudliner, B. S.; Collins, R. W.

    Experimental procedures are described to enhance the accuracy of a novel rotating polarizer multichannel ellipsometer, designed for real-time spectroscopic studies of film growth and surfaces. For the fastest such instrument 128-point (psi, delta) spectra from 1.5 to 4.5 eV can be acquired in less than 10 ms. Ellipsometry places stringent demands on the photodiode-array-based detection system, as the irradiance incident on the separate pixels is waveform analyzed. A detailed characterization of the detection system is presented which provides the means to correct for stray light, image persistence, non-linearity, and integration errors. We also outline techniques for characterization of imperfection associated with the source and polarization optics. We present calibration and data reduction equations which have been derived to include source and polarization system imperfection parameters to first order.

  3. Infrared Spectroscopic Evidences of Strong Electronic Correlations in (Sr1‑xLax)3Ir2O7

    NASA Astrophysics Data System (ADS)

    Ahn, Gihyeon; Song, S. J.; Hogan, T.; Wilson, S. D.; Moon, S. J.

    2016-09-01

    We report on infrared spectroscopic studies of the electronic response of the (Sr1‑xLax)3Ir2O7 system. Our experiments revealed hallmarks of strong electronic correlations in the evolution of the electronic response across the filling-controlled insulator-metal transition. We observed a collapse of the Jeff = 1/2 Mott gap accompanying the transfer of the spectral weight from the high-energy region to the gap region with electron doping. The intraband conductivity at the metallic side of the transition was found to consist of coherent Drude-like and incoherent responses. The sum rule and the extended Drude model analyses further indicated a large mass enhancement. Our results demonstrate a critical role of the electronic correlations in the charge dynamics of the (Sr1‑xLax)3Ir2O7 system.

  4. Infrared Spectroscopic Evidences of Strong Electronic Correlations in (Sr1−xLax)3Ir2O7

    PubMed Central

    Ahn, Gihyeon; Song, S. J.; Hogan, T.; Wilson, S. D.; Moon, S. J.

    2016-01-01

    We report on infrared spectroscopic studies of the electronic response of the (Sr1−xLax)3Ir2O7 system. Our experiments revealed hallmarks of strong electronic correlations in the evolution of the electronic response across the filling-controlled insulator-metal transition. We observed a collapse of the Jeff = 1/2 Mott gap accompanying the transfer of the spectral weight from the high-energy region to the gap region with electron doping. The intraband conductivity at the metallic side of the transition was found to consist of coherent Drude-like and incoherent responses. The sum rule and the extended Drude model analyses further indicated a large mass enhancement. Our results demonstrate a critical role of the electronic correlations in the charge dynamics of the (Sr1−xLax)3Ir2O7 system. PMID:27599573

  5. Infrared Spectroscopic Data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE), SDSS-III Data Release 10

    DOE Data Explorer

    Sloan Digital Sky Survey (SDSS) Data Release 10 is the first spectroscopic release from the Apache Point Observatory Galactic Evolution Experiment (APOGEE), including spectra and derived stellar parameters for more than 50,000 stars. APOGEE is an ongoing survey of ~100,000 stars accessing all parts of the Milky Way. By operating in the infrared (H-band) portion of the electromagnetic spectrum, APOGEE is better able to detect light from stars lying in dusty regions of the Milky Way than surveys conducted in the optical, making this survey particularly well-suited for exploring the Galactic disk and bulge. APOGEE's high resolution spectra provide detailed information about the stellar atmospheres; DR10 provides derived effective temperatures, surface gravities, overall metallicities, and information on the abundances of several chemical elements. [copied from http://www.sdss3.org/dr10/irspec/

  6. Infrared Spectroscopic Evidences of Strong Electronic Correlations in (Sr1-xLax)3Ir2O7.

    PubMed

    Ahn, Gihyeon; Song, S J; Hogan, T; Wilson, S D; Moon, S J

    2016-01-01

    We report on infrared spectroscopic studies of the electronic response of the (Sr1-xLax)3Ir2O7 system. Our experiments revealed hallmarks of strong electronic correlations in the evolution of the electronic response across the filling-controlled insulator-metal transition. We observed a collapse of the Jeff = 1/2 Mott gap accompanying the transfer of the spectral weight from the high-energy region to the gap region with electron doping. The intraband conductivity at the metallic side of the transition was found to consist of coherent Drude-like and incoherent responses. The sum rule and the extended Drude model analyses further indicated a large mass enhancement. Our results demonstrate a critical role of the electronic correlations in the charge dynamics of the (Sr1-xLax)3Ir2O7 system. PMID:27599573

  7. Ab initio molecular orbital and infrared spectroscopic study of the conformation of secondary amides: derivatives of formanilide, acetanilide and benzylamides

    NASA Astrophysics Data System (ADS)

    Ilieva, S.; Hadjieva, B.; Galabov, B.

    1999-09-01

    Ab initio molecular orbital calculations at HF/4-31G level and infrared spectroscopic data for the frequencies are applied to analyse the grouping in a series model aromatic secondary amides: formanilide; acetanilide; o-methylacetanilide; 2,6-dimethylformanilide, 2,6-dimethylacetanilide; N-benzylacetamide and N-benzylformamide. The theoretical and experimental data obtained show that the conformational state of the molecules studied is determined by the fine balance of several intramolecular factors: resonance effect between the amide group and the aromatic ring, steric interaction between various substituents around the -NH-CO- grouping in the aromatic ring, conjugation between the carbonyl bond and the nitrogen lone pair as well as direct field influences inside the amide group.

  8. Non-invasive cerebral blood volume measurement during seizures using multi-channel near infrared spectroscopic topography

    NASA Astrophysics Data System (ADS)

    Watanabe, Eiju; Maki, Atsushi; Kawaguchi, Fumio; Yamashita, Yuichi; Koizumi, Hideaki; Mayanagi, Yoshiaki

    2000-07-01

    Near infrared spectroscopic topography (NIRS) is widely recognized as a noninvasive method to measure the regional cerebral blood volume (rCBV) dynamics coupled with neuronal activities. We analyzed the rCBV change in the early phase of epileptic seizures in 12 consecutive patients with medically intractable epilepsy. Seizure was induced by bemegride injection. We used eight-channel NIRS in nine cases and 24 channel in three cases. In all of the cases, rCBV increased rapidly after the seizure onset on the focus side. The increased rCBV was observed for about 30 - 60 s. The NIRS method can be applied to monitor the rCBV change continuously during seizures. Therefore, this method may be combined with ictal SPECT as one of the most reliable noninvasive methods of focus diagnosis.

  9. Non-invasive detection of superimposed latent fingerprints and inter-ridge trace evidence by infrared spectroscopic imaging.

    PubMed

    Bhargava, Rohit; Perlman, Rebecca Schwartz; Fernandez, Daniel C; Levin, Ira W; Bartick, Edward G

    2009-08-01

    Current latent print and trace evidence collecting technologies are usually invasive and can be destructive to the original deposits. We describe a non-invasive vibrational spectroscopic approach that yields latent fingerprints that are overlaid on top of one another or that may contain trace evidence that needs to be distinguished from the print. Because of the variation in the chemical composition distribution within the fingerprint, we demonstrate that linear unmixing applied to the spectral content of the data can be used to provide images that reveal superimposed fingerprints. In addition, we demonstrate that the chemical composition of the trace evidence located in the region of the print can potentially be identified by its infrared spectrum. Thus, trace evidence found at a crime scene that previously could not be directly related to an individual, now has the potential to be directly related by its presence in the individual-identifying fingerprints.

  10. Spectroscopic pilot study in the near infrared of a sample of star-forming galaxies at z = 2

    NASA Astrophysics Data System (ADS)

    Gallego, J.; Sánchez de Miguel, A.; Zamorano, J.; Pérez-González, P. G.; Cardiel, N.; Barro, G.

    2011-11-01

    In this work we present the results of the spectroscopic analysis inthe near-infrared K band of a sample of 12 active star forminggalaxies at z ˜ 2. The sample was selected by using photometricredshifts, blue colors and large fluxes in the 24 μ m band ofMIPS/Spitzer. To analyze their physical properties we have computedtheir sizes, colors, stellar masses, extinctions and other parametersavailable in literature and in the "Rainbow" database. We computeHα luminosities and star formation rates for all galaxies atthat redshift. We were able to estimate metallicities from [NII]6584for a sub sample of the objects. In particular the dependence of the metallicitywith the stellar mass has been studied and compared with the results of other samples ofgalaxies at several redshifts. For a fixed mass, the metallicities ofour galaxies are compatible than those similar at the corresponding redshift, following the general trend of lower metallicities for higher redshifts.

  11. The water vapour continuum in near-infrared windows - Current understanding and prospects for its inclusion in spectroscopic databases

    NASA Astrophysics Data System (ADS)

    Shine, Keith P.; Campargue, Alain; Mondelain, Didier; McPheat, Robert A.; Ptashnik, Igor V.; Weidmann, Damien

    2016-09-01

    Spectroscopic catalogues, such as GEISA and HITRAN, do not yet include information on the water vapour continuum that pervades visible, infrared and microwave spectral regions. This is partly because, in some spectral regions, there are rather few laboratory measurements in conditions close to those in the Earth's atmosphere; hence understanding of the characteristics of the continuum absorption is still emerging. This is particularly so in the near-infrared and visible, where there has been renewed interest and activity in recent years. In this paper we present a critical review focusing on recent laboratory measurements in two near-infrared window regions (centred on 4700 and 6300 cm-1) and include reference to the window centred on 2600 cm-1 where more measurements have been reported. The rather few available measurements, have used Fourier transform spectroscopy (FTS), cavity ring down spectroscopy, optical-feedback - cavity enhanced laser spectroscopy and, in very narrow regions, calorimetric interferometry. These systems have different advantages and disadvantages. Fourier Transform Spectroscopy can measure the continuum across both these and neighbouring windows; by contrast, the cavity laser techniques are limited to fewer wavenumbers, but have a much higher inherent sensitivity. The available results present a diverse view of the characteristics of continuum absorption, with differences in continuum strength exceeding a factor of 10 in the cores of these windows. In individual windows, the temperature dependence of the water vapour self-continuum differs significantly in the few sets of measurements that allow an analysis. The available data also indicate that the temperature dependence differs significantly between different near-infrared windows. These pioneering measurements provide an impetus for further measurements. Improvements and/or extensions in existing techniques would aid progress to a full characterisation of the continuum - as an example, we

  12. Preliminary evaluation of hydrocarbon removal power of Caulerpa racemosa in seawater by means of infrared and visible spectroscopic measurements

    NASA Astrophysics Data System (ADS)

    Pietroletti, Marco; Capobianchi, Alfredo; Ragosta, Emanuela; Mecozzi, Mauro

    2010-10-01

    In this paper we tested the power of Caulerpa racemosa for removal hydrocarbons from seawater. C. racemosa was implanted in two aquariums filled with natural seawater having a hydrocarbon content lower than 0.05 mg/L which is the detection limit of the FTIR spectrophotometric method used for the determination. One aquarium was submitted to sequential additions of hydrocarbons (n-esadecane 10, 20 and 40 mg/L, n-docosane 15 mg/L) and diesel fuels (20 mg/L) while the second one remained uncontaminated and used as control. After any addition, hydrocarbon content in seawater was determined at regular time intervals (one or two days) and when comparable hydrocarbon contents (i.e. lower than 0.05 mg/L) were again observed, the real removal power of hydrocarbons was verified by several spectroscopic measurements performed on algae from both aquariums. Total hydrocarbon contents in algae determined by infrared (FTIR) spectroscopy, always resulted higher in the polluted aquarium for all the concentrations of added pollutants. Further FTIR studies performed on algae showed the presence of marked quantitative and structural molecular modifications involving carbohydrates, proteins, lipids, nucleic acids and chlorophyll pigments in C. racemosa from the aquarium test. In addition, visible (VIS) spectroscopic examination of C. racemosa showed a reduction of chlorophyll pigments in the polluted aquarium with respect to the control one. At last, FTIR spectra all the algal samples submitted to hydrocarbon pollution were re-examined by means of two-dimensional correlation analysis, a statistical tool helpful for studying the dynamic evolution of any molecular and biological system submitted to an external perturbation producing compositional and structural changes. This approach showed differences among the molecular modifications caused by any type of hydrocarbon used, modifications related reasonably to the molecular dimensions and concentration of the added pollutants. All these

  13. FAR-IR/SUBMILLIMETER SPECTROSCOPIC COSMOLOGICAL SURVEYS: PREDICTIONS OF INFRARED LINE LUMINOSITY FUNCTIONS FOR z < 4 GALAXIES

    SciTech Connect

    Spinoglio, Luigi; Dasyra, Kalliopi M.; Gruppioni, Carlotta; Valiante, Elisabetta; Isaak, Kate

    2012-02-01

    Star formation and accretion onto supermassive black holes in the nuclei of galaxies are the two most energetic processes in the universe, producing the bulk of the observed emission throughout its history. We simulated the luminosity functions of star-forming and active galaxies for spectral lines that are thought to be good spectroscopic tracers of either phenomenon, as a function of redshift. We focused on the infrared (IR) and submillimeter domains, where the effects of dust obscuration are minimal. Using three different and independent theoretical models for galaxy formation and evolution, constrained by multi-wavelength luminosity functions, we computed the number of star-forming and active galaxies per IR luminosity and redshift bin. We converted the continuum luminosity counts into spectral line counts using relationships that we calibrated on mid- and far-IR spectroscopic surveys of galaxies in the local universe. Our results demonstrate that future facilities optimized for survey-mode observations, i.e., the Space Infrared telescope for Cosmology and Astrophysics and the Cerro Chajnantor Atacama Telescope, will be able to observe thousands of z > 1 galaxies in key fine-structure lines, e.g., [Si II], [O I], [O III], [C II], in a half-square-degree survey, with 1 hr integration time per field of view. Fainter lines such as [O IV], [Ne V], and H{sub 2} (0-0)S1 will be observed in several tens of bright galaxies at 1 < z < 2, while diagnostic diagrams of active nucleus versus star formation activity will be feasible even for normal z {approx} 1 galaxies. We discuss the new parameter space that these future telescopes will cover and that strongly motivates their construction.

  14. A four class model for digital breast histopathology using high-definition Fourier transform infrared (FT-IR) spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Mittal, Shachi; Wrobel, Tomasz P.; Leslie, L. S.; Kadjacsy-Balla, Andre; Bhargava, Rohit

    2016-03-01

    High-definition (HD) Fourier transform infrared (FT-IR) spectroscopic imaging is an emerging technique that not only enables chemistry-based visualization of tissue constituents, and label free extraction of biochemical information but its higher spatial detail makes it a potentially useful platform to conduct digital pathology. This methodology, along with fast and efficient data analysis, can enable both quantitative and automated pathology. Here we demonstrate a combination of HD FT-IR spectroscopic imaging of breast tissue microarrays (TMAs) with data analysis algorithms to perform histologic analysis. The samples comprise four tissue states, namely hyperplasia, dysplasia, cancerous and normal. We identify various cell types which would act as biomarkers for breast cancer detection and differentiate between them using statistical pattern recognition tools i.e. Random Forest (RF) and Bayesian algorithms. Feature optimization is integrally carried out for the RF algorithm, reducing computation time as well as redundant spectral features. We achieved an order of magnitude reduction in the number of features with comparable prediction accuracy to that of the original feature set. Together, the demonstration of histology and selection of features paves the way for future applications in more complex models and rapid data acquisition.

  15. Visualization of the human face skin moisturizing ability by spectroscopic imaging using two near-infrared bands

    NASA Astrophysics Data System (ADS)

    Iwasaki, Hiroaki; Miyazawa, Kanae; Nakauchi, Shigeki

    2006-01-01

    The skin's ability to retain moisture, which is hereafter referred as skin moisturizing-ability, is one of the important factors in skin health. Skin defends the biological tissue from the outside influences, skin sebum and moisture especially play an important role in that protection. The sebum and moisture meters available on the market, however, need to contact with skin. As a non-contact method, near-infrared (NIR) spectroscopic imaging, using absorption of the OH stretching overtone, has recently been capable of detecting changes in skin hydration of the forearms. However, face skin hydration has not been measured, and the moisture-related sebum has not been paid attention to, even though the face is important from the cosmetic and medical point of view. This study, therefore, aims to measure and visualize the spatial distribution of moisturizing-ability of the face skin by NIR spectroscopic imaging. The NIR spectral imaging system consists of two interference filters (1060 nm and 1450 nm) mounted on a filter wheel and a NIR camera with indiumgallium arsenide array sensor. We measured human face skins with/without moisturizing lotion and found that the glabella and nose have strong moisturizing-ability because of sebaceous glands. It was also shown that the areas where moisturizing lotion was applied were successfully displayed by subtracting two absorbance images measured at different wavelength bands. This technique can be applied to the functional assessment of face skin moisturizer in medicine and cosmetics.

  16. Development of Single-Seed Near-Infrared Spectroscopic Predictions of Corn and Soybeans Constituents Using Bulk Teference Values and Mean Spectra

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Near-Infrared reflectance spectroscopic prediction models were developed for common constituents of corn and soybeans using bulk reference values and mean spectra from single-seeds. The bulk reference model and a true single-seed model for soybean protein were compared to determine how well the bul...

  17. Do Infants Recognize the Arcimboldo Images as Faces? Behavioral and Near-Infrared Spectroscopic Study

    ERIC Educational Resources Information Center

    Kobayashi, Megumi; Otsuka, Yumiko; Nakato, Emi; Kanazawa, So; Yamaguchi, Masami K.; Kakigi, Ryusuke

    2012-01-01

    Arcimboldo images induce the perception of faces when shown upright despite the fact that only nonfacial objects such as vegetables and fruits are painted. In the current study, we examined whether infants recognize a face in the Arcimboldo images by using the preferential looking technique and near-infrared spectroscopy (NIRS). In the first…

  18. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic analysis of regenerated bone

    NASA Astrophysics Data System (ADS)

    Benetti, Carolina; Kazarain, Sergei G.; Alves, Marco A. V.; Blay, Alberto; Correa, Luciana; Zezell, Denise M.

    2014-03-01

    The cutting of bone is routinely required in medical procedures, especially in dental applications. In such cases, bone regeneration and new bone quality can determine the success of the treatment. This study investigated the main spectral differences of undamaged and healed bone using the ATR-FTIR spectroscopy technique. Three rabbits were submitted to a surgical procedure; a small piece of bone (3x3 mm2) was removed from both sides of their jaws using a high speed drill. After 15 days, the rabbits were euthanized and the jaws were removed. A bone slice was cut from each side of the jaw containing regions of undamaged and newly formed bone, resulting in six samples which were polished for spectroscopic comparison. The samples were analyzed by FTIR spectroscopy using a diamond ATR accessory. Spectral characteristics were compared and particular attention was paid to the proportion of phosphate to amide I bands and the width of the phosphate band. The results show that the ratio of phosphate to amide I is smaller in new bone tissue than in the undamaged bone, indicating a higher organic content in the newly formed bone. The analysis of the width of the phosphate band suggests a crystallinity difference between both tissues, since the width was higher in the new bone than in the natural bone. These results suggest that the differences observed in bone aging processes by FTIR spectroscopic can be applied to the study of healing processes.

  19. Evaluating the health of compromised tissues using a near-infrared spectroscopic imaging system in clinical settings: lessons learned

    NASA Astrophysics Data System (ADS)

    Leonardi, Lorenzo; Sowa, Michael G.; Hewko, Mark D.; Schattka, Bernhard J.; Payette, Jeri R.; Hastings, Michelle; Posthumus, Trevor B.; Mantsch, Henry H.

    2003-07-01

    The present and accepted standard for determining the status of tissue relies on visual inspection of the tissue. Based on the surface appearance of the tissue, medical personnel will make an assessment of the tissue and proceed to a course of action or treatment. Visual inspection of tissue is central to many areas of clinical medicine, and remains a cornerstone of dermatology, reconstructive plastic surgery, and in the management of chronic wounds, and burn injuries. Near infrared spectroscopic imaging holds the promise of being able to monitor the dynamics of tissue physiology in real-time and detect pathology in living tissue. The continuous measurement of metabolic, physiological, or structural changes in tissue is of primary concern in many clinical and biomedical domains. A near infrared hyperspectral imaging system was constructed for the assessment of burn injuries and skin flaps or skin grafts. This device merged basic science with engineering and integrated manufacturing to develop a device suitable to detect ischemic tissue. This device has the potential of providing measures of tissue physiology, oxygen delivery and tissue hydration during patient screening, in the operating room or during therapy and post-operative/treatment monitoring. Results from a pre-clinical burn injury study will be presented.

  20. Matrix isolation infrared spectroscopic and theoretical study of 1,1,1-trifluoro-2-chloroethane (HCFC-133a)

    SciTech Connect

    Rodrigues, Gessenildo Pereira; Ventura, Elizete E-mail: rfausto@ci.uc.pt; Andrade do Monte, Silmar; Lucena, Juracy Régis; Reva, Igor; Fausto, Rui E-mail: rfausto@ci.uc.pt

    2013-11-28

    The molecular structure and infrared spectrum of the atmospheric pollutant 1,1,1-trifluoro-2-chloroethane (HCFC-133a; CF{sub 3}CH{sub 2}Cl) in the ground electronic state were characterized experimentally and theoretically. Excited state calculations (at the CASSCF, MR-CISD, and MR-CISD+Q levels) have also been performed in the range up to ∼9.8 eV. The theoretical calculations show the existence of one (staggered) conformer, which has been identified spectroscopically for the monomeric compound isolated in cryogenic (∼10 K) argon and xenon matrices. The observed infrared spectra of the matrix-isolated HCFC-133a were interpreted with the aid of MP2/aug-cc-pVTZ calculations and normal coordinate analysis, which allowed a detailed assignment of the observed spectra to be carried out, including identification of bands due to different isotopologues ({sup 35}Cl and {sup 37}Cl containing molecules). The calculated energies of the several excited states along with the values of oscillator strengths and previous results obtained for CFCs and HCFCs suggest that the previously reported photolyses of the title compound at 147 and 123.6 nm [T. Ichimura, A. W. Kirk, and E. Tschuikow-Roux, J. Phys. Chem. 81, 1153 (1977)] are likely to be initiated in the n-4s and n-4p Rydberg states, respectively.

  1. Sculpting narrowband Fano resonances inherent in the large-area mid-infrared photonic crystal microresonators for spectroscopic imaging

    PubMed Central

    Liu, Jui-Nung; Schulmerich, Matthew V.; Bhargava, Rohit; Cunningham, Brian T.

    2014-01-01

    Fourier transform infrared (FT-IR) imaging spectrometers are almost universally used to record microspectroscopic imaging data in the mid-infrared (mid-IR) spectral region. While the commercial standard, interferometry necessitates collection of large spectral regions, requires a large data handling overhead for microscopic imaging and is slow. Here we demonstrate an approach for mid-IR spectroscopic imaging at selected discrete wavelengths using narrowband resonant filtering of a broadband thermal source, enabled by high-performance guided-mode Fano resonances in one-layer, large-area mid-IR photonic crystals on a glass substrate. The microresonant devices enable discrete frequency IR (DF-IR), in which a limited number of wavelengths that are of interest are recorded using a mechanically robust instrument. This considerably simplifies instrumentation as well as overhead of data acquisition, storage and analysis for large format imaging with array detectors. To demonstrate the approach, we perform DF-IR spectral imaging of a polymer USAF resolution target and human tissue in the C−H stretching region (2600−3300 cm−1). DF-IR spectroscopy and imaging can be generalized to other IR spectral regions and can serve as an analytical tool for environmental and biomedical applications. PMID:25089433

  2. Analysis of Molecular Contamination on Genesis Collectors Through Spectroscopic Ellipsometry

    NASA Technical Reports Server (NTRS)

    McNamara, K. M.; Stansbery, Eileen K.

    2005-01-01

    Before the spacecraft returned to Earth in September, the Genesis mission had a preliminary assessment plan in place for the purpose of providing information on the condition and availability of collector materials to the science community as a basis for allocation requests. One important component of that plan was the evaluation of collector surfaces for molecular contamination. Sources of molecular contamination might be the on-orbit outgassing of spacecraft and science canister components, the condensation of thruster by-products during spacecraft maneuvers, or the condensation of volatile species associated with reentry. Although the non-nominal return of the Genesis spacecraft introduced particulate contamination to the collectors, such as dust and heatshield carbon-carbon, it is unlikely to have caused any molecular deposition. The contingency team's quick action in returning the damaged payload the UTTR cleanroom by 6 PM the evening of recovery help to ensure that exposure to weather conditions and the environment were kept to a minimum.

  3. Reactions of yttrium and scandium atoms with acetylene: a matrix isolation infrared spectroscopic and theoretical study.

    PubMed

    Teng, Yun-Lei; Xu, Qiang

    2010-09-01

    Laser-ablated yttrium and scandium metal atoms have been codeposited at 4 K with acetylene in excess argon. Products, Y(C(2)H(2)), HYCCH, HScCCH(-), and HScScCCH(-), have been formed in the present experiments and characterized using infrared spectroscopy on the basis of the results of the isotopic shifts, mixed isotopic splitting patterns, stepwise annealing, the change of reagent concentration and laser energy, and the comparison with theoretical predictions. Density functional theory calculations have been performed on these molecules. The agreement between the experimental and calculated vibrational frequencies, relative absorption intensities, and isotopic shifts supports the identification of these molecules from the matrix infrared spectra. Plausible reaction mechanisms have been proposed to account for the formation of these molecules.

  4. Reactions of group 14 metal atoms with acetylene: a matrix isolation infrared spectroscopic and theoretical study.

    PubMed

    Teng, Yun-Lei; Xu, Qiang

    2009-11-01

    Laser-ablated group 14 metal atoms have been codeposited at 4 K with acetylene in excess argon. Products, Ge(C2H2), HGeCCH, Sn(C2H2), Sn2CCH2, HSnCCH, and HPbCCH, have been formed in the present experiments and characterized using infrared spectroscopy on the basis of the results of the isotopic shifts, mixed isotopic splitting patterns, stepwise annealing, the change of reagent concentration and laser energy, and the comparison with theoretical predictions. Density functional theory calculations have been performed on these molecules. The agreement between the experimental and the calculated vibrational frequencies, relative absorption intensities, and isotopic shifts supports the identification of these molecules from the matrix infrared spectra. Plausible reaction mechanisms have been proposed to account for the formation of these molecules.

  5. An infrared spectroscopic study of H-bond network in hyperbranched polyester polyol

    NASA Astrophysics Data System (ADS)

    Žagar, Ema; Grdadolnik, Jože

    2003-10-01

    A FTIR study of aliphatic hyperbranched polyester of the fourth generation Boltorn H40 (BH40) is presented. In order to properly assign the main vibrational bands in infrared spectrum temperature measurements, hydration and H/D exchange experiments were performed. Beside these experiments, difference spectroscopy, 2D generalized correlation infrared spectroscopy (2-DGCS) and band fitting procedure were employed to study the main interactions in polymer. On the basis of the detected interactions between various groups the structure of a H-bond network in hyperbranched polyester is proposed. Three main H-bond interactions were detected. Besides CO⋯HO and HO⋯HO a third type of H-bond is present (CO⋯HO⋯HO). A minor type of interactions represent the hydrogen bond formed with the carboxyl COOH group and impurities, which may be present in lower concentration.

  6. Near-infrared spectroscopic survey of B-type asteroids: compositional analysis

    NASA Astrophysics Data System (ADS)

    de Leon, J.; Pinilla-Alonso, N.; Licandro, J.; Campins, H.; Marzo, G. A.

    2011-10-01

    We present near-infrared spectra of 23 B-type asteroids obtained with the NICS cameraspectrograph at the 3.56 m Telescopio Nazionale Galileo. We also include visible and near-infrared spectra of 20 additional B-type asteroids from the literature, including near-Earth asteroid 1999 RQ36, primary target of NASA's OSIRIS-Rex sample return mission. A plot of the spectra of all the asteroids shows a continuous trend in the nearinfrared between red and blue slopes. We apply a clustering technique to reduce the volume of data to six "average spectra" or "centroids" representative of the whole sample. These spectra are then compared against the entire RELAB database to search for best analogs.

  7. A near infrared spectroscopic study of the interstellar gas in the starburst core of M82

    NASA Technical Reports Server (NTRS)

    Lester, Dan F.; Carr, John; Joy, Marshall; Gaffney, Niall

    1990-01-01

    Researchers used the McDonald Observatory Infrared Grating Spectrometer, to complete a program of spatially resolved spectroscopy of M82. The inner 300 pc of the starburst was observed with 4 inch (50 pc) resolution. Complete J, H and K band spectra with resolution 0.0035 micron (lambda/delta lambda=620 at K) were measured at the near-infrared nucleus of the galaxy. Measurements of selected spectral features including lines of FeII, HII and H2 were observed along the starburst ridge-line, so the relative distribution of the diagnostic features could be understood. This information was used to better define the extinction towards the starburst region, the excitation conditions in the gas, and to characterize the stellar populations there.

  8. Infrared spectroscopic study of molecular hydrogen bonding in chiral smectic liquid crystals

    PubMed

    Jang; Park; Kim; Glaser; Clark

    2000-10-01

    We report the use of Fourier-transform infrared (IR) spectroscopy to probe intermolecular and intramolecular hydrogen bonding in thermotropic liquid-crystal phases. Infrared spectra of aligned smectic liquid crystal materials vs temperature, and of isotropic liquid-crystal mixtures vs concentration were measured in homologs both with and without hydrogen bonding. Hydrogen bonding significantly changes the direction and magnitude of the vibrational dipole transition moments, causing marked changes in the IR dichroic absorbance profiles of hydrogen-bonded molecular subfragments. A GAUSSIAN94 computation of the directions, magnitudes, and frequencies of the vibrational dipole moments of molecular subfragments shows good agreement with the experimental data. The results show that IR dichroism can be an effective probe of hydrogen bonding in liquid-crystal phases.

  9. SPECTROSCOPIC CONFIRMATION OF A z = 2.79 MULTIPLY IMAGED LUMINOUS INFRARED GALAXY BEHIND THE BULLET CLUSTER

    SciTech Connect

    Gonzalez, Anthony H.; Papovich, Casey; Bradac, Marusa; Jones, Christine

    2010-09-01

    We report spectroscopic confirmation and high-resolution infrared imaging of a z = 2.79 triply imaged galaxy behind the Bullet Cluster. This source, a Spitzer-selected luminous infrared galaxy, is confirmed via polycyclic aromatic hydrocarbon (PAH) features using the Spitzer Infrared Spectrograph (IRS) and resolved with Hubble Space Telescope Wide Field Camera 3 imaging. In this galaxy, which with a stellar mass M{sub *} {approx} 4 x 10{sup 9} M{sub sun} is one of the two least massive ones studied with IRS at z>2, we also detect H{sub 2} S(4) and H{sub 2} S(5) pure rotational lines (at 3.1{sigma} and 2.1{sigma})-the first detection of these molecular hydrogen lines in a high-redshift galaxy. From the molecular hydrogen lines we infer an excitation temperature T = 377{sup +68}{sub -84} K. The detection of these lines indicates that the warm molecular gas mass is 6{sup +36}{sub -4}% of the stellar mass and implies the likely existence of a substantial reservoir of cold molecular gas in the galaxy. Future spectral observations at longer wavelengths with facilities such as the Herschel Space Observatory, the Large Millimeter Telescope, and the Atacama Pathfinder Experiment thus hold the promise of precisely determining the total molecular gas mass. Given the redshift, and using refined astrometric positions from the high-resolution imaging, we also update the magnification estimate and derived fundamental physical properties of this system. The previously published values for L{sub IR}, star formation rate, and dust temperature are confirmed modulo the revised magnification; however, we find that PAH emission is roughly a factor of 5 stronger than would be predicted by the relations between L{sub IR} and L{sub PAH} reported for SMGs and starbursts in Pope et al.

  10. Far-infrared emission spectra of selected gas-phase PAHs: Spectroscopic fingerprints

    SciTech Connect

    Zhang, K.; Guo, B.; Colarusso, P.; Bernath, P.F.

    1996-10-25

    The emission spectra of the gaseous polycyclic aromatic hydrocarbons (PAHs) naphthalene, chrysene, and pyrene were recorded in the far-infrared (far-IR) region. The vibrational bands that lie in the far IR are unique for each PAH molecule and allow discrimination among the three PAH molecules. The far-IR PAH spectra, therefore, may prove useful in the assignment of unidentified spectral features from astronomical objects. 23 refs., 1 fig., 1 tab.

  11. Regression models based on new local strategies for near infrared spectroscopic data.

    PubMed

    Allegrini, F; Fernández Pierna, J A; Fragoso, W D; Olivieri, A C; Baeten, V; Dardenne, P

    2016-08-24

    In this work, a comparative study of two novel algorithms to perform sample selection in local regression based on Partial Least Squares Regression (PLS) is presented. These methodologies were applied for Near Infrared Spectroscopy (NIRS) quantification of five major constituents in corn seeds and are compared and contrasted with global PLS calibrations. Validation results show a significant improvement in the prediction quality when local models implemented by the proposed algorithms are applied to large data bases. PMID:27496996

  12. Matrix Infrared Spectroscopic and Computational Investigations of Novel Small Uranium Containing Molecules - Final Technical Report

    SciTech Connect

    Andrews, Lester

    2014-10-17

    Direct reactions of f-element uranium, thorium and lanthanide metal atoms were investigated with small molecules. These metal atoms were generated by laser ablation and mixed with the reagent molecules then condensed with noble gases at 4K. The products were analyzed by absorption of infrared light to measure vibrational frequencies which were confirmed by quantum chemical calculations. We have learned more about the reactivity of uranium atoms with common molecules, which will aid in the develolpment of further applications of uranium.

  13. Impact of Spectroscopic Line Parameters on Carbon Monoxide Column Density Retrievals from Shortwave Infrared Nadir Observations

    NASA Astrophysics Data System (ADS)

    Schmidt, Denise; Gimeno Garcia, Sebastian; Schreier, Franz; Lichtenberg, Gunter

    2015-06-01

    Among the various input data required for the retrieval of atmospheric state parameters from infrared remote sensing observations molecular spectroscopy line data have a central role, because their quality is critical for the quality of the final product. Here we discuss the impact of the line parameters on vertical column densities (VCD) estimated from short wave infrared nadir observations. Using BIRRA (the Beer InfraRed Retrieval Algorithm) comprising a line-by-line radiative transfer code (forward model) and a separable nonlinear least squares solver for inversion we retrieve carbon monoxide from observations of SCIAMACHY aboard Envisat. Retrievals using recent versions of HITRAN und GEISA have been performed and the results are compared in terms of residual norms, molecular density scaling factors, their corresponding errors, and the final VCD product. The retrievals turn out to be quite similar for all three databases, so a definite recommendation in favor of one of these databases is difficult for the considered spectral range around 2:3 μm . Nevertheless, HITRAN 2012 appears to be advantageous when evaluating the different quality criteria.

  14. Differences in infrared spectroscopic data of connective tissues in transflectance and transmittance modes.

    PubMed

    Hanifi, Arash; McGoverin, Cushla; Ou, Ya-Ting; Safadi, Fayez; Spencer, Richard G; Pleshko, Nancy

    2013-05-24

    Fourier transform infrared imaging spectroscopy (FT-IRIS) has been used extensively to characterize the composition and orientation of macromolecules in thin tissue sections. Earlier and current studies of normal and polarized FT-IRIS data have primarily used tissues sectioned onto infrared transmissive substrates, such as salt windows. Recently, the use of low-emissivity ("low-e") substrates has become of great interest because of their low cost and favorable infrared optical properties. However, data are collected in transflectance mode when using low-e slides and in transmittance mode using salt windows. In the current study we investigated the comparability of these two modes for assessment of the composition of connective tissues. FT-IRIS data were obtained in transflectance and transmittance modes from serial sections of cartilage, bone and tendon, and from a standard polymer, polymethylmethacrylate. Both non-polarized and polarized FTIR data differed in absorbance, and in some cases peak position, between transflectance and transmittance modes. However, the FT-IRIS analysis of the collagen fibril orientation in cartilage resulted in the expected zonal arrangement of fibrils in both transmittance and transflectance. We conclude that numerical comparison of FT-IRIS-derived parameters of tissue composition should account for substrate type and data collection mode, while analysis of overall tissue architecture may be more invariant between modes.

  15. Automated High-Pressure Titration System with In Situ Infrared Spectroscopic Detection

    SciTech Connect

    Thompson, Christopher J.; Martin, Paul F.; Chen, Jeffrey; Benezeth, Pascale; Schaef, Herbert T.; Rosso, Kevin M.; Felmy, Andrew R.; Loring, John S.

    2014-04-17

    A fully automated titration system with infrared detection was developed for investigating interfacial chemistry at high pressures. The apparatus consists of a high-pressure fluid generation and delivery system coupled to a high-pressure cell with infrared optics. A manifold of electronically actuated valves is used to direct pressurized fluids into the cell. Precise reagent additions to the pressurized cell are made with calibrated tubing loops that are filled with reagent and placed in-line with the cell and a syringe pump. The cell’s infrared optics facilitate both transmission and attenuated total reflection (ATR) measurements to monitor bulk-fluid composition and solid-surface phenomena such as adsorption, desorption, complexation, dissolution, and precipitation. Switching between the two measurement modes is accomplished with moveable mirrors that direct radiation from a Fourier transform infrared spectrometer into the cell along transmission or ATR light paths. The versatility of the high-pressure IR titration system is demonstrated with three case studies. First, we titrated water into supercritical CO2 (scCO2) to generate an infrared calibration curve and determine the solubility of water in CO2 at 50 °C and 90 bar. Next, we characterized the partitioning of water between a montmorillonite clay and scCO2 at 50 °C and 90 bar. Transmission-mode spectra were used to quantify changes in the clay’s sorbed water concentration as a function of scCO2 hydration, and ATR measurements provided insights into competitive residency of water and CO2 on the clay surface and in the interlayer. Finally, we demonstrated how time-dependent studies can be conducted with the system by monitoring the carbonation reaction of forsterite (Mg2SiO4) in water-bearing scCO2 at 50 °C and 90 bar. Immediately after water dissolved in the scCO2, a thin film of adsorbed water formed on the mineral surface, and the film thickness increased with time as the forsterite began to dissolve

  16. Automated high-pressure titration system with in situ infrared spectroscopic detection

    NASA Astrophysics Data System (ADS)

    Thompson, Christopher J.; Martin, Paul F.; Chen, Jeffrey; Benezeth, Pascale; Schaef, Herbert T.; Rosso, Kevin M.; Felmy, Andrew R.; Loring, John S.

    2014-04-01

    A fully automated titration system with infrared detection was developed for investigating interfacial chemistry at high pressures. The apparatus consists of a high-pressure fluid generation and delivery system coupled to a high-pressure cell with infrared optics. A manifold of electronically actuated valves is used to direct pressurized fluids into the cell. Precise reagent additions to the pressurized cell are made with calibrated tubing loops that are filled with reagent and placed in-line with the cell and a syringe pump. The cell's infrared optics facilitate both transmission and attenuated total reflection (ATR) measurements to monitor bulk-fluid composition and solid-surface phenomena such as adsorption, desorption, complexation, dissolution, and precipitation. Switching between the two measurement modes is accomplished with moveable mirrors that direct the light path of a Fourier transform infrared spectrometer into the cell along transmission or ATR light paths. The versatility of the high-pressure IR titration system was demonstrated with three case studies. First, we titrated water into supercritical CO2 (scCO2) to generate an infrared calibration curve and determine the solubility of water in CO2 at 50 °C and 90 bar. Next, we characterized the partitioning of water between a montmorillonite clay and scCO2 at 50 °C and 90 bar. Transmission-mode spectra were used to quantify changes in the clay's sorbed water concentration as a function of scCO2 hydration, and ATR measurements provided insights into competitive residency of water and CO2 on the clay surface and in the interlayer. Finally, we demonstrated how time-dependent studies can be conducted with the system by monitoring the carbonation reaction of forsterite (Mg2SiO4) in water-bearing scCO2 at 50 °C and 90 bar. Immediately after water dissolved in the scCO2, a thin film of adsorbed water formed on the mineral surface, and the film thickness increased with time as the forsterite began to dissolve

  17. Attenuated total reflection-Fourier transform infrared spectroscopic imaging of pharmaceuticals in microfluidic devices.

    PubMed

    Ewing, Andrew V; Clarke, Graham S; Kazarian, Sergei G

    2016-03-01

    The poor aqueous solubility of many active pharmaceutical ingredients presents challenges for effective drug delivery. In this study, the combination of attenuated total reflection (ATR)-FTIR spectroscopic imaging with specifically designed polydimethylsiloxane microfluidic devices to study drug release from pharmaceutical formulations has been developed. First, the high-throughput analysis of the dissolution of micro-formulations studied under flowing conditions has been introduced using a model formulation of ibuprofen and polyethylene glycol. The behaviour and release of the drug was monitored in situ under different pH conditions. In contrast to the neutral solution, where both the drug and excipient dissolved at a similar rate, structural change from the molecularly dispersed to a crystalline form of ibuprofen was characterised in the obtained spectroscopic images and the corresponding ATR-FTIR spectra for the experiments carried out in the acidic medium. Further investigations into the behaviour of the drug after its release from formulations (i.e., dissolved drug) were also undertaken. Different solutions of sodium ibuprofen dissolved in a neutral medium were studied upon contact with acidic conditions. The phase transition from a dissolved species of sodium ibuprofen to the formation of solid crystalline ibuprofen was revealed in the microfluidic channels. This innovative approach could offer a promising platform for high-throughput analysis of a range of micro-formulations, which are of current interest due to the advent of 3D printed pharmaceutical and microparticulate delivery systems. Furthermore, the ability to study dissolved drug in solution under flowing conditions can be useful for the studies of the diffusion of drugs into tissues or live cells. PMID:27158293

  18. Fourier Transform Infrared Spectroscopic Analysis Of Plastic Capsule Materials Exposed To Deuterium-Tritium (DT) Gas

    SciTech Connect

    Schoonover, J R; Steckle, Jr., W P; Elliot, N; Ebey, P S; Nobile, A; Nikroo, A; Cook, R C; Letts, S A

    2005-06-16

    Planar samples of varying thicknesses of both CH and CD glow discharge polymer have been measured with Fourier transform infrared (FTIR) spectroscopy before and after exposure to deuterium-tritium (DT) gas at elevated temperature and pressure. Planar samples of polyimide films made from both hydrogenated and deuterated precursors have also been examined by FTIR before and after DT exposure. The post-exposure FTIR spectra demonstrated no measurable exchange of hydrogen with deuterium or tritium for either polymer. Evidence for oxidation of the glow discharge polymer due to atmospheric oxygen was the only chemical change indicated by the FTIR data.

  19. Near-infrared spectroscopic study on the effects of chewing on short-term memory.

    PubMed

    Wada, Mayumi; Hoshi, Yoko; Iguchi, Yoshinobu; Kida, Ikuhiro

    2011-12-01

    Using near-infrared spectroscopy, we examined whether chewing gum improves performance in a short-term memory task - immediate recall of random eight-digit numbers - by assessing cerebral hemodynamic response in the prefrontal cortex. We found that the oxyhemoglobin concentration during and after chewing gum was higher than that before chewing; further, the concentration increased during the task, and this increase was reduced with chewing, although non-significantly. Chewing did not improve task performance. Therefore, chewing-induced hemodynamic responses were unrelated to the performance in short-term memory tasks.

  20. Investigating the origin and spectroscopic variability of the near-infrared H I lines in the Herbig star VV Ser

    NASA Astrophysics Data System (ADS)

    Garcia Lopez, Rebeca; Kurosawa, Ryuichi; Caratti o Garatti, Alessio; Kreplin, Alexander; Weigelt, Gerd; Tambovtseva, Larisa V.; Grinin, Vladimir P.; Ray, Thomas P.

    2016-02-01

    The origin of the near-infrared (NIR) H I emission lines in young stellar objects are not yet understood. To probe it, we present multi-epoch LBT-LUCIFER spectroscopic observations of the Paδ, Paβ, and Brγ lines observed in the Herbig star VV Ser, along with Very Large Telescope Interferometer-AMBER Brγ spectro-interferometric observations at medium resolution. Our spectroscopic observations show line profile variability in all the H I lines. The strongest variability is observed in the redshifted part of the line profiles. The Brγ spectro-interferometric observations indicate that the Brγ line emitting region is smaller than the continuum emitting region. To interpret our results, we employed radiative transfer models with three different flow configurations: magnetospheric accretion, a magnetocentrifugally driven disc wind, and a schematic bipolar outflow. Our models suggest that the H I line emission in VV Ser is dominated by the contribution of an extended wind, perhaps a bipolar outflow. Although the exact physical process for producing such outflow is not known, this model is capable of reproducing the averaged single-peaked line profiles of the H I lines. Additionally, the observed visibilities, differential and closure phases are best reproduced when a wind is considered. Nevertheless, the complex line profiles and variability could be explained by changes in the relative contribution of the magnetosphere and/or winds to the line emission. This might indicate that the NIR H I lines are formed in a complex inner disc region where inflow and outflow components might coexist. Furthermore, the contribution of each of these mechanisms to the line appears time variable, suggesting a non-steady accretion/ejection flow.

  1. In Situ Fourier transform infrared spectroscopic study of the thermal degradation of isotactic poly(propylene).

    PubMed

    He, Peng; Xiao, Yan; Zhang, Puming; Zhu, Na; Zhu, Xinyuan; Yan, Deyue

    2005-01-01

    The conformational change of isotactic poly(propylene) (iPP) during the thermal degradation process has been carefully studied by in situ Fourier transform infrared (FT-IR) spectroscopy. This new method of studying thermal degradation of iPP not only shows the conventional kinetic parameter information of thermal degradation such as the degradation activation energy DeltaE and the degradation factor n, which are in accord with the results of traditional thermogravimetry experiments, but also indicates that many significant molecular structure changes occur during the thermal degradation process that come from some characteristic absorption band changes of in situ FT-IR. A multivariate approach, principal components analysis (PCA), is applied to the analysis of infrared (IR) data, and the results further confirm the multi-step processes of the thermal degradation of iPP. Above all, this is a new application to polymer thermal degradation by in situ FT-IR that connects the intermediate conformational change with final results during thermal degradation.

  2. Single-mode interband cascade laser sources for mid-infrared spectroscopic applications

    NASA Astrophysics Data System (ADS)

    Scheuermann, J.; von Edlinger, M.; Weih, R.; Becker, S.; Nähle, L.; Fischer, M.; Koeth, J.; Kamp, M.; Höfling, S.

    2016-05-01

    Compared to the near infrared, many technologically and industrially relevant gas species have more than an order of magnitude higher absorption features in the mid-infrared (MIR) wavelength range. These species include for example important hydrocarbons (methane, acetylene), nitrogen oxides and sulfur oxides. Tunable laser absorption spectroscopy (TLAS) has proven to be a versatile tool for gas sensing applications with significant advantages compared to other techniques. These advantages include real time measurement, standoff detection and ruggedness of the sensor. We present interband cascade lasers (ICLs), which have evolved into important laser sources for the MIR spectral range from 3 to 7 μm. ICLs achieve high efficiency by cascading optically active zones whilst using interband transitions, so they combine common diode laser as well as quantum cascade laser based technologies. Our application grade singlemode distributed feedback devices operate continuous wave at room temperature and are offering several features especially useful for high performance TLAS applications like: side mode suppression ratio of > 30 dB, continuous tuning ranges up to 30 nm, low threshold power densities and low overall power consumption. The devices are typically integrated in a thermoelectrically cooled TO-style package, hermetically sealed using a cap with anti-reflection coated window. This low power consumption as well as the compact size and ruggedness of the fabricated laser sources makes them perfectly suited for battery powered portable solutions for in field spectroscopy applications.

  3. Near-infrared spectroscopic survey of B-type asteroids: Compositional analysis

    NASA Astrophysics Data System (ADS)

    de León, J.; Pinilla-Alonso, N.; Campins, H.; Licandro, J.; Marzo, G. A.

    2012-03-01

    We present near-infrared spectra of 23 B-type asteroids obtained with the NICS camera-spectrograph at the 3.56 m Telescopio Nazionale Galileo. We also compile additional visible and near-infrared spectra of another 22 B-type asteroids from the literature. A total of 45 B-types are analyzed. No significant trends in orbital properties of our sample were detected when compared with all known B-types and all known asteroids. The reflectance spectra of the asteroids in the 0.8-2.5 μm range show a continuous shape variation, from a monotonic negative (blue) slope to a positive (red) slope. This continuous spectral trend is filling the gap between the two main groups of B-types published by Clark et al. ([2010]. J. Geophys. Res., 115, 6005-6027). We found no clear correlations between the spectral slope and the asteroids’ sizes or heliocentric distances. We apply a clustering technique to reduce the volume of data to six optimized “average spectra” or “centroids”, representative of the whole sample. These centroids are then compared against meteorite spectra from the RELAB database. We found carbonaceous chondrites as the best meteorite analogs for the six centroids. There is a progressive change in analogs that correlates with the spectral slope: from CM2 chondrites (water-rich, aqueously altered) for the reddest centroid, to CK4 chondrites (dry, heated/thermally altered) for the bluest one.

  4. Reflective and photoacoustic infrared spectroscopic techniques in assessment of binding media in paintings

    NASA Astrophysics Data System (ADS)

    Łojewski, Tomasz; Bagniuk, Jacek; Kołodziej, Andrzej; Łojewska, Joanna

    2011-11-01

    This study proposes a method to estimate the lipid content in binding media in paintings that can be used at any laboratory equipped with an infrared spectrometer. The lipid content estimator, termed greasiness index (GI), is defined as a ratio of lipid ν(C=O) and protein amide I bands at 1743 and 1635 cm-1, respectively. Three Fourier transform infrared (FTIR) sampling techniques were evaluated for GI determination: reflective attenuated total reflection—ATR, specular reflection microscopy— μSR and photoacoustic—PAS. A set of model painting samples containing three tempera binding media (casein, egg, egg + oil), seven pigments and one varnish type were used in the study. Multivariate analysis was used to evaluate the resulting data. A good reproducibility of GI was obtained by ATR and PAS but not with μSR. The discriminative power of the technique is higher for unvarnished samples, but, generally, the GI estimator can be used for the categorisation of binding media in large populations of painting samples analysed with the same FTIR technique (sampling technique, detection, etc.).

  5. Automated high-pressure titration system with in situ infrared spectroscopic detection

    SciTech Connect

    Thompson, Christopher J. Martin, Paul F.; Chen, Jeffrey; Schaef, Herbert T.; Rosso, Kevin M.; Felmy, Andrew R.; Loring, John S.; Benezeth, Pascale

    2014-04-15

    A fully automated titration system with infrared detection was developed for investigating interfacial chemistry at high pressures. The apparatus consists of a high-pressure fluid generation and delivery system coupled to a high-pressure cell with infrared optics. A manifold of electronically actuated valves is used to direct pressurized fluids into the cell. Precise reagent additions to the pressurized cell are made with calibrated tubing loops that are filled with reagent and placed in-line with the cell and a syringe pump. The cell's infrared optics facilitate both transmission and attenuated total reflection (ATR) measurements to monitor bulk-fluid composition and solid-surface phenomena such as adsorption, desorption, complexation, dissolution, and precipitation. Switching between the two measurement modes is accomplished with moveable mirrors that direct the light path of a Fourier transform infrared spectrometer into the cell along transmission or ATR light paths. The versatility of the high-pressure IR titration system was demonstrated with three case studies. First, we titrated water into supercritical CO{sub 2} (scCO{sub 2}) to generate an infrared calibration curve and determine the solubility of water in CO{sub 2} at 50 °C and 90 bar. Next, we characterized the partitioning of water between a montmorillonite clay and scCO{sub 2} at 50 °C and 90 bar. Transmission-mode spectra were used to quantify changes in the clay's sorbed water concentration as a function of scCO{sub 2} hydration, and ATR measurements provided insights into competitive residency of water and CO{sub 2} on the clay surface and in the interlayer. Finally, we demonstrated how time-dependent studies can be conducted with the system by monitoring the carbonation reaction of forsterite (Mg{sub 2}SiO{sub 4}) in water-bearing scCO{sub 2} at 50 °C and 90 bar. Immediately after water dissolved in the scCO{sub 2}, a thin film of adsorbed water formed on the mineral surface, and the film

  6. Infrared and fluorescence spectroscopic studies of a phospholipid bilayer supported by a soft cationic hydrogel scaffold.

    PubMed

    Grossutti, Michael; Seenath, Ryan; Noël, John A; Lipkowski, Jacek

    2016-07-01

    Polarized attenuated total reflection (ATR-IR) spectroscopy and fluorescence microscopy techniques were used to characterize a 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC) membrane supported on porous, cationic hydrogel beads. Fluorescence microscopy images showed that the DPhPC coated the external surface of the hydrogel scaffold. In addition, a fluorescence assay of the emission intensity of the Tb(3+)/dipicolinic acid complex demonstrated that the DPhPC coating acted as a barrier to Tb(3+) efflux from the scaffolded vesicle and successfully sealed the porous hydrogel bead. Fluorescence quenching and ATR-IR spectroscopic measurements revealed that the lipid coating has a bilayer structure. The phytanoyl chains were found to exhibit significant trans-gauche isomerization, characteristic of the fluid liquid phase. However, no lipid lateral mobility was observed by fluorescence recovery after photobleaching (FRAP) measurements. The phosphocholine headgroup was found to be well hydrated and oriented such that the cationic choline group tucked in behind the anionic phosphate group, consistent with an electrostatic attraction between the cationic scaffold and zwitterionic lipid. The absence of lipid lateral mobility may be due to the strength of this attraction.

  7. Infrared spectroscopic measurements of the vertical column abundance of sulfur hexafluoride, SF6, from the ground

    NASA Technical Reports Server (NTRS)

    Zander, R.; Demoulin, P.; Rinsland, C. P.

    1991-01-01

    The solar observations involved in the present monitoring evaluation were made at two facilities, using Fourier-transform spectrometers achieving spectral resolutions of 0.005/cm and signal-to-rms noise ratios for individual scans from near 500 to near 1000. The monthly mean total vertical-column abundances of SF6 above both facilities are reported for time intervals from June 1986 to June 1990 and from March 1981 to June 1990. It is found that the vertical-column abundances increased at mean rates of 6.9 +/- 2.8 pct above one station and 6.6 +/- 7.2 pct above the other. Since all the results were retrieved using the same spectroscopic parameters and similar nonlinear least-squares curve-fitting algorithms validated through intercomparison exercises, the large error reported for the second station is attributed to a larger measurement uncertainty due to stronger H2O and C2O interferences, and a greater variability during each month.

  8. Opening of an icosahedral boron framework: A combined infrared spectroscopic and computational study

    NASA Astrophysics Data System (ADS)

    Fagiani, Matias R.; Liu Zeonjuk, L.; Esser, Tim K.; Gabel, Detlef; Heine, Thomas; Asmis, Knut R.; Warneke, Jonas

    2015-04-01

    The opening of an icosahderal boron cage in the periodinated closo-dodecaborate B12I122- upon deiodination is studied using cryogenic ion trap vibrational spectroscopy combined with electronic structure calculations. Comparison of simulated vibrational spectra to the infrared photodissociation spectra of messenger-tagged B12I122- and B12In- (n = 7-9) formed by skimmer collision induced dissociation shows that the larger clusters absorb exclusively below 975 cm-1 and hence exhibit quasi-icosahedral B12-cage structures, while the higher energy absorptions in-between 1000 and 1300 cm-1 observed for n = 7 can only be recovered by considering a breakup of the icosahedral cage upon deiodination from n = 8 to n = 7.

  9. Infrared spectroscopic studies on reaction induced conformational changes in the NADH ubiquinone oxidoreductase (complex I).

    PubMed

    Hellwig, Petra; Kriegel, Sébastien; Friedrich, Thorsten

    2016-07-01

    Redox-dependent conformational changes are currently discussed to be a crucial part of the reaction mechanism of the respiratory complex I. Specialized difference Fourier transform infrared techniques allow the detection of side-chain movements and minute secondary structure changes. For complex I, (1)H/(2)H exchange kinetics of the amide modes revealed a better accessibility of the backbone in the presence of NADH and quinone. Interestingly, the presence of phospholipids, that is crucial for the catalytic activity of the isolated enzyme complex, changes the overall conformation. When comparing complex I samples from different species, very similar electrochemically induced FTIR difference spectra and very similar rearrangements are reported. Finally, the information obtained with variants and from Zn(2+) inhibited samples for the conformational reorganization of complex I upon electron transfer are discussed in this review. This article is part of a Special Issue entitled Respiratory complex I, edited by Volker Zickermann and Ulrich Brandt.

  10. [Infrared spectroscopic study on storage substance mobilization of crop seeds in germination].

    PubMed

    Liu, Gang; Tan, Li-Ping; Dong, Qin

    2008-01-01

    The traditional method to study the storage substance mobilization of seeds during the process of germination is chemical extraction, which is troublesome and time consuming. In the present paper, Fourier transform infrared spectroscopy was used to study the storage substance mobilization of legume and cereal seeds in germination. The spectral results show that legume seeds (soybean, pea and broad bean) exhibit similar remarkable changes in the region from 1 000 to 1 200 cm(-1) in germination, which suggest that the storage carbohydrates in endosperm of legume seeds are mobilized during the process of germination. Notable changes were observed on amide bands of protein and lipid band in the spectra of germinating cereal seeds (rice, wheat and barley), indicating that storage proteins and lipids in cotyledon were utilized during the process of cereal seed germination. The results suggest that vibrational spectroscopy has the advantages of rapidress and convenience in the study of crop seeds and seed physiology.

  11. Probing depth and dynamic response of speckles in near infrared region for spectroscopic blood flow imaging

    NASA Astrophysics Data System (ADS)

    Yokoi, Naomichi; Aizu, Yoshihisa

    2016-04-01

    Imaging method based on bio-speckles is a useful means for blood flow visualization of living bodies and, it has been utilized for analyzing the condition or the health state of living bodies. Actually, the sensitivity of blood flow is influenced by tissue optical properties, which depend on the wavelength of illuminating laser light. In the present study, we experimentally investigate characteristics of the blood flow images obtained with two wavelengths of 780 nm and 830 nm in the near-infrared region. Experiments are conducted for sample models using a pork layer, horse blood layer and mirror, and for a human wrist and finger, to investigate optical penetration depth and dynamic response of speckles to the blood flow velocity for two wavelengths.

  12. Modeling Ellipsometry Measurements of Molecular Thin-Film Contamination on Genesis Array Samples

    NASA Technical Reports Server (NTRS)

    Calaway, Michael J.; Stansbery, E. K.; McNamara, K. M.

    2006-01-01

    The discovery of a molecular thin-film contamination on Genesis flown array samples changed the course of preliminary assessment strategies. Analytical techniques developed to measure solar wind elemental abundances must now compensate for a thin-film contamination. Currently, this is done either by experimental cleaning before analyses or by depth-profiling techniques that bypass the surface contamination. Inside Johnson Space Center s Genesis dedicated ISO Class 4 (Class 10) cleanroom laboratory, the selection of collector array fragments allocated for solar wind analyses are based on the documentation of overall surface quality, visible surface particle contamination greater than 1 m, and the amount of thin film contamination measured by spectroscopic ellipsometry. Documenting the exact thickness, surface topography, and chemical composition of these contaminates is also critical for developing accurate cleaning methods. However, the first step in characterization of the molecular film is to develop accurate ellipsometry models that will determine an accurate thickness measurement of the contamination film.

  13. An Overview of Ultraviolet Through Infrared Reflectance Spectroscopic Observations of Mercury During the First MESSENGER Flyby

    NASA Astrophysics Data System (ADS)

    Izenberg, N. R.; McClintock, W. E.; Holsclaw, G. M.; Robinson, M. S.; Blewett, D. T.; Domingue, D. L.; Head, J. W.; Jensen, E. A.; Kochte, M. C.; Lankton, M. R.; Murchie, S. L.; Sprague, A. L.; Vilas, F.; Solomon, S. C.

    2008-05-01

    During the first MESSENGER flyby of Mercury on January 14, 2008, the Mercury Atmospheric and Surface Composition Spectrometer (MASCS) measured reflectance spectra from Mercury's surface over the wavelength range 220-1450 nm. These are the first high-spatial-resolution (<10 km) spectra at any wavelength and the first reported ultraviolet (UV, wavelength < 360 nm) observations of the surface. MASCS observed the sunlit surface for approximately 14 minutes after closest approach, acquiring over 650 spectra with the Visible and Infrared Spectrograph (VIRS) detectors of MASCS sensitive to wavelengths of 350-1450 nm. MASCS also obtained just under four grating scans in the middle ultraviolet (220-320 nm) using MASCS's Ultraviolet and Visible Spectrometer (UVVS) component. Most of the near-equatorial ground track of the observation covered terrain in the previously unseen hemisphere of Mercury but also crossed into the hemisphere viewed by Mariner 10 south of Mozart crater and in Tir Planitia. Ground-based observations of Mercury reveal a surface with a red, nearly featureless spectrum in the visible and near-infrared (wavelengths greater than ~ 500 nm) that has been interpreted as evidence for a largely iron-poor feldspathic composition. Initial analyses of VIRS spectra also show strongly red-sloped, near featureless spectra, appearing to support contentions of low iron abundance in surface materials. However, interpretation of Mercury's spectral reflectance is complicated by our lack of knowledge about the effects on its surface materials of space weathering, which both suppresses the strength of spectral absorption features and reddens the spectrum. Brightness variations and absorption bands in ultraviolet reflectance may help determine both the nature and extent of processes that modify observed reflectance at longer wavelengths. MASCS surface observation data demonstrate spectral variations across the Mercury surface that can be related to previous telescopic

  14. Interaction between beta-Purothionin and dimyristoylphosphatidylglycerol: a (31)P-NMR and infrared spectroscopic study.

    PubMed Central

    Richard, Julie-Andrée; Kelly, Isabelle; Marion, Didier; Pézolet, Michel; Auger, Michèle

    2002-01-01

    The interaction of beta-purothionin, a small basic and antimicrobial protein from the endosperm of wheat seeds, with multilamellar vesicles of dimyristoylphosphatidylglycerol (DMPG) was investigated by (31)P solid-state NMR and infrared spectroscopy. NMR was used to study the organization and dynamics of DMPG in the absence and presence of beta-purothionin. The results indicate that beta-purothionin does not induce the formation of nonlamellar phases in DMPG. Two-dimensional exchange spectroscopy shows that beta-purothionin decreases the lateral diffusion of DMPG in the fluid phase. Infrared spectroscopy was used to investigate the perturbations, induced by beta-purothionin, of the polar and nonpolar regions of the phospholipid bilayers. At low concentration of beta-purothionin, the temperature of the gel-to-fluid phase transition of DMPG increases from 24 degrees C to ~33 degrees C, in agreement with the formation of electrostatic interactions between the cationic protein and the anionic phospholipid. At higher protein concentration, the lipid transition is slightly shifted toward lower temperature and a second transition is observed below 20 degrees C, suggesting an insertion of the protein in the hydrophobic core of the lipid bilayer. The results also suggest that the presence of beta-purothionin significantly modifies the lipid packing at the surface of the bilayer to increase the accessibility of water molecules in the interfacial region. Finally, orientation measurements indicate that the alpha-helices and the beta-sheet of beta-purothionin have tilt angles of ~60 degrees and 30 degrees, respectively, relative to the normal of the ATR crystal. PMID:12324425

  15. Automated high-throughput assessment of prostate biopsy tissue using infrared spectroscopic chemical imaging

    NASA Astrophysics Data System (ADS)

    Bassan, Paul; Sachdeva, Ashwin; Shanks, Jonathan H.; Brown, Mick D.; Clarke, Noel W.; Gardner, Peter

    2014-03-01

    Fourier transform infrared (FT-IR) chemical imaging has been demonstrated as a promising technique to complement histopathological assessment of biomedical tissue samples. Current histopathology practice involves preparing thin tissue sections and staining them using hematoxylin and eosin (H&E) after which a histopathologist manually assess the tissue architecture under a visible microscope. Studies have shown that there is disagreement between operators viewing the same tissue suggesting that a complementary technique for verification could improve the robustness of the evaluation, and improve patient care. FT-IR chemical imaging allows the spatial distribution of chemistry to be rapidly imaged at a high (diffraction-limited) spatial resolution where each pixel represents an area of 5.5 × 5.5 μm2 and contains a full infrared spectrum providing a chemical fingerprint which studies have shown contains the diagnostic potential to discriminate between different cell-types, and even the benign or malignant state of prostatic epithelial cells. We report a label-free (i.e. no chemical de-waxing, or staining) method of imaging large pieces of prostate tissue (typically 1 cm × 2 cm) in tens of minutes (at a rate of 0.704 × 0.704 mm2 every 14.5 s) yielding images containing millions of spectra. Due to refractive index matching between sample and surrounding paraffin, minimal signal processing is required to recover spectra with their natural profile as opposed to harsh baseline correction methods, paving the way for future quantitative analysis of biochemical signatures. The quality of the spectral information is demonstrated by building and testing an automated cell-type classifier based upon spectral features.

  16. TRANSITIONAL DISKS AND THEIR ORIGINS: AN INFRARED SPECTROSCOPIC SURVEY OF ORION A

    SciTech Connect

    Kim, K. H.; Watson, Dan M.; Manoj, P.; Forrest, W. J.; Arnold, Laura; Najita, Joan; Furlan, Elise; Sargent, Benjamin; Espaillat, Catherine; Muzerolle, James; Megeath, S. T.; Calvet, Nuria; Green, Joel D.

    2013-06-01

    Transitional disks are protoplanetary disks around young stars, with inner holes or gaps which are surrounded by optically thick outer, and often inner, disks. Here we present observations of 62 new transitional disks in the Orion A star-forming region. These were identified using the Spitzer Space Telescope's Infrared Spectrograph and followed up with determinations of stellar and accretion parameters using the Infrared Telescope Facility's SpeX. We combine these new observations with our previous results on transitional disks in Taurus, Chamaeleon I, Ophiuchus, and Perseus, and with archival X-ray observations. This produces a sample of 105 transitional disks of ''cluster'' age 3 Myr or less, by far the largest hitherto assembled. We use this sample to search for trends between the radial structure in the disks and many other system properties, in order to place constraints on the possible origins of transitional disks. We see a clear progression of host-star accretion rate and the different disk morphologies. We confirm that transitional disks with complete central clearings have median accretion rates an order of magnitude smaller than radially continuous disks of the same population. Pre-transitional disks-those objects with gaps that separate inner and outer disks-have median accretion rates intermediate between the two. Our results from the search for statistically significant trends, especially related to M-dot , strongly support that in both cases the gaps are far more likely to be due to the gravitational influence of Jovian planets or brown dwarfs orbiting within the gaps, than to any of the photoevaporative, turbulent, or grain-growth processes that can lead to disk dissipation. We also find that the fraction of Class II YSOs which are transitional disks is large, 0.1-0.2, especially in the youngest associations.

  17. Infrared spectroscopic characterization of dehydration and accompanying phase transition behaviors in NAT-topology zeolites

    SciTech Connect

    Wang, Hsiu-Wen; Bishop, David

    2012-01-01

    Relative humidity (PH2O, partial pressure of water)-dependent dehydration and accompanying phase transitions in NAT-topology zeolites (natrolite, scolecite, and mesolite) were studied under controlled temperature and known PH2O conditions by in situ diffuse-reflectance infrared Fourier transform spectroscopy and parallel X-ray powder diffraction. Dehydration was characterized by the disappearance of internal H2O vibrational modes. The loss of H2O molecules caused a sequence of structural transitions in which the host framework transformation path was coupled primarily via the thermal motion of guest Na?/Ca2? cations and H2O molecules. The observation of different interactions of H2O molecules and Na?/Ca2? cations with host aluminosilicate frameworks under highand low-PH2O conditions indicated the development of different local strain fields, arising from cation H2O interactions in NAT-type channels. These strain fields influence the Si O/Al O bond strength and tilting angles within and between tetrahedra as the dehydration temperature is approached. The newly observed infrared bands (at 2,139 cm-1 in natrolite, 2,276 cm-1 in scolecite, and 2,176 and 2,259 cm-1 in mesolite) result from strong cation H2O Al Si framework interactions in NAT-type channels, and these bands can be used to evaluate the energetic evolution of Na?/Ca2? cations before and after phase transitions, especially for scolecite and mesolite. The 2,176 and 2,259 cm-1 absorption bands in mesolite also appear to be related to Na?/Ca2? order disorder that occur when mesolite loses its Ow4 H2O molecules.

  18. Vertical profiling of methane and carbon dioxide using high resolution near-infrared heterodyne spectroscopic observations

    NASA Astrophysics Data System (ADS)

    Rodin, Alexander; Klimchuk, Artem; Churbanov, Dmitry; Pereslavtseva, Anastasia; Spiridonov, Maxim; Nadezhdinskyi, Alexander

    2014-05-01

    We present new method of monitoring greenhouse gases using spectroscopic observations of solar radiation passed through the atmosphere with spectral resolution ΛvδΛ up to 108. Such a high resolution is achieved by heterodyne technique and allows to retrieve full information about spectral line shape which, in turn, is used to distinguish contribution of different atmospheric layers to the resulting absorption. Weak absorption line at 6056.5 cm-1 was selected for CO2 measurements and a quartet of lines centered at 6057 cm-1for CH4. The instrument setup includes Sun tracker with a microtelescope and chopper, diode DFB laser used as a local oscillator, a bundle of single mode optical fibers that provides medium for radiation transfer and beam coupling, reference cell with depressurized methane for LO frequency stabilization, and Fabry-Perot etalon for LO frequency calibration. A commercial p-i-n diode with squared detector replaces a mixer and IF spectrometer, providing measurement of heterodyne beating within a bandpass of few MHz, which determines the effective spectral resolution of the instrument. Spectral coverage within narrow range (about 1 cm-1) is provided by ramping the LO frequency based on feedback from the reference channel. Observations of Sun in the Moscow region have resulted for the first time in measurements of the atmospheric transmission near 1.65 μm with sub-Doppler spectral resolution. In order to retrieve vertical profiles of methane and carbon dioxide we developed the inversion algorithm implementing Tikhonov regularization approach. With measured transmission having S/N ratio of 100 or higher, the uncertainty of CH4 profile is about 10 ppb, with the uncertainty of CO2 profile at 1 ppm. This techniques is promising an affordable opportunity or widespread monitoring of greenhouse gases and may be implemented on existing ground-based stations. This work has been supported by the grant of Russian Ministry of education and science #11.G34.31.0074

  19. IN SITU ELLIPSOMETRY FOR SHOCK COMPRESSION MEASUREMENTS

    SciTech Connect

    Bakshi, L.; Eliezer, S.; Appelbaum, G.; Nissim, N.; Perelmutter, L.; Mond, M.

    2009-12-28

    Knowledge about the optical properties of materials at high pressure and high temperature is needed for EOS research. Ellipsometry measures the change in the polarization of a probe beam reflected from a surface. From the change in polarization, the real and imaginary parts of the time dependent complex index of refraction can be extracted. From the measured optical properties, fundamental physical properties of the material, such as emissivity, phase transitions, and electrical conductivity can be extracted. A dynamic ellipsometry measurement system with nanosecond resolution was built in order to measure all four stocks parameters. Gas gun was used to accelerate the impact flyer. Our experiments concentrated on the optical properties of 1020 steel targets with impact pressure range of 40-250 kbar. Although there are intrinsic difficulties with dynamic ellipsometric measurements, distinct changes were observed for 1020 steel under shock compression larger than 130 kbar, the alpha->epsilon phase transition.

  20. Generalized Ellipsometry on Ferromagnetic Sculptured Thin Films.

    NASA Astrophysics Data System (ADS)

    Schmidt, Daniel; Hofmann, Tino; Mok, Kah; Schmidt, Heidemarie; Skomski, Ralf; Schubert, Eva; Schubert, Mathias

    2011-03-01

    We present and discuss generalized ellipsometry and generalized vector-magneto-optic ellipsometry investigations on cobalt nanostructured thin films with slanted, highly-spatially coherent, columnar arrangement. The samples were prepared by glancing angle deposition. The thin films are highly transparent and reveal strong form-induced birefringence. We observe giant Kerr rotation in the visible spectral region, tunable by choice of the nanostructure geometry. Spatial magnetization orientation hysteresis and magnetization magnitude hysteresis properties are studied using a 3-dimensional Helmholtz coil arrangement allowing for arbitrary magnetic field direction at the sample position for field strengths up to 0.4 Tesla. Analysis of data obtained within this novel vector-magneto-optic setup reveals magnetization anisotropy of the Co slanted nanocolumns supported by mean-field theory modeling.

  1. Fourier Transform Infrared Spectroscopic characterization and optimization of Pb(II) biosorption by fish (Labeo rohita) scales.

    PubMed

    Nadeem, Raziya; Ansari, Tariq Mahmood; Khalid, Ahmad Mukhtar

    2008-08-15

    The present study reports the use of locally available fish (Labeo rohita) scales for Pb(II) removal from aqueous solutions under different experimental conditions. Maximum Pb(II) adsorption (196.8 mg g(-1)) occurred at pH 3.5. Pb(II) sorption was found to be pH, dose, initial metal concentration, contact time and shaking speed dependent while particle size and temperature independent. Experimental data of Pb(II) biosorption onto fish scales fitted well to Freundlich isotherm model in comparison to the model of Langmuir. The fast adsorption process in first 30 min followed by subsequent slow adsorption rate was suitably described by pseudo-second order model. In addition, this study was designed to evaluate the effect of physical and chemical pretreatments on surface properties of fish scales by the application of Fourier Transform Infrared (FTIR) Spectroscopic analysis. Physical pretreatments resulted in partial degradation of some functional groups. Alkaline pretreatments of fish scales did not have any significant influence on the nature of functional groups responsible for Pb(II) uptake, while acidic pretreatments resulted in degeneration of the most of functional groups on biosorbent cell wall. FTIR analysis confirmed the involvement of amino, carboxylic, phosphate and carbonyl groups in Pb(II) biosorption by fish scales.

  2. Infrared spectroscopic imaging of the biochemical modifications induced in the cerebellum of the Niemann-Pick type C mouse

    NASA Astrophysics Data System (ADS)

    Kidder, Linda H.; Colarusso, Pina; Stewart, Sarah A.; Levin, Ira W.; Appel, Nathan M.; Lester, David S.; Pentchev, Peter G.; Lewis, E. N.

    1999-01-01

    WE have applied Fourier transform infrared (IR) spectroscopic imaging to the investigation of the neuropathologic effects of a genetic lipid storage disease, Niemann-Pick type C (NPC). Tissue sections both from the cerebella of a strain of BALB/c mice that demonstrated morphology and pathology of the human disease and from control animals were used. These samples were analyzed by standard histopathological procedures as well as this new IR imaging approach. The IR absorbance images exhibit contrast based on biochemical variations and allow for the identification of the cellular layers within the tissue samples. Furthermore, these images provide a qualitative description of the localized biochemical differences existing between the diseased and control tissue in the absence of histological staining. Statistical analyses of the IR spectra extracted from individual cell layers of the imaging data sets provide concise quantitative descriptions of these biochemical changes. The results indicate that lipid is depleted specifically in the white matter of the NPC mouse in comparison to the control samples. Minor differences were noted for the granular layers, but no significant differences were observed in the molecular layers of the cerebellar tissue. These changes are consistent with significant demyelination within the cerebellum of the NPC mouse.

  3. Matrix isolation infrared spectroscopic and theoretical studies on the reactions of niobium and tantalum mono- and dioxides with methane.

    PubMed

    Wang, Guanjun; Lai, Sixue; Chen, Mohua; Zhou, Mingfei

    2005-10-27

    The reactions of niobium and tantalum monoxides and dioxides with methane have been investigated using matrix isolation infrared spectroscopic and theoretical calculations. The niobium and tantalum oxide molecules were prepared by laser evaporation of Nb(2)O(5) and Ta(2)O(5) bulk targets. The niobium monoxide molecule interacted with methane to form the ONb(CH(4)) complex, which was predicted to have C(3)(v)() symmetry with the metal atom coordinated to three hydrogen atoms of the methane molecule. The ONb(CH(4)) complex rearranged to the CH(3)Nb(O)H isomer upon 300 nm < lambda < 580 nm irradiation. The analogous OTa(CH(4)) complex was not observed, but the CH(3)Ta(O)H molecule was produced upon UV irradiation. The niobium and tantalum dioxide molecules reacted with methane to form the O(2)Nb(CH(4)) and O(2)Ta(CH(4)) complexes with C(s)() symmetry, which underwent photochemical rearrangement to the CH(3)Nb(O)OH and CH(3)Ta(O)OH isomers upon ultraviolet irradiation.

  4. Near-infrared spectroscopic monitoring of a series of industrial batch processes using a bilinear grey model.

    PubMed

    van Sprang, Eric N M; Ramaker, Henk-Jan; Westerhuis, Johan A; Smilde, Age K; Gurden, Stephen P; Wienke, Dietrich

    2003-08-01

    A good process understanding is the foundation for process optimization, process monitoring, end-point detection, and estimation of the end-product quality. Performing good process measurements and the construction of process models will contribute to a better process understanding. To improve the process knowledge it is common to build process models. These models are often based on first principles such as kinetic rates or mass balances. These types of models are also known as hard or white models. White models are characterized by being generally applicable but often having only a reasonable fit to real process data. Other commonly used types of models are empirical or black-box models such as regression and neural nets. Black-box models are characterized by having a good data fit but they lack a chemically meaningful model interpretation. Alternative models are grey models, which are combinations of white models and black models. The aim of a grey model is to combine the advantages of both black-box models and white models. In a qualitative case study of monitoring industrial batches using near-infrared (NIR) spectroscopy, it is shown that grey models are a good tool for detecting batch-to-batch variations and an excellent tool for process diagnosis compared to common spectroscopic monitoring tools.

  5. Infra-red spectroscopic characteristics of naphthalocyanine in bis(naphthalocyaninato) rare earth complexes peripherally substituted with thiophenyl derivatives.

    PubMed

    Li, Xiaobo; Mao, Yajun; Xiao, Chi; Lu, Fanli

    2015-04-01

    The infra-red (IR) spectroscopic data for a series of eleven rare earth double-deckers MIII[Nc(SPh)8]2 (M=Y, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Er) have been collected and systematically investigated. For MIII[Nc(SPh)8]2, typical IR marker bands for the naphthalocyanine anion radical [Nc(SPh)8].- were observed at 1317-1325 cm(-1) as the most intense absorption bands, which can be attributed to the pyrrole stretching. As for Ce[Nc(SPh)8]2, the typical IR marker band was also observed at 1317 cm(-1), which shows that the cerium complex exists as the form of CeIII[Nc(SPh)8]2-[Nc(SPh)8].-. In addition, both the Q-bands of electronic absorption spectra and the typical IR absorption bands of naphthalocyanine radical anion [Nc(SPh)8].- move to the high energy as the decrease of rare earth metal ionic radius. These facts suggest that the π-π electron interaction in these double-deckers becomes stronger along with the lanthanide contraction.

  6. Investigating the biochemical progression of liver disease through fibrosis, cirrhosis, dysplasia, and hepatocellular carcinoma using Fourier transform infrared spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Sreedhar, Hari; Pant, Mamta; Ronquillo, Nemencio R.; Davidson, Bennett; Nguyen, Peter; Chennuri, Rohini; Choi, Jacqueline; Herrera, Joaquin A.; Hinojosa, Ana C.; Jin, Ming; Kajdacsy-Balla, Andre; Guzman, Grace; Walsh, Michael J.

    2014-03-01

    Hepatocellular carcinoma (HCC) is the most common form of primary hepatic carcinoma. HCC ranks the fourth most prevalent malignant tumor and the third leading cause of cancer related death in the world. Hepatocellular carcinoma develops in the context of chronic liver disease and its evolution is characterized by progression through intermediate stages to advanced disease and possibly even death. The primary sequence of hepatocarcinogenesis includes the development of cirrhosis, followed by dysplasia, and hepatocellular carcinoma.1 We addressed the utility of Fourier Transform Infrared (FT-IR) spectroscopic imaging, both as a diagnostic tool of the different stages of the disease and to gain insight into the biochemical process associated with disease progression. Tissue microarrays were obtained from the University of Illinois at Chicago tissue bank consisting of liver explants from 12 transplant patients. Tissue core biopsies were obtained from each explant targeting regions of normal, liver cell dysplasia including large cell change and small cell change, and hepatocellular carcinoma. We obtained FT-IR images of these tissues using a modified FT-IR system with high definition capabilities. Firstly, a supervised spectral classifier was built to discriminate between normal and cancerous hepatocytes. Secondly, an expanded classifier was built to discriminate small cell and large cell changes in liver disease. With the emerging advances in FT-IR instrumentation and computation there is a strong drive to develop this technology as a powerful adjunct to current histopathology approaches to improve disease diagnosis and prognosis.

  7. The protein environment surrounding tyrosyl radicals D. and Z. in photosystem II: a difference Fourier-transform infrared spectroscopic study.

    PubMed Central

    Kim, S; Barry, B A

    1998-01-01

    Photosystem II contains two redox-active tyrosine residues, termed D and Z, which have different midpoint potentials and oxidation/reduction kinetics. To understand the functional properties of redox-active tyrosines, we report a difference Fourier-transform infrared (FT-IR) spectroscopic study of these species. Vibrational spectra associated with the oxidation of each tyrosine residue are acquired; electron paramagnetic resonance (EPR) and fluorescence experiments demonstrate that there is no detectable contribution of Q(A)- to these spectra. Vibrational lines are assigned to the radicals by isotopic labeling of tyrosine. Global 15N labeling, 2H exchange, and changes in pH identify differences in the reversible interactions of the two redox-active tyrosines with N-containing, titratable amino acid side chains in their environments. To identify the amino acid residue that contributes to the spectrum of D, mutations at His189 in the D2 polypeptide were examined. Mutations at this site result in substantial changes in the spectrum of tyrosine D. Previously, mutations at the analogous histidine, His190 in the D1 polypeptide, were shown to have no significant effect on the FT-IR spectrum of tyrosine Z (Bernard, M. T., et al. 1995. J. Biol. Chem. 270:1589-1594). A disparity in the number of accessible, proton-accepting groups could influence electron transfer rates and energetics and account for functional differences between the two redox-active tyrosines. PMID:9591683

  8. The dynamics of cyanobacterial silicification: an infrared micro-spectroscopic investigation

    NASA Astrophysics Data System (ADS)

    Benning, Liane G.; Phoenix, V. R.; Yee, N.; Konhauser, K. O.

    2004-02-01

    The dynamics of cyanobacterial silicification was investigated using synchrotron-based Fourier transform infrared micro-spectroscopy. The changes in exo-polymeric polysaccharide and silica vibrational characteristics of individual Calothrix sp. filaments was determined over time in a series of microcosms in which the microbially sorbed silica or silica and iron load was increased sequentially. The changes in intensity and integrated area of specific infrared spectral features were used to develop an empirical quantitative dynamic model and to derive silica load-dependent parameters for each quasi-equilibrium stage in the biomineralization process. The degree of change in spectral features was derived from the increase in integrated area of the combined silica/polysaccharide region (Si-O/C-O, at 1150-950 cm -1) and the Si-O band at 800 cm -1, the latter representing specific silica bonds corresponding to hydrated amorphous SiO 4 tetrahedra. From the degree of change, a two-phase model with concurrent change in process was derived. In the first phase, a biologically controlled increase in thickness of the exo-polymeric polysaccharide sheath around the cell was observed. In phase two, a transition to an inorganically controlled accumulation of silica on the surface of the cyanobacterial cells was derived from the change in integrated area for the mixed Si-O/C-O spectral region. This second process is further corroborated by the synchronous formation of non-microbially associated inorganic SiO 4 units indicated by the growth of the singular Si-O band at 800 cm -1. During silicification, silica accumulates (1) independently of the growth of the sheath polysaccharides and (2) via an increase in chain lengths of the silica polymers by expelling water from the siloxane bonds. IR evidence suggest that an inorganic, apparently surface catalyzed process, which leads to the accumulation of silica nanospheres on the cyanobacterial surfaces governs this second stage. In

  9. Molecular Shocks Associated with Massive Young Stars: CO Line Images with a New Far-Infrared Spectroscopic Camera on the Kuiper Airborne Observatory

    NASA Technical Reports Server (NTRS)

    Watson, Dan M.

    1997-01-01

    Under the terms of our contract with NASA Ames Research Center, the University of Rochester (UR) offers the following final technical report on grant NAG 2-958, Molecular shocks associated with massive young stars: CO line images with a new far-infrared spectroscopic camera, given for implementation of the UR Far-Infrared Spectroscopic Camera (FISC) on the Kuiper Airborne Observatory (KAO), and use of this camera for observations of star-formation regions 1. Two KAO flights in FY 1995, the final year of KAO operations, were awarded to this program, conditional upon a technical readiness confirmation which was given in January 1995. The funding period covered in this report is 1 October 1994 - 30 September 1996. The project was supported with $30,000, and no funds remained at the conclusion of the project.

  10. Infrared spectroscopic investigation of nuclear spin conversion in solid CH{sub 4}

    SciTech Connect

    Sugimoto, Takeru; Yamakawa, Koichiro Arakawa, Ichiro

    2015-12-14

    Infrared spectra of solid CH{sub 4} were studied in the ν{sub 3} and ν{sub 4} vibrational regions. The phase I crystal around 30 K showed broad absorption bands, whereas the phase II crystal at 6.9–10.3 K exhibited splitting of these bands after annealing above 20 K. The split peaks were assigned to the librating and almost freely rotating molecules in phase II on the basis of the peak spacings and time evolution of the peak intensities. From the quantitative analysis of the temporal changes of the R(0) and R(1) peak intensities, the relaxation rates of the numbers of molecules with J = 0 (I = 2) and J = 1 (I = 1) were determined in the temperature range of 6.9–10.3 K. We fitted the function resulting from a combination of direct and indirect relaxation processes mediated by phonons to the temperature dependence of these rates and obtained the activation energies of the indirect process: C ≃ 36 K. Since this value is higher than the energies of perturbed J = 2 states relative to the J = 1 state, we argue that the nuclear spin conversion through the J = 3 state also takes place.

  11. A portable cross-shape near-infrared spectroscopic detector for bone marrow lesions diagnosis

    NASA Astrophysics Data System (ADS)

    Su, Yu; Li, Ting

    2016-02-01

    Bone marrow lesions (BMLs) is an incidence-increasing disease which seriously hazard to human health and possibly contribute to paralysis. Delayed treatment often occurred to BMLs patients due to its characteristics such as complex and diverse clinical manifestations, non-specific, easy to misdiagnosis and etc. The conventional diagnosis methods of BMLs mainly rely on bone marrow biopsy/aspiration, which are invasive, painful, high health risk, and discontinuous which disabled monitoring and during-surgery guidance. Thus we proposed to develop a noninvasive, real-time, continuous measurement, easy-operated device aimed at detecting bone marrow diseases. This device is based on near-infrared spectroscopy and the probe is designed with a cross-shape to tightly and comfortably attach human spine. Space-resolved source-detector placement and measurement algorithm are employed. Four selected wavelength were utilized here to extract BMLs-related component contents of oxy-, deoxy-hemoglobin, fat, scattering index corresponding to fibrosis. We carried out an ink experiment and one clinical measurement to verify the feasibility of our device. The potential of NIRS in BMLs clinics is revealed.

  12. Spectroscopic signature of mouse embryonic stem cell-derived hepatocytes using synchrotron Fourier transform infrared microspectroscopy

    NASA Astrophysics Data System (ADS)

    Thumanu, Kanjana; Tanthanuch, Waraporn; Ye, Danna; Sangmalee, Anawat; Lorthongpanich, Chanchao; Parnpai, Rangsun; Heraud, Philip

    2011-05-01

    Stem cell-based therapy for liver regeneration has been proposed to overcome the persistent shortage in the supply of suitable donor organs. A requirement for this to succeed is to find a rapid method to detect functional hepatocytes, differentiated from embryonic stem cells. We propose Fourier transform infrared (FTIR) microspectroscopy as a versatile method to identify the early and last stages of the differentiation process leading to the formation of hepatocytes. Using synchrotron-FTIR microspectroscopy, the means of identifying hepatocytes at the single-cell level is possible and explored. Principal component analysis and subsequent partial least-squares (PLS) discriminant analysis is applied to distinguish endoderm induction from hepatic progenitor cells and matured hepatocyte-like cells. The data are well modeled by PLS with endoderm induction, hepatic progenitor cells, and mature hepatocyte-like cells able to be discriminated with very high sensitivity and specificity. This method provides a practical tool to monitor endoderm induction and has the potential to be applied for quality control of cell differentiation leading to hepatocyte formation.

  13. Infrared Spectroscope for Electron Bunch-length Measurement: Heat Sensor Parameters Analysis

    SciTech Connect

    Domgmo-Momo, Gilles; /Towson U. /SLAC

    2012-09-05

    The Linac Coherent Light Source (LCLS) is used for many experiments. Taking advantage of the free electron laser (FEL) process, scientists of various fields perform experiments of all kind. Some for example study protein folding; other experiments are more interested in the way electrons interact with the molecules before they are destroyed. These experiments among many others have very little information about the electrons x-ray produced by the FEL, except that the FEL is using bunches less than 10 femtoseconds long. To be able to interpret the data collected from those experiments, more accurate information is needed about the electron's bunch-length. Existing bunch length measurement techniques are not suitable for the measurement of such small time scales. Hence the need to design a device that will provide more precise information about the electron bunch length. This paper investigates the use of a pyreoelectric heat sensor that has a sensitivity of about 1.34 micro amps per watt for the single cell detector. Such sensitivity, added to the fact that the detector is an array sensor, makes the detector studied the primary candidate to be integrated to an infrared spectrometer designed to better measure the LCLS electron bunch length.

  14. Visible and near-infrared spectroscopic survey of Jupiter Trojan asteroids: investigation of dynamical families

    NASA Astrophysics Data System (ADS)

    Dotto, E.; Fornasier, S.; Barucci, M. A.; Boehnhardt, H.; Hainaut, O.; Marzari, F.; Licandro, J.; de Bergh, C.

    2004-11-01

    Trojan asteroids located in the Jupiter Lagrangian points L4 and L5 (60 degrees ahead and behind Jupiter) are widely believed to be primordial bodies since their orbits are stable over the age of the Solar System. They seem to have been formed in a region of the solar nebula rich in frozen volatiles and to have never suffered selective induction heating. They probably still contain ices in their interiors.Moreover the discovery of several dynamical families among Trojans suggests that they are at least as collisionally evolved as the main asteroid belt. Since 2002, we started an observational program on Jupiter Trojans at ESO-NTT, ESO-VLT and TNG. In particular we concentrated on members of dynamical families, as defined by Beauge and Roig (2001), and we observed also several background objects. We carry out visible and near-infrared spectroscopy and photometry in order to i) characterize the mineralogical composition of families, ii) give evidence of ongoing space weathering, and iii) confirm family membership. As expected, the spectra of the non-family members are more heterogeneous compared to the spectra of family members. The obtained results will be presented and discussed.

  15. A validated near-infrared spectroscopic method for methanol detection in biodiesel

    NASA Astrophysics Data System (ADS)

    Paul, Andrea; Bräuer, Bastian; Nieuwenkamp, Gerard; Ent, Hugo; Bremser, Wolfram

    2016-06-01

    Biodiesel quality control is a relevant issue as biodiesel properties influence diesel engine performance and integrity. Within the European metrology research program (EMRP) ENG09 project ‘Metrology for Biofuels’, an on-line/at-site suitable near-infrared spectroscopy (NIRS) method has been developed in parallel with an improved EN14110 headspace gas chromatography (GC) analysis method for methanol in biodiesel. Both methods have been optimized for a methanol content of 0.2 mass% as this represents the maximum limit of methanol content in FAME according to EN 14214:2009. The NIRS method is based on a mobile NIR spectrometer equipped with a fiber-optic coupled probe. Due to the high volatility of methanol, a tailored air-tight adaptor was constructed to prevent methanol evaporation during measurement. The methanol content of biodiesel was determined from evaluation of NIRS spectra by partial least squares regression (PLS). Both GC analysis and NIRS exhibited a significant dependence on biodiesel feedstock. The NIRS method is applicable to a content range of 0.1% (m/m) to 0.4% (m/m) of methanol with uncertainties at around 6% relative for the different feedstocks. A direct comparison of headspace GC and NIRS for samples of FAMEs yielded that the results of both methods are fully compatible within their stated uncertainties.

  16. Instrument for near infrared emission spectroscopic probing of human fingertips in vivo

    NASA Astrophysics Data System (ADS)

    Chaiken, J.; Deng, Bin; Bussjager, Rebecca J.; Shaheen, George; Rice, David; Stehlik, Dave; Fayos, John

    2010-03-01

    We present instrumentation for probing of volar side fingertip capillary beds with free space coupled near infrared light while collecting Raman, Rayleigh, and Mie scattered light as well as fluorescence. Fingertip skin capillary beds are highly vascularized relative to other tissues and present a desirable target for noninvasive probing of blood. But human hands and fingers in particular are also highly idiosyncratic body parts requiring specific apparatus to allow careful and methodical spectoscopic probing. The apparatus includes means for precise and reproducible placement of the tissues relative to the optical aperture. Appropriate means are provided for applying and maintaining pressure to keep surface tissues immobile during experiments while obtaining the desired blood content and flow. Soft matter, e.g., skin, extrudes into the aperture in response to any applied pressure, e.g., to keep the tissue in registration with the optical system, so the position, contact area, pressure, and force are continuously measured and recorded to produce feedback for an actuator applying force and to discern the compliance of the test subject. The compliance strongly affects the reliability of the measurement and human factors must be adequately managed in the case of in vivo probing. The apparatus produces reproducible observations and measurements that allow consistent probing of the tissues of a wide range of skin types.

  17. Infrared spectroscopic investigation of nuclear spin conversion in solid CH4

    NASA Astrophysics Data System (ADS)

    Sugimoto, Takeru; Yamakawa, Koichiro; Arakawa, Ichiro

    2015-12-01

    Infrared spectra of solid CH4 were studied in the ν3 and ν4 vibrational regions. The phase I crystal around 30 K showed broad absorption bands, whereas the phase II crystal at 6.9-10.3 K exhibited splitting of these bands after annealing above 20 K. The split peaks were assigned to the librating and almost freely rotating molecules in phase II on the basis of the peak spacings and time evolution of the peak intensities. From the quantitative analysis of the temporal changes of the R(0) and R(1) peak intensities, the relaxation rates of the numbers of molecules with J = 0 (I = 2) and J = 1 (I = 1) were determined in the temperature range of 6.9-10.3 K. We fitted the function resulting from a combination of direct and indirect relaxation processes mediated by phonons to the temperature dependence of these rates and obtained the activation energies of the indirect process: C ≃ 36 K. Since this value is higher than the energies of perturbed J = 2 states relative to the J = 1 state, we argue that the nuclear spin conversion through the J = 3 state also takes place.

  18. FT-infrared spectroscopic studies of lymphoma, lymphoid, and myeloid leukemia cell lines

    NASA Astrophysics Data System (ADS)

    Babrah, Jaspreet; McCarthy, Keith P.; Lush, Richard; Rye, Adam D.; Bessant, Conrad; Stone, Nicholas

    2007-07-01

    This paper presents a novel method to characterise spectral differences that distinguish leukaemia and lymphoma cell lines. This is based on objective spectral measurements of major cellular biochemical constituents and multivariate spectral processing. Fourier transform infrared (FT-IR) maps of the lymphoma, lymphoid and myeloid leukaemia cell samples were obtained using a Perkin-Elmer Spotlight 300 FT-IR imaging spectrometer. Multivariate statistical techniques incorporating principal component analysis (PCA) and linear discriminant analysis (LDA) were used to construct a mathematical model. This model was validated for reproducibility. Multivariate statistical analysis of FTIR spectra collected for each cell sample permit a combination of unsupervised and supervised methods of distinguishing cell line types. This resulted in the clustering of cell line populations, indicating distinct bio-molecular differences. Major spectral differences were observed in the 4000 to 800 cm -1 spectral region. Bands in the averaged spectra for the cell line were assigned to the major biochemical constituents including; proteins, fatty acids, carbohydrates and nucleic acids. The combination of FT-IR spectroscopy and multivariate statistical analysis provides an important insight into the fundamental spectral differences between the cell lines, which differ according to the cellular biochemical composition. These spectral differences can serve as potential biomarkers for the differentiation of leukaemia and lymphoma cells. Consequently these differences could be used as the basis for developing a spectral method for the detection and identification of haematological malignancies.

  19. Microstructural and Photoacoustic Infrared Spectroscopic Studies of Human Cortical Bone with Osteogenesis Imperfecta

    NASA Astrophysics Data System (ADS)

    Gu, Chunju; Katti, Dinesh R.; Katti, Kalpana S.

    2016-04-01

    The molecular basis of bone disease osteogenesis imperfecta (OI) and the mineralization of hydroxyapatite in OI bone have been of significant research interest. To further investigate the mechanism of OI disease and bone mineralization, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, and x-ray diffraction (XRD) are used in the present study to describe the structural and compositional differences between OI and healthy bone. OI bone exhibits more porous, fibrous features, abnormal collagen fibrils, and abnormal mineral deposits. Likewise, photoacoustic-FTIR experiments indicate an aberrant collagen structure and an altered mineral structure in OI. In contrast, there is neither significant difference in the non-collagenous proteins (NCPs) composition observed nor apparent change in the crystal structure between OI and healthy bone minerals as shown in XRD and energy-dispersive x-ray spectroscopy (EDS) results. This observation indicates that the biomineralization process is more controlled by the bone cells and non-collagenous phosphorylated proteins. The present study also confirms that there is an orientational influence on the stoichiometry of the mineral in OI bone. Also, a larger volume of the hydrated layer in the transverse plane than the longitudinal plane of the mineral crystal structure is proposed. The appearance of a new C-S band in the FTIR spectra in OI bone suggests the substitution of glycine by cysteine in collagen molecules or/and an increased amount of cysteine-rich osteonectin that relates to mineral nucleation and mineral crystal formation.

  20. Mid-infrared spectroscopic investigation of the perfect vitrification of poly(ethylene glycol) aqueous solutions.

    PubMed

    Gemmei-Ide, Makoto; Miyashita, Takashi; Kagaya, Shigehiro; Kitano, Hiromi

    2015-10-01

    Crystallization/recrystallization behaviors of poly(ethylene glycol) (PEG) aqueous solutions with water contents (WC's) of ∼36-51 wt % were investigated by temperature-variable mid-infrared spectroscopy. At a WC of 43.2 wt %, crystallization and recrystallization of water and PEG were not observed. At this specific WC value (WCPV), perfect vitrification occurred. Below and above the WCPV value, crystallization/recrystallization behaviors changed drastically. The crystallization temperature below WCPV (237 K) was ∼10 K greater than that above WCPV (226 K). Recrystallization above and below WCPV occurred in one (213 K) and two (198 and 210 K) steps, respectively. These findings resulted from the difference in the (re)crystallization behaviors of water molecules associated with PEG chains with helical and random-coil conformations. These two types of water molecules might have limiting concentrations for their (re)crystallization, indicating that perfect vitrification might have occurred when the concentrations of the two types of water molecules were less than the limiting concentrations of their (re)crystallization.

  1. In Situ Infrared Spectroscopic Study of Forsterite Carbonation in Wet Supercritical CO2

    SciTech Connect

    Loring, John S.; Thompson, Christopher J.; Wang, Zheming; Joly, Alan G.; Sklarew, Deborah S.; Schaef, Herbert T.; Ilton, Eugene S.; Rosso, Kevin M.; Felmy, Andrew R.

    2011-07-19

    Carbonation reactions are central to the prospect of CO2 trapping by mineralization in geologic reservoirs. In contrast to the relevant aqueous-mediated reactions, little is known about the propensity for carbonation in the long-term partner fluid: water-containing supercritical carbon dioxide (‘wet’ scCO2). We employed in situ mid-infrared spectroscopy to follow the reaction of a model silicate mineral (forsterite, Mg2SiO4) for 24 hr with wet scCO2 at 50°C and 180 atm, using water concentrations corresponding to 0%, 55%, 95%, and 136% saturation. Results show a dramatic dependence of reactivity on water concentration and the presence of liquid water on the forsterite particles. Exposure to neat scCO2 showed no detectable carbonation reaction. At 55% and 95% water saturation, a liquid-like thin water film was detected on the forsterite particles; less than 1% of the forsterite transformed, mostly within the first 3 hours of exposure to the fluid. At 136% saturation, where an (excess) liquid water film approximately several nanometers thick was intentionally condensed on the forsterite, the carbonation reaction proceeded continuously for 24 hr with 10% to 15% transformation. Our collective results suggest constitutive links between water concentration, water film formation, reaction rate and extent, and reaction products in wet scCO2.

  2. Advances in passive-remote and extractive Fourier transform infrared spectroscopic systems

    SciTech Connect

    Demirgian, J.C.; Hammer, C.; Hwang, E.; Mao, Zhuoxiong

    1993-10-01

    The Clean Air Act of 1990 requires the monitoring of air toxics including those from incinerator emissions. Continuous emission monitors (CEM) would demonstrate the safety of incinerators and address public concern about emissions of hazardous organic compounds. Fourier transform infrared (FTIR) spectroscopy can provide the technology for continuous emission monitoring of stacks. Stack effluent can be extracted and analyzed in less than one minute with conventional FTIR spectrometers. Passive-remote FTIR spectrometers can detect certain emission gases over 1 km away from a stack. The authors discuss advances in both extractive and passive-remote FTIR technology. Extractive systems are being tested with EPA protocols, which will soon replace periodic testing methods. Standard operating procedures for extractive systems are being developed and tested. Passive-remote FTIR spectrometers have the advantage of not requiring an extracted sample; however, they have less sensitivity. We have evaluated the ability of commercially available systems to detect fugitive plumes and to monitor carbon monoxide at a coal-fired power plant.

  3. New quasars behind the Magellanic Clouds. Spectroscopic confirmation of near-infrared selected candidates

    NASA Astrophysics Data System (ADS)

    Ivanov, Valentin D.; Cioni, Maria-Rosa L.; Bekki, Kenji; de Grijs, Richard; Emerson, Jim; Gibson, Brad K.; Kamath, Devika; van Loon, Jacco Th.; Piatti, Andrés E.; For, Bi-Qing

    2016-04-01

    Context. Quasi-stellar objects (quasars) located behind nearby galaxies provide an excellent absolute reference system for astrometric studies, but they are difficult to identify because of fore- and background contamination. Deep wide-field, high angular resolution surveys spanning the entire area of nearby galaxies are needed to obtain a complete census of such quasars. Aims: We embarked on a program to expand the quasar reference system behind the Large and the Small Magellanic Clouds, the Magellanic Bridge, and the Magellanic Stream that connects the Clouds with the Milky Way. Methods: Hundreds of quasar candidates were selected based on their near-infrared colors and variability properties from the ongoing public ESO VISTA Magellanic Clouds survey. A subset of 49 objects was followed up with optical spectroscopy. Results: We confirmed the quasar nature of 37 objects (34 new identifications): four are low redshift objects, three are probably stars, and the remaining three lack prominent spectral features for a secure classification. The bona fide quasars, identified from their broad emisison lines, are located as follows: 10 behind the LMC, 13 behind the SMC, and 14 behind the Bridge. The quasars span a redshift range from z ~ 0.5 to z ~ 4.1. Conclusions: Upon completion the VMC survey is expected to yield a total of ~1500 quasars with Y< 19.32 mag, J< 19.09 mag, and Ks< 18.04 mag.

  4. Infrared spectroscopic characterization of organic matter associated with microbial bioalteration textures in basaltic glass.

    PubMed

    Preston, L J; Izawa, M R M; Banerjee, N R

    2011-09-01

    Microorganisms have been found to etch volcanic glass within volcaniclastic deposits from the Ontong Java Plateau, creating micron-sized tunnels and pits. The fossil record of such bioalteration textures is interpreted to extend back ∼3.5 billion years to include meta-volcanic glass from ophiolites and Precambrian greenstone belts. Bioalteration features within glass clasts from Leg 192 of the Ocean Drilling Program were investigated through optical microscopy and Fourier transform infrared (FTIR) spectroscopy of petrographic thin sections. Extended depth of focus optical microscopic imaging was used to identify bioalteration tubules within the samples and later combined with FTIR spectroscopy to study the organic molecules present within tubule clusters. The tubule-rich areas are characterized by absorption bands indicative of aliphatic hydrocarbons, amides, esters, and carboxylic groups. FTIR analysis of the tubule-free areas in the cores of glass clasts indicated that they were free of organics. This study further constrains the nature of the carbon compounds preserved within the tubules and supports previous studies that suggest the tubules formed through microbial activity. PMID:21848422

  5. Pb+ irradiation of synthetic zircon (ZrSiO4): Infrared spectroscopic investigation - Reply

    SciTech Connect

    Zhang, Ming; Ewing, Rodney C.; Boatner, Lynn A.; Salje, E K H.; Weber, William J.; Daniel, Philippe; Zhang, Yanwen; Farnan, Ian E.

    2009-06-01

    We appreciate the opportunity to respond to the comment by Nasdala (2009) concerning our interpretation of infrared spectra used to investigate the change in the structure of Pb-irradiated zircon as a function of increasing fluence (Zhang et al. 2008a, 2008b). Nasdala is correct in cautioning experimentalists to carefully match the analytical technique to the expected irradiation damage profile in order to optimally probe the irradiation effects, and in fact, this point was emphasize by Ewing et al. (2003) in a review of radiation effects in zircon. However, Nasdala’s discussion fails to fully appreciate three important points: i) There is a difference between in situ irradiations of TEM samples that must be electron transparent, ~200 nm thick, as were completed by Weber et al. (1994), and more bulk-like irradiations that were completed in the Zhang et al. (2008a and 2008b) studies; ii) The particle-solid interactions change along the path of an implanted ion, that is the distribution and nature of the damage changes with depth as the ion loses energy, resulting in the greatest number of ballistic interactions near the end of the particle trajectory (see Figure 1 of Ewing et al. 2003); iii) In comparing natural zircon damaged by alpha-decay events with ion irradiated zircon, one must be aware that the recoil nucleus and the alpha particle cause different types of damage, and the use of the Pb-implantation experiment is meant to simulate only the alpha-recoil damage.

  6. High-resolution infrared spectroscopic measurements of Comet 2P/Encke: Unusual organic composition and low rotational temperatures

    NASA Astrophysics Data System (ADS)

    Radeva, Yana L.; Mumma, Michael J.; Villanueva, Geronimo L.; Bonev, Boncho P.; DiSanti, Michael A.; A'Hearn, Michael F.; Dello Russo, Neil

    2013-03-01

    We present high-resolution infrared spectroscopic measurements of the ecliptic Comet 2P/Encke, observed on 4-6 November 2003 during its close approach to the Earth, using the Near Infrared Echelle Spectrograph on the Keck II telescope. We present flux-calibrated spectra, production rates, and mixing ratios for H2O, CH3OH, HCN, H2CO, C2H2, C2H6, CH4 and CO. Comet 2P/Encke is a dynamical end-member among comets because of its short period of 3.3 years. Relative to “organics-normal” comets, we determined that 2P/Encke is depleted in HCN, H2CO, C2H2, C2H6, CH4 and CO, but it is enriched in CH3OH. We compared mixing ratios of these organic species measured on separate dates, and we see no evidence of macroscopic chemical heterogeneity in the nucleus of 2P/Encke, however, this conclusion is limited by sparse temporal sampling. The depleted abundances of most measured species suggest that 2P/Encke may have formed closer to the young Sun, before its insertion to the Kuiper belt, compared with “organics-normal” comets - as was previously suggested for other depleted comets (e.g. C/1999 S4 (LINEAR)). We measured very low rotational temperatures of 20-30 K for H2O, CH3OH and HCN in the near nucleus region of 2P/Encke, which correlate with one of the lowest cometary gas production rates (∼2.6 × 1027 molecules s-1) measured thus far in the infrared. This suggests that we are seeing the effects of more efficient radiative cooling, insufficient collisional excitation, and/or inefficient heating by fast H-atoms (and icy grains) in the observed region of the coma. Its extremely short orbital period, very low gas production rate, and classification as an ecliptic comet, make 2P/Encke an important addition to our growing database, and contribute significantly to the establishment of a chemical taxonomy of comets.

  7. High-Resolution Infrared Spectroscopic Measurements of Comet 2PlEncke: Unusual Organic Composition and Low Rotational Temperatures

    NASA Technical Reports Server (NTRS)

    Radeva, Yana L.; Mumma, Michael J.; Villanueva, Geronimo L.; Bonev, Boncho P.; DiSanti, Michael A.; A'Hearn, Michael F.; Dello Russo, Neil

    2013-01-01

    We present high-resolution infrared spectroscopic measurements of the ecliptic comet 2P/Encke, observed on 4-6 Nov. 2003 during its close approach to the Earth, using the Near Infrared Echelle Spectrograph on the Keck II telescope. We present flux-calibrated spectra, production rates, and mixing ratios for H2O, CH3OH, HCN, H2CO, C2H2, C2H6, CH4 and CO. Comet 2P/Encke is a dynamical end-member among comets because of its short period of 3.3 years. Relative to "organics-normal" comets, we determined that 2PlEncke is depleted in HCN, H2CO, C2H2, C2H6, CH4 and CO, but it is enriched in CH3OH. We compared mixing ratios of these organic species measured on separate dates, and we see no evidence of macroscopic chemical heterogeneity in the nucleus of 2P/Encke, however, this conclusion is limited by sparse temporal sampling. The depleted abundances of most measured species suggest that 2P/Encke may have formed closer to the young Sun, before its insertion to the Kuiper belt, compared with "organics-normal" comets - as was previously suggested for other depleted comets (e.g. C/1999 S4 (LINEAR)). We measured very low rotational temperatures of 20 - 30 K for H2O, CH3OH and HCN in the near nucleus region of 2P/Encke, which correlate with one of the lowest cometary gas production rates (approx. 2.6 x 10(exp 27) molecules/s) measured thus far in the infrared. This suggests that we are seeing the effects of more efficient radiative cooling, insufficient collisional excitation, and/or inefficient heating by fast H-atoms (and icy grains) in the observed region of the coma. Its extremely short orbital period, very low gas production rate, and classification as an ecliptic comet, make 2PlEncke an important addition to our growing database, and contribute significantly to the establishment of a chemical taxonomy of comets.

  8. [Attenuated total reflection-fourier transform infrared spectroscopic study of dried shark fin products].

    PubMed

    Han, Wan-qing; Luo, Hai-ying; Xian, Yan-ping; Luo, Dong-hui; Mu, Torng-na; Guo, Xin-dong

    2015-02-01

    Sixty-four pieces of shark fin dried products (including real, fake and artificial shark fin products) and real products coated with gelatin were rapidly and nondestructively analyzed by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR). The characteristic of IR spectrograms among the above four kinds of samples were systematically studied and comparied, the results showed that the spectrograms of the same kind of samples were repeatable, and different kinds of shark fin products presented significant differences in the spectrograms, which mainly manifested as the specific absorption peaks of amido bonds in protein (1650, 1544 cm(-1)) and skeletal vibration in polysaccharide (1050 cm(-1)). The spectrograms of real shark fins were characterized by the strong absorption peaks of protein characteristic amide I and II absorbent (1650, 1544 cm(-1)) and relatively weak C--O--C vibration absorbent (1050 cm(-1)) owing to the high content of protein and relatively low level of polysaccharide. For fake shark fin products that were molded form by mixing together with the offcut of shark, collagen and other substances, the introduction of non-protein materials leaded to the weaker amido bonds absorbent than real products along with a 30 cm(-1) blue shift of amide I absorbent. Opposite to the real sample, the relatively strong absorption peak of polysaccharide (approximately 1047 cm(-1)) and barely existed amide absorbent were the key features of the spectrogram of artificial samples, which was synthersized by polysaccharide like sodium alginate. Real samples coated with gelatin, the peak strength of protein and polysaccharide were decreased simultaneously when the data collection was taken at the surface of sample, while the spectrogram presented no significant difference to real samples when the data was collected in the section. The results above indicated that by analyzing the characteristic of IR spectrograms and the value range of Apro

  9. Ion irradiation of the Murchison meteorite: Visible to mid-infrared spectroscopic results

    NASA Astrophysics Data System (ADS)

    Lantz, C.; Brunetto, R.; Barucci, M. A.; Dartois, E.; Duprat, J.; Engrand, C.; Godard, M.; Ledu, D.; Quirico, E.

    2015-05-01

    Aims: The goal of this study is to simulate space weathering processes on primitive bodies. We use ion implantation as a simulation of solar wind irradiation, which has been suggested by several authors to be the major component of space weathering on main belt asteroids. The laboratory analogs we irradiate and analyze are carbonaceous chondrites; we started the study with the Allende CV meteorite and in this companion paper we present results on the Murchison CM meteorite. Methods: We performed irradiations on pressed pellets of Murchison with 40 keV He+ and Ar+ ions using fluences up to 3 × 1016 ions/cm2. Reflectance spectra were acquired ex situ before and after irradiation in the visible to mid-infrared range (0.4-16 μm). A Raman analysis was also performed to investigate the modifications of the aromatic carbonaceous component. Results: Our results indicate that spectral variations after irradiation within the visible range are smaller than spectral variations due to sample grain size or viewing geometry of the Murchison meteorite. The aqueous alteration band profile near 3 μm changes after irradiation, as adsorbed water is removed, and phyllosilicates are affected. Raman spectroscopy highlights the insoluble organic matter (IOM) modification under irradiation. We observe a shift of the silicates band at 9.9 μm, probably due to a preferential loss of Mg (compared to Fe, the lighter Mg is more easily sputtered backward) and/or amorphization of Mg-rich materials. We compare our results to previous experiments on organic-rich materials (like asphaltite or carbonaceous chondrites), and on ordinary chondrites and olivine grains. We find that the reddening/darkening trend observed on silicate-rich surfaces is not valid for all carbonaceous chondrites, and that the spectral modifications after irradiation are a function of the initial albedo.

  10. Infrared spectroscopic examination of the interaction of urea with the naturally occurring zeolite clinoptilolite

    USGS Publications Warehouse

    Byler, D.M.; Gerasimowicz, W.V.; Stockette, V.M.; Eberl, D.D.

    1991-01-01

    Infrared spectroscopy has shown for the first time that the naturally occurring zeolite clinoptilolite can absorb urea, (NH2)2CO, under ambient conditions from either aqueous or ethanolic solutions. The two strongest NH stretching bands at 3441 and 3344 cm-1 in pure, solid urea shift to higher frequency (about 3504 and 3401 cm-1) after absorption. Two of the four urea bands in the 1800-1300 cm-1 range (at 1683 and 1467 cm-1) undergo marked downward shifts to about 1670 and 1445 cm-1. The other two bands show little change in frequency. The strong band at 1602 cm-1, however, diminishes in intensity to little more than an ill-defined shoulder on the 1626-cm-1 peak. When clinoptilolite is heated to 450 ??C and then treated with molten urea (ca. 140 ??C) for several minutes, and finally washed twice with ethanol to remove excess unreacted urea, further changes become apparent in the spectrum of the urea-treated clinoptilolite. The two NH stretching bands broaden without significant change in frequency. Two new bands appear in the midfrequency range at 1777 (weak) and 1719 (medium strong) cm-1. Of the four original midfrequency peaks, the one at 1602 cm-1 is now absent. Two others (1627 and 1440 cm-1) exhibit little change, while the fourth has broadened and shifted down to 1663 cm-1, where it appears as a shoulder on the band at 1627 cm-1. Both treatments clearly induce interaction between urea and the zeolite which seems to result in significant modifications in the nature of the hydrogen bonding of the substrate. ?? 1991.

  11. OT1_nlu_1: Herschel Spectroscopic Survey of Warm Molecular Gas in Local Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Lu, N.

    2010-07-01

    We propose to survey CO spectral line energy distribution (SLED), from J=4-3 up to J=13-12, on 93 local luminous infrared galaxies (LIRGs; L_{IR} > 1.0E11 L_{sun}) with Herschel SPIRE FTS spectrometer. These galaxies, plus 32 additional LIRGs that will have similar data from existing Herschel programs (mainly the HerCULES project), form a flux-limited subset of the Great Observatories All-Sky LIRGs Survey (GOALS) sample. Our proposal is built on the legacy of GOALS and extends beyond the existing Herschel HerCULES program, which emphasizes more on ULIRGs, to a much needed sample coverage of the more numerous and diverse population of less luminous LIRGs. The data from the proposed observations will not only provide much needed local LIRG templates for future ALMA studies of high-redshift counterparts, but also lend us a powerful diagnostic tool to probe the warm and dense molecular gas that are more closely related to the starburst or AGN activity in the nuclei of LIRGs. The data from this proposal will provide important statistical clues to the interplay between the cold and warm molecular gas, IR luminosity, star formation rate and efficiency, and the diverse properties of LIRGs. Specifically, using the homogeneous CO SLED data from this proposal, together with ground-base, low-order CO line data (mainly J=1-0) and other data that have been compiled for the GOALS sample, we will address the following questions: (1) What is the dominant nuclear power source in individual sample galaxy: starburst or AGN? (2) What are the typical physical properties of warm molecular gas in the nuclei of LIRGs? (3) How do the nuclear warm gas components correlate to the cold gas component, star formation rate and efficiency, dust temperature, etc? and (4) How does molecular gas excitation change along a merger sequence?

  12. Recognizing impact glass on Mars using surface texture, mechanical properties, and mid-infrared spectroscopic methods

    NASA Astrophysics Data System (ADS)

    Bradley, James Thomson

    breccias. In Part 4, systematic variations in glass mid-infrared reststrahlen band positions were determined with variations in glass chemistry, degree of crystallinity, and quench rate. Results indicate that the spectra of rapidly quenched glasses with a high fictive temperature exhibit shifts to shorter wavelengths, causing them to appear more silica-rich.

  13. Infrared Spectroscopic Studies of OCS Trapped in Solid Parahydrogen: Indirect Evidence of Large Amplitude Motions

    NASA Astrophysics Data System (ADS)

    Anderson, David T.

    2016-06-01

    The high-resolution infrared rovibrational spectroscopy of OCS clustered with multiple hydrogen molecules has previously been studied in helium nanodroplets and in the gas-phase in search of another substance other than helium that displays superfluidity. Para-hydrogen (pH2) is one of the most likely candidates because it is a spinless (I=0) composite boson with a light mass similar to helium. However, compared to helium, the pH2-pH2 intermolecular potential is significantly stronger and thus pH2 solidifies at higher temperatures than the predicted superfluid transition temperature thereby blocking access to the superfluid state. Both of these previous studies reveal intriguing results linked to the microscopic details of superfluidity. We were therefore interested to characterize the IR spectrum of OCS in solid pH2. The conventional wisdom is that because pH2 solidifies into a quantum solid, the effects of superfluidity detected in the finite sized clusters should not be manifest in solid pH2. However, the OCS-H2 intermolecular potential strongly favors arranging the first 5 pH2 molecules in a ring around the equator of the OCS (R=3.2 Å). Isolation of OCS in bulk pH2 therefore may result in a solvation site where 6 pH2 molecules in the same basal plane form a ring around the OCS and are pulled inward decoupling them from the bulk. If the periodic barriers to motion around the ring are small, one might expect the 6 equatorial pH2 molecules to become delocalized while still maintaining the permutation symmetry of bosons. These 6 particles-on-a-ring may only show this behavior at low temperatures when thermal excitations are minimized. Analysis of the IR spectroscopy of OCS in solid pH2 indicates 1) the OCS molecule does not freely rotate and 2) there are at least two preferred OCS solvation sites. In principle, the measured OCS peak frequency for these two solvation sites should depend sensitively on the "structure" of the first pH2 solvation shell and therefore

  14. Near-Infrared Spectroscopic Measurements of Calf Muscle during Walking at Simulated Reduced Gravity - Preliminary Results

    NASA Technical Reports Server (NTRS)

    Ellerby, Gwenn E. C.; Lee, Stuart M. C.; Stroud, Leah; Norcross, Jason; Gernhardt, Michael; Soller, Babs R.

    2008-01-01

    Consideration for lunar and planetary exploration space suit design can be enhanced by investigating the physiologic responses of individual muscles during locomotion in reduced gravity. Near-infrared spectroscopy (NIRS) provides a non-invasive method to study the physiology of individual muscles in ambulatory subjects during reduced gravity simulations. PURPOSE: To investigate calf muscle oxygen saturation (SmO2) and pH during reduced gravity walking at varying treadmill inclines and added mass conditions using NIRS. METHODS: Four male subjects aged 42.3 +/- 1.7 years (mean +/- SE) and weighing 77.9 +/- 2.4 kg walked at a moderate speed (3.2 +/- 0.2 km/h) on a treadmill at inclines of 0, 10, 20, and 30%. Unsuited subjects were attached to a partial gravity simulator which unloaded the subject to simulate body weight plus the additional weight of a space suit (121 kg) in lunar gravity (0.17G). Masses of 0, 11, 23, and 34 kg were added to the subject and then unloaded to maintain constant weight. Spectra were collected from the lateral gastrocnemius (LG), and SmO2 and pH were calculated using previously published methods (Yang et al. 2007 Optics Express ; Soller et al. 2008 J Appl Physiol). The effects of incline and added mass on SmO2 and pH were analyzed through repeated measures ANOVA. RESULTS: SmO2 and pH were both unchanged by added mass (p>0.05), so data from trials at the same incline were averaged. LG SmO2 decreased significantly with increasing incline (p=0.003) from 61.1 +/- 2.0% at 0% incline to 48.7 +/- 2.6% at 30% incline, while pH was unchanged by incline (p=0.12). CONCLUSION: Increasing the incline (and thus work performed) during walking causes the LG to extract more oxygen from the blood supply, presumably to support the increased metabolic cost of uphill walking. The lack of an effect of incline on pH may indicate that, while the intensity of exercise has increased, the LG has not reached a level of work above the anaerobic threshold. In these

  15. Brown dwarf photospheres are patchy: A Hubble space telescope near-infrared spectroscopic survey finds frequent low-level variability

    SciTech Connect

    Buenzli, Esther; Apai, Dániel; Radigan, Jacqueline; Reid, I. Neill; Flateau, Davin

    2014-02-20

    Condensate clouds strongly impact the spectra of brown dwarfs and exoplanets. Recent discoveries of variable L/T transition dwarfs argued for patchy clouds in at least some ultracool atmospheres. This study aims to measure the frequency and level of spectral variability in brown dwarfs and to search for correlations with spectral type. We used Hubble Space Telescope/Wide Field Camera 3 to obtain spectroscopic time series for 22 brown dwarfs of spectral types ranging from L5 to T6 at 1.1-1.7 μm for ≈40 minutes per object. Using Bayesian analysis, we find six brown dwarfs with confident (p > 95%) variability in the relative flux in at least one wavelength region at sub-percent precision, and five brown dwarfs with tentative (p > 68%) variability. We derive a minimum variability fraction f{sub min}=27{sub −7}{sup +11}% over all covered spectral types. The fraction of variables is equal within errors for mid-L, late-L, and mid-T spectral types; for early-T dwarfs we do not find any confident variable but the sample is too small to derive meaningful limits. For some objects, the variability occurs primarily in the flux peak in the J or H band, others are variable throughout the spectrum or only in specific absorption regions. Four sources may have broadband peak-to-peak amplitudes exceeding 1%. Our measurements are not sensitive to very long periods, inclinations near pole-on and rotationally symmetric heterogeneity. The detection statistics are consistent with most brown dwarf photospheres being patchy. While multiple-percent near-infrared variability may be rare and confined to the L/T transition, low-level heterogeneities are a frequent characteristic of brown dwarf atmospheres.

  16. Infrared and Raman spectroscopic features of the self-interstitial defect in diamond from exact-exchange hybrid DFT calculations.

    PubMed

    Salustro, Simone; Erba, Alessandro; Zicovich-Wilson, Claudio M; Nöel, Yves; Maschio, Lorenzo; Dovesi, Roberto

    2016-08-01

    Quantum-mechanical calculations are performed to investigate the structural, electronic, and infrared (IR) and Raman spectroscopic features of one of the most common radiation-induced defects in diamond: the "dumb-bell" 〈100〉 split self-interstitial. A periodic super-cell approach is used in combination with all-electron basis sets and hybrid functionals of density-functional-theory (DFT), which include a fraction of exact non-local exchange and are known to provide a correct description of the electronic spin localization at the defect, at variance with simpler formulations of the DFT. The effects of both defect concentration and spin state are explicitly addressed. Geometrical constraints are found to prevent the formation of a double bond between the two three-fold coordinated carbon atoms. In contrast, two unpaired electrons are fully localized on each of the carbon atoms involved in the defect. The open-shell singlet state is slightly more stable than the triplet (the energy difference being just 30 meV, as the unpaired electrons occupy orthogonal orbitals) while the closed-shell solution is less stable by about 1.55 eV. The formation energy of the defect from pristine diamond is about 12 eV. The Raman spectrum presents only two peaks of low intensity at wave-numbers higher than the pristine diamond peak (characterized by normal modes extremely localized on the defect), whose positions strongly depend on defect concentration as they blue shift up to 1550 and 1927 cm(-1) at infinite defect dilution. The first of these peaks, also IR active, is characterized by a very high IR intensity, and might then be related to the strong experimental feature of the IR spectrum occurring at 1570 cm(-1). A second very intense IR peak appears at about 500 cm(-1), which, despite being originated from a "wagging" motion of the self-interstitial defect, exhibits a more collective, less localized character.

  17. Genesis Silicon Carbide Concentrator Target 60003 Preliminary Ellipsometry Mapping Results

    NASA Technical Reports Server (NTRS)

    Calaway, M. J.; Rodriquez, M. C.; Stansbery, E. K.

    2007-01-01

    The Genesis concentrator was custom designed to focus solar wind ions primarily for terrestrial isotopic analysis of O-17/O-16 and O-18/O-16 to +/-1%, N-15/N-14 to +/-1%, and secondarily to conduct elemental and isotopic analysis of Li, Be, and B. The circular 6.2 cm diameter concentrator target holder was comprised of four quadrants of highly pure semiconductor materials that included one amorphous diamond-like carbon, one C-13 diamond, and two silicon carbide (SiC). The amorphous diamond-like carbon quadrant was fractured upon impact at Utah Test and Training Range (UTTR), but the remaining three quadrants survived fully intact and all four quadrants hold an important collection of solar wind. The quadrants were removed from the target holder at NASA Johnso n Space Center Genesis Curation Laboratory in April 2005, and have been housed in stainless steel containers under continual nitrogen purge since time of disintegration. In preparation for allocation of a silicon carbide target for oxygen isotope analyses at UCLA, the two SiC targets were photographed for preliminary inspection of macro particle contamination from the hard non-nominal landing as well as characterized by spectroscopic ellipsometry to evaluate thin film contamination. This report is focused on Genesis SiC target sample number 60003.

  18. Built-in hyperspectral camera for smartphone in visible, near-infrared and middle-infrared lights region (second report): sensitivity improvement of Fourier-spectroscopic imaging to detect diffuse reflection lights from internal human tissues for healthcare sensors

    NASA Astrophysics Data System (ADS)

    Kawashima, Natsumi; Hosono, Satsuki; Ishimaru, Ichiro

    2016-05-01

    We proposed the snapshot-type Fourier spectroscopic imaging for smartphone that was mentioned in 1st. report in this conference. For spectroscopic components analysis, such as non-invasive blood glucose sensors, the diffuse reflection lights from internal human skins are very weak for conventional hyperspectral cameras, such as AOTF (Acousto-Optic Tunable Filter) type. Furthermore, it is well known that the spectral absorption of mid-infrared lights or Raman spectroscopy especially in long wavelength region is effective to distinguish specific biomedical components quantitatively, such as glucose concentration. But the main issue was that photon energies of middle infrared lights and light intensities of Raman scattering are extremely weak. For improving sensitivity of our spectroscopic imager, the wide-field-stop & beam-expansion method was proposed. Our line spectroscopic imager introduced a single slit for field stop on the conjugate objective plane. Obviously to increase detected light intensities, the wider slit width of the field stop makes light intensities higher, regardless of deterioration of spatial resolutions. Because our method is based on wavefront-division interferometry, it becomes problems that the wider width of single slit makes the diffraction angle narrower. This means that the narrower diameter of collimated objective beams deteriorates visibilities of interferograms. By installing the relative inclined phaseshifter onto optical Fourier transform plane of infinity corrected optical systems, the collimated half flux of objective beams derived from single-bright points on objective surface penetrate through the wedge prism and the cuboid glass respectively. These two beams interfere each other and form the infererogram as spatial fringe patterns. Thus, we installed concave-cylindrical lens between the wider slit and objective lens as a beam expander. We successfully obtained the spectroscopic characters of hemoglobin from reflected lights from

  19. Expanding the analytical toolbox for identity testing of pharmaceutical ingredients: Spectroscopic screening of dextrose using portable Raman and near infrared spectrometers.

    PubMed

    Srivastava, Hirsch K; Wolfgang, Steven; Rodriguez, Jason D

    2016-03-31

    In the pharmaceutical industry, dextrose is used as an active ingredient in parenteral solutions and as an inactive ingredient (excipient) in tablets and capsules. In order to address the need for more sophisticated analytical techniques, we report our efforts to develop enhanced identification methods to screen pharmaceutical ingredients at risk for adulteration or substitution using field-deployable spectroscopic screening. In this paper, we report our results for a study designed to evaluate the performance of field-deployable Raman and near infrared (NIR) methods to identify dextrose samples. We report a comparison of the sensitivity of the spectroscopic screening methods against current compendial identification tests that rely largely on a colorimetric assay. Our findings indicate that NIR and Raman spectroscopy are both able to distinguish dextrose by hydration state and from other sugar substitutes with 100% accuracy for all methods tested including spectral correlation based library methods, principal component analysis and classification methods.

  20. Expanding the analytical toolbox for identity testing of pharmaceutical ingredients: Spectroscopic screening of dextrose using portable Raman and near infrared spectrometers.

    PubMed

    Srivastava, Hirsch K; Wolfgang, Steven; Rodriguez, Jason D

    2016-03-31

    In the pharmaceutical industry, dextrose is used as an active ingredient in parenteral solutions and as an inactive ingredient (excipient) in tablets and capsules. In order to address the need for more sophisticated analytical techniques, we report our efforts to develop enhanced identification methods to screen pharmaceutical ingredients at risk for adulteration or substitution using field-deployable spectroscopic screening. In this paper, we report our results for a study designed to evaluate the performance of field-deployable Raman and near infrared (NIR) methods to identify dextrose samples. We report a comparison of the sensitivity of the spectroscopic screening methods against current compendial identification tests that rely largely on a colorimetric assay. Our findings indicate that NIR and Raman spectroscopy are both able to distinguish dextrose by hydration state and from other sugar substitutes with 100% accuracy for all methods tested including spectral correlation based library methods, principal component analysis and classification methods. PMID:26965331

  1. A Markov random field based approach to the identification of meat and bone meal in feed by near-infrared spectroscopic imaging.

    PubMed

    Jiang, Xunpeng; Yang, Zengling; Han, Lujia

    2014-07-01

    Contaminated meat and bone meal (MBM) in animal feedstuff has been the source of bovine spongiform encephalopathy (BSE) disease in cattle, leading to a ban in its use, so methods for its detection are essential. In this study, five pure feed and five pure MBM samples were used to prepare two sets of sample arrangements: set A for investigating the discrimination of individual feed/MBM particles and set B for larger numbers of overlapping particles. The two sets were used to test a Markov random field (MRF)-based approach. A Fourier transform infrared (FT-IR) imaging system was used for data acquisition. The spatial resolution of the near-infrared (NIR) spectroscopic image was 25 μm × 25 μm. Each spectrum was the average of 16 scans across the wavenumber range 7,000-4,000 cm(-1), at intervals of 8 cm(-1). This study introduces an innovative approach to analyzing NIR spectroscopic images: an MRF-based approach has been developed using the iterated conditional mode (ICM) algorithm, integrating initial labeling-derived results from support vector machine discriminant analysis (SVMDA) and observation data derived from the results of principal component analysis (PCA). The results showed that MBM covered by feed could be successfully recognized with an overall accuracy of 86.59% and a Kappa coefficient of 0.68. Compared with conventional methods, the MRF-based approach is capable of extracting spectral information combined with spatial information from NIR spectroscopic images. This new approach enhances the identification of MBM using NIR spectroscopic imaging.

  2. Infrared and Raman spectroscopic features of the self-interstitial defect in diamond from exact-exchange hybrid DFT calculations.

    PubMed

    Salustro, Simone; Erba, Alessandro; Zicovich-Wilson, Claudio M; Nöel, Yves; Maschio, Lorenzo; Dovesi, Roberto

    2016-08-01

    Quantum-mechanical calculations are performed to investigate the structural, electronic, and infrared (IR) and Raman spectroscopic features of one of the most common radiation-induced defects in diamond: the "dumb-bell" 〈100〉 split self-interstitial. A periodic super-cell approach is used in combination with all-electron basis sets and hybrid functionals of density-functional-theory (DFT), which include a fraction of exact non-local exchange and are known to provide a correct description of the electronic spin localization at the defect, at variance with simpler formulations of the DFT. The effects of both defect concentration and spin state are explicitly addressed. Geometrical constraints are found to prevent the formation of a double bond between the two three-fold coordinated carbon atoms. In contrast, two unpaired electrons are fully localized on each of the carbon atoms involved in the defect. The open-shell singlet state is slightly more stable than the triplet (the energy difference being just 30 meV, as the unpaired electrons occupy orthogonal orbitals) while the closed-shell solution is less stable by about 1.55 eV. The formation energy of the defect from pristine diamond is about 12 eV. The Raman spectrum presents only two peaks of low intensity at wave-numbers higher than the pristine diamond peak (characterized by normal modes extremely localized on the defect), whose positions strongly depend on defect concentration as they blue shift up to 1550 and 1927 cm(-1) at infinite defect dilution. The first of these peaks, also IR active, is characterized by a very high IR intensity, and might then be related to the strong experimental feature of the IR spectrum occurring at 1570 cm(-1). A second very intense IR peak appears at about 500 cm(-1), which, despite being originated from a "wagging" motion of the self-interstitial defect, exhibits a more collective, less localized character. PMID:27326546

  3. Self-formation of bilayer lipid membranes on agarose-coated silicon surfaces studied by simultaneous electrophysiological and surface infrared spectroscopic measurements

    NASA Astrophysics Data System (ADS)

    Hirano-Iwata, Ayumi; Oshima, Azusa; Onodera, Kota; Aoto, Kouji; Taira, Tasuku; Yamaguchi, Ryo-taro; Kimura, Yasuo; Niwano, Michio

    2009-06-01

    Self-formation process of bilayer lipid membranes (BLMs) cushioned on agarose-coated Si surfaces was in situ monitored by simultaneous electrophysiological and infrared absorption spectroscopic (IRAS) measurements using IRAS with the multiple internal reflection geometry. IRAS signals corresponding to self-thinning of lipid solution to form BLMs were demonstrated. It was found that the appearance of IRAS bands due to C=O modes of phosphstidylcholine is related to formation of BLMs with a gigaohm seal. The functionality of the present BLM system was also demonstrated by incorporating gramicidin into the BLMs and recording its channel activities.

  4. Oxidation of SiC investigated by ellipsometry and Rutherford backscattering spectrometry

    SciTech Connect

    Szilagyi, E.; Petrik, P.; Lohner, T.; Koos, A. A.; Fried, M.; Battistig, G.

    2008-07-01

    Oxidation of SiC was performed in Ar-O{sub 2} mixture of atmospheric pressure at 1100 deg. C and compared with that of Si. The partial pressure of O{sub 2} varied from 100 to 1000 mbar, while the oxidation time ranged from 0.5 to 45 h. The thickness of the oxide films was determined by spectroscopic ellipsometry and Rutherford backscattering spectrometry. The time and the pressure dependence of the oxidation kinetics of SiC are well described by the modified Deal-Grove model. In the diffusion-limited region, even for the faster case, the oxidation kinetics of the C-terminated face of SiC is not clearly limited by oxygen indiffusion, as for pure silicon. To interpret the ellipsometry spectra, two models of possible structure were used. In the case of the one-layer model, for layer thicknesses above 30 nm, the refractive index of the oxide layers is identical to that of thermally oxidized Si, and it increases rapidly with decreasing thickness below about 15 nm. This increase is significantly larger for C-terminated than for Si-terminated faces, and this difference can be explained by a transition layer introduced into the two-layer model. This model contains a pure SiO{sub 2} layer and a transition layer modeled by a mixture of 50 % SiO{sub 2} and 50 % SiC. The transition layer is thicker on the C-terminated surface than on the Si-terminated one. The thickness ratio of the transition layers is slightly larger than the surface roughness ratio on the two different sides determined by atomic force microscopy. The density of the oxide films, which can be determined from the backscattering and spectroscopic ellipsometry spectra, decreases with decreasing thickness below about 30 nm. For thicker films, the density of the oxide is equal to the bulk density of SiO{sub 2}.

  5. Combined ellipsometry and refractometry technique for characterisation of liquid crystal based nanocomposites.

    PubMed

    Warenghem, Marc; Henninot, Jean François; Blach, Jean François; Buchnev, Oleksandr; Kaczmarek, Malgosia; Stchakovsky, Michel

    2012-03-01

    Spectroscopic ellipsometry is a technique especially well suited to measure the effective optical properties of a composite material. However, as the sample is optically thick and anisotropic, this technique loses its accuracy for two reasons: anisotropy means that two parameters have to be determined (ordinary and extraordinary indices) and optically thick means a large order of interference. In that case, several dielectric functions can emerge out of the fitting procedure with a similar mean square error and no criterion to discriminate the right solution. In this paper, we develop a methodology to overcome that drawback. It combines ellipsometry with refractometry. The same sample is used in a total internal reflection (TIR) setup and in a spectroscopic ellipsometer. The number of parameters to be determined by the fitting procedure is reduced in analysing two spectra, the correct final solution is found by using the TIR results both as initial values for the parameters and as check for the final dielectric function. A prefitting routine is developed to enter the right initial values in the fitting procedure and so to approach the right solution. As an example, this methodology is used to analyse the optical properties of BaTiO(3) nanoparticles embedded in a nematic liquid crystal. Such a methodology can also be used to analyse experimentally the validity of the mixing laws, since ellipsometry gives the effective dielectric function and thus, can be compared to the dielectric function of the components of the mixture, as it is shown on the example of BaTiO(3)/nematic composite.

  6. New spectroscopic tools and techniques for characterizing M dwarfs and discovering their planets in the near-infrared

    NASA Astrophysics Data System (ADS)

    Terrien, Ryan C.

    M dwarfs are the least massive and most common stars in the Galaxy. Due to their prevalence and long lifetimes, these diminutive stars play an outsize role in several fields of astronomical study. In particular, it is now known that they commonly host planetary systems, and may be the most common hosts of Earth-size, rocky planets in the habitable zone. A comprehensive understanding of M dwarfs is crucial for understanding the origins and conditions of their planetary systems, including their potential habitability. Such an understanding depends on methods for precisely and accurately measuring their properties. These tools have broader applicability as well, underlying the use of M dwarfs as fossils of Galactic evolution, and helping to constrain the structures and interiors of these stars. The measurement of the fundamental parameters of M dwarfs is encumbered by their spectral complexity. Unlike stars of spectral type F, G, or K that are similar to our G type Sun, whose spectra are dominated by continuum emission and atomic features, the cool atmospheres of M dwarfs are dominated by complex molecular absorption. Another challenge for studies of M dwarfs is that these stars are optically faint, emitting much of their radiation in the near-infrared (NIR). The availability and performance of NIR spectrographs have lagged behind those of optical spectrographs due to the challenges of producing low-noise, high-sensitivity NIR detector arrays, which have only recently become available. This thesis discusses two related lines of work that address these challenges, motivated by the development of the Habitable Zone Planet Finder (HPF), a NIR radial velocity (RV) spectrograph under development at Penn State that will search for and confirm planets around nearby M dwarfs. This work includes the development and application of new NIR spectroscopic techniques for characterizing M dwarfs, and the development and optimization of new NIR instrumentation for HPF. The first line

  7. Potential Modulation on Total Internal Reflection Ellipsometry.

    PubMed

    Liu, Wei; Niu, Yu; Viana, A S; Correia, Jorge P; Jin, Gang

    2016-03-15

    Electrochemical-total internal reflection ellipsometry (EC-TIRE) has been proposed as a technique to observe the redox reactions on the electrode surface due to its high phase sensitivity to the electrolyte/electrode interface. In this paper, we mainly focus on the influence of the potential modulation on the TIRE response. The analysis suggests that both dielectric constant variation of gold and the electric double layer transformation would modulate the reflection polarization of the surface. For a nonfaradaic process, the signal of TIRE would be proportional to the potential modulation. To testify the analysis, linear sweep voltammetry and open circuit measurement have been performed. The results strongly support the system analysis. PMID:26889871

  8. Characterization on Smart Optics Using Ellipsometry

    NASA Technical Reports Server (NTRS)

    Song, Kyo D.

    2002-01-01

    Recently, NASA Langley Research Center developed a smart active optical concept to filter narrow band pass or to control optical intensity. To characterize developed smart optics materials, we have measured thickness and reflection properties of the materials using a WVASE32 ellipsometry. This project allowed us to: (1) prepare the smart optical materials for measurement of thickness and optical properties at NASA Langley Research Center; (2) measure thickness and optical properties of the smart optical materials; (3) evaluate the measured properties in terms of applications for narrow band-pass filters. The outcomes of this research provide optical properties and physical properties of the smart optics on a selected spectral range. The applications of this development were used for field-controlled spectral smart filters.

  9. ACCURATE SPECTROSCOPIC CHARACTERIZATION OF OXIRANE: A VALUABLE ROUTE TO ITS IDENTIFICATION IN TITAN’S ATMOSPHERE AND THE ASSIGNMENT OF UNIDENTIFIED INFRARED BANDS

    PubMed Central

    Puzzarini, Cristina; Biczysko, Malgorzata; Bloino, Julien; Barone, Vincenzo

    2015-01-01

    In an effort to provide an accurate spectroscopic characterization of oxirane, state-of-the-art computational methods and approaches have been employed to determine highly accurate fundamental vibrational frequencies and rotational parameters. Available experimental data were used to assess the reliability of our computations, and an accuracy on average of 10 cm−1 for fundamental transitions as well as overtones and combination bands has been pointed out. Moving to rotational spectroscopy, relative discrepancies of 0.1%, 2%–3%, and 3%–4% were observed for rotational, quartic, and sextic centrifugal-distortion constants, respectively. We are therefore confident that the highly accurate spectroscopic data provided herein can be useful for identification of oxirane in Titan’s atmosphere and the assignment of unidentified infrared bands. Since oxirane was already observed in the interstellar medium and some astronomical objects are characterized by very high D/H ratios, we also considered the accurate determination of the spectroscopic parameters for the mono-deuterated species, oxirane-d1. For the latter, an empirical scaling procedure allowed us to improve our computed data and to provide predictions for rotational transitions with a relative accuracy of about 0.02% (i.e., an uncertainty of about 40 MHz for a transition lying at 200 GHz). PMID:26543240

  10. Infrared and infrared emission spectroscopic study of selected magnesium carbonate minerals containing ferric iron--implications for the geosequestration of greenhouse gases.

    PubMed

    Frost, Ray L; Bahfenne, Silmarilly; Graham, Jessica

    2008-12-15

    The proposal to remove greenhouse gases by pumping liquid carbon dioxide several kilometres below ground level implies that many carbonate containing minerals will be formed. Among these minerals, the formation of two hydrotalcite-like minerals coalingite and brugnatellite is possible, thus necessitating a study of such minerals and their thermal stability. The two such carbonate-bearing minerals brugnatellite and coalingite have been characterised by a combination of infrared and infrared emission spectroscopy. Infrared emission spectroscopy is most useful to determine the stability of these minerals. The infrared spectra of the OH stretching region are characterised by OH and water stretching vibrations. Intense (CO3)(2-) symmetric and antisymmetric stretching vibrations support the concept that the carbonate ion is distorted in these minerals. The position of the water bending vibration indicates that the water is strongly hydrogen bonded in the mineral structure. IES spectra show the temperature range of the thermal stability of these minerals.

  11. Near-infrared diode laser based spectroscopic detection of ammonia: a comparative study of photoacoustic and direct optical absorption methods

    NASA Technical Reports Server (NTRS)

    Bozoki, Zoltan; Mohacsi, Arpad; Szabo, Gabor; Bor, Zsolt; Erdelyi, Miklos; Chen, Weidong; Tittel, Frank K.

    2002-01-01

    A photoacoustic spectroscopic (PAS) and a direct optical absorption spectroscopic (OAS) gas sensor, both using continuous-wave room-temperature diode lasers operating at 1531.8 nm, were compared on the basis of ammonia detection. Excellent linear correlation between the detector signals of the two systems was found. Although the physical properties and the mode of operation of both sensors were significantly different, their performances were found to be remarkably similar, with a sub-ppm level minimum detectable concentration of ammonia and a fast response time in the range of a few minutes.

  12. Spectroscopic Monitoring of Spent Nuclear Fuel Reprocessing Streams: An Evaluation of Spent Fuel Solutions via Raman, Visible, and Near-Infrared Spectroscopy

    SciTech Connect

    Bryan, Samuel A.; Levitskaia, Tatiana G.; Johnsen, Amanda M.; Orton, Christopher R.; Peterson, James M.

    2011-09-01

    The potential of using optical spectroscopic techniques, such as Raman and Visible/Near Infrared (Vis/NIR), for on-line process control and special nuclear materials accountability applications at a spent nuclear fuel reprocessing facility was evaluated. Availability of on-line real-time techniques that directly measure process concentrations of nuclear materials will enhance performance and proliferation resistance of the solvent extraction processes. Further, on-line monitoring of radiochemical streams will also improve reprocessing plant operation and safety. This report reviews current state of development of the spectroscopic on-line monitoring techniques for such solutions. To further examine applicability of optical spectroscopy for monitoring reprocessing solutions, segments of a spent nuclear fuel, with approximate burn-up values of 70 MWd/kgM, were dissolved in concentrated nitric acid and adjusted to varying final concentrations of HNO3. The resulting spent fuel solutions were batch-contacted with tributyl phosphate/dodecane organic solvent. The feed and equilibrium aqueous and loaded organic solutions were subjected to optical measurements. The obtained spectra showed the presence of the quantifiable Raman bands due to NO3- and UO22+ and Vis/NIR bands due to multiple species of Pu(IV), Pu(VI), Np(V), the Np(V)-U(VI) cation-cation complex, and Nd(III) in fuel solutions, justifying spectroscopic techniques as a promising methodology for monitoring spent fuel processing solutions in real-time. Quantitative evaluation of the fuel solution was performed based on spectroscopic measurements and compared to ICP-MS analysis.

  13. Monitoring of the Binding Between EGFR Protein and EGFR Aptamer Using In-Situ Total Internal Reflection Ellipsometry.

    PubMed

    Kang, Yu Ri; Byun, Jun Seok; Kim, Tae Jung; Park, Han Gyeol; Park, Jae Chan; Barange, Nilesh; Nam, Koo Hyun; Kim, Young Dong

    2016-06-01

    The epidermal growth factor receptor (EGFR) protein has received significant attention in medical biotechnology because it is an important component in cell growth and division. We report the results of a study on the binding between the EGFR protein and the associated aptamer, measured in real time. Aptamers can be used for clinical purposes including macromolecular medicine and basic research. In particular, EGFR aptamers are promising molecular agents for targeting cancer. The data were obtained in-situ with total internal reflection ellipsometry (TIRE), which combines the analytic capability of spectroscopic ellipsometry with the high surface sensitivity of surface plasmon resonance measurements. Our results show that TIRE can be used to determine adsorption of nanoscale biomolecules. Our results are supported by additional data obtained by liquid atomic-force-microscopy. PMID:27427733

  14. Ultrafast dynamic ellipsometry and spectroscopies of laser shocked materials

    SciTech Connect

    Mcgrane, Shawn David; Bolme, Cindy B; Whitley, Von H; Moore, David S

    2010-01-01

    Ultrafast ellipsometry and transient absorption spectroscopies are used to measure material dynamics under extreme conditions of temperature, pressure, and volumetric compression induced by shock wave loading with a chirped, spectrally clipped shock drive pulse.

  15. Built-in hyperspectral camera for smartphone in visible, near-infrared and middle-infrared lights region (third report): spectroscopic imaging for broad-area and real-time componential analysis system against local unexpected terrorism and disasters

    NASA Astrophysics Data System (ADS)

    Hosono, Satsuki; Kawashima, Natsumi; Wollherr, Dirk; Ishimaru, Ichiro

    2016-05-01

    The distributed networks for information collection of chemical components with high-mobility objects, such as drones or smartphones, will work effectively for investigations, clarifications and predictions against unexpected local terrorisms and disasters like localized torrential downpours. We proposed and reported the proposed spectroscopic line-imager for smartphones in this conference. In this paper, we will mention the wide-area spectroscopic-image construction by estimating 6 DOF (Degrees Of Freedom: parallel movements=x,y,z and rotational movements=θx, θy, θz) from line data to observe and analyze surrounding chemical-environments. Recently, smartphone movies, what were photographed by peoples happened to be there, had worked effectively to analyze what kinds of phenomenon had happened around there. But when a gas tank suddenly blew up, we did not recognize from visible-light RGB-color cameras what kinds of chemical gas components were polluting surrounding atmospheres. Conventionally Fourier spectroscopy had been well known as chemical components analysis in laboratory usages. But volatile gases should be analyzed promptly at accident sites. And because the humidity absorption in near and middle infrared lights has very high sensitivity, we will be able to detect humidity in the sky from wide field spectroscopic image. And also recently, 6-DOF sensors are easily utilized for estimation of position and attitude for UAV (Unmanned Air Vehicle) or smartphone. But for observing long-distance views, accuracies of angle measurements were not sufficient to merge line data because of leverage theory. Thus, by searching corresponding pixels between line spectroscopic images, we are trying to estimate 6-DOF in high accuracy.

  16. Mauna Kea Observatory infrared observations

    NASA Technical Reports Server (NTRS)

    Jefferies, J. T.

    1974-01-01

    Galactic and solar system infrared observations are reported using a broad variety of radiometric and spectroscopic instrumentation. Infrared programs and papers published during this period are listed.

  17. Built-in hyperspectral camera for smartphone in visible, near-infrared and middle-infrared lights region (first report): trial products of beans-size Fourier-spectroscopic line-imager and feasibility experimental results of middle-infrared spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Ishimaru, Ichiro; Kawashima, Natsumi; Hosono, Satsuki

    2016-05-01

    We had already proposed and reported the little-finger size hyperspectral-camera that was able to be applied to visible and infrared lights. The proposed method has been expected to be mounted on smartphones for healthcare sensors, and unmanned air vehicles such as drones for antiterrorism measures or environmental measurements. In this report, we will mention the trial product of the thumb size apparatus whose lens diameter was 5[mm]. The proposed Fourier spectroscopic imager is a kind of wavefront-division and common-path phase-shift interferometers. We installed the relative inclined phase-shifter onto optical Fourier transform plane of infinity corrected optical systems. The infinity corrected optical systems was configured with an objective lens and a cylindrical imaging lens. The relative inclined phase-shifter, what was made from a thin glass less than 0.3[mm] thick, had the wedge-prism and cuboid-glass region, because half surface of a thin glass was polished at an oblique angle of around 1[deg.]. The collimated half flux of objective beams derived from single-bright points on objective surface penetrate through the wedge prism and the cuboid glass respectively. These two beams are interfered each other and form the infererogram as spatial fringe patterns. In this case, the horizontal axis on 2-dimensional light receiving device is assigned to the amount of phase-shift. And also the vertical axis is assigned to the imaging coordinates on a line view field. Thus, by installing thin phase-shifter onto optical Fourier transform plane, the line spectroscopic imager, what obtains 1 dimensional spectral character distributions, were able to be realized.

  18. Assessment of natural radioactivity and function of minerals in soils of Yelagiri hills, Tamilnadu, India by Gamma Ray spectroscopic and Fourier Transform Infrared (FTIR) techniques with statistical approach.

    PubMed

    Chandrasekaran, A; Ravisankar, R; Rajalakshmi, A; Eswaran, P; Vijayagopal, P; Venkatraman, B

    2015-02-01

    Gamma Ray and Fourier Transform Infrared (FTIR) spectroscopic techniques were used to evaluate the natural radioactivity due to natural radionuclides and mineralogical characterization in soils of Yelagiri hills, Tamilnadu, India. Various radiological parameters were calculated to assess the radiation hazards associated with the soil. The distribution pattern of activity due to natural radionuclides is explained by Kriging method of mapping. Using FTIR spectroscopic technique the minerals such as quartz, microcline feldspar, orthoclase feldspar, kaolinite, montmorillonite, illite, and organic carbon were identified and characterized. The extinction coefficient values were calculated to know the relative distribution of major minerals such as quartz, microcline feldspar, orthoclase feldspar and kaolinite. The calculated values indicate that the amount of quartz is higher than orthoclase feldspar, microcline feldspar and much higher than kaolinite. Crystallinity index was calculated to know the crystalline nature of quartz. The result indicates that the presence of disordered crystalline quartz in soils. The relation between minerals and radioactivity was assessed by multivariate statistical analysis (Pearson's correlation and cluster analysis). The statistical analysis confirms that the clay mineral kaolinite and non-clay mineral quartz is the major factor than other major minerals to induce the important radioactivity variables and concentrations of uranium and thorium.

  19. Assessment of natural radioactivity and function of minerals in soils of Yelagiri hills, Tamilnadu, India by Gamma Ray spectroscopic and Fourier Transform Infrared (FTIR) techniques with statistical approach

    NASA Astrophysics Data System (ADS)

    Chandrasekaran, A.; Ravisankar, R.; Rajalakshmi, A.; Eswaran, P.; Vijayagopal, P.; Venkatraman, B.

    2015-02-01

    Gamma Ray and Fourier Transform Infrared (FTIR) spectroscopic techniques were used to evaluate the natural radioactivity due to natural radionuclides and mineralogical characterization in soils of Yelagiri hills, Tamilnadu, India. Various radiological parameters were calculated to assess the radiation hazards associated with the soil. The distribution pattern of activity due to natural radionuclides is explained by Kriging method of mapping. Using FTIR spectroscopic technique the minerals such as quartz, microcline feldspar, orthoclase feldspar, kaolinite, montmorillonite, illite, and organic carbon were identified and characterized. The extinction coefficient values were calculated to know the relative distribution of major minerals such as quartz, microcline feldspar, orthoclase feldspar and kaolinite. The calculated values indicate that the amount of quartz is higher than orthoclase feldspar, microcline feldspar and much higher than kaolinite. Crystallinity index was calculated to know the crystalline nature of quartz. The result indicates that the presence of disordered crystalline quartz in soils. The relation between minerals and radioactivity was assessed by multivariate statistical analysis (Pearson's correlation and cluster analysis). The statistical analysis confirms that the clay mineral kaolinite and non-clay mineral quartz is the major factor than other major minerals to induce the important radioactivity variables and concentrations of uranium and thorium.

  20. Fourier transform infrared spectroscopic characterisation of heavy metal-induced metabolic changes in the plant-associated soil bacterium Azospirillum brasilense Sp7

    NASA Astrophysics Data System (ADS)

    Kamnev, A. A.; Antonyuk, L. P.; Tugarova, A. V.; Tarantilis, P. A.; Polissiou, M. G.; Gardiner, P. H. E.

    2002-06-01

    Structural and compositional features of whole cells of the plant-growth-promoting rhizobacterium Azospirillum brasilense Sp7 under standard and heavy metal-stressed conditions are analysed using Fourier transform infrared (FTIR) spectroscopy and compared with the FT-Raman spectroscopic data obtained previously [J. Mol. Struct. 563-564 (2001) 199]. The structural spectroscopic information is considered together with inductively coupled plasma-mass spectrometric (ICP-MS) analytical data on the content of the heavy metal cations (Co 2+, Cu 2+ and Zn 2+) in the bacterial cells. As a bacterial response to heavy metal stress, all the three metals, being taken up by bacterial cells from the culture medium (0.2 mM) in significant amounts (ca. 0.12, 0.48 and 4.2 mg per gram of dry biomass for Co, Cu and Zn, respectively), are shown to induce essential metabolic changes in the bacterium revealed in the spectra, including the accumulation of polyester compounds in bacterial cells and their enhanced hydration affecting certain IR vibrational modes of functional groups involved.

  1. Reactions of rhodium and ruthenium atoms with nitrous oxide: a combined matrix infrared spectroscopic and theoretical study.

    PubMed

    Jiang, Ling; Xu, Qiang

    2009-05-14

    Reactions of laser-ablated Rh and Ru atoms with N(2)O molecules in excess argon have been investigated using matrix-isolation infrared spectroscopy. Rhodium and ruthenium nitrous oxide complexes, M(NNO)(x) (M = Rh, Ru; x = 1, 2), have been observed and identified on the basis of isotopic shifts, mixed isotopic splitting patterns, and CCl(4)-doping experiments. Density functional theory calculations have been performed on the products. The overall agreement between the experimental and calculated vibrational frequencies, relative absorption intensities, and isotopic shifts supports the identification of these species from the matrix infrared spectra. Furthermore, a plausible reaction mechanism for the formation of the products has been proposed.

  2. Waves of the Future (for Mars): In-Situ Mid-infrared, Near-infrared, and Visible Spectroscopic Analysis of Antarctic Cryptoendolithic Communities.

    NASA Astrophysics Data System (ADS)

    Hand, K. P.; Calrson, R.; Sun, H.; Anderson, M.; Wynn, W.; Levy, R.

    2005-12-01

    We have analyzed both the surface expression and depth profile of cryptoendolithic microbial communities at Battleship Promontory, in the Dry Valleys of Antarctica. Data was collected on site with an active mid-infrared Fourier transform microspectrometer (2.6 - 15 um), a near-infrared spectrometer (0.9-1.8 um), and a visible spectrometer (0.4-1 um). The trio of instruments are connected to microscopes that yield ~1 mm2 spatial resolution on the sample and they are mounted on two perpendicular motorized stages that allow for spatial scanning over an area of ~2cm2. Here we present results on the surface expression of the subsurface microbes in these three spectral regions and we present results on the analysis of a colonized sample examined in cross section. The former case has direct application to the remote, robotic detection of life within the rocks of Mars and the later case provides fundamental insights into the geological and biological interactions that make the Antarctic cryptoendolithic ecosystems possible. Non-invasive surface detection of cyanobacterial dominated communities was possible through the observation of several distinct bands: the carbon-hydrogen stretching modes (symmetric and asymmetric) for CH, CH2, and CH3 in the regions of 3.3-3.6 um and 3.6-3.7 um; the NH2 scissoring and C=O stretch near 6.0 um; the amide I of beta-pleated structures at ~6.1 um; and the 6.4 um - 6.6 um bands of N-H in plane bend of the amide II functional group. In combination, these bands make a strong case for carbohydrates and proteins associated with life. Not surprisingly, as the integrity of the amorphous silica surface varnish improved, our ability to detected the subsurface biosignature decreased. We note, however, that by utilizing the JPL rock crusher in Antarctica, a device designed to fly on the Mars Science Laboratory mission, the mid-infrared biosignature was easily detected. In the cross-section analysis the mid-infrared data provide a depth profile

  3. GTC/OSIRIS SPECTROSCOPIC IDENTIFICATION OF A FAINT L SUBDWARF IN THE UKIRT INFRARED DEEP SKY SURVEY

    SciTech Connect

    Lodieu, N.

    2010-01-10

    We present the discovery of an L subdwarf in 234 deg{sup 2} common to the UK InfraRed Telescope (UKIRT) Infrared Deep Sky Survey Large Area Survey Data Release 2 and the Sloan Digital Sky Survey Data Release 3. This is the fifth L subdwarf announced to date, the first one identified in the UKIRT Infrared Deep Sky Survey, and the faintest known. The blue optical and near-infrared colors of ULAS J135058.86+081506.8 and its overall spectra energy distribution are similar to the known mid-L subdwarfs. Low-resolution optical (700-1000 nm) spectroscopy with the Optical System for Imaging and low Resolution Integrated Spectroscopy spectrograph on the 10.4 m Gran Telescopio de Canarias reveals that ULAS J135058.86+081506.8 exhibits a strong K I pressure-broadened line at 770 nm and a red slope longward of 800 nm, features characteristics of L-type dwarfs. From direct comparison with the four known L subdwarfs, we estimate its spectral type to be sdL4-sdL6 and derive a distance in the interval 94-170 pc. We provide a rough estimate of the space density for mid-L subdwarfs of 1.5 x 10{sup -4} pc{sup -3}.

  4. Infrared spectroscopic investigation of two isomers of the weakly bound complex OCS-(CO2)2.

    PubMed

    Oliaee, J Norooz; Mivehvar, F; Dehghany, M; Moazzen-Ahmadi, N

    2010-12-16

    Vibration-rotation spectra of the OCS-(CO(2))(2) van der Waals complex were studied by means of direct infrared absorption spectroscopy. Complexes were generated in a supersonic slit-jet apparatus, and the expansion gas was probed using a rapid-scan tunable diode laser. Infrared bands were observed for two different isomeric forms of the complex. A relatively strong band centered at 2058.799 cm(-1) was assigned to the most stable isomer, which has a barrel-shaped geometry and is already known from microwave spectroscopy. A weaker infrared band centered at 2050.702 cm(-1) was assigned to a new isomeric form, observed here for the first time, which was expected on the basis of ab initio calculations. Infrared bands for seven isotopomers were recorded in an attempt to quantify the structure of the new isomer. Because it has no symmetry elements, nine parameters are needed to fully define the geometry. It was possible to determine six of these which define the relative position of the OCS monomer with respect to the CO(2) dimer fragment in the complex while the remaining three were fixed at their ab initio values. Similarities and differences between the faces of the two isomers of OCS-(CO(2))(2) and the associated dimers are discussed.

  5. Near-infrared spectroscopic evaluation of single kernel deoxynivalenol accumulation and Fusarium head blight resistance components in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium head blight (FHB) symptoms, single kernel deoxynivalenol (DON) levels, and distribution of DON levels among kernels were investigated in wheat cultivars that had different levels of FHB resistance. DON levels were estimated using near-infrared spectroscopy (NIRS). The percentage of DON-co...

  6. Determination of the Vibrational Constants of Some Diatomic Molecules: A Combined Infrared Spectroscopic and Quantum Chemical Third Year Chemistry Project.

    ERIC Educational Resources Information Center

    Ford, T. A.

    1979-01-01

    In one option for this project, the rotation-vibration infrared spectra of a number of gaseous diatomic molecules were recorded, from which the fundamental vibrational wavenumber, the force constant, the rotation-vibration interaction constant, the equilibrium rotational constant, and the equilibrium internuclear distance were determined.…

  7. Infrared

    NASA Astrophysics Data System (ADS)

    Vollmer, M.

    2013-11-01

    'Infrared' is a very wide field in physics and the natural sciences which has evolved enormously in recent decades. It all started in 1800 with Friedrich Wilhelm Herschel's discovery of infrared (IR) radiation within the spectrum of the Sun. Thereafter a few important milestones towards widespread use of IR were the quantitative description of the laws of blackbody radiation by Max Planck in 1900; the application of quantum mechanics to understand the rotational-vibrational spectra of molecules starting in the first half of the 20th century; and the revolution in source and detector technologies due to micro-technological breakthroughs towards the end of the 20th century. This has led to much high-quality and sophisticated equipment in terms of detectors, sources and instruments in the IR spectral range, with a multitude of different applications in science and technology. This special issue tries to focus on a few aspects of the astonishing variety of different disciplines, techniques and applications concerning the general topic of infrared radiation. Part of the content is based upon an interdisciplinary international conference on the topic held in 2012 in Bad Honnef, Germany. It is hoped that the information provided here may be useful for teaching the general topic of electromagnetic radiation in the IR spectral range in advanced university courses for postgraduate students. In the most general terms, the infrared spectral range is defined to extend from wavelengths of 780 nm (upper range of the VIS spectral range) up to wavelengths of 1 mm (lower end of the microwave range). Various definitions of near, middle and far infrared or thermal infrared, and lately terahertz frequencies, are used, which all fall in this range. These special definitions often depend on the scientific field of research. Unfortunately, many of these fields seem to have developed independently from neighbouring disciplines, although they deal with very similar topics in respect of the

  8. Fast IR laser mapping ellipsometry for the study of functional organic thin films.

    PubMed

    Furchner, Andreas; Sun, Guoguang; Ketelsen, Helge; Rappich, Jörg; Hinrichs, Karsten

    2015-03-21

    Fast infrared mapping with sub-millimeter lateral resolution as well as time-resolved infrared studies of kinetic processes of functional organic thin films require a new generation of infrared ellipsometers. We present a novel laboratory-based infrared (IR) laser mapping ellipsometer, in which a laser is coupled to a variable-angle rotating analyzer ellipsometer. Compared to conventional Fourier-transform infrared (FT-IR) ellipsometers, the IR laser ellipsometer provides ten- to hundredfold shorter measurement times down to 80 ms per measured spot, as well as about tenfold increased lateral resolution of 120 μm, thus enabling mapping of small sample areas with thin-film sensitivity. The ellipsometer, equipped with a HeNe laser emitting at about 2949 cm(-1), was applied for the optical characterization of inhomogeneous poly(3-hexylthiophene) [P3HT] and poly(N-isopropylacrylamide) [PNIPAAm] organic thin films used for opto-electronics and bioapplications. With the constant development of tunable IR laser sources, laser-based infrared ellipsometry is a promising technique for fast in-depth mapping characterization of thin films and blends.

  9. Fast IR laser mapping ellipsometry for the study of functional organic thin films.

    PubMed

    Furchner, Andreas; Sun, Guoguang; Ketelsen, Helge; Rappich, Jörg; Hinrichs, Karsten

    2015-03-21

    Fast infrared mapping with sub-millimeter lateral resolution as well as time-resolved infrared studies of kinetic processes of functional organic thin films require a new generation of infrared ellipsometers. We present a novel laboratory-based infrared (IR) laser mapping ellipsometer, in which a laser is coupled to a variable-angle rotating analyzer ellipsometer. Compared to conventional Fourier-transform infrared (FT-IR) ellipsometers, the IR laser ellipsometer provides ten- to hundredfold shorter measurement times down to 80 ms per measured spot, as well as about tenfold increased lateral resolution of 120 μm, thus enabling mapping of small sample areas with thin-film sensitivity. The ellipsometer, equipped with a HeNe laser emitting at about 2949 cm(-1), was applied for the optical characterization of inhomogeneous poly(3-hexylthiophene) [P3HT] and poly(N-isopropylacrylamide) [PNIPAAm] organic thin films used for opto-electronics and bioapplications. With the constant development of tunable IR laser sources, laser-based infrared ellipsometry is a promising technique for fast in-depth mapping characterization of thin films and blends. PMID:25668189

  10. Comment on "A spectroscopic comparison of selected Chinese kaolinite, coal bearing kaolinite and halloysite--a mid-infrared and near-infrared study" and "Infrared and infrared emission spectroscopic study of typical Chinese kaolinite and halloysite" by Hongfei Cheng et al. (2010).

    PubMed

    Kloprogge, J Theo

    2015-02-01

    In two papers Cheng et al. (2010) reported in this journal on the mid-infrared, near-infrared and infrared emission spectroscopy of a halloysite from Hunan Xianrenwan, China. This halloysite contains around 8% of quartz (SiO2) and nearly 9% gibbsite (Al(OH)3). In their interpretation of the spectra these impurities were completely ignored. Careful comparison with a phase pure halloysite from Southern Belgium, synthetic gibbsite, gibbsite from Minas Gerais, and quartz show that these impurities do have a marked influence on the mid-infrared and infrared emission spectra. In the near-infrared, the effect is much less pronounced. Quartz does not show bands in this region and the gibbsite bands will be very weak. Comparison still show that the presence of gibbsite does contribute to the overall spectrum and bands that were ascribed to the halloysite alone do coincide with those of gibbsite.

  11. Comment on "A spectroscopic comparison of selected Chinese kaolinite, coal bearing kaolinite and halloysite - A mid-infrared and near-infrared study" and "Infrared and infrared emission spectroscopic study of typical Chinese kaolinite and halloysite" by Hongfei Cheng et al. (2010)

    NASA Astrophysics Data System (ADS)

    Kloprogge, J. Theo

    2015-02-01

    In two papers Cheng et al. (2010) reported in this journal on the mid-infrared, near-infrared and infrared emission spectroscopy of a halloysite from Hunan Xianrenwan, China. This halloysite contains around 8% of quartz (SiO2) and nearly 9% gibbsite (Al(OH)3). In their interpretation of the spectra these impurities were completely ignored. Careful comparison with a phase pure halloysite from Southern Belgium, synthetic gibbsite, gibbsite from Minas Gerais, and quartz show that these impurities do have a marked influence on the mid-infrared and infrared emission spectra. In the near-infrared, the effect is much less pronounced. Quartz does not show bands in this region and the gibbsite bands will be very weak. Comparison still show that the presence of gibbsite does contribute to the overall spectrum and bands that were ascribed to the halloysite alone do coincide with those of gibbsite.

  12. A rapid Fourier-transform infrared (FTIR) spectroscopic method for direct quantification of paracetamol content in solid pharmaceutical formulations

    NASA Astrophysics Data System (ADS)

    Mallah, Muhammad Ali; Sherazi, Syed Tufail Hussain; Bhanger, Muhammad Iqbal; Mahesar, Sarfaraz Ahmed; Bajeer, Muhammad Ashraf

    2015-04-01

    A transmission FTIR spectroscopic method was developed for direct, inexpensive and fast quantification of paracetamol content in solid pharmaceutical formulations. In this method paracetamol content is directly analyzed without solvent extraction. KBr pellets were formulated for the acquisition of FTIR spectra in transmission mode. Two chemometric models: simple Beer's law and partial least squares employed over the spectral region of 1800-1000 cm-1 for quantification of paracetamol content had a regression coefficient of (R2) of 0.999. The limits of detection and quantification using FTIR spectroscopy were 0.005 mg g-1 and 0.018 mg g-1, respectively. Study for interference was also done to check effect of the excipients. There was no significant interference from the sample matrix. The results obviously showed the sensitivity of transmission FTIR spectroscopic method for pharmaceutical analysis. This method is green in the sense that it does not require large volumes of hazardous solvents or long run times and avoids prior sample preparation.

  13. Magellan FIRE Spectroscopy of Star-Forming Galaxies at 1.5 < z < 2.3 Selected from the WFC3 Infrared Spectroscopic Parallels (WISP) Survey

    NASA Astrophysics Data System (ADS)

    Masters, Daniel C.; McCarthy, P. J.; Hathi, N. P.; WISP survey Team

    2013-01-01

    We present high-resolution, near-infrared echelle spectra of strongly star-forming emission line galaxies at 1.5 < z < 2.3 taken with FIRE on Magellan. The sample was selected from the WFC3 Infrared Spectroscopic Parallels (WISP) survey, using the slitless grism capability of the WFC3 to identify galaxies with strong emission lines in an unbiased way. We are able to identify low-mass, high sSFR galaxies at these redshifts, which are likely analogues to galaxies in the early stages of formation at much higher redshifts. FIRE follow-up observations provide high-resolution rest-frame optical spectra, allowing us to identify possible AGN activity in the sample, estimate metallicity, and investigate the gas-phase dynamics of the galaxies. By obtaining high-resolution near-IR spectra of a statistically significant number of these galaxies we can begin to understand the population in detail and probe the low-mass end of the mass-metallicity relationship at 2.

  14. Chemical Synthesis and High Resolution Spectroscopic Characterization of 1-AZA-ADAMANTANE-4-ONE C_9H13NO from the Microwave to the Infrared

    NASA Astrophysics Data System (ADS)

    Pirali, Olivier; Goubet, Manuel; Boudon, Vincent; D'accolti, Lucia; Annese, Cosimo; Fusco, Caterina

    2016-06-01

    We have synthesized 1-aza-adamantane-4-one (C_9H13NO) starting from commercial 1,4-cyclohexanedionemonoethylene acetal and tosylmethylisocianide and following a procedure described in details in the literature. The high degree of sample purity was demonstrated by gas chromatography and mass spectrometric measurements, and its structure evidenced by 1H and 13C NMR spectroscopy. We present a thorough spectroscopic characterization of this molecule by gas phase vibrational and rotational spectroscopy. Accurate vibrational frequencies have been determined by infrared and far-infrared spectra. The pure rotational spectrum of the molecule has been recorded both by cavity-based Fourier-transform microwave spectroscopy in the 2-20 GHz region, by supersonically expanding the vapor pressure of the warm sample, and by room-temperature absorption spectroscopy in the 140-220 GHz range. Quantum-chemical calculations have enabled a fast analysis of the spectra. Accurate sets of rotational and centrifugal distorsion parameters of 1-aza-adamantane-4-one in its ground state and five vibrationally excited states have been derived from these measurements. Black, R. M. Synthesis, 1981, 829

  15. In situ ellipsometry of Cu surfaces immersed in benzotriazole-hydrogen peroxide solutions

    NASA Astrophysics Data System (ADS)

    Kondoh, Eiichi; Kawakami, Tatsuya; Watanabe, Mitsuhiro; Jin, Lianhua; Hamada, Satomi; Shima, Shohei; Hiyama, Hirokuni

    2016-06-01

    In the chemical mechanical polishing (CMP) of Cu, the Cu surface is oxidized and is concurrently removed by the mechanical function of an abrasive. Surface oxidation can lead to severe surface corrosion, and to prevent this, a corrosion inhibitor is added to slurries. Accurate understanding of the competition between oxidation and passivation is essential for advanced Cu CMP technologies. In this work, layer formation on clean Cu surfaces in benzotriazole (BTA), H2O2, and BTA-H2O2 aqueous solutions was studied by in situ spectroscopic ellipsometry. Time changes of ellipsometric parameters are discussed with respect to BTA and H2O2 concentrations. It was found that the BTA adsorbs onto the Cu surface and the adsorbed BTA transforms into a Cu-BTA complex in about 3 min after the onset of adsorption. The BTA/complex layer passivates the Cu surface against oxidation by H2O2.

  16. Infrared

    NASA Astrophysics Data System (ADS)

    Vollmer, M.

    2013-11-01

    'Infrared' is a very wide field in physics and the natural sciences which has evolved enormously in recent decades. It all started in 1800 with Friedrich Wilhelm Herschel's discovery of infrared (IR) radiation within the spectrum of the Sun. Thereafter a few important milestones towards widespread use of IR were the quantitative description of the laws of blackbody radiation by Max Planck in 1900; the application of quantum mechanics to understand the rotational-vibrational spectra of molecules starting in the first half of the 20th century; and the revolution in source and detector technologies due to micro-technological breakthroughs towards the end of the 20th century. This has led to much high-quality and sophisticated equipment in terms of detectors, sources and instruments in the IR spectral range, with a multitude of different applications in science and technology. This special issue tries to focus on a few aspects of the astonishing variety of different disciplines, techniques and applications concerning the general topic of infrared radiation. Part of the content is based upon an interdisciplinary international conference on the topic held in 2012 in Bad Honnef, Germany. It is hoped that the information provided here may be useful for teaching the general topic of electromagnetic radiation in the IR spectral range in advanced university courses for postgraduate students. In the most general terms, the infrared spectral range is defined to extend from wavelengths of 780 nm (upper range of the VIS spectral range) up to wavelengths of 1 mm (lower end of the microwave range). Various definitions of near, middle and far infrared or thermal infrared, and lately terahertz frequencies, are used, which all fall in this range. These special definitions often depend on the scientific field of research. Unfortunately, many of these fields seem to have developed independently from neighbouring disciplines, although they deal with very similar topics in respect of the

  17. Matrix infrared spectroscopic and theoretical studies on the reactions of late lanthanoid atoms with nitrous oxide in excess argon.

    PubMed

    Jiang, Ling; Xu, Qiang

    2009-04-01

    Reactions of laser-ablated late lanthanoid atoms (Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) with N(2)O molecules in excess argon have been investigated using matrix-isolation infrared spectroscopy. Lanthanoid monoxide-dinitrogen complexes, OLn(N(2)) and OLnNN, are observed for Gd, Tb, Ho, and Er, and the OLnNN(+) cations are observed for Gd to Lu except for Yb. The new products are characterized on the basis of isotopic shifts, mixed isotopic splitting patterns, and CCl(4)-doping experiments. Density functional theory calculations have been performed on the new species, which support identification of the OLn(N(2)), OLnNN, and OLnNN(+) complexes from the matrix infrared spectra. Together with our earlier work involving early lanthanoid atoms, several trends are identified for the reactions of lanthanoid atoms with N(2)O molecules.

  18. Infrared Spectroscopic Investigation of the Acidic CH Bonds in Cationic n-Alkanes: Pentane, Hexane, and Heptane.

    PubMed

    Xie, Min; Matsuda, Yoshiyuki; Fujii, Asuka

    2016-08-18

    Radical cations of n-alkanes (pentane, hexane, and heptane) in the gas phase are investigated by infrared predissociation spectroscopy with the argon or nitrogen tagging. All-trans and gauche-involving conformers are identified for these cations by comparisons of observed infrared spectra and vibrational simulations. Intense CH stretch bands are observed in the frequency region lower than the normal alkyl CH stretch frequency. These low frequencies and high intensities of the CH stretch bands are caused by the CH bond weakening and the enhanced positive charge of the hydrogen atoms through the delocalization of the σ electron in the CH bonds. These effects of the delocalization of the σ electron result in the enhanced acidity of the CH bonds. The conformation as well as alkyl chain length dependence of the acidity of the CH bonds is demonstrated by the CH stretch frequency shift trend. PMID:27467194

  19. Infrared and Raman spectroscopic characterization of the carbonate bearing silicate mineral aerinite - Implications for the molecular structure

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; Scholz, Ricardo; López, Andrés

    2015-10-01

    The mineral aerinite is an interesting mineral because it contains both silicate and carbonate units which is unusual. It is also a highly colored mineral being bright blue/purple. We have studied aerinite using a combination of techniques which included scanning electron microscopy, energy dispersive X-ray analysis, Raman and infrared spectroscopy. Raman bands at 1049 and 1072 cm-1 are assigned to the carbonate symmetric stretching mode. This observation supports the concept of the non-equivalence of the carbonate units in the structure of aerinite. Multiple infrared bands at 1354, 1390 and 1450 cm-1 supports this concept. Raman bands at 933 and 974 cm-1 are assigned to silicon-oxygen stretching vibrations. Multiple hydroxyl stretching and bending vibrations show that water is in different molecular environments in the aerinite structure.

  20. Evaluation of spectroscopic properties of Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal for use in mid-infrared lasers

    NASA Astrophysics Data System (ADS)

    Xia, Houping; Feng, Jianghe; Wang, Yan; Li, Jianfu; Jia, Zhitai; Tu, Chaoyang

    2015-09-01

    Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal was firstly grown by Czochralski method. Detailed spectroscopic analyses of Er3+/Yb3+/Pr3+: SrGdGa3O7 were carried out. Besides better absorption characteristic, the spectra of Er3+/Yb3+/Pr3+: SrGdGa3O7 show weaker up-conversion and near-infrared emissions as well as superior mid-infrared emission in comparison to Er3+: SrGdGa3O7 and Er3+/Yb3+: SrGdGa3O7 crystals. Furthermore, the self-termination effect for Er3+ 2.7 μm laser is suppressed successfully because the fluorescence lifetime of the 4I13/2 lower level of Er3+ decreases markedly while that of the upper 4I11/2 level changes slightly in Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal. The sensitization effect of Yb3+ and deactivation effect of Pr3+ ions as well as the energy transfer mechanism in Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal were also studied in this work. The introduction of Yb3+ and Pr3+ is favorable for achieving an enhanced 2.7 μm emission in Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal which can act as a promising candidate for mid-infrared lasers.

  1. Evaluation of spectroscopic properties of Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal for use in mid-infrared lasers

    PubMed Central

    Xia, Houping; Feng, Jianghe; Wang, Yan; Li, Jianfu; Jia, Zhitai; Tu, Chaoyang

    2015-01-01

    Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal was firstly grown by Czochralski method. Detailed spectroscopic analyses of Er3+/Yb3+/Pr3+: SrGdGa3O7 were carried out. Besides better absorption characteristic, the spectra of Er3+/Yb3+/Pr3+: SrGdGa3O7 show weaker up-conversion and near-infrared emissions as well as superior mid-infrared emission in comparison to Er3+: SrGdGa3O7 and Er3+/Yb3+: SrGdGa3O7 crystals. Furthermore, the self-termination effect for Er3+ 2.7 μm laser is suppressed successfully because the fluorescence lifetime of the 4I13/2 lower level of Er3+ decreases markedly while that of the upper 4I11/2 level changes slightly in Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal. The sensitization effect of Yb3+ and deactivation effect of Pr3+ ions as well as the energy transfer mechanism in Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal were also studied in this work. The introduction of Yb3+ and Pr3+ is favorable for achieving an enhanced 2.7 μm emission in Er3+/Yb3+/Pr3+: SrGdGa3O7 crystal which can act as a promising candidate for mid-infrared lasers. PMID:26369289

  2. On-line preferential solvation studies of polymers by coupled chromatographic-Fourier transform infrared spectroscopic flow-cell technique.

    PubMed

    Malanin, M; Eichhorn, K-J; Lederer, A; Treppe, P; Adam, G; Fischer, D; Voigt, D

    2009-12-18

    Qualitative and quantitative comparison between liquid chromatography (LC) and LC coupled with Fourier transform infrared spectroscopy (LC-FTIR) to evaluate preferential solvation phenomenon of polymers in a mixed solvent has been performed. These studies show that LC-FTIR technique leads to detailed structural information without the requirement for determination of additional parameters for quantitative analysis except calibration. Appropriate experimental conditions for preferential solvation study have been established by variation of polymer concentration, molar mass and eluent content.

  3. State of Water Molecules and Silanol Groups in Opal Minerals: a Near Infrared Spectroscopic Study of Opals from Slovakia

    NASA Astrophysics Data System (ADS)

    Bobon, Miroslav; Christy, Alfred A.; Kluvanec, Daniel; Illasova, L'udmila

    2011-06-01

    Recently near infrared spectroscopy in combination with double derivative technique has been effectively used by Christy [1] to differentiate between free silanol groups and hydrogen bonded silanol groups on silica gel. The method has given some insight into the type of functionalities and their location in silica gel samples. The inportant information in this respect comes from the overtones of the OH groups of water molecules hydrogen bonded to free silanol groups, and hydrogen bonded silanol groups absorbing in the region 5500- 5100 Cm-1 region. The approach was adapted to study the state of water and silanol functionalities and their locations in opals from Slovakia. Twenty opal samples classified into CT and A classes and one quartz sample were used in this work. The samples were crushed using a hydrolic press and powderised. Each sample was then subjected to evacuation process to remove surface adsorbed water at 200°C and the near infrared spectrum of the sample was measured using a Perkin Elmer NTS near infrared spectrometer equipped with a transflectance accessory. The detailed analysis of the sample was carried out using the second derivative profile of the spectrum. The samples were also heated to 750°C to study the state of water molecules in Opal minerals. The results indicate that the opal samples contain 1) surface adsorbed water 2) free and hydrogen bonded silanol groups on the surface 3) Trapped water in the bulk 4) free and hydrogen bonded silanol groups in the cavity surfaces in the bulk. A part of the water molecules found in the bulk of opal minerals are free molecules and the rest are found in hydrogen bonded state to free and hydrogen bonded silanol groups. [1] A. A. Christy, New insights into the surface functionalities and adsorption evolution of water molecules on silica gel surface: A study by second derivative Near Infrared Spectroscopy, Vib. Spectrosc. 54 (2010) 42-49.

  4. Determining Concentration of Nanoparticles from Ellipsometry

    NASA Technical Reports Server (NTRS)

    Venkatasubbarao, Srivatsa; Kempen, Lothar U.; Chipman, Russell

    2008-01-01

    A method of using ellipsometry or polarization analysis of light in total internal reflection of a surface to determine the number density of gold nanoparticles on a smooth substrate has been developed. The method can be modified to enable determination of densities of sparse distributions of nanoparticles in general, and is expected to be especially useful for measuring gold-nanoparticle-labeled biomolecules on microarrays. The method is based on theoretical calculations of the ellipsometric responses of gold nanoparticles. Elements of the calculations include the following: For simplicity, the gold nanoparticles are assumed to be spherical and to have the same radius. The distribution of gold nanoparticles is assumed to be a sub-monolayer (that is, sparser than a monolayer). The optical response of the sub-monolayer is modeled by use of a thin-island-film theory, according to which the polarizabilities parallel and perpendicular to the substrate are functions of the wavelength of light, the dielectric functions (permittivities expressed as complex functions of frequency or wavelength) of the gold and the suspending medium (in this case, the suspending medium is air), the fraction of the substrate area covered by the nanoparticles, and the radius of the nanoparticles. For the purpose of the thin-island-film theory, the dielectric function of the gold nanoparticles is modeled as the known dielectric function of bulk gold plus a correction term that is necessitated by the fact that the mean free path length for electrons in gold decreases with decreasing radius, in such a manner as to cause the imaginary part of the dielectric function to increase with decreasing radius (see figure). The correction term is a function of the nanoparticle radius, the wavelength of light, the mean free path and the Fermi speed of electrons in bulk gold, the plasma frequency of gold, and the speed of light in a vacuum. These models are used to calculate ellipsometric responses for

  5. Diffraction Ellipsometry Studies on Insect Flight Muscle

    NASA Astrophysics Data System (ADS)

    Shen, Sui

    Characterization of the orientation and distribution of myosin cross-bridge at rigor, relax, low ionic strength (36 mM) and activation (pCa 4.3) conditions are of great interest since these states have been proposed to be transient steps in the cyclical interaction of myosin heads with actin during contraction. Measurements sensitive to the cross-bridge orientation in chemically skinned single muscle fibers of the insect, Lethocerus collossicus have been performed under various physiological conditions using laser diffraction ellipsometry. Determination of both the total birefringence, Deltan, and the differential field ratio, rm DFR (defined as {E_parallel -E_|over E_parallel-E _|}),is necessary for complete characterization of the optical polarization state. For rigor insect fiber, the birefringence value was close to the value we obtained from chemically skinned frog muscle fibers. However, the differential field ratio, DFR, was a negative value for insect fiber, while we always measured a positive value from frog muscle fibers. Polarization states of light diffracted from fibers exhibited a dependence on configurations of structural proteins at different conditions: fluid index matching using o-toluidine, alpha -chymotrypsin cleavage, KCl myosin extraction, rigor state, relaxed state, exogenous S-1 binding on rigor fiber, low ionic strength state, activation state at resting or stretched length. Results of our data analysis suggested that: (1) the negative DFR value of the insect flight muscle was contributed by alpha-actinin arranged perpendicular to the fiber axis in the Z-line, (2) in rigor fiber, 70% of myosin heads are doubly bound (45^circ and 90^ circ) while the rest of 30% are in single head binding configuration (90^circ), (3) myosin heads are randomly oriented in relaxed fiber, (4) mean axial angle is about 62^ circ for exogenous myosin heads binding on rigor fiber, (5) at low ionic strength, 25% of the total myosin heads are weakly attached to actin

  6. An infrared and inelastic neutron scattering spectroscopic investigation on the interaction of eta-alumina and methanol.

    PubMed

    McInroy, Alastair R; Lundie, David T; Winfield, John M; Dudman, Chris C; Jones, Peter; Parker, Stewart F; Taylor, Jon W; Lennon, D

    2005-08-21

    The industrially important interaction of methanol with an eta-alumina catalyst has been investigated by a combination of infrared spectroscopy (diffuse reflectance and transmission) and inelastic neutron scattering (INS) spectroscopy. The infrared and INS spectra together show that chemisorbed methoxy is the only surface species present. Confirmation of the assignments was provided by a periodic DFT calculation of methoxy on eta-alumina (110). The thermal conversion of adsorbed methoxy groups to form dimethylether was also followed by INS, with DFT calculations assisting assignments. An intense feature about 2600 cm(-1) was observed in the diffuse reflectance spectrum. This band is poorly described in the extensive literature on the alumina/methanol adsorption system and its observation raised the possibility of a new surface species existing on this particular catalyst surface. INS measurements established that the 2600 cm(-1) feature could be assigned to a combination band of the methyl rock with the methyl deformation modes. This assignment was reinforced by an analysis of the neutron scattering intensity at a particular energy as a function of momentum transfer, which confirmed this particular adsorbed methoxy feature to arise from a second order transition. Similar behaviour was observed in the model compound Al(OCH3)3. The anomalous infrared intensity of the 2600 cm(-1) peak in the diffuse reflectance spectrum is a consequence of the different absorption coefficients of the C-H stretch and the combination mode. The implications for catalyst studies are discussed.

  7. On the structure of erythritol and L-threitol in the solid state: An infrared spectroscopic study

    NASA Astrophysics Data System (ADS)

    Jesus, A. J. Lopes; Redinha, J. S.

    2009-12-01

    FTIR spectra of crystalline erythritol and L-threitol were recorded between 4000 and 400 cm -1, at temperatures ranging from 298 K to 15 K. The most important bands were assigned by comparing the experimental and theoretical spectra. The latter were obtained from optimizations that started with the original crystal coordinates taken from the X-ray and neutron diffraction data, using the B3LYP/6-311++G(d, p) model chemistry. Spectra of the deuterated solids at 15 K were also used to help with the spectral assignments, particularly in the OH stretching region. The hydrogen bonding network of both isomers was the object of particular attention in the optimized conformations as well as in the crystalline solids. The possible existence of intramolecular hydrogen bonds in the optimized structures was checked by Atoms-In-Molecules (AIM) and Natural Bond Orbital (NBO) theories. A correlation between the spectroscopic results and the diffraction data was obtained.

  8. Mid-infrared spectroscopic characterisation of an ultra-broadband tunable EC-QCL system intended for biomedical applications

    NASA Astrophysics Data System (ADS)

    Vahlsing, T.; Moser, H.; Grafen, M.; Nalpantidis, K.; Brandstetter, M.; Heise, H. M.; Lendl, B.; Leonhardt, S.; Ihrig, D.; Ostendorf, A.

    2015-07-01

    Mid-infrared spectroscopy has been successfully applied for reagent-free clinical chemistry applications. Our aim is to design a portable bed-side system for ICU patient monitoring, based on mid-infrared absorption spectra of continuously sampled body-fluids. Robust and miniature bed-side systems can be achieved with tunable external cavity quantum cascade lasers (EC-QCL). Previously, single EC-QCL modules covering a wavenumber interval up to 250 cm-1 have been utilized. However, for broader applicability in biomedical research an extended interval around the mid-infrared fingerprint region should be accessible, which is possible with at least three or four EC-QCL modules. For such purpose, a tunable ultra-broadband system (1920 - 780 cm-1, Block Engineering) has been studied with regard to its transient emission characteristics in ns time resolution during different laser pulse widths using a VERTEX 80v FTIR spectrometer with step-scan option. Furthermore, laser emission line profiles of all four incorporated EC-QCL modules have been analysed at high spectral resolution (0.08 cm-1) and beam profiles with few deviations from the TEM 00 spatial mode have been manifested. Emission line reproducibility has been tested for various wavenumbers in step tune mode. The overall accuracy of manufacturer default wavenumber setting has been found between ± 3 cm-1 compared to the FTIR spectrometer scale. With regard to an application in clinical chemistry, theoretically achievable concentration accuracies for different blood substrates based on blood plasma and dialysate spectra previously recorded by FTIRspectrometers have been estimated taking into account the now accessible extended wavenumber interval.

  9. First High-Resolution Infrared Spectroscopic Measurements of Comet 2P/Encke: Unusual Organic Composition and Low Rotational Temperatures

    NASA Astrophysics Data System (ADS)

    Radeva, Yana L.; Mumma, M. J.; Villanueva, G. L.; Bonev, B. P.; DiSanti, M. A.; A'Hearn, M. F.; Dello Russo, N.

    2012-10-01

    We present the first high-resolution infrared spectra of the ecliptic comet 2P/Encke, acquired on UT 4 - 6 Nov. 2003, with the Near Infrared Echelle Spectrograph (NIRSPEC) on the Keck II telescope. 2P/Encke is a dynamical end-member among comets. Its very short period of 3.3 years (with perihelion at 0.34 AU and aphelion at 4.09 AU) exposes the nucleus to unusually high insolation throughout its orbit, raising the prospect that native ices may have experienced significant fractionation over time. Here, we present flux-calibrated spectra, production rates, and mixing ratios for H2O, CH3OH, HCN, H2CO, C2H2, C2H6, CH4 and CO, and compare the abundance ratios with the “organics-normal” population. We also extracted very low rotational temperatures (20 - 30 K) for H2O, HCN, and CH3OH in the near-nucleus coma, which correlate with one of the lowest cometary gas production rates ( 1027 molecules s-1) measured thus far in the infrared. We determined that 2P/Encke is enriched in CH3OH, but depleted in C2H6, C2H2, HCN, CH4, H2CO and CO. We compared mixing ratios of these organic species measured on separate dates, and found no evidence of macroscopic chemical heterogeneity in this cometary nucleus, however, we are limited by sparse temporal sampling of our observations. The depleted abundances of most measured species but retention of the high temperature volatiles (H2O, CH3OH) are consistent with fractionation of 2P/Encke’s native ices by thermal processing while in its current orbit. 2P/Encke is unique in terms of its short period, unusual organic composition, low rotational temperatures and low production rates. The discovery of its unusual organic composition is an important contribution to the emerging chemical taxonomy of comets.

  10. State of water molecules and silanol groups in opal minerals: a near infrared spectroscopic study of opals from Slovakia

    NASA Astrophysics Data System (ADS)

    Boboň, Miroslav; Christy, Alfred A.; Kluvanec, Daniel; Illášová, L'udmila

    2011-12-01

    Recently, near infrared spectroscopy in combination with double derivative technique has been effectively used by Christy (Vib Spectrosc 54:42-49, 2010) to study and differentiate between free and hydrogen bonded silanol groups on silica gel surface. The method has given some insight into the type of functionalities, their location in silica gel samples, and the way the water molecules bind onto the silanol groups. The important information in this respect comes from the overtones of the OH groups of water molecules hydrogen-bonded to free silanol groups, and hydrogen-bonded silanol groups absorbing in the region 5,500-5,100 cm-1. Chemically, opal minerals are hydrated silica and the same approach was adapted to study the state of water molecules, silanol functionalities, and their locations in opal samples from Slovakia. Twenty opal samples classified into CT and A classes and one quartz sample were used in this work. The samples were crushed using a hydraulic press and powderized. Each sample was then subjected to evacuation process to remove surface-adsorbed water at 200°C, and the near infrared spectrum of each sample was measured using a Perkin Elmer NTS FT-NIR spectrometer equipped with a transflectance accessory and a DTGS detector. The samples were also heated to 750°C to remove the hydrogen-bonded silanol groups on the surface to reveal their locality. Second derivative profiles of the near infrared reflectance spectra were obtained using the instrument's software and used in the detailed analysis of the samples. The analysis of the near infrared spectra and their second derivative profiles had the aim in finding relationships between the surface chemical structure and the classification of opal samples. The dry opal samples were also tested for their surface adsorption effectivity toward water molecules. The results indicate that the opal samples contain (1) surface-adsorbed water, (2) free and hydrogen-bonded silanol groups on the surface, (3) trapped

  11. Co-treatment of fruit and vegetable waste in sludge digesters: Chemical and spectroscopic investigation by fluorescence and Fourier transform infrared spectroscopy.

    PubMed

    Provenzano, Maria Rosaria; Cavallo, Ornella; Malerba, Anna Daniela; Di Maria, Francesco; Cucina, Mirko; Massaccesi, Luisa; Gigliotti, Giovanni

    2016-04-01

    In a previous work co-digestion of food waste and sewage sludge was performed in a pilot apparatus reproducing operating conditions of an existing full scale digester and processing waste mixed sludge (WMS) and fruit and vegetable waste (FVW) at different organic loading rates. An analysis of the relationship among bio-methane generation, process stability and digestate phytotoxicity was conducted. In this paper we considered humification parameters and spectroscopic analysis. Humification parameters indicated a higher not humified fraction (NH) and a lower degree of humification (DH) of FVW with respect to WMS (NH=19.22 and 5.10%; DH=36.65 and 61.94% for FVW and WMS, respectively) associated with their different chemical compositions and with the stabilization process previously undergone by sludge. FVW additions seemed to be favourable from an agronomical point of view since a lower percentage of organic carbon was lost. Fourier transform infrared spectra suggested consumption of aliphatics associated with rising in bio-methane generation followed by accumulation of aliphatics and carboxylic acids when the biogas production dropped. The trend of peaks ratios can be used as an indicator of the process efficiency. Fluorescence intensity of peak B associated with tryptophan-like substances and peak D associated with humic-like substances observed on tridimensional Excitation Emission Matrix maps increased up to sample corresponding to the highest rate of biogas production. Overall spectroscopic results provided evidence of different chemical pathways of anaerobic digestion associated with increasing amount of FVW which led to different levels of biogas production.

  12. A mid-infrared spectroscopic atlas of local active galactic nuclei on sub-arcsecond resolution using GTC/CanariCam

    NASA Astrophysics Data System (ADS)

    Alonso-Herrero, A.; Esquej, P.; Roche, P. F.; Ramos Almeida, C.; González-Martín, O.; Packham, C.; Levenson, N. A.; Mason, R. E.; Hernán-Caballero, A.; Pereira-Santaella, M.; Alvarez, C.; Aretxaga, I.; López-Rodríguez, E.; Colina, L.; Díaz-Santos, T.; Imanishi, M.; Rodríguez Espinosa, J. M.; Perlman, E.

    2016-01-01

    We present an atlas of mid-infrared (mid-IR) ˜ 7.5-13 μm spectra of 45 local active galactic nuclei (AGN) obtained with CanariCam on the 10.4 m Gran Telescopio CANARIAS (GTC) as part of an ESO/GTC large programme. The sample includes Seyferts and other low-luminosity AGN (LLAGN) at a median distance of 35 Mpc and luminous AGN, namely PG quasars, (U)LIRGs, and radio galaxies (RG) at a median distance of 254 Mpc. To date, this is the largest mid-IR spectroscopic catalogue of local AGN at sub-arcsecond resolution (median 0.3 arcsec). The goal of this work is to give an overview of the spectroscopic properties of the sample. The nuclear 12 μm luminosities of the AGN span more than four orders of magnitude, νL12 μm ˜ 3 × 1041-1046 erg s-1. In a simple mid-IR spectral index versus strength of the 9.7 μm silicate feature diagram most LLAGN, Seyfert nuclei, PG quasars, and RGs lie in the region occupied by clumpy torus model tracks. However, the mid-IR spectra of some might include contributions from other mechanisms. Most (U)LIRG nuclei in our sample have deeper silicate features and flatter spectral indices than predicted by these models suggesting deeply embedded dust heating sources and/or contribution from star formation. The 11.3 μm polycyclic aromatic hydrocarbon (PAH) feature is clearly detected in approximately half of the Seyfert nuclei, LLAGN, and (U)LIRGs. While the RG, PG quasars, and (U)LIRGs in our sample have similar nuclear νL12 μm, we do not detect nuclear PAH emission in the RGs and PG quasars.

  13. Reactions of gold atoms with nitrous oxide in excess argon: a matrix infrared spectroscopic and theoretical study.

    PubMed

    Jiang, Ling; Kohyama, Masanori; Haruta, Masatake; Xu, Qiang

    2008-12-25

    Reactions of laser-ablated Au atoms with N(2)O molecules in excess argon have been investigated using matrix-isolation infrared spectroscopy and density functional theory calculation. On the basis of isotopic shifts, mixed isotopic splitting patterns, CCl(4)-doping experiments, and the comparison with theoretical calculations, the absorption at 2047.5 cm(-1) is assigned to the OAuNN(-) anion, and the absorption at 1512.3 cm(-1) is assigned to the AuNO(-) anion, respectively. No evidence is found for the formation of new neutral and cationic products in the present experiments. It is predicted that the OAuNN(-) anion is a linear singlet molecule and the AuNO(-) anion is a bent doublet molecule. The agreement between the experimental and calculated vibrational frequencies, relative absorption intensities, and isotopic shifts supports the identifications of these species from the matrix infrared spectra. Plausible reaction pathways have also been discussed for the formation of these products.

  14. Time-resolved and spatially-resolved infrared spectroscopic observation of seeded nucleation controlling geopolymer gel formation.

    PubMed

    Hajimohammadi, Ailar; Provis, John L; van Deventer, Jannie S J

    2011-05-15

    The effect of seeded nucleation on the formation and structural evolution of one-part ("just add water") geopolymer gels is investigated. Gel-forming systems are seeded with each of three different oxide nanoparticles, and seeding is shown to have an important role in controlling the silica release rate from the solid geothermal silica precursor, and in the development of physical properties of the gels. Nucleation accelerates the chemical changes taking place during geopolymer formation. The nature of the seeds affects the structure of the growing gel by affecting the extent of phase separation, identified by the presence of a distinct silica-rich gel in addition to the main, more alumina-rich gel phase. Synchrotron radiation-based infrared microscopy (SR-FTIR) shows the effect of nucleation on the heterogeneous nanostructure and microstructure of geopolymer gels, and is combined with data obtained by time-resolved FTIR analysis to provide a more holistic view of the reaction processes at a level of detail that has not previously been available. While spatially averaged (ATR-FTIR) infrared results show similar spectra for seeded and unseeded samples which have been cured for more than 3 weeks, SR-FTIR results show marked differences in gel structure as a result of seeding.

  15. Cesium and cobalt adsorption on synthetic nano manganese oxide: A two dimensional infra-red correlation spectroscopic investigation

    NASA Astrophysics Data System (ADS)

    Al Lafi, Abdul G.; Al Abdullah, Jamal

    2015-08-01

    Molecular scale information is of prime importance to understand ions coordination to mineral surfaces and consequently to aid in the design of improved ion exchange materials. This paper reports on the use of two-dimensional correlation infra-red spectroscopy (2D-COS-IR) to investigate the time dependent adsorptions of cesium and cobalt ions onto nano manganese oxide (NMO). The metal ions uptake was driven mainly by inner-sphere complex formation as demonstrated by the production of new absorption bands at 1160, 1100, 585 and 525 cm-1, which were assigned to the O-O bond vibration and the coupled vibrations of M-O and Mn-O bonds. The progressive development of the 3100 cm-1 band, which is attributed to the stretching vibration of the lattice-OH group, indicates an M+/H+ ion-exchange reaction. The new bands at 700 and 755 cm-1 in the case of cobalt ion adsorption and at 800 and 810 cm-1 in the case of cesium ion adsorption, and the splitting of other bands at 1135 and 875 cm-1 indicate the presence of different O-O bond lengths. This suggests different coordination of the two metal ions with oxygen. The infrared spectroscopy combined with 2D-COS provides a powerful tool to investigate the mechanism of interaction between heavy metals and manganese oxide.

  16. Matrix infrared spectroscopic and computational studies on the reactions of osmium and iron atoms with carbon monoxide and dinitrogen mixtures.

    PubMed

    Lu, Zhang-Hui; Xu, Qiang

    2011-10-01

    Reactions of laser-ablated osmium and iron atoms with CO and N(2) mixtures in excess neon have been investigated using matrix isolation infrared spectroscopy. The (NN)(x)MCO (M = Os, Fe; x = 1, 2) complexes are formed as reaction products during sample deposition and on annealing. These reaction products are characterized on the basis of the results of isotopic substitution, mixed isotopic splitting patterns, stepwise annealing, broad-band irradiation, and change of reagent concentration and laser energy. Density functional theory calculations have been performed on these products. Overall agreement between the experimental and calculated results supports the identification of these species from the matrix infrared spectra. The bonding characteristics and reaction mechanisms have been discussed. The M-C bonds are stronger than the M-N bonds in the same molecules. The formation of metal carbonyl dinitrogen complexes from the addition of CO to metal dinitrogen complexes is found to be more energetically favorable than that from the reactions of N(2) with metal carbonyls.

  17. Raman and infrared spectroscopic characterization of beryllonite, a sodium and beryllium phosphate mineral - implications for mineral collectors.

    PubMed

    Frost, Ray L; Xi, Yunfei; Scholz, Ricardo; Belotti, Fernanda M; Alberto Dias Menezes Filho, Luiz

    2012-11-01

    The mineral beryllonite has been characterized by the combination of Raman spectroscopy and infrared spectroscopy. SEM-EDX was used for the chemical analysis of the mineral. The intense sharp Raman band at 1011 cm(-1), was assigned to the phosphate symmetric stretching mode. Raman bands at 1046, 1053, 1068 and the low intensity bands at 1147, 1160 and 1175 cm(-1) are attributed to the phosphate antisymmetric stretching vibrations. The number of bands in the antisymmetric stretching region supports the concept of symmetry reduction of the phosphate anion in the beryllonite structure. This concept is supported by the number of bands found in the out-of-plane bending region. Multiple bands are also found in the in-plane bending region with Raman bands at 399, 418, 431 and 466 cm(-1). Strong Raman bands at 304 and 354 cm(-1) are attributed to metal oxygen vibrations. Vibrational spectroscopy served to determine the molecular structure of the mineral. The pegmatitic phosphate minerals such as beryllonite are more readily studied by Raman spectroscopy than infrared spectroscopy.

  18. AKARI NEAR-INFRARED SPECTROSCOPIC OBSERVATIONS OF INTERSTELLAR ICES IN THE EDGE-ON STARBURST GALAXY NGC 253

    SciTech Connect

    Yamagishi, Mitsuyoshi; Kaneda, Hidehiro; Ishihara, Daisuke; Oyabu, Shinki; Onaka, Takashi; Shimonishi, Takashi; Suzuki, Toyoaki

    2011-04-10

    We present the spatially resolved near-infrared (2.5-5.0 {mu}m) spectra of the edge-on starburst galaxy NGC 253 obtained with the Infrared Camera on board AKARI. Near the center of the galaxy, we clearly detect the absorption features of interstellar ices (H{sub 2}O: 3.05 {mu}m, CO{sub 2}: 4.27 {mu}m, and XCN: 4.62 {mu}m) and the emission of polycyclic aromatic hydrocarbons (PAHs) at 3.29 {mu}m and the hydrogen recombination line Br{alpha} at 4.05 {mu}m. We find that the distributions of the ices differ from those of the PAH and gas. We calculate the column densities of the ices and derive the abundance ratios of N(CO{sub 2})/N(H{sub 2}O) = 0.17 {+-} 0.05. They are similar to those obtained around the massive young stellar objects in our Galaxy (0.17 {+-} 0.03), although a much stronger interstellar radiation field and higher dust temperature are expected near the center of NGC 253.

  19. Matrix infrared spectroscopic and computational studies on the reactions of osmium and iron atoms with carbon monoxide and dinitrogen mixtures.

    PubMed

    Lu, Zhang-Hui; Xu, Qiang

    2011-10-01

    Reactions of laser-ablated osmium and iron atoms with CO and N(2) mixtures in excess neon have been investigated using matrix isolation infrared spectroscopy. The (NN)(x)MCO (M = Os, Fe; x = 1, 2) complexes are formed as reaction products during sample deposition and on annealing. These reaction products are characterized on the basis of the results of isotopic substitution, mixed isotopic splitting patterns, stepwise annealing, broad-band irradiation, and change of reagent concentration and laser energy. Density functional theory calculations have been performed on these products. Overall agreement between the experimental and calculated results supports the identification of these species from the matrix infrared spectra. The bonding characteristics and reaction mechanisms have been discussed. The M-C bonds are stronger than the M-N bonds in the same molecules. The formation of metal carbonyl dinitrogen complexes from the addition of CO to metal dinitrogen complexes is found to be more energetically favorable than that from the reactions of N(2) with metal carbonyls. PMID:21877714

  20. VERY STRONG EMISSION-LINE GALAXIES IN THE WFC3 INFRARED SPECTROSCOPIC PARALLEL SURVEY AND IMPLICATIONS FOR HIGH-REDSHIFT GALAXIES

    SciTech Connect

    Atek, H.; Colbert, J.; Shim, H.; Siana, B.; Bridge, C.; Scarlata, C.; Malkan, M.; Ross, N. R.; McCarthy, P.; Dressler, A.; Hathi, N. P.; Teplitz, H.; Henry, A.; Martin, C.; Bunker, A. J.; Fosbury, R. A. E.

    2011-12-20

    The WFC3 Infrared Spectroscopic Parallel Survey uses the Hubble Space Telescope (HST) infrared grism capabilities to obtain slitless spectra of thousands of galaxies over a wide redshift range including the peak of star formation history of the universe. We select a population of very strong emission-line galaxies with rest-frame equivalent widths (EWs) higher than 200 A. A total of 176 objects are found over the redshift range 0.35 < z < 2.3 in the 180 arcmin{sup 2} area that we have analyzed so far. This population consists of young and low-mass starbursts with high specific star formation rates (sSFR). After spectroscopic follow-up of one of these galaxies with Keck/Low Resolution Imaging Spectrometer, we report the detection at z = 0.7 of an extremely metal-poor galaxy with 12 + log(O/H) =7.47 {+-} 0.11. After estimating the active galactic nucleus fraction in the sample, we show that the high-EW galaxies have higher sSFR than normal star-forming galaxies at any redshift. We find that the nebular emission lines can substantially affect the total broadband flux density with a median brightening of 0.3 mag, with some examples of line contamination producing brightening of up to 1 mag. We show that the presence of strong emission lines in low-z galaxies can mimic the color-selection criteria used in the z {approx} 8 dropout surveys. In order to effectively remove low-redshift interlopers, deep optical imaging is needed, at least 1 mag deeper than the bands in which the objects are detected. Without deep optical data, most of the interlopers cannot be ruled out in the wide shallow HST imaging surveys. Finally, we empirically demonstrate that strong nebular lines can lead to an overestimation of the mass and the age of galaxies derived from fitting of their spectral energy distribution (SED). Without removing emission lines, the age and the stellar mass estimates are overestimated by a factor of 2 on average and up to a factor of 10 for the high-EW galaxies

  1. Interaction of collagen with chlorosulphonated paraffin tanning agents: Fourier transform infrared spectroscopic analysis and molecular dynamics simulations.

    PubMed

    Monti, Susanna; Bramanti, Emilia; Della Porta, Valentina; Onor, Massimo; D'Ulivo, Alessandro; Barone, Vincenzo

    2013-09-21

    The binding of chlorosulphonated paraffins to collagen triple helices is studied by means of classical molecular dynamics simulations and experimental spectroscopic techniques in order to disclose the principal characteristics of their interaction during the leather fattening process. Indeed, collagen is the main target to develop new leather modifying agents with specific characteristics, and an accurate design of the collagen binders, supported by predictive computational strategies, could be a successful tool to obtain new effective eco-compatible compounds able to impart to the leather the required functionalities and distinctive mechanical properties. Possible effects caused by the tanning agents on the collagen matrix have been identified from both experimental and theoretical points of view. Computational data in agreement with experiment have revealed that chlorosulphonated paraffins can interact favorably with the collagen residues having amine groups in their side chains (Arg, Lys, Asn and Gln) and reduce the tendency of the solvated collagen matrix to swell. However, the interference of chlorosulphonated paraffins with the unfolding process, which is operated mainly by the action of water, can be due both to covalent cross-linking of the collagen chains and intermolecular hydrogen bonding interactions involving also the hydroxyl groups of Hyp, Ser and Thr residues.

  2. Molecular dynamics simulation and computational two-dimensional infrared spectroscopic study of model amyloid β-peptide oligomers.

    PubMed

    Xu, Jun; Zhang, John Z H; Xiang, Yun

    2013-07-25

    Molecular dynamics simulations were carried out to study the structure stability of model amyloid β40 (Aβ40) peptide oligomers, from monomer to hexamer, in aqueous solution at room temperature. The initial oligomer models were built by using the parallel in-register β-sheet fibril structure and then allowed to relax in the simulations. Our simulation results indicated that the stable Aβ40 monomer was a random coil, while the oligomer structures became more fibril-like with the increase of the peptide strands. Linear absorption and two-dimensional infrared spectra of the isotope-labeled oligomers were calculated and analyzed in detail, which revealed the differential secondary structural features characteristic of Aβ40 aggregation. A quantitative relation was established to make connection between the calculated spectra and experimental ensemble measurements.

  3. Infrared Spectroscopic Study on Structural Change and Interfacial Interaction in Rubber Composites Filled with Silica-Kaolin Hybrid Fillers

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Guan, J.; Hu, H.; Gao, H.; Zhang, L.

    2016-07-01

    A series of natural rubber/styrene butadiene rubber/polybutadiene rubber composites was prepared with nanometer silica and micron kaolin by a dry modification process, mechanical compounding, and mold vulcanization. Fourier transform infrared spectroscopy and a scanning electron microscope were used to investigate the structural changes and interfacial interactions in composites. The results showed that the "seesaw" structure was formed particularly with the incorporation of silica particles in the preparation process, which would be beneficial to the dispersibility of fillers in the rubber matrix. The kaolinite platelets were generally arranged in directional alignment. Kaolinite with smaller particle size and low-defect structure was more stable in preparation, but kaolinite with larger particle size and high defect structure tended to change the crystal structure. The composite prepared in this research exhibited excellent mechanical and thermal properties.

  4. Measuring changes in chemistry, composition, and molecular structure within hair fibers by infrared and Raman spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Zhang, Guojin; Senak, Laurence; Moore, David J.

    2011-05-01

    Spatially resolved infrared (IR) and Raman images are acquired from human hair cross sections or intact hair fibers. The full informational content of these spectra are spatially correlated to hair chemistry, anatomy, and structural organization through univariate and multivariate data analysis. Specific IR and Raman images from untreated human hair describing the spatial dependence of lipid and protein distribution, protein secondary structure, lipid chain conformational order, and distribution of disulfide cross-links in hair protein are presented in this study. Factor analysis of the image plane acquired with IR microscopy in hair sections, permits delineation of specific micro-regions within the hair. These data indicate that both IR and Raman imaging of molecular structural changes in a specific region of hair will prove to be valuable tools in the understanding of hair structure, physiology, and the effect of various stresses upon its integrity.

  5. Circular dichroism and infrared spectroscopic characterization of secondary structure components of protein Z during mashing and boiling processes.

    PubMed

    Han, Yupeng; Wang, Jinjing; Li, Yongxian; Hang, Yu; Yin, Xiangsheng; Li, Qi

    2015-12-01

    In beer brewing, protein Z is hypothesized to stabilize beer foam. However, few investigations have revealed the relationship between conformational alterations to protein Z during the brewing process and beer foam. In this report, protein Z from sweet wort was isolated during mashing and boiling processes. Circular dichroism (CD) and Fourier transform infrared spectroscopy (FTIR) were used to monitor the structural characteristics of protein Z. The results showed that the α-helix and β-sheet content decreased, whereas the content of β-turn and random coil increased. The complex environment rich in polysaccharides may facilitate conformational alterations and modifications to protein Z. Additionally, the formation of extended structural features to protein Z provides access to reactive amino acid side chains that can undergo modifications and the exposure of hydrophobic core regions of the protein. Analyzing structural transformations should provide a deeper understanding of the mechanism of protein Z on maintaining beer foam.

  6. Infrared spectroscopic analysis of staghorn calculi obtained after open renal surgery in a urology unit of Sri Lanka.

    PubMed

    Wijayarathna, K S; Weerasingha, G G; Weligamage, A S; Chandrajith, R; Abeygunasekera, A M

    2016-06-01

    The composition of renal stones varies widely among populations. The aim of our study was to determine the composition of staghorn renal stones using Fourier transform infrared (FTIR) spectroscopy in a cohort of Sri Lankan patients. Forty two staghorn calculi removed from kidneys of adult patients during open surgery were analysed. There were 32 men. Nineteen (45%) were calcium oxalate monohydrate (whewellite) stones. Stones containing a mixture of calcium oxalate and calcium hydroxyl phosphate (apatite) were found in 16 (38%). Only 4 (10%) staghorn calculi were coposed of struvite. Three (7%) were uric acid stones. So most staghorn renal stones in Sri Lanka are calcium oxalate. Contrary to the traditional view based on studies done in the western world, only 10% of staghorn calculi removed from patients in Sri Lanka are struvite or infection stones. This could be the reason for kidneys with staghorn calculi in Sri Lanka to retain their function. PMID:27423749

  7. A near infrared spectroscopic assay for stalk soluble sugars, bagasse enzymatic saccharification and wall polymers in sweet sorghum.

    PubMed

    Wu, Leiming; Li, Meng; Huang, Jiangfeng; Zhang, Hui; Zou, Weihua; Hu, Shiwei; Li, Ying; Fan, Chunfen; Zhang, Rui; Jing, Haichun; Peng, Liangcai; Feng, Shengqiu

    2015-02-01

    In this study, 123 sweet sorghum (Sorghum bicolor L.) accessions and 50 mutants were examined with diverse stalk soluble sugars, bagasse enzymatic saccharification and wall polymers, indicating the potential near infrared spectroscopy (NIRS) assay for those three important parameters. Using the calibration and validation sets and modified squares method, nine calibration optimal equations were generated with high determination coefficient on the calibration (R(2)) (0.81-0.99), cross-validation (R(2)cv) (0.77-0.98), and the ratio performance deviation (RPD) (2.07-7.45), which were at first time applied by single spectra for simultaneous assay of stalk soluble sugars, bagasse hydrolyzed sugars, and three major wall polymers in bioenergy sweet sorghum.

  8. Near infrared Raman spectroscopic study of reactive gliosis and the glial scar in injured rat spinal cords

    NASA Astrophysics Data System (ADS)

    Saxena, Tarun; Deng, Bin; Lewis-Clark, Eric; Hoellger, Kyle; Stelzner, Dennis; Hasenwinkel, Julie; Chaiken, Joseph

    2010-02-01

    Comparative Raman spectra of ex vivo, saline-perfused, injured and healthy rat spinal cord as well as experiments using enzymatic digestion suggest that proteoglycan over expression may be observable in injured tissue. Comparison with authentic materials in vitro suggest the occurrence of side reactions between products of cord digestion with chondroitinase (cABC) that produce lactones and similar species with distinct Raman features that are often not overlapped with Raman features from other chemical species. Since the glial scar is thought to be a biochemical and physical barrier to nerve regeneration, this observation suggests the possibility of using near infrared Raman spectroscopy to study disease progression and explore potential treatments ex vivo and if potential treatments can be designed, perhaps to monitor potential remedial treatments within the spinal cord in vivo.

  9. Infrared and Raman spectroscopic characterization of the carbonate mineral huanghoite - And in comparison with selected rare earth carbonates

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; López, Andrés; Scholz, Ricardo; Xi, Yunfei; Belotti, Fernanda Maria

    2013-11-01

    Raman spectroscopy complimented with infrared spectroscopy has been used to study the rare earth based mineral huanghoite with possible formula given as BaCe(CO3)2F and compared with the Raman spectra of a series of selected natural halogenated carbonates from different origins including bastnasite, parisite and northupite. The Raman spectrum of huanghoite displays three bands are at 1072, 1084 and 1091 cm-1 attributed to the CO32- symmetric stretching vibration. The observation of three symmetric stretching vibrations is very unusual. The position of CO32- symmetric stretching vibration varies with mineral composition. Infrared spectroscopy of huanghoite show bands at 1319, 1382, 1422 and 1470 cm-1. No Raman bands of huanghoite were observed in these positions. Raman spectra of bastnasite, parisite and northupite show a single band at 1433, 1420 and 1554 cm-1 assigned to the ν3 (CO3)2- antisymmetric stretching mode. The observation of additional Raman bands for the ν3 modes for some halogenated carbonates is significant in that it shows distortion of the carbonate anion in the mineral structure. Four Raman bands for huanghoite are observed at 687, 704, 718 and 730 cm-1and assigned to the (CO3)2- ν2 bending modes. Raman bands are observed for huanghoite at around 627 cm-1 and are assigned to the (CO3)2- ν4 bending modes. Raman bands are observed for the carbonate ν4 in phase bending modes at 722 cm-1 for bastnasite, 736 and 684 cm-1 for parisite, 714 cm-1 for northupite. Raman bands for huanghoite observed at 3259, 3484 and 3589 cm-1 are attributed to water stretching bands. Multiple bands are observed in the OH stretching region for bastnasite and parisite indicating the presence of water and OH units in their mineral structure. Vibrational spectroscopy enables new information on the structure of huanghoite to be assessed.

  10. Ellipsometry study of (0001) cadmium crystal faces during vapour growth

    NASA Astrophysics Data System (ADS)

    Gauch, M.; Quentel, G.

    1981-07-01

    Ellipsometry analysis of (0001) cadium faces during vapour growth reveal periodic fluctuations of the dielectric constant which are related to supersaturation. We show that they can be interpreted by the instability of monoatomic step trains produced by spiral growth. Such a model of surface roughness is also treated using the effective medium approximation of Bruggeman, which corroborates the experimental results.

  11. Responses of Azospirillum brasilense to nitrogen deficiency and to wheat lectin: a diffuse reflectance infrared fourier transform (DRIFT) spectroscopic study.

    PubMed

    Kamnev, Alexander A; Sadovnikova, Julia N; Tarantilis, Petros A; Polissiou, Moschos G; Antonyuk, Lyudmila P

    2008-11-01

    For the rhizobacterium Azospirillum brasilense, the optimal nutritional range of C:N ratios corresponds to the presence of malate (ca. 3 to 5 g l(-1) of its sodium salt) and ammonium (ca. 0.5 to 3 g l(-1) of NH4Cl) as preferred carbon and nitrogen sources, respectively. This microaerophilic aerotactic bacterium is known to have a narrow optimal oxygen concentration range of ca. 3 to 5 microM, which is 1.2% to 2% of oxygen solubility in air-saturated water under normal conditions. In this work, the effects of stress conditions (bound-nitrogen deficiency related to a high C:N ratio in the medium; excess of oxygen) on aerobically grown A. brasilense Sp245, a native wheat-associated endophyte, were investigated in the absence and presence of wheat germ agglutinin (WGA, plant stress protein and a molecular host-plant signal for the bacterium) using FTIR spectroscopy of whole cells in the diffuse reflectance mode (DRIFT). The nutritional stress resulted in the appearance of prominent spectroscopic signs of poly-3-hydroxybutyrate (PHB) accumulation in the bacterial cells; in addition, splitting of the amide I band related to bacterial cellular proteins indicated some stress-induced alterations in their secondary structure components. Similar structural changes were observed in the presence of nanomolar WGA both in stressed A. brasilense cells and under normal nutritional conditions. Comparative analysis of the data obtained and the relevant literature data indicated that the stress conditions applied (which resulted in the accumulation of PHB involved in stress tolerance) and/or the presence of nanomolar concentrations of WGA induced synthesis of bacterial cell-surface (glyco)proteins rich in beta-structures, that could be represented by hemagglutinin and/or porin.

  12. THE MID-INFRARED LUMINOSITY FUNCTION AT z < 0.3 FROM 5MUSES: UNDERSTANDING THE STAR FORMATION/ACTIVE GALACTIC NUCLEUS BALANCE FROM A SPECTROSCOPIC VIEW

    SciTech Connect

    Wu Yanling; Shi Yong; Helou, George; Armus, Lee; Stierwalt, Sabrina; Dale, Daniel A.; Papovich, Casey; Rahman, Nurur; Dasyra, Kalliopi E-mail: yong@ipac.caltech.edu E-mail: lee@ipac.caltech.edu E-mail: ddale@uwyo.edu E-mail: nurur@astro.umd.edu

    2011-06-10

    We present rest-frame 15 and 24 {mu}m luminosity functions (LFs) and the corresponding star-forming LFs at z < 0.3 derived from the 5MUSES sample. Spectroscopic redshifts have been obtained for {approx}98% of the objects and the median redshift is {approx}0.12. The 5-35 {mu}m Infrared Spectrograph spectra allow us to estimate accurately the luminosities and build the LFs. Using a combination of starburst and quasar templates, we quantify the star formation (SF) and active galactic nucleus (AGN) contributions in the mid-IR spectral energy distribution. We then compute the SF LFs at 15 and 24 {mu}m, and compare with the total 15 and 24 {mu}m LFs. When we remove the contribution of AGNs, the bright end of the LF exhibits a strong decline, consistent with the exponential cutoff of a Schechter function. Integrating the differential LF, we find that the fractional contribution by SF to the energy density is 58% at 15 {mu}m and 78% at 24 {mu}m, while it goes up to {approx}86% when we extrapolate our mid-IR results to the total IR luminosity density. We confirm that the AGNs play more important roles energetically at high luminosities. Finally, we compare our results with work at z {approx} 0.7 and confirm that evolution on both luminosity and density is required to explain the difference in the LFs at different redshifts.

  13. Infrared spectroscopic demonstration of cooperative and anti-cooperative effects in C-H--O hydrogen bonds

    NASA Astrophysics Data System (ADS)

    Samanta, Amit K.; Chakraborty, Tapas

    2010-06-01

    Matrix isolation infrared spectra of 1,2-cyclohexanedione (1,2-CHD) and 3-methyl-1,2-cyclohexanedione are measured in a nitrogen matrix at 8K temperature. The spectra reveal that in the matrix environment both the molecules exist exclusively in monohydroxy tautomeric forms with an intramolecular O-H⋯O=C hydrogen bonding. In the case of 3-MeCD, the fundamental of OH stretching νO--H band appears more red-shifted with larger bandwidth indicating that the intramolecular O-H⋯O hydrogen bond of this molecule is somewhat stronger compared to that of 1,2-CD. Electronic structure calculations at B3LYP/6-311++G∗∗ and MP2/cc-pVTZ levels predict that the monohydroxy tautomer of 1,2-CD is nearly 4.5 kcal/mol more stable than the corresponding diketo tautomer, but in the case of 3-MeCD, the stability difference between the diketo and preferred enol tautomer is more than 7.5 kcal/mol. Analysis of the geometric parameters reveals that the excess stabilization of the latter originates as a result of formation of an intramolecular O⋯H-O⋯H-C type interconnected hydrogen bonding network involving a methyl C-H bond, which interact in a cooperative fashion. The predicted infrared spectrum shows that the formation of such hydrogen bonding network causes large blue-shifting of the H-bonded methyl νC--H transition, and this spectral prediction matches well with the features displayed in the measured spectrum.For intermolecular case, 1:1 complex between 1,2-cyclohexanedione and chloroform have been studied. Here two types of complex is possible, interconnected and bifurcated. In the interconnected complex a cooperative stabilizing effect and in the bifurcated complex an anti-cooperative destabilizing effect of the C-H⋯O hydrogen bond on the intramolecular O-H⋯O bond is observable. In the room temperature solution phase of FTIR spectra, the anti-cooperative complex is observable.

  14. Infrared spectroscopic demonstration of cooperative and anti-cooperative effects in C-H--O hydrogen bonds

    NASA Astrophysics Data System (ADS)

    Samanta, Amit K.; Chakraborty, Tapas

    Matrix isolation infrared spectra of 1,2-cyclohexanedione (1,2-CHD) and 3-methyl-1,2-cyclohexanedione are measured in a nitrogen matrix at 8K temperature. The spectra reveal that in the matrix environment both the molecules exist exclusively in monohydroxy tautomeric forms with an intramolecular O-H⋯O=C hydrogen bonding. In the case of 3-MeCD, the fundamental of OH stretching νO--H band appears more red-shifted with larger bandwidth indicating that the intramolecular O-H⋯O hydrogen bond of this molecule is somewhat stronger compared to that of 1,2-CD. Electronic structure calculations at B3LYP/6-311++G∗∗ and MP2/cc-pVTZ levels predict that the monohydroxy tautomer of 1,2-CD is nearly 4.5 kcal/mol more stable than the corresponding diketo tautomer, but in the case of 3-MeCD, the stability difference between the diketo and preferred enol tautomer is more than 7.5 kcal/mol. Analysis of the geometric parameters reveals that the excess stabilization of the latter originates as a result of formation of an intramolecular O⋯H-O⋯H-C type interconnected hydrogen bonding network involving a methyl C-H bond, which interact in a cooperative fashion. The predicted infrared spectrum shows that the formation of such hydrogen bonding network causes large blue-shifting of the H-bonded methyl νC--H transition, and this spectral prediction matches well with the features displayed in the measured spectrum.For intermolecular case, 1:1 complex between 1,2-cyclohexanedione and chloroform have been studied. Here two types of complex is possible, interconnected and bifurcated. In the interconnected complex a cooperative stabilizing effect and in the bifurcated complex an anti-cooperative destabilizing effect of the C-H⋯O hydrogen bond on the intramolecular O-H⋯O bond is observable. In the room temperature solution phase of FTIR spectra, the anti-cooperative complex is observable.

  15. INFRARED SPECTROSCOPIC SURVEY OF THE QUIESCENT MEDIUM OF NEARBY CLOUDS. I. ICE FORMATION AND GRAIN GROWTH IN LUPUS

    SciTech Connect

    Boogert, A. C. A.; Chiar, J. E.; Knez, C.; Mundy, L. G.; Öberg, K. I.; Pendleton, Y. J.; Tielens, A. G. G. M.; Van Dishoeck, E. F.

    2013-11-01

    Infrared photometry and spectroscopy (1-25 μm) of background stars reddened by the Lupus molecular cloud complex are used to determine the properties of grains and the composition of ices before they are incorporated into circumstellar envelopes and disks. H{sub 2}O ices form at extinctions of A{sub K} = 0.25 ± 0.07 mag (A{sub V} = 2.1 ± 0.6). Such a low ice formation threshold is consistent with the absence of nearby hot stars. Overall, the Lupus clouds are in an early chemical phase. The abundance of H{sub 2}O ice (2.3 ± 0.1 × 10{sup –5} relative to N{sub H}) is typical for quiescent regions, but lower by a factor of three to four compared to dense envelopes of young stellar objects. The low solid CH{sub 3}OH abundance (<3%-8% relative to H{sub 2}O) indicates a low gas phase H/CO ratio, which is consistent with the observed incomplete CO freeze out. Furthermore it is found that the grains in Lupus experienced growth by coagulation. The mid-infrared (>5 μm) continuum extinction relative to A{sub K} increases as a function of A{sub K}. Most Lupus lines of sight are well fitted with empirically derived extinction curves corresponding to R{sub V} ∼ 3.5 (A{sub K} = 0.71) and R{sub V} ∼ 5.0 (A{sub K} = 1.47). For lines of sight with A{sub K} > 1.0 mag, the τ{sub 9.7}/A{sub K} ratio is a factor of two lower compared to the diffuse medium. Below 1.0 mag, values scatter between the dense and diffuse medium ratios. The absence of a gradual transition between diffuse and dense medium-type dust indicates that local conditions matter in the process that sets the τ{sub 9.7}/A{sub K} ratio. This process is likely related to grain growth by coagulation, as traced by the A{sub 7.4}/A{sub K} continuum extinction ratio, but not to ice mantle formation. Conversely, grains acquire ice mantles before the process of coagulation starts.

  16. NEAR-INFRARED IMAGING AND SPECTROSCOPIC SURVEY OF THE SOUTHERN REGION OF THE YOUNG OPEN CLUSTER NGC 2264

    SciTech Connect

    Marinas, Naibi; Lada, Elizabeth A.; Teixiera, Paula S.; Lada, Charles J.

    2013-08-01

    We have obtained JHK near-IR images and JH band low-resolution spectra of candidate members of the southern region of the young open cluster NGC 2264. We have determined spectral types from H-band spectra for 54 sources, 25 of which are classified for the first time. The stars in our sample cover a large range of spectral types (A8-M8). Using a cluster distance of 780 pc, we determined a median age of 1 Myr for this region of NGC 2264, with 90% of the stars being 5 Myr or younger. To improve the statistical significance of our sample, we included 66 additional cluster members within our field of view with optical spectral classification in the literature. We derived infrared excesses using stellar properties to model the photospheric emission for each source and the extinction to correct FLAMINGOS near-IR and Spitzer mid-IR photometry, and obtained a disk fraction of 51% {+-} 5% for the region. Binning the stars by stellar mass, we find a disk fraction of 38% {+-} 9% for the 0.1-0.3 solar mass group, 55% {+-} 6% for 0.3-1 solar masses, and 58% {+-} 10% for the higher than 1 solar mass group. The lower disk fraction for the lower mass stars is similar to the results found in non-cluster regions like Taurus and Chamaeleon, but differs from the older 3 Myr cluster IC 348 in which the disk fraction is lower for the higher mass stars. This mass-dependent disk fraction is accentuated in the sample with isochrone ages younger than 2 Myr. Here, we find that 45% {+-} 11% of the 0.1-0.3 solar mass stars have disks, 60% {+-} 7% of the 0.3-1 solar mass stars have disks, and all 1-3 solar mass stars have disks. Stellar masses might be an important factor in the ability of a system to form or retain a disk early on. However, regardless of the stellar mass, the large infrared excesses expected from optically thick disks disappear within the first 2 Myr for all stars in our study and small excesses from optically thin disks are found mostly in sources younger than 4 Myr.

  17. Near-infrared Imaging and Spectroscopic Survey of the Southern Region of the Young Open Cluster NGC 2264

    NASA Astrophysics Data System (ADS)

    Mariñas, Naibí; Lada, Elizabeth A.; Teixeira, Paula S.; Lada, Charles J.

    2013-08-01

    We have obtained JHK near-IR images and JH band low-resolution spectra of candidate members of the southern region of the young open cluster NGC 2264. We have determined spectral types from H-band spectra for 54 sources, 25 of which are classified for the first time. The stars in our sample cover a large range of spectral types (A8-M8). Using a cluster distance of 780 pc, we determined a median age of 1 Myr for this region of NGC 2264, with 90% of the stars being 5 Myr or younger. To improve the statistical significance of our sample, we included 66 additional cluster members within our field of view with optical spectral classification in the literature. We derived infrared excesses using stellar properties to model the photospheric emission for each source and the extinction to correct FLAMINGOS near-IR and Spitzer mid-IR photometry, and obtained a disk fraction of 51% ± 5% for the region. Binning the stars by stellar mass, we find a disk fraction of 38% ± 9% for the 0.1-0.3 solar mass group, 55% ± 6% for 0.3-1 solar masses, and 58% ± 10% for the higher than 1 solar mass group. The lower disk fraction for the lower mass stars is similar to the results found in non-cluster regions like Taurus and Chamaeleon, but differs from the older 3 Myr cluster IC 348 in which the disk fraction is lower for the higher mass stars. This mass-dependent disk fraction is accentuated in the sample with isochrone ages younger than 2 Myr. Here, we find that 45% ± 11% of the 0.1-0.3 solar mass stars have disks, 60% ± 7% of the 0.3-1 solar mass stars have disks, and all 1-3 solar mass stars have disks. Stellar masses might be an important factor in the ability of a system to form or retain a disk early on. However, regardless of the stellar mass, the large infrared excesses expected from optically thick disks disappear within the first 2 Myr for all stars in our study and small excesses from optically thin disks are found mostly in sources younger than 4 Myr. Based on observations

  18. Ellipsometry study on gold-nanoparticle-coated gold thin film for biosensing application

    PubMed Central

    Moirangthem, Rakesh Singh; Chang, Yia-Chung; Wei, Pei-Kuen

    2011-01-01

    The amplified plasmonic response from various distributions of gold nanoparticles (AuNPs) coated on top of gold thin film was studied via ellipsometry under total internal reflection mode. The surface plasmon resonance dip can be tuned from the visible to near infrared by simply varying the AuNP concentration. Theoretical modeling based on effective medium theory with a multi-slice model has been employed to fit the experimental results. Additionally, this experimental tool has been further extended to study bio-molecular interactions with metal surfaces as well as in studying protein-protein interaction without any labeling. Hence, this technique could provide a non-destructive way of designing tunable label-free optical biosensors with very high sensitivity. PMID:21991549

  19. In Situ Infrared Spectroscopic Study of Brucite Carbonation in Dry to Water-Saturated Supercritical Carbon Dioxide

    SciTech Connect

    Loring, John S.; Thompson, Christopher J.; Zhang, Changyong; Wang, Zheming; Schaef, Herbert T.; Rosso, Kevin M.

    2012-04-25

    In geologic carbon sequestration, while part of the injected carbon dioxide will dissolve into host brine, some will remain as neat to water saturated super critical CO2 (scCO2) near the well bore and at the caprock, especially in the short-term life cycle of the sequestration site. Little is known about the reactivity of minerals with scCO2 containing variable concentrations of water. In this study, we used high-pressure infrared spectroscopy to examine the carbonation of brucite (Mg(OH)2) in situ over a 24 hr reaction period with scCO2 containing water concentrations between 0% and 100% saturation, at temperatures of 35, 50, and 70 °C, and at a pressure of 100 bar. Little or no detectable carbonation was observed when brucite was reacted with neat scCO2. Higher water concentrations and higher temperatures led to greater brucite carbonation rates and larger extents of conversion to magnesium carbonate products. The only observed carbonation product at 35 °C was nesquehonite (MgCO3 • 3H2O). Mixtures of nesquehonite and magnesite (MgCO3) were detected at 50 °C, but magnesite was more prevalent with increasing water concentration. Both an amorphous hydrated magnesium carbonate solid and magnesite were detected at 70 °C, but magnesite predominated with increasing water concentration. The identity of the magnesium carbonate products appears strongly linked to magnesium water exchange kinetics through temperature and water availability effects.

  20. Near infrared spectroscopic (NIRS) analysis of drug-loading rate and particle size of risperidone microspheres by improved chemometric model.

    PubMed

    Song, Jia; Xie, Jing; Li, Chenliang; Lu, Jia-Hui; Meng, Qing-Fan; Yang, Zhaogang; Lee, Robert J; Wang, Di; Teng, Le-Sheng

    2014-09-10

    Microspheres have been developed as drug carriers in controlled drug delivery systems for years. In our present study, near infrared spectroscopy (NIRS) is applied to analyze the particle size and drug loading rate in risperidone poly(d,l-lactide-co-glycolide) (PLGA) microspheres. Various batches of risperidone PLGA microspheres were designed and prepared successfully. The particle size and drug-loading rate of all the samples were determined by a laser diffraction particle size analyzer and high performance liquid chromatography (HPLC) system. Monte Carlo algorithm combined with partial least squares (MCPLS) method was applied to identify the outliers and choose the numbers of calibration set. Furthermore, a series of preprocessing methods were performed to remove signal noise in NIR spectra. Moving window PLS and radical basis function neural network (RBFNN) methods were employed to establish calibration model. Our data demonstrated that PLS-developed model was only suitable for drug loading analysis in risperidone PLGA microspheres. Comparatively, RBFNN-based predictive models possess better fitting quality, predictive effect, and stability for both drug loading rate and particle size analysis. The correlation coefficients of calibration set (Rc(2)) were 0.935 and 0.880, respectively. The performance of optimum RBFNN models was confirmed by independent verification test with 15 samples. Collectively, our method is successfully performed to monitor drug-loading rate and particle size during risperidone PLGA microspheres preparation.

  1. Relation Between Prefrontal Cortex Activity and Respiratory Rate During Mental Stress Tasks: A Near-Infrared Spectroscopic Study.

    PubMed

    Murayama, Yuta; Hu, Lizhen; Sakatani, Kaoru

    2016-01-01

    In order to clarify the central mechanism controlling respiratory rate during mental stress, we examined the relation between prefrontal cortex (PFC) activity and respiratory rate during mental arithmetic (MA) tasks. Employing two-channel near-infrared spectroscopy (NIRS), we measured hemoglobin (Hb) concentration changes in the bilateral PFC during MA tasks in normal adults. To evaluate asymmetry of the PFC activity, we calculated the laterality index (LI); (R-L)/(R + L) of oxy-Hb concentration changes (R = right, L = left); positive LI scores indicate right-dominant activity, while negative scores indicate left-dominant activity. For measurements of respiratory rate, we employed a Kinect motion sensor (Microsoft). The MA tasks increased both oxy-Hb in the bilateral PFC and respiratory rate (p < 0.001). In addition, there was a significant correlation between LI and respiratory rate (r = 0.582, p < 0.02). These results indicate that the MA-induced activity in the right PFC was greater than that in the left PFC in subjects with large increases of respiratory rate, suggesting that the right PFC has a greater role in cerebral regulation of respiratory rate during mental stress. PMID:27526145

  2. Multivariate analysis of attenuated total reflection-Fourier transform infrared spectroscopic data to confirm the origin of honeys.

    PubMed

    Hennessy, Siobhán; Downey, Gerard; O'Donnell, Colm

    2008-10-01

    Fourier transform infrared (FT-IR) spectroscopy and chemometrics were used to verify the origin of honey samples (n=150) from Europe and South America. Authentic honey samples were collected from five sources, namely unfiltered samples from Mexico in 2004, commercially filtered samples from Ireland and Argentina in 2004, commercially filtered samples from the Czech Republic in 2005 and 2006, and commercially filtered samples from Hungary in 2006. Samples were diluted with distilled water to a standard solids content (70 degrees Brix) and their spectra (2500-12 500 nm) recorded at room temperature using an FT-IR spectrometer equipped with a germanium attenuated total reflection (ATR) accessory. First- and second-derivative and standard normal variate (SNV) data pretreatments were applied to the recorded spectra, which were analyzed using partial least squares (PLS) regression analysis, factorial discriminant analysis (FDA), and soft independent modeling of class analogy (SIMCA). In general, when an attenuated wavelength range (6800-11 500 nm) rather than the whole spectrum (2500-12 500 nm) was studied, higher correct classification rates were achieved. An overall correct classification of 93.3% was obtained for honeys by PLS discriminant analysis, while FDA techniques correctly classified 94.7% of honey samples. Correct classifications of up to 100% were achieved using SIMCA, but models describing some classes had very high false positive rates.

  3. Near-infrared spectroscopy with Spectroscopic technique with wide range of wavelength information detects tissue oxygenation level clearly

    NASA Astrophysics Data System (ADS)

    Eda, Hideo; Aoki, Hiromichi; Eura, Shigeru; Ebe, Kazutoshi

    2010-02-01

    Near-infrared spectroscopy (NIRS) is based on the modified-Lambert-Beer's law that changes in absorbance are proportional to changes in hemoglobin parameters. Majority of the conventional measurement methods uses only two or three wavelengths. In this research, basic examination of NIRS measurement was approached by acquiring wide range of wavelength information. Arterial occlusion task was performed by using the blood pressure cuff around the upper arm. Pressure of 200mmHg was then applied for about 3 minutes. During the arterial occlusion, the spectrum of the lower arm muscles was measured every 15 seconds, within the range of 600 to 1100nm. The secondary derivative spectrum was calculated from the measured spectrum. Arterial occlusion is a task which changes the oxygenation level of the tissue. The change can be regarded as the change of the spectrum form, not as the change of the baseline. Furthermore, it was found that other wavelength bands hold information correlating to this arterial occlusion task.

  4. A surface-enhanced infrared absorption spectroscopic study of pH dependent water adsorption on Au

    NASA Astrophysics Data System (ADS)

    Dunwell, Marco; Yan, Yushan; Xu, Bingjun

    2016-08-01

    The potential dependent behavior of near-surface water on Au film electrodes in acidic and alkaline solutions is studied using a combination of attenuated total reflectance surface enhanced infrared spectroscopy and chronoamperometry. In acid, sharp νOH peaks appear at 3583 cm- 1 at high potentials attributed to non-H-bonded water coadsorbed in the hydration sphere of perchlorate near the electrode surface. Adsorbed hydronium bending mode at near 1680 cm- 1 is observed at low potentials in low pH solutions (1.4, 4.0, 6.8). At high pH (10.0, 12.3), a potential-dependent OH stretching band assigned to adsorbed hydroxide emerges from 3400-3506 cm- 1. The observation of adsorbed hydroxide, even on a weakly oxophilic metal such as Au, provides the framework for further studies of hydroxide adsorption on other electrodes to determine the role of adsorbed hydroxide on important reactions such as the hydrogen oxidation reaction.

  5. Indium phosphide all air-gap Fabry-Pérot filters for near-infrared spectroscopic applications

    NASA Astrophysics Data System (ADS)

    Ullah, A.; Butt, M. A.; Fomchenkov, S. A.; Khonina, S. N.

    2016-08-01

    Food quality can be characterized by noninvasive techniques such as spectroscopy in the Near Infrared wavelength range. For example, 930 -1450 nm wavelength range can be used to detect diseases and differentiate between meat samples. Miniaturization of such NIR spectrometers is useful for quick and mobile characterization of food samples. Spectrometers can be miniaturized, without compromising the spectral resolution, using Fabry-Pérot (FP) filters consisting of two highly reflecting mirrors with a central cavity in between. The most commonly used mirrors in the design of FP filters are Distributed Bragg Reflections (DBRs) consisting of alternating high and low refractive index material pairs, due to their high reflectivity compared to metal mirrors. However, DBRs have high reflectivity for a selected range of wavelengths known as the stopband of the DBR. This range is usually much smaller than the sensitivity range of the spectrometer detector. Therefore, a bandpass filter is usually required to restrict wavelengths outside the stopband of the FP DBRs. Such bandpass filters are difficult to design and implement. Alternatively, high index contrast materials must be can be used to broaden the stopband width of the FP DBRs. In this work, Indium phosphide all air-gap filters are proposed in conjunction with InGaAs based detectors. The designed filter has a wide stopband covering the entire InGaAs detector sensitivity range. The filter can be tuned in the 950-1450 nm with single mode operation. The designed filter can hence be used for noninvasive meat quality control.

  6. Fast, noninvasive and simultaneous near-infrared spectroscopic characterisation of physicochemical stationary phases' properties: from silica particles towards monoliths.

    PubMed

    Petter, Christine H; Heigl, Nico; Bonn, Günther K; Huck, Christian W

    2008-08-01

    The design of novel stationary phases is a permanent demanding challenge in chromatographic separation science to enable analysis with enhanced selectivity, specificity and speed. Therefore, the characterisation of chemical and physical properties is next to calculation of chromatographic parameters essential. Conventionally, chemical parameters including surface coverage are determined by burning combustion or frontal analysis, physical parameters including particle size, pore size, pore volume and surface area are determined by SEM, mercury intrusion porosimetry (MIP) and Brunauer-Emmett-Teller (BET). All these methods are time consuming, invasive and require besides special equipment some special trained laboratory staff. Therefore, we introduced near-infrared spectroscopy (NIRS) as a noninvasive, easy-to-handle technology with wavenumber ranging from 4000 to 10,000 cm(-1) enabling analysis within only a few seconds at higher precision than the conventional methods. Investigated materials comprise porous and nonporous silica gel, carbon-based nanomaterials (fullerenes), polymer beads and monoliths. Different carriers themselves and their kind of derivatisations (RP, normal-phase, ion-exchanger, IMAC (immobilised metal affinity chromatography), affinity) can be determined by applying principal component analysis (PCA) of recorded spectra. Partial least square regression (PLSR) enables the determination of particle size, pore size, pore volume, porosity, total porosity and surface area with one single measurement. For the optimised design of well-defined polymer beads and monoliths, real-time in situ monitoring to control, e. g. particle and pore sizes as well as monomer content during the polymerisation process, can be extremely helpful. In this article, the advantages of this fast, noninvasive high-throughput NIRS methods are summarised, discussed in detail and different applications of the individual characterised materials are shown.

  7. An infrared spectroscopic study of aortic valve. A possible mechanism of calcification and the role of magnesium salts.

    PubMed

    Dritsa, Vassiliki; Pissaridi, Katerina; Koutoulakis, Emmanouil; Mamarelis, Ioannis; Kotoulas, Christoforos; Anastassopoulou, Jane

    2014-01-01

    In the present study fourier transform infrared (FT-IR) spectroscopy was used to study the mechanism of pathogenesis of aortic valve calcification. The high intensity bands of vCH3 and vCH2 groups of lipids and phospholipids of membranes, in the spectral region 3000-2800 cm(-1), show the high concentration of lipids and fatty components in aortic valve, resulting from degradation of the main aliphatic chain of the membranes, with a change of their permeability and fluidity. The presence of bands at 3075 and 1744 cm(-1), assigned to olefinic (v=CH) and aldehyde carbonyl groups, respectively, implies that reactive oxygen species are involved in the initiation of peroxidation of the lipids and phospholipids. These latter bands are related to the oxidative stress of the patients. From the shifts of bands to lower frequencies of the characteristic absorption bands of amide I and amide II, it is suggested that the proteins change their secondary structure from α-helix to β-sheets and random coil due to modifications of collagen, associated with the permeability of aortic valve atherosclerosis. From the spectral region 1150-900 cm(-1), where the characteristic stretching vibration bands of the phosphate groups (vPO4(-3)) absorb, the calcified aortic valve was found to contain biological hydroxyapatite (Ca10(PO4)6(OH)2), as well as amorphous hydroxyapatite (Ca5(PO4)xOH) and CaHPO4. These findings are in agreement with scanning electron microscopy energy-dispersive X-ray analysis and X-ray diffraction analyses. SEM micrographs show that the valves are rich in fibrils and that the protein-protein cross-linked chemical bonds seem to be the points of initiation of calcification.

  8. Structure, Raman and infrared spectroscopic properties of new nonlinear optical material Na3VO2B6O11

    NASA Astrophysics Data System (ADS)

    Zhang, Ji; Dou, Renqin; Zhang, Deming; Zhang, Qingli; Yin, Shaotang

    2016-08-01

    In this paper we report on the structure of Na3VO2B6O11 (NVBO) single crystals which were investigated by XRD, polarized Raman spectra in the range from 10 to 1600 cm-1 and infrared spectrum (IR) in the range from 100 to 1600 cm-1. Factor group analysis has been used to study the full vibrational representation of the crystal. More than 120 phonon modes have been obtained, which are related to Bsbnd O and Vsbnd O vibration in the trigonal planar BO3 triangle groups and tetrahedral BO4/VO4 groups. The high frequency bands located at 1300-1415 cm-1 are assigned to stretching modes of the trigonal planar BO3 groups. Moreover, intense Raman modes located at 631 cm-1 is related to BO3 bending vibration as well. The weak band at 1158 cm-1 (A1 mode) and strong band at 431 cm-1 (A1 mode) are attributed to asymmetric stretching and bending vibration mode of tetrahedral BO4 groups respectively. The vibrational band at 765-738 cm-1 in the Raman spectra of NVBO crystal maybe related to the breathing vibration of the boroxol ring consisting of two BO4 tetrahedra. In addition, we assigned the intense band 900 (A1 mode) and 831 cm-1 (B2 mode) are relative to the v1 symmetric stretching vibration of VO4 tetrahedra. And the middle intense band at 382 (A1 mode) and 385 (A2 mode) are due to Osbnd Vsbnd O vibration in VO4 tetrahedra.

  9. Infrared and Fluorescence Spectroscopic Investigations of the Acyl Surface Modification of Hydrogel Beads for the Deposition of a Phospholipid Coating.

    PubMed

    Grossutti, Michael; Seenath, Ryan; Lipkowski, Jacek

    2015-10-27

    The scaffolded vesicle has been employed as an alternative means of developing natural model membranes and envisioned as a potential nutraceutical transporter. Furthering the research of the scaffolded vesicle system, a nucleophilic substitution reaction was implemented to form an ester linkage between palmitate and terminal hydroxyl groups of dextran in order to hydrophobically modify the hydrogel scaffold. An average tilt angle of 38° of the hydrophobic palmitate modifying layer on the surface of the hydrogel was determined from dichroic ratios obtained from infrared spectra collected in the attenuated total reflection (ATR) configuration. ATR-IR studies of the DMPC-coated acylated hydrogel demonstrated that the hydrocarbon chains of the DMPC coating was similar to those of the DMPC bilayers and that the underlying palmitate layer had a negligible effect on the average tilt angle (26°) of the DMPC coating. The permeability of this acylated hydrogel was investigated with fluorescence spectroscopy and the terbium/dipicolinic acid assay. The hydrophobic modification on the surface of the hydrogel bead allowed for an efficient deposition of a DMPC layer that served as an impermeable barrier to terbium efflux. About 72% of DMPC-coated acylated hydrogel beads showed ideal barrier properties. The remaining 28% were leaking, but the half-life of terbium efflux of the DMPC-coated acylated hydrogel was increasing, and the total amount of leaked terbium was decreasing with the incubation time. The half-life time and the retention were considered a marked improvement relative to past scaffolded vesicle preparations. The process of acylating hydrogel beads for efficient DMPC deposition has been identified as another viable method for controlling the permeability of the scaffolded vesicle.

  10. Fourier transform-infrared spectroscopic methods for microbial ecology: analysis of bacteria, bacteria-polymer mixtures and biofilms

    NASA Technical Reports Server (NTRS)

    Nichols, P. D.; Henson, J. M.; Guckert, J. B.; Nivens, D. E.; White, D. C.

    1985-01-01

    Fourier transform-infrared (FT-IR) spectroscopy has been used to rapidly and nondestructively analyze bacteria, bacteria-polymer mixtures, digester samples and microbial biofilms. Diffuse reflectance FT-IR (DRIFT) analysis of freeze-dried, powdered samples offered a means of obtaining structural information. The bacteria examined were divided into two groups. The first group was characterized by a dominant amide I band and the second group of organisms displayed an additional strong carbonyl stretch at approximately 1740 cm-1. The differences illustrated by the subtraction spectra obtained for microbes of the two groups suggest that FT-IR spectroscopy can be utilized to recognize differences in microbial community structure. Calculation of specific band ratios has enabled the composition of bacteria and extracellular or intracellular storage product polymer mixtures to be determined for bacteria-gum arabic (amide I/carbohydrate C-O approximately 1150 cm-1) and bacteria-poly-beta-hydroxybutyrate (amide I/carbonyl approximately 1740 cm-1). The key band ratios correlate with the compositions of the material and provide useful information for the application of FT-IR spectroscopy to environmental biofilm samples and for distinguishing bacteria grown under differing nutrient conditions. DRIFT spectra have been obtained for biofilms produced by Vibrio natriegens on stainless steel disks. Between 48 and 144 h, an increase in bands at approximately 1440 and 1090 cm-1 was seen in FT-IR spectra of the V. natriegens biofilm. DRIFT spectra of mixed culture effluents of anaerobic digesters show differences induced by shifts in input feedstocks. The use of flow-through attenuated total reflectance has permitted in situ real-time changes in biofilm formation to be monitored and provides a powerful tool for understanding the interactions within adherent microbial consortia.

  11. Infrared and Fluorescence Spectroscopic Investigations of the Acyl Surface Modification of Hydrogel Beads for the Deposition of a Phospholipid Coating.

    PubMed

    Grossutti, Michael; Seenath, Ryan; Lipkowski, Jacek

    2015-10-27

    The scaffolded vesicle has been employed as an alternative means of developing natural model membranes and envisioned as a potential nutraceutical transporter. Furthering the research of the scaffolded vesicle system, a nucleophilic substitution reaction was implemented to form an ester linkage between palmitate and terminal hydroxyl groups of dextran in order to hydrophobically modify the hydrogel scaffold. An average tilt angle of 38° of the hydrophobic palmitate modifying layer on the surface of the hydrogel was determined from dichroic ratios obtained from infrared spectra collected in the attenuated total reflection (ATR) configuration. ATR-IR studies of the DMPC-coated acylated hydrogel demonstrated that the hydrocarbon chains of the DMPC coating was similar to those of the DMPC bilayers and that the underlying palmitate layer had a negligible effect on the average tilt angle (26°) of the DMPC coating. The permeability of this acylated hydrogel was investigated with fluorescence spectroscopy and the terbium/dipicolinic acid assay. The hydrophobic modification on the surface of the hydrogel bead allowed for an efficient deposition of a DMPC layer that served as an impermeable barrier to terbium efflux. About 72% of DMPC-coated acylated hydrogel beads showed ideal barrier properties. The remaining 28% were leaking, but the half-life of terbium efflux of the DMPC-coated acylated hydrogel was increasing, and the total amount of leaked terbium was decreasing with the incubation time. The half-life time and the retention were considered a marked improvement relative to past scaffolded vesicle preparations. The process of acylating hydrogel beads for efficient DMPC deposition has been identified as another viable method for controlling the permeability of the scaffolded vesicle. PMID:26429738

  12. Spectroscopic and Computational Study of Acetic Acid and Its Cyclic Dimer in the Near-Infrared Region.

    PubMed

    Beć, Krzysztof B; Futami, Yoshisuke; Wójcik, Marek J; Nakajima, Takahito; Ozaki, Yukihiro

    2016-08-11

    Anharmonic vibrational analysis of near-infrared (NIR) spectra of acetic acid was carried out by anharmonic quantum chemical calculation in a wide concentration range of its CCl4 solution. By predicting vibrational spectra of acetic acid for the first time over a wide NIR region, it was possible to elucidate the influence of the formation of acetic acid cyclic dimer on its NIR spectrum. Quantum chemical simulations were based on coupled cluster and density functional theory quantum methods. Additionally, Møller-Plesset perturbation theory was employed for the additional calculation of hydrogen bonding stabilization energies. An anharmonic vibrational analysis was performed with the use of generalized second-order vibrational perturbation theory (GVPT2). A hybrid approach was assumed, in which monomeric species was treated by CCSD(T)/aug-cc-pVDZ (harmonic approximation) and B3LYP/SNSD (anharmonic approximation) methods. For the cyclic dimer, B3LYP and B2PLYP single and double hybrid functionals, paired with an SNSD basis set, were employed. DFT calculations were augmented with additional empirical dispersion correction. It was found that quantum chemically calculated vibrational modes in the NIR region are in a good agreement with experimental data. The results of anharmonic vibrational analysis were supported by a harmonic shift analysis, for elucidating the very strong anharmonic coupling observed between stretching modes of hydrogen bonded bridge in the cyclic dimer. However, the calculated wavenumbers for combination modes of double hydrogen bonded bridge in the cyclic dimer, which are very sensitive to the formation of hydrogen bonding, were found to be underestimated by quantum chemical methods. Therefore, by band fitting, the wavenumbers and shape parameters for these bands were found, and the modeled spectra were adjusted accordingly. A high accuracy of simulated spectra was achieved, and a detailed analysis of the experimental NIR spectra of acetic acid

  13. Near-infrared spectroscopic investigation of water in supercritical CO2 and the effect of CaCl2

    SciTech Connect

    Wang, Zheming; Felmy, Andrew R.; Thompson, Christopher J.; Loring, John S.; Joly, Alan G.; Rosso, Kevin M.; Schaef, Herbert T.; Dixon, David A.

    2013-01-01

    Near-infrared (NIR) spectroscopy was applied to investigate the dissolution and chemical interaction of water dissolved into supercritical carbon dioxide (scCO2) and the influence of CaCl2 in the co-existing aqueous phase at fo empe e : 40 50 75 nd 100 C at 90 atm. Consistent with the trend of the vapor pressure of water, the solubility of pure water in scCO2 inc e ed f om 40 °C (0.32 mole%) o 100 °C (1.61 mole%). The presence of CaCl2 negatively affects the solubility of water in scCO2: at a given temperature and pressure the solubility of water decreased as the concentration of CaCl2 in the aqueous phase increased, following the trend of the activity of water. A 40 °C, the water concentration in scCO2 in contact with saturated CaCl2 aqueous solution was only 0.16 mole%, a drop of more than 50% as compared to pure water while that a 100 °C was 1.12 mole%, a drop of over 30% as compared to pure water, under otherwise the same conditions. Analysis of the spectral profiles suggested that water dissolved into scCO2 exists in the monomeric form under the evaluated temperature and pressure conditions, for both neat water and CaCl2 solutions. However, its rotational degrees of freedom decrease at lower temperatures due to higher fluid densities, leading to formation of weak H2O:CO2 Lewis acid-base complexes. Similarly, the nearly invariant spectral profiles of dissolved water in the presence and absence of saturated CaCl2 under the same experimental conditions was taken as evidence that CaCl2 dissolution in scCO2 was limited as the dissolved Ca2+/CaCl2 would likely be highly hydrated and would alter the overall spectra of waters in the scCO2 phase.

  14. Spectroscopic and Computational Study of Acetic Acid and Its Cyclic Dimer in the Near-Infrared Region.

    PubMed

    Beć, Krzysztof B; Futami, Yoshisuke; Wójcik, Marek J; Nakajima, Takahito; Ozaki, Yukihiro

    2016-08-11

    Anharmonic vibrational analysis of near-infrared (NIR) spectra of acetic acid was carried out by anharmonic quantum chemical calculation in a wide concentration range of its CCl4 solution. By predicting vibrational spectra of acetic acid for the first time over a wide NIR region, it was possible to elucidate the influence of the formation of acetic acid cyclic dimer on its NIR spectrum. Quantum chemical simulations were based on coupled cluster and density functional theory quantum methods. Additionally, Møller-Plesset perturbation theory was employed for the additional calculation of hydrogen bonding stabilization energies. An anharmonic vibrational analysis was performed with the use of generalized second-order vibrational perturbation theory (GVPT2). A hybrid approach was assumed, in which monomeric species was treated by CCSD(T)/aug-cc-pVDZ (harmonic approximation) and B3LYP/SNSD (anharmonic approximation) methods. For the cyclic dimer, B3LYP and B2PLYP single and double hybrid functionals, paired with an SNSD basis set, were employed. DFT calculations were augmented with additional empirical dispersion correction. It was found that quantum chemically calculated vibrational modes in the NIR region are in a good agreement with experimental data. The results of anharmonic vibrational analysis were supported by a harmonic shift analysis, for elucidating the very strong anharmonic coupling observed between stretching modes of hydrogen bonded bridge in the cyclic dimer. However, the calculated wavenumbers for combination modes of double hydrogen bonded bridge in the cyclic dimer, which are very sensitive to the formation of hydrogen bonding, were found to be underestimated by quantum chemical methods. Therefore, by band fitting, the wavenumbers and shape parameters for these bands were found, and the modeled spectra were adjusted accordingly. A high accuracy of simulated spectra was achieved, and a detailed analysis of the experimental NIR spectra of acetic acid

  15. Near-Infrared Spectroscopic Measurement of the Effect of Leg Dominance on Muscle Oxygen Saturation During Cycling

    NASA Technical Reports Server (NTRS)

    Ellerby, Gwenn E. C.; Lee, Stuart M. C.; Paunescu, Lelia Adelina; Pereira, Chelsea; Smith, Charles P.; Soller, Babs R.

    2011-01-01

    The effect of leg dominance on the symmetry of the biomechanics during cycling remains uncertain -- asymmetries have been observed in kinematics and kinetics, while symmetries were found in muscle activation. No studies have yet investigated the symmetry of muscle metabolism during cycling. Near-infrared spectroscopy (NIRS) provides a non-invasive method to investigate the metabolic responses of specific muscles during cycling. PURPOSE: To determine whether there was an effect of leg dominance on thigh muscle oxygen saturation (SmO2) during incrementally loaded submaximal cycling using NIRS. METHODS: Eight right leg dominant, untrained subjects (5 men, 3 women; 31+/-2 yrs; 168.6+/-1.0 cm; 67.2+/-1.8 kg, mean +/- SE) volunteered to participate. Spectra were collected bilaterally from the vastus lateralis (VL) during supine rest and cycling. SmO2 was calculated using previously published methods. Subjects pedaled at 65 rpm while resistance to pedaling was increased in 0.5 kp increments from 0.5 kp every 3 min until the subject reached 80% of age-predicted maximal heart rate. SmO2 was averaged over 3 min for each completed stage. A two-way ANOVA was performed to test for leg differences. A priori contrasts were used to compare work levels to rest. RESULTS: VL SmO2 was not different between the dominant and non-dominant legs at rest and during exercise (p=0.57). How SmO2 changed with workload was also not different between legs (p=0.32). SmO2 at 0.5 kp (60.3+/-4.0, p=0.12) and 1.0 kp (59.5+/-4.0, p=0.10) was not different from rest (69.1+/-4.0). SmO2 at 1.5 kp (55.4 4.0, p=0.02), 2.0 kp (55.7+/-5.0, p=0.04), and 2.5 kp (43.4+/-7.9, p=0.01) was significantly lower than rest. CONCLUSION: VL SmO2 during cycling is not different between dominant and non-dominant legs and decreases with moderate workload in untrained cyclists. Assuming blood flow is directed equally to both legs, similar levels of oxygen extraction (as indicated by SmO2) suggests the metabolic load of

  16. An investigation using Spectroscopic Ellipsometery in Bio-Physical

    NASA Astrophysics Data System (ADS)

    Pfeiffer, Galen; Thompson, Daniel; Berberov, Emil; Woollam, John; Bleiweiss, Michael; Datta, Timir

    2001-03-01

    The present work is an investigation of bio-physical systems using spectroscopic ellipsometry (SE), with wavelengths ranging from deep-ultraviolet to the far infrared. Recent advances in SE hardware, software and data analysis permit rapid, non-contact investigation of physical properties of nano-dimensional soft-material films and interfaces such as bio-films under liquids. The kinetics of attachment, layer thickness, density of coverage, and identification of interfacial chemistry of proteins, for example, on surfaces is of practical and fundamental importance in biology and medicine, and are potentially measurable by SE. Our initial findings determine adsorption rates of Bovine Serum Albumin (BSA) and other bio-films on gold and polystyrene substrates, as well as their spatial distributions. We were also able to identify attachment of a 2.5 nm layer of the diarrhea causing E. coli enterotoxin (LT) to ganglioside (GM1) receptor, potentially simplifying and providing more information to standard enzyme linked immuno sorbent assay (ELISA) methods. Results of studies of several different bio-physical systems using SE will be discussed.

  17. Implementation of Single-Shot Ellipsometry on Gas Gun Experiments

    NASA Astrophysics Data System (ADS)

    Grant, Sean; Ao, Tommy; Bernstein, Aaron; Davis, Jean-Paul; Ditmire, Todd; Dolan, Daniel; Lin, Jung-Fu; Seagle, Christopher

    2015-06-01

    We have built and implemented a time-resolved ellipsometry diagnostic for dynamic testing at Sandia National Laboratories. This diagnostic measures refractive index of a sample under dynamic conditions with a time resolution of a few nanoseconds. We show and discuss results from our first dynamic experiments on a gas gun. Future work will study geophysical materials under relevant pressure-temperature conditions. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000. SAND2015-0376 A.

  18. Application of imaging ellipsometry to the detection of latent fingermarks.

    PubMed

    An, Ilsin

    2015-08-01

    Imaging ellipsometry (IE) is applied to visualize latent fingermarks on specular surfaces. Instead of a real image, IE provides images related to the polarization states, which are changed by the imprinted layer on a surface. Fingermarks formed on the surfaces of various materials are investigated, including a shiny metal and a black-colored plastic. Relatively clear IE images are obtained from most surfaces on which the optical properties are distinguishable from those of the fingermarks. Also, it is shown that discernible IE images can be obtained even after a fingermark is vigorously rubbed with lab tissues.

  19. Application of imaging ellipsometry to the detection of latent fingermarks.

    PubMed

    An, Ilsin

    2015-08-01

    Imaging ellipsometry (IE) is applied to visualize latent fingermarks on specular surfaces. Instead of a real image, IE provides images related to the polarization states, which are changed by the imprinted layer on a surface. Fingermarks formed on the surfaces of various materials are investigated, including a shiny metal and a black-colored plastic. Relatively clear IE images are obtained from most surfaces on which the optical properties are distinguishable from those of the fingermarks. Also, it is shown that discernible IE images can be obtained even after a fingermark is vigorously rubbed with lab tissues. PMID:26042438

  20. Analysis of Toxic Amyloid Fibril Interactions at Natively Derived Membranes by Ellipsometry

    PubMed Central

    Smith, Rachel A. S.; Nabok, Aleksey; Blakeman, Ben J. F.; Xue, Wei-Feng; Abell, Benjamin; Smith, David P.

    2015-01-01

    There is an ongoing debate regarding the culprits of cytotoxicity associated with amyloid disorders. Although small pre-fibrillar amyloid oligomers have been implicated as the primary toxic species, the fibrillar amyloid material itself can also induce cytotoxicity. To investigate membrane disruption and cytotoxic effects associated with intact and fragmented fibrils, the novel in situ spectroscopic technique of Total Internal Reflection Ellipsometry (TIRE) was used. Fibril lipid interactions were monitored using natively derived whole cell membranes as a model of the in vivo environment. We show that fragmented fibrils have an increased ability to disrupt these natively derived membranes by causing a loss of material from the deposited surface when compared with unfragmented fibrils. This effect was corroborated by observations of membrane disruption in live cells, and by dye release assay using synthetic liposomes. Through these studies we demonstrate the use of TIRE for the analysis of protein-lipid interactions on natively derived lipid surfaces, and provide an explanation on how amyloid fibrils can cause a toxic gain of function, while entangled amyloid plaques exert minimal biological activity. PMID:26172440

  1. Analysis of Toxic Amyloid Fibril Interactions at Natively Derived Membranes by Ellipsometry.

    PubMed

    Smith, Rachel A S; Nabok, Aleksey; Blakeman, Ben J F; Xue, Wei-Feng; Abell, Benjamin; Smith, David P

    2015-01-01

    There is an ongoing debate regarding the culprits of cytotoxicity associated with amyloid disorders. Although small pre-fibrillar amyloid oligomers have been implicated as the primary toxic species, the fibrillar amyloid material itself can also induce cytotoxicity. To investigate membrane disruption and cytotoxic effects associated with intact and fragmented fibrils, the novel in situ spectroscopic technique of Total Internal Reflection Ellipsometry (TIRE) was used. Fibril lipid interactions were monitored using natively derived whole cell membranes as a model of the in vivo environment. We show that fragmented fibrils have an increased ability to disrupt these natively derived membranes by causing a loss of material from the deposited surface when compared with unfragmented fibrils. This effect was corroborated by observations of membrane disruption in live cells, and by dye release assay using synthetic liposomes. Through these studies we demonstrate the use of TIRE for the analysis of protein-lipid interactions on natively derived lipid surfaces, and provide an explanation on how amyloid fibrils can cause a toxic gain of function, while entangled amyloid plaques exert minimal biological activity.

  2. Spectral ellipsometry studying of iron's optical and electronic properties

    NASA Astrophysics Data System (ADS)

    Chernukha, Yevheniia; Stashchuk, Vasyl S.; Polianska, Olena; Oshtuk, Olexsandr

    2014-05-01

    Fe's optical and electronic properties were investigated at room temperature in different structural states. The sample's surface was explored in wide spectral range λ = 0,23-17,0 μm (E = 4,96 - 0,07 еV ) by the Beatty's spectral ellipsometry method. While an experiment was carried out ellipsometry parameters Δ and ψ were measure near the principal angle of incidence. The refraction index R , permittivity Ɛ and optical conductivity σ( hν ) , that is proportional to the interband density of electronic states, were calculated using these parameters. Fe's optical conductivities in liquid, amorphous and crystalline states were compared in this work. The optical conductivity was calculated using the published data of the iron's density of electronic states in crystalline, amorphous and liquid states for the comparison of the experimental and theoretical results. It is shown that, at structural transformations "amorphous, liquid state- crystalline state", the optical properties of metallic iron are determined, in the first turn, by the nearest neighborhood, and the electronic structure is not subjected to significant modifications.

  3. Waveform analysis with optical multichannel detectors: Applications for rapid-scan spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    An, Ilsin; Collins, R. W.

    1991-08-01

    A unique rapid-scanning ellipsometer employing a rotating polarizer optical configuration and a multichannel detector for a 1.5-4.5 eV spectral range, has been developed recently for real time studies of film growth and surfaces. This is a new application of the photodiode array-based optical multichannel detector that entails waveform analysis of the incident irradiance at each photon energy. For accurate ellipsometric spectra {ψ(hν),Δ(hν)}, the raw data in the form of photon counts, integrated over four or more equal sectors of polarizer rotation, must be corrected for systematic errors originating from the detection system. Simple procedures are described to characterize and correct for the most significant errors including detection system nonlinearity, image persistence, and scattered stray light in the spectrograph/detector enclosure.

  4. Optical properties of {gamma}- and {alpha}-Ce by spectroscopic ellipsometry

    SciTech Connect

    Joo Yull, Rhee

    1992-07-20

    A rotating analyzer type ellipsometer with an ultra high vacuum sample chamber was built. The dielectric functions of {gamma}- and {alpha}-Ce were measured in the energy range from 1.5 to 5.4 eV to investigate the role of the 4f electron in the isostructural phase transition. {gamma}- and {alpha}-Ce were made by evaporation of Ce on sapphire substrates at room temperature and 25 K. All measurements were performed inside a UHV chamber at pressures lower than l {times} 10{sup {minus}10}Torr. The measured dielectric functions showed a thickness dependence. The thicker sample has the smaller optical conductivities. Both overlayer thickness and void fraction increase as sample thickness increases. Repeating cooling-heating-cooling or heating-cooling-heating cycles causes the sample surface to become rougher but the relative volume fractions of both phases and the void fraction in the bulk remain unchanged. The optical conductivity increases upon entering the a-phase but the number of electrons per atom, N{sub eff}/N{sub A}, contributing to the optical conductivity does not change. The valence electrons lose oscillator strength in the above energy range due to volume collapse. This reduces N{sub eff}/NA but the increased 4f-sd valence band hybridization exactly compensates the reduced oscillator strength. Therefore the net effects of the {gamma}{yields}{alpha} isostructural phase transition are an increase of optical conductivity and constancy of N{sub eff}/N{sub A}.

  5. A flexible experimental setup for femtosecond time-resolved broad-band ellipsometry and magneto-optics.

    PubMed

    Boschini, F; Hedayat, H; Piovera, C; Dallera, C; Gupta, A; Carpene, E

    2015-01-01

    A versatile experimental setup for femtosecond time-resolved ellipsometry and magneto-optical Kerr effect measurements in the visible light range is described. The apparatus is based on the pump-probe technique and combines a broad-band probing beam with an intense near-infrared pump. According to Fresnel scattering matrix formalism, the analysis of the reflected beam at different polarization states of the incident probe light allows one to determine the diagonal and the off-diagonal elements of the dielectric tensor in the investigated sample. Moreover, the pump-probe method permits to study the dynamics of the dielectric response after a short and intense optical excitation. The performance of the experimental apparatus is tested on CrO2 single crystals as a benchmark.

  6. A flexible experimental setup for femtosecond time-resolved broad-band ellipsometry and magneto-optics

    NASA Astrophysics Data System (ADS)

    Boschini, F.; Hedayat, H.; Piovera, C.; Dallera, C.; Gupta, A.; Carpene, E.

    2015-01-01

    A versatile experimental setup for femtosecond time-resolved ellipsometry and magneto-optical Kerr effect measurements in the visible light range is described. The apparatus is based on the pump-probe technique and combines a broad-band probing beam with an intense near-infrared pump. According to Fresnel scattering matrix formalism, the analysis of the reflected beam at different polarization states of the incident probe light allows one to determine the diagonal and the off-diagonal elements of the dielectric tensor in the investigated sample. Moreover, the pump-probe method permits to study the dynamics of the dielectric response after a short and intense optical excitation. The performance of the experimental apparatus is tested on CrO2 single crystals as a benchmark.

  7. A flexible experimental setup for femtosecond time-resolved broad-band ellipsometry and magneto-optics

    SciTech Connect

    Boschini, F.; Hedayat, H.; Piovera, C.; Dallera, C.; Gupta, A.; Carpene, E.

    2015-01-15

    A versatile experimental setup for femtosecond time-resolved ellipsometry and magneto-optical Kerr effect measurements in the visible light range is described. The apparatus is based on the pump-probe technique and combines a broad-band probing beam with an intense near-infrared pump. According to Fresnel scattering matrix formalism, the analysis of the reflected beam at different polarization states of the incident probe light allows one to determine the diagonal and the off-diagonal elements of the dielectric tensor in the investigated sample. Moreover, the pump-probe method permits to study the dynamics of the dielectric response after a short and intense optical excitation. The performance of the experimental apparatus is tested on CrO{sub 2} single crystals as a benchmark.

  8. A Comparison of Near- and Mid-Infrared Spectroscopic Methods for the Analysis of Several Nutritionally Important Chemical Substances in the Chinese Yam (Dioscorea opposita): Total Sugar, Polysaccharides, and Flavonoids.

    PubMed

    Zhuang, Hua; Ni, Yongnian; Kokot, Serge

    2015-04-01

    The Chinese yam (Dioscorea opposita) is a basic food in Asia and especially China. Consequently, an uncomplicated, reliable method should be available for the analysis of the quality and origin of the yams. Thus, near-infrared (NIR) and mid-infrared (mid-IR) spectroscopic methods were developed to discriminate among Chinese yam samples collected from four geographical regions. The yam samples were analyzed also for total sugar, polysaccharides, and flavonoids. These three analytes were used to compare the performance of the analytical methods. Overlapping spectra were resolved using chemometrics methods. Such spectra were compared qualitatively using principal component analysis (PCA) and quantitatively using partial least squares (PLS) and least squares-support vector machine (LS-SVM) models. We discriminated among the four sets of yam data using PCA, and the NIR data performed somewhat better than the mid-IR data. We constructed the PLS and LS-SVM calibration models for the prediction of the three key variables, and the LS-SVM model produced better results. Also, the NIR prediction model produced better outcomes than the mid-IR prediction model. Thus, both infrared (IR) techniques performed well for the analysis of the three key analytes, and the samples were qualitatively discriminated according to their provinces of origin. Both techniques may be recommended for the analysis of Chinese yams, although the NIR technique would be preferred.

  9. Infrared optical properties of LaNiO3-platinized silicon and PbZrχTi1-χO3-LaNiO3-platinized silicon heterostructures

    NASA Astrophysics Data System (ADS)

    Yu, J.; Huang, Z. M.; Meng, X. J.; Sun, J. L.; Chu, J. H.; Tang, D. Y.

    2001-02-01

    Using infrared spectroscopic ellipsometry, the optical constants of LaNiO3 thin films on Pt(111)-Ti-SiO2-Si substrates are obtained in the 2.5-12.6 μm range, in which the infrared optical constants decrease when the annealing temperature increases from 600 to 650 °C. At the same time, the infrared optical properties of PbZrχTi1-χO3(PZT) thin films with χ=0.3 and 0.5 on LaNiO3-Pt-Ti-SiO2-Si substrates are simultaneously studied with respect to annealing temperatures. The infrared optical properties are associated closely with the grain size and crystallographic orientation of the films induced by annealing temperature, combined by the particular substrate. For the Ni-PZT-LaNiO3-Pt multilayer heterostructures, the infrared absorptance better than 99% can be achieved for PZT pyroelectric thin film infrared microsensors.

  10. Optical response of ferromagnetic YTiO3 studied by spectral ellipsometry

    NASA Astrophysics Data System (ADS)

    Kovaleva, N. N.; Boris, A. V.; Yordanov, P.; Maljuk, A.; Brücher, E.; Strempfer, J.; Konuma, M.; Zegkinoglou, I.; Bernhard, C.; Stoneham, A. M.; Keimer, B.

    2007-10-01

    We have studied the temperature dependence of spectroscopic ellipsometry spectra of an electrically insulating, nearly stoichiometric YTiO3 single crystal with ferromagnetic Curie temperature TC=30K . The optical response exhibits a weak but noticeable anisotropy. Using a classical dispersion analysis, we identify three low-energy optical bands at 2.0, 2.9, and 3.7eV . Although the optical conductivity spectra are only weakly temperature dependent below 300K , we are able to distinguish high- and low-temperature regimes with a distinct crossover point around 100K . The low-temperature regime in the optical response coincides with the temperature range in which significant deviations from a Curie-Weiss mean-field behavior are observed in the magnetization. Using an analysis based on a simple superexchange model, the spectral weight rearrangement can be attributed to intersite di1dj1→di2dj0 optical transitions. In particular, Kramers-Kronig consistent changes in optical spectra around 2.9eV can be associated with the high-spin-state (T13) optical transition. This indicates that other mechanisms, such as weakly dipole-allowed p-d transitions and/or exciton-polaron excitations, can contribute significantly to the optical band at 2eV . The recorded optical spectral weight gain of the 2.9eV optical band is significantly suppressed and anisotropic, which we associate with complex spin-orbit-lattice phenomena near the ferromagnetic ordering temperature in YTiO3 .

  11. LiFeSi2O6 and NaFeSi2O6 at low temperatures: an infrared spectroscopic study

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Redhammer, G. J.; Salje, E. K. H.; Mookherjee, M.

    Synthetic aegirine LiFeSi2O6 and NaFeSi2O6 were characterized using infrared spectroscopy in the frequency range 50-2000cm-1, and at temperatures between 20 and 300K. For the C2/c phase of LiFeSi2O6, 25 of the 27 predicted infrared bands and 26 of 30 predicted Raman bands are recorded at room temperature. NaFeSi2O6 (with symmetry C2/c) shows 25 infrared and 26 Raman bands. On cooling, the C2/c-P21/c structural phase transition of LiFeSi2O6 is characterized by the appearance of 13 additional recorded peaks. This observation indicates the enlargement of the unit cell at the transition point. The appearance of an extra band near 688cm-1 in the monoclinic P21/c phase, which is due to the Si-O-Si vibration in the Si2O6 chains, indicates that there are two non-equivalent Si sites with different Si-O bond lengths. Most significant spectral changes appear in the far-infrared region, where Li-O and Fe-O vibrations are mainly located. Infrared bands between 300 and 330cm-1 show unusually dramatic changes at temperatures far below the transition. Compared with the infrared data of NaFeSi2O6 measured at low temperatures, the change in LiFeSi2O6 is interpreted as the consequence of mode crossing in the frequency region. A generalized Landau theory was used to analyze the order parameter of the C2/c-P21/c phase transition, and the results suggest that the transition is close to tricritical.

  12. Reflectometry-Ellipsometry Reveals Thickness, Growth Rate, and Phase Composition in Oxidation of Copper.

    PubMed

    Diaz Leon, Juan J; Fryauf, David M; Cormia, Robert D; Zhang, Min-Xian Max; Samuels, Kathryn; Williams, R Stanley; Kobayashi, Nobuhiko P

    2016-08-31

    The oxidation of copper is a complicated process. Copper oxide develops two stable phases at room temperature and standard pressure (RTSP): cuprous oxide (Cu2O) and cupric oxide (CuO). Both phases have different optical and electrical characteristics that make them interesting for applications such as solar cells or resistive switching devices. For a given application, it is necessary to selectively control oxide thickness and cupric/cuprous oxide phase volume fraction. The thickness and composition of a copper oxide film growing on the surface of copper widely depend on the characteristics of as-deposited copper. In this Research Article, two samples, copper films prepared by two different deposition techniques, electron-beam evaporation and sputtering, were studied. As the core part of the study, the formation of the oxidized copper was analyzed routinely over a period of 253 days using spectroscopic polarized reflectometry-spectroscopic ellipsometry (RE). An effective medium approximation (EMA) model was used to fit the RE data. The RE measurements were complemented and validated by using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and X-ray diffraction (XRD). Our results show that the two samples oxidized under identical laboratory ambient conditions (RTSP, 87% average relative humidity) developed unique oxide films following an inverse-logarithmic growth rate with thickness and composition different from each other over time. Discussion is focused on the ability of RE to simultaneously extract thickness (i.e., growth rate) and composition of copper oxide films and on plausible physical mechanisms responsible for unique oxidation habits observed in the two copper samples. It appears that extended surface characteristics (i.e., surface roughness and grain boundaries) and preferential crystalline orientation of as-deposited polycrystalline copper films control the growth kinetics of the copper oxide film. Analysis based on a noncontact

  13. [Dynamics of cerebral circulation in patients with chronic cerebrovascular disease--analysis with multi-channel near infra-red spectroscopic topography plus hand grasp as the exercise task].

    PubMed

    Harada, Kunyu; Ishizaki, Fumiko; Ozawa, Yoshiaki; Imaizumi, Satoshi; Harada, Toshihide; Yamada, Tohru

    2008-12-01

    We used multi-channel near infra-red spectroscopic topography to evaluate the dynamics of cerebral circulation of patients with cerebrovascular disease (CVD). The subjects included 17 patients with chronic CVD, while 11 physically unimpaired persons served as controls. We used a spectroscopic topography device (Hitachi, ETG -100) to determine the topographic values of oxy-Hb, deoxy-Hb, and total-Hb in the right and left cerebral hemispheres. Hand grasp for 30 or 60 second duration was used as the exercise task, and each task was tried twice. In the control group, the oxy-Hb values of the left cerebral hemisphere were elevated by bilateral hand grasp, while those of the right cerebral hemisphere were elevated by left hand grasp. In patients with a lesion in the left cerebral hemisphere, oxy-Hb values of the left hemisphere were elevated by the bilateral hand grasp, while those of the right hemisphere were elevated only by the healthy left hand grasp. When the 30- and 60-second-duration grasp exercises were compared, it was found that the oxy-Hb values in the control group corresponded to the loading time. In patients with either right or left cerebral lesion, the oxy-Hb peak values were lower than those of the control group, while the peak values did not show any difference between the 30-and 60-seconds hand grip durations themselves. The latency from the start of the grasp to the maximum peak of the oxy-Hb value was significantly prolonged in CVD patients as compared with that in the control group. As for the relation between the degree of hemiparesis and the oxy-Hb values, the value of the oxy-Hb in the left cerebral hemisphere during right hand grasp decreases depending on the severity of paralysis induced by the left cerebral lesion. The determination of cerebral oxy-Hb values by near infra-red spectroscopic topography using exercise test appeared to be useful for the evaluation of the dynamic of cerebral circulation in stroke patients. Furthermore, the

  14. Method on camouflaged target recognition using the angle of ellipsometry

    NASA Astrophysics Data System (ADS)

    Zhuansun, Xiao-bo; Wu, Wen-Yuan; Huang, Yan-hua; Li, Zhao-zhao

    2015-10-01

    Using polarimetric information of the camouflaged target surface to identify camouflage has been a hot research area in camouflage detecting. The main method is to use the difference in the degree of polarization(DOP) between background and target to add the contrast ratio of them. The measurement of the DOP has some requirements on the intensity of reflected radiation. In case of low reflected radiation intensity, the difference in the DOP for different materials is not so distinguishable. In addition, the linear degree of polarization is largely under the effects of detection angle and surface roughness, so it is hard to differentiate the degree of polarization when the targets with similar surface roughness are detected at the same detection angle. By analyzing the elements affecting the reflected electromagnetic radiation amplitudes and phase on the camouflaged target surface, this article makes a research on the polarization character of reflected radiation A method on camouflaged target recognition directly or indirectly by taking the angle of ellipsometry (AOE) imaging under the linear polarized light. The function model of the angle of incidence, complex refractive index and AOE was modeled, then the model was simulated by MATLAB and the results showed it can describe the distribution properties of AOE. A new thought for the approach of identifying camouflaged target recognition by detecting polarimetric information was proposed, and it has a deep theoretical and practical significance in camouflaged target recognition.

  15. Building global models for fat and total protein content in raw milk based on historical spectroscopic data in the visible and short-wave near infrared range.

    PubMed

    Melenteva, Anastasiia; Galyanin, Vladislav; Savenkova, Elena; Bogomolov, Andrey

    2016-07-15

    A large set of fresh cow milk samples collected from many suppliers over a large geographical area in Russia during a year has been analyzed by optical spectroscopy in the range 400-1100 nm in accordance with previously developed scatter-based technique. The global (i.e. resistant to seasonal, genetic, regional and other variations of the milk composition) models for fat and total protein content, which were built using partial least-squares (PLS) regression, exhibit satisfactory prediction performances enabling their practical application in the dairy. The root mean-square errors of prediction (RMSEP) were 0.09 and 0.10 for fat and total protein content, respectively. The issues of raw milk analysis and multivariate modelling based on the historical spectroscopic data have been considered and approaches to the creation of global models and their transfer between the instruments have been proposed. Availability of global models should significantly facilitate the dissemination of optical spectroscopic methods for the laboratory and in-line quantitative milk analysis.

  16. Noninvasive in-vivo near-infrared vibrational spectroscopic study of lipid and aqueous phases of skin and near-surface tissues

    NASA Astrophysics Data System (ADS)

    Chaiken, Joseph; Finney, William F.; Peterson, Karen P.; Peterson, Charles M.; Knudson, Paul E.; Weinstock, Ruth S.; Lein, Paul

    2000-05-01

    We report the use of near infrared vibrational spectroscopy to noninvasively probe the in-vivo lipid and aqueous phases of skin and near surface tissues under conditions of thermal and chemical modulation. We demonstrate thermally induced order- disorder transitions in lipids that can be directly compared to well known behavior of in-vitro samples of phospholipid bilayers and bulk fatty acids. We show reversible chemical modification of aqueous phase proteins which are also directly comparable to well known phenomena involving in-vitro proteins. The results of these studies demonstrate the capacity for noninvasively probing live human tissues on the molecular level using near infrared vibrational spectroscopy. This capacity suggests numerous potential applications ranging from assessing the efficacy of cosmetics, skin care treatments and transdermal therapeutic agents/treatments to serving as a diagnostic of various skin ailments, e.g. melanoma.

  17. Proton location in (CH3)3N-H+-(CH3OH)n: A theoretical and infrared spectroscopic study

    NASA Astrophysics Data System (ADS)

    Bing, Dan; Hamashima, Toru; Tsai, Chen-Wei; Fujii, Asuka; Kuo, Jer-Lai

    2013-06-01

    The dependence of the preferential protonated site in (CH3)3N-H+-(CH3OH)n on the cluster size was investigated using theoretical calculations and infrared spectroscopy measurements. While simple estimation from the magnitude of proton affinity suggested that the excess proton prefers the methanol site in n ⩾ 4, density functional theory calculations of the stabilization energy indicated the clear preference as protonation of the trimethylamine site, even for n = 9. Infrared spectra of the clusters were observed for n = 3-7. Spectral simulations were also performed using the quantum harmonic superposition approximation. The observed (CH3)3N-H+-(CH3OH)n spectra were well interpreted by simulations of the isomers with the protonated trimethylamine ion core. It was shown that both the proton affinity and the mutual solvation energy govern the preferential location of the excess proton in binary component clusters.

  18. Quantitative characterization of chitosan in the skin by Fourier-transform infrared spectroscopic imaging and ninhydrin assay: application in transdermal sciences.

    PubMed

    Nawaz, A; Wong, T W

    2016-07-01

    The chitosan has been used as the primary excipient in transdermal particulate dosage form design. Its distribution pattern across the epidermis and dermis is not easily accessible through chemical assay and limited to radiolabelled molecules via quantitative autoradiography. This study explored Fourier-transform infrared spectroscopy imaging technique with built-in microscope as the means to examine chitosan molecular distribution over epidermis and dermis with the aid of histology operation. Fourier-transform infrared spectroscopy skin imaging was conducted using chitosan of varying molecular weights, deacetylation degrees, particle sizes and zeta potentials, obtained via microwave ligation of polymer chains at solution state. Both skin permeation and retention characteristics of chitosan increased with the use of smaller chitosan molecules with reduced acetyl content and size, and increased positive charge density. The ratio of epidermal to dermal chitosan content decreased with the use of these chitosan molecules as their accumulation in dermis (3.90% to 18.22%) was raised to a greater extent than epidermis (0.62% to 1.92%). A larger dermal chitosan accumulation nonetheless did not promote the transdermal polymer passage more than the epidermal chitosan. A small increase in epidermal chitosan content apparently could fluidize the stratum corneum and was more essential to dictate molecular permeation into dermis and systemic circulation. The histology technique aided Fourier-transform infrared spectroscopy imaging approach introduces a new dimension to the mechanistic aspect of chitosan in transdermal delivery. PMID:26695532

  19. Symposium on Recent Results in Infrared Astrophysics

    NASA Technical Reports Server (NTRS)

    Dyal, P. (Editor)

    1977-01-01

    Abstracts of papers presented at a symposium titled Recent Results in Infrared Astrophysics are set forth. The abstracts emphasize photometric, spectroscopic, polarization, and theoretical results on a broad range of current topics in infrared astrophysics.

  20. Kinetic analysis of biomolecular interactions by surface plasmon enhanced ellipsometry

    NASA Astrophysics Data System (ADS)

    Cho, Hyun Mo; Chegal, Won; Cho, Yong Jai; Won, Jong Myoung; Lee, Hak Min; Jo, Jae Heung

    2011-10-01

    We present the application of ellipsometry to the phase measurement of surface plasmon resonance (SPR) in biomolecular detection. In this work, the experimental setup for the SPR sensor was based on a custom-built rotating analyzer ellipsometer, which was equipped with a SPR cell and a microfluidic system. We investigate the sensitivity of SPR sensor which is dependent on the thickness and roughness of metal film, alignment of optical system, and stability of microfluidics. In the drug discovery process, to directly monitor the interaction of small molecule-protein, it is necessary to design a high-sensitivity SPR sensor with a sensitivity of greater than 1 pg/mm2. Our sensor demonstrates a much better sensitivity in comparison to other SPR sensors based on reflectometry or phase measurements. The results of calibration indicate that the phase change, δ▵, had an almost linear response to the concentration of ethanol in the double-distilled water solutions. A quantitative analysis of refractive index variation was possible using the results of the ellipsometric model fits for the multilayered thin film on the gold film. Thus, this method is applicable not only to sensor applications, such as affinity biosensors, but also to highly sensitive kinetics for drug discovery. In this paper, we demonstrate how a custom-built rotating analyzer ellipsometer in the SPR condition can be used to directly obtain the interactions and binding kinetics of analytes (biotins, peptides) with immobilized ligand (streptavidin, antibody). We achieved a detection limit of lower than 1.0 x10-7 RIU, which is the equivalent of 0.1 pg/mm2.