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Sample records for infrared spectroscopic ellipsometry

  1. Spectroscopic infrared ellipsometry

    NASA Astrophysics Data System (ADS)

    Roseler, A.

    1992-03-01

    The spectroscopic infrared ellipsometry (SIRE) by means of the combination of a photometric ellipsometer with a Fourier transform spectrometer is used to measure optical properties in the infrared. From the observed four Stokes parameters, the spectrum of the degree of polarization after the reflection at the sample is calculated and discussed.

  2. Progress in spectroscopic ellipsometry: Applications from vacuum ultraviolet to infrared

    NASA Astrophysics Data System (ADS)

    Hilfiker, James N.; Bungay, Corey L.; Synowicki, Ron A.; Tiwald, Thomas E.; Herzinger, Craig M.; Johs, Blaine; Pribil, Greg K.; Woollam, John A.

    2003-07-01

    Spectroscopic ellipsometry (SE) is a noncontact and nondestructive optical technique for thin film characterization. In the past 10 yr, it has migrated from the research laboratory into the semiconductor, data storage, display, communication, and optical coating industries. The wide acceptance of SE is a result of its flexibility to measure most material types: dielectrics, semiconductors, metals, superconductors, polymers, biological coatings, and even multilayers of these materials. Measurement of anisotropic materials has also made huge strides in recent years. Traditional SE measurements cover the ultraviolet, visible, and near infrared wavelengths. This spectral range is now acquired within seconds with high accuracy due to innovative optical configurations and charge coupled device detection. In addition, commercial SE has expanded into both the vacuum ultraviolet (VUV) and midinfrared (IR). This wide spectral coverage was achieved by utilizing new optical elements and detection systems, along with UV or Fourier transform IR light sources. Modern instrumentation is now available with unprecedented flexibility promoting a new range of possible applications. For example, the VUV spectral region is capable of characterizing lithographic materials for 157 nm photolithography. The VUV also provides increased sensitivity for thin layers (e.g., gate oxides or self-assembled monolayers) and allows investigation of high-energy electronic transitions. The infrared spectral region contains information about semiconductor doping concentration, phonon absorption, and molecular bond vibrational absorptions. In this work, we review the latest progress in SE wavelength coverage. Areas of significant application in both research and industrial fields will be surveyed, with emphasis on wavelength-specific information content.

  3. Rotatable broadband retarders for far infrared spectroscopic ellipsometry

    SciTech Connect

    Kang, T.D.; Carr, G.; Zhou, T.; Kotelyanskii, M.; Sirenko, A.A.

    2010-12-09

    Rotatable retarders have been developed for applications in spectroscopic, full Mueller Matrix ellipsometry in the far-IR spectral range. Several materials, such as silicon, KRS-5, and a commercial polymer plastic (TOPAS) have been utilized to achieve a fully adjustable retardation between 0{sup o} and 90{sup o}. Experimental characteristics of the rotatable retarders that utilize three- and four-bounce designs are compared with calculations. We discuss the effect of light focusing on the performance of these rotatable retarders. Broadband optical retarders are required for spectroscopic ellipsometry in its full Mueller matrix (MM) realization. Performance of the MM ellipsometer depends on the capability to produce substantially linearly-independent Stokes vectors for the light incident onto the sample. As has been shown, the errors in the measuredMMof the sample are proportional to the condition number of the 4 x 4 matrix composed of the Stokes vectors of four polarization states incident at the sample. It can be proven that it is impossible to cover the Poincare sphere with linearly-independent Stokes vectors by only changing the linear polarization at the input surface of a stationary retarder. As we will illustrate further in this paper, total coverage of the Poincare sphere is possible by rotating a tandem of a linear polarizer and a retarder with a retardation of 90{sup o}. It is this goal that we are trying to achieve in the retarder designs described in this paper.

  4. Skeletal silica characterization in porous-silica low-dielectric-constant films by infrared spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Takada, Syozo; Hata, Nobuhiro; Seino, Yutaka; Fujii, Nobutoshi; Kikkawa, Takamaro

    2005-06-01

    Porous-silica low-dielectric-constant (low-k) films were prepared using a sol-gel method based on the self-assembly of surfactant templates. No change in the refractive index at 633 nm nor in the infrared-absorption intensities of C-H and O-H stretching vibrations at around 2900 and 3400cm-1 of porous-silica low-k films were observed after annealing at each temperature from 523 to 723 K. On the other hand, the Young's elastic modulus and hardness increased with the increase of annealing temperature. The structure in the complex dielectric function of porous-silica low-k films observed in between 1000 and 1400cm-1 is assigned as the asymmetric stretching vibration mode of the Si-O-Si bond. By applying the effective-medium theory by Bruggeman to the experimental results from infrared spectroscopic ellipsometry, we analyzed the skeletal silica structures. The peak positions of transverse (ωTO) and longitudinal (ωLO) vibration modes for Si-O-Si network in the silica skeleton of porous-silica films changed from 1061 to 1068cm-1 and from 1219 to 1232cm-1, respectively, with the annealing temperature. It is shown that the ωLO2/ωTO2 of skeletal silica correlates with Young's elastic modulus of porous-silica low-k films.

  5. Spectroscopic rotating compensator ellipsometry in the infrared: retarder design and measurement

    NASA Astrophysics Data System (ADS)

    den Boer, J. H. W. G.; Kroesen, G. M. W.; de Hoog, F. J.

    1997-05-01

    Rotating compensator ellipsometry (RCE) is an approach to ellipsometry that is superior to the widely used rotating analyser ellipsometry (RAE). An essential component in RCE is a retarder that generates a retardance close to 0957-0233/8/5/004/img1. In contrast to RCE at a single wavelength, spectroscopic RCE requires a retarder that performs well over a wide range of the used spectrum. The designed retarder is capable of this and works on the principle of total internal reflection. Making use of this retarder, RCE is tested by measuring the optical characteristics of a Teflon-like layer on an aluminium substrate. The results show good agreement with similar RAE measurements, as well as data calculated from an ellipsometric model.

  6. 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.

  7. Study of the interface Si-nc/SiO 2 by infrared spectroscopic ellipsometry and X-ray photoelectron spectroscopy

    NASA Astrophysics Data System (ADS)

    Stenger, I.; Gallas, B.; Siozade, L.; Fisson, S.; Vuye, G.; Chenot, S.; Rivory, J.

    2007-04-01

    SiO x films (1< x<2), 0.5 μm thick, have been elaborated by electron-gun evaporation. A thermal annealing of these films induced a phase separation leading to the formation of Si nanocrystals embedded in a SiO 2 matrix. These films have been studied by infrared spectroscopic ellipsometry and by X-ray photoelectron spectroscopy (XPS). The effective dielectric function of the thin films has been extracted in the 600-5000 cm -1 range which allowed us to deduce the dielectric function of the matrix surrounding the Si-nc. A study of the Transverse Optical (TO) vibration mode has revealed the presence of SiO x into the matrix. Before XPS measurements, the films have been etched in fluorhydric acid to remove the superficial SiO 2 layer formed during air exposure. The Si 2p core-level emission has been recorded. The decomposition of the Si 2p peak into contributions of the usual five tetrahedrons Si-(Si 4-nO n) ( n=0-4) has also revealed the presence of a SiO x phase. Consistency between infra-red and XPS results is discussed.

  8. Spectroscopic Ellipsometry Applications in Advanced Lithography Research

    NASA Astrophysics Data System (ADS)

    Synowicki, R. A.; Pribil, Greg K.; Hilfiker, James N.; Edwards, Kevin

    2005-09-01

    Spectroscopic ellipsometry (SE) is an optical metrology technique widely used in the semiconductor industry. For lithography applications SE is routinely used for measurement of film thickness and refractive index of polymer photoresist and antireflective coatings. While this remains a primary use of SE, applications are now expanding into other areas of advanced lithography research. New applications include immersion lithography, phase-shift photomasks, transparent pellicles, 193 and 157 nm lithography, stepper optical coatings, imprint lithography, and even real-time monitoring of etch development rate in liquid ambients. Of recent interest are studies of immersion fluids where knowledge of the fluid refractive index and absorption are critical to their use in immersion lithography. Phase-shift photomasks are also of interest as the thickness and index of the phase-shift and absorber layers must be critically controlled for accurate intensity and phase transmission. Thin transparent pellicles to protect these masks must be also characterized for thickness and refractive index. Infrared ellipsometry is sensitive to chemical composition, film thickness, and how film chemistry changes with processing. Real-time monitoring of polymer film thickness during etching in a liquid developer allows etch rate and endpoint determination with monolayer sensitivity. This work considers these emerging applications to survey the current status of spectroscopic ellipsometry as a characterization technique in advanced lithography applications.

  9. Infrared optical properties of mixed-phase thin films studied by spectroscopic ellipsometry using boron nitride as an example

    NASA Astrophysics Data System (ADS)

    Schubert, M.; Rheinländer, B.; Franke, E.; Neumann, H.; Tiwald, T. E.; Woollam, J. A.; Hahn, J.; Richter, F.

    1997-11-01

    We present a microstructure-dependent anisotropic infrared-optical dielectric function model for mixed-phase polycrystalline material from which we derive the transverse and longitudinal-optical modes observable in thin films. Infrared ellipsometry over the wavelength range from 700 to 3000 cm-1 is then used to determine the phase and microstructure of polycrystalline and multilayered hexagonal and cubic boron nitride thin films deposited by magnetron sputtering onto (100) silicon. The ellipsometric data depend on the thin-film multilayer structure, the layer-phase composition, and the average orientation of the hexagonal grain c axes. In particular, we demonstrate the existence of spectral shifts of longitudinal optical phonons as a function of microstructure, i.e., the average grain crystallographic orientation within the mixed-phase material.

  10. 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.

  11. Spectroscopic ellipsometry as a sensitive monitor of materials contamination

    NASA Technical Reports Server (NTRS)

    Hale, Jeffrey S.; Hilfiker, James N.; Spady, Blaine; Synowicki, R.; Woollam, John A.

    1995-01-01

    Spectroscopic ellipsometry is demonstrated to be extremely sensitive to contamination layers in the thickness range from 0.1 nm to 10 microns. In the present experiments we deposit either a thin lubricating oil (WD-40) or mineral oil continuously onto Ir, Cu, Al, Au, and V substrates from a bubbler, and monitor its thickness growth from sub-nanometer to tens of nanometers as a function of time. Re-evaporation of contaminant oils is also monitored in real-time by ellipsometry.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Anisotropic dielectric functions of (0001) sapphire from spectroscopic ellipsometry and first-principles study

    NASA Astrophysics Data System (ADS)

    Yang, J. Y.; Zhang, W. J.; Liu, L. H.

    2015-09-01

    This work aims at understanding and predicting the high-temperature anisotropic dielectric functions of (0001) sapphire over the entire infrared-visible-ultraviolet spectrum via the state-of-the-art infrared variable angle spectroscopic ellipsometry (IR-VASE) and first-principles method without empirical parameters. Upon measuring the high-symmetry orientation of c-plane surface, the IR-VASE determines the anisotropic infrared dielectric functions of (0001) sapphire for wavelengths ranging from 10 to 25 μm and temperatures from 300 to 573 K. As ellipsometry experiments indicate, the maxima of ordinary infrared dielectric functions consistently decrease and shift to longer wavelength as temperature increases. By fitting ellipsometry data with the Lorentz oscillator model, the Lorentz parameters, e.g., oscillator strength, resonance frequency and broadening parameter, for infrared-active phonon modes are obtained to interpret the temperature effect. Moreover, the calculated vibration frequencies at varying temperatures by the first-principles method coincide with the positions of infrared absorption peaks, indicating that infrared optical absorption mainly arises from the coupling of incident photon with lattice vibration. In the visible-ultraviolet spectral range, the first-principles and lattice dynamics methods are combined to understand the temperature effect on dielectric functions of (0001) sapphire. This method reproduces the essential feature of previous room-temperature reflectivity experiments and detects the slight change of dielectric functions as temperature increases. The convincing results enable us to predict the high-temperature visible-ultraviolet dielectric functions of (0001) sapphire by the first-principles method.

  17. 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.

  18. 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.

  19. Measurement of the dielectric function spectra of low dielectric constant using the spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Horie, Masahiro; Postava, Kamil; Yamaguchi, Tomuo; Akashika, Kumiko; Hayashi, Hideki; Kitamura, Fujikazu

    2003-05-01

    The dielectric function spectra of low dielectric constants (low-k) materials have been determined using spectroscopic ellipsometry, normal incidence spectroscopic reflectometry, and Fourier transform infrared transmission spectrometry over a wide spectral range from 0.03 to 5.4 eV (230nm to 40.5um wavelength region). The electric and ionic contributions to the overall static dielectric constants were determined for representative materials used in the semiconductor industry for interlayer dielectrics: (1) FLARE - organic spin-on polymer, (2) HOSP - spin-on hybrid organic-siloxane polymer from the Honeywell Electric Materials Company, and (3) SiLK- organic dielectric resin from the Dow Chemical Company. The main contributions to the static dielectric constant of the low-k materials studied were found to be the electric and ionic absorption.

  20. Ellipsometry

    SciTech Connect

    Podraza, N J; Jellison Jr, Gerald Earle

    2014-01-01

    Ellipsometry is a technique often used to measure the thickness and properties of a thin film. This article covers the instrumental, theoretical, and practical aspects of this technique. Notably, different types of instruments including nulling ellipsometer, rotating compensator ellipsometer, and photoelastic modulator ellipsometer designs are presented. Elements of proper data analysis are also included, such as the use of an error-based figure of merit.

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    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.

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

    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.

  3. 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.

  4. 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.

  5. 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.

  6. 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. PMID:27460278

  7. Nanoscale Ice: Spectroscopic Ellipsometry of Epitaxially-Grown Crystals

    NASA Astrophysics Data System (ADS)

    Cumiskey, A.; Grippaldi, J.; Magee, N. B.

    2011-12-01

    A new laboratory technique has been developed to examine the surface characteristics and kinetics of ice crystals at the nanoscale. Uncertainties remain regarding the fundamental physics of nucleation and depositional growth in atmospheric ice crystals. These molecular-scale uncertainties propagate upward into modeling outcomes at all scales of atmospheric interest: particle models, cloud models, mesoscale models, and climate models. Molecular-scale growth mechanisms and kinetics have been mainly inferred from bulk and particle-scale experiments as well as crystal-growth theory. The precarious nature of the ice surface resisted the first generation of direct nanoscale probing technologies, but new in-situ techniques including ESEM, AFM, and ellipsometry promise to divulge a wealth of new knowledge. Spectroscopic ellipsometry measures changes in the polarization state of light as it reflects off the surface of a thin film. This non-destructive technique is capable of measuring layer thicknesses as small as a single monolayer (~1 Å) and up to thicknesses of ~10 μm. Other physical parameters including index of refraction and surface roughness are also accessible. At the TCNJ Cloud Physics Laboratory, a Horiba Scientific Auto-SE ellipsometer (440 - 1000 nm spectral range) has been adapted for in-situ measurements of ice crystals. The ice crystals are grown epitaxially on various horizontal substrates in a custom-built static diffusion chamber. The diffusion chamber is housed within a vacuum chamber and an optical path is provided from the ellipsometer light source to sample stage and back to the ellipsometer analyzer at 75° from normal. The diffusion chamber is cooled in two stages, with initial cooling accomplished with a fluid-chilled block and final chilling controlled by two independent thermoelectric cells. A wide range of temperatures, pressures, and saturation ratios are accessible: from 0°C to -30°C, 50mb to atmospheric pressure, and from subsaturated to

  8. 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.

  9. 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

  10. Fourier transform infrared synchrotron ellipsometry for studying the anisotropy of small organic samples.

    PubMed

    Hinrichs, K; Gensch, M; Röseler, A; Korte, E H; Sahre, K; Eichhorn, K J; Esser, N; Schade, U

    2003-10-01

    An experimental setup for polarization-dependent and spectroscopic ellipsometric measurements was developed that utilizes the brilliance of synchrotron infrared radiation at the electron storage ring at BESSY II for investigations of small samples and sample areas. During commissioning of the beamline and the experimental setup, a 1 mm2 piece of a well-characterized polyimide film was studied to show the benefits of Fourier transform infrared (FT-IR) synchrotron ellipsometry. The band shapes are interpreted with respect to the anisotropic distribution of transition dipole moments within the film. In comparison to a globar source, the signal intensity has been improved by more than one order of magnitude for this example. PMID:14639753

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. Optical characterization of ferroelectric PZT thin films by variable angle spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Rahman, Md. Shafiqur; Garcia, Carlos D.; Bhalla, Amar; Guo, Ruyan

    2014-09-01

    Ferroelectric thin films are used as high dielectric constant capacitors, infrared detectors, piezoelectric transducers, optical modulators, optical waveguides, and nonvolatile memory chips for dynamic random access memory (DRAM) etc. While ferroelectric and dielectric properties of these films have been extensively investigated, their optical properties have been comparatively less studied and of limited use in quantitative evaluation of multilayer thin films. In this work we explored the variable angle spectroscopic ellipsometry (VASE) technique for its effectiveness in physical property characterization. The VASE combined with its computer modeling tool enables nondestructive, nonintrusive, and contactless optical means for optical characterization. Crystalline Lead Zirconium Titanate PbZr0.52Ti0.48O3 (PZT) thin films, fabricated on SrTiO3 layer atop of Si substrates, were characterized using VASE (J.A. Woollam; Lincoln, NE, USA) by determining the ellipsometric parameters Ψ and Δ as a function of wavelengths (200-1000 nm) and incident angles (65°, 70°,75°) at room temperature. A physical representation of the multilayer system was constructed by a six layer model (analysis software WVASE32, J.A. Woollam) through a step-by-step method. Other physical properties characterized by several well-known techniques on structure, morphology and topographical features correspond well with the models developed using VASE alone. The technique and the methodology developed have shown promises in identifying the respective thickness and optical properties of multilayer thin film system, with limited input of processing or composition information.

  17. Thin-film hermeticity - A quantitative analysis of diamondlike carbon using variable angle spectroscopic ellipsometry

    NASA Technical Reports Server (NTRS)

    Orzeszko, S.; De, Bhola N.; Woollam, John A.; Pouch, John J.; Alterovitz, Samuel A.

    1988-01-01

    This paper reports on the successful application of variable-angle spectroscopic ellipsometry to quantitative thin-film hermeticity evaluation. It is shown that, under a variety of film preparations and moisture introduction conditions, water penetrates only a very thin diamondlike carbon (DLC) top surface-roughness region. Thus, DLC is an excellent candidate for use as protective coatings in adverse chemical and aqueous environments.

  18. 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.

  19. Optical characterization of isotactic polypropylene and carbon nanotube composites using spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Sarkar, Sabyasachi; Kalakonda, Parvathalu; Georgiev, Georgi; Iannacchione, Germano

    2013-03-01

    We report the dielectric properties of optically characterized isotactic polypropylene (iPP) and its composites with carbon nanotubes (CNTs) using spectroscopic ellipsometry. Characterization was performed at angles ranging from 50 to 70 degrees and for the spectral range between 300-1000 nm. CNT concentrations varied from 0 to 5 wt% in the iPP/CNT composites investigated. Ellipsometry is a non-invasive and non-destructive technique that enabled us to determine the dielectric properties of the materials investigated. A concentration dependency on CNT wt% was found to exist for both the refractive index and the extinction coefficient for the iPP/CNT composites. At higher concentrations however, this distinction was not very clear, suggesting that saturation levels were reached in the material. We will also discuss our efforts to separate the optical properties of bound CNT from the analyzed nanocomposites.

  20. 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.

  1. Bonding structure of carbon nitride films by infrared ellipsometry

    NASA Astrophysics Data System (ADS)

    Laskarakis, A.; Logothetidis, S.; Gioti, M.

    2001-09-01

    Carbon nitride (CNx) films were deposited by reactive sputtering to study the effect of the ion bombardment during deposition (IBD) on their bonding structure. Fourier-transform infrared (IR) ellipsometry (FTIRE) was used to identify and distinguish the characteristic bands of the sp3 C-N, sp2 C=N, sp1 (-C≡N, -N≡C) and the IR-inactive C=C bonds. The results are compared and discussed in view of the films' electronic behavior through the dielectric function ɛ(ω) in NIR-visible-UV region and with those obtained by nanoindentation measurements. The low-energy IBD is suggested to promote the homogeneous N distribution in the films, resulting in films with low hardness (~6 GPa) and stress. On the contrary, the high-energy IBD results in high-N concentration in localized regions of the films, where possibly the formation of fullerenelike and C3N4 structures is favored. Indeed, hardness values up to 45 GPa were measured at some regions of these films, along with the high stress and hardness that they exhibit. Their absorption due to π-->π* electronic transitions is higher and exhibit strong absorption ~1.6 eV where the low-energy IBD films are transparent. Furthermore, the effect of postdeposition thermal annealing to 900 °C on the bonding structure of the films was investigated. It was found that the structural modifications induced by the N removal from the carbon-nitrogen bonds depend on the bonding structure of the films, as determined by the IBD energy. The N evolution from sp3 C-N bonds is more intense in low-energy IBD films and more pronounced around 450 °C, while the C-N bonds of pentagons and C3N4 structures, contained mainly in high-energy IBD films, are more stable and break at higher temperatures. Above 600 °C, N is evolved from the sp2 C=N bonds, while the most stable structures (i.e., sp1 -N≡C and -C≡N groups) break above 700 °C. The thermal treatment differentially affects the electronic transitions; the π-->π* are almost stable, while

  2. Measurement of the optical properties of a transparent, conductive carbon nanotube film using spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Kuwahara, Masashi; Kim, Yeji; Azumi, Reiko

    2015-07-01

    We have measured the complex refractive indices of a transparent, conductive carbon nanotube film by spectroscopic ellipsometry at wavelengths of 300-1700 nm (this includes the visible range). The film was produced on a quartz substrate by the doctor-blade method using single-walled carbon nanotube-polymer ink. The imaginary part of the complex refractive index of the film was found to be lower than 0.09 over the entire wavelength range. This film has a large advantage as a transparent, flexible, and conductive material.

  3. Investigation of the optical properties of MoS{sub 2} thin films using spectroscopic ellipsometry

    SciTech Connect

    Yim, Chanyoung; O'Brien, Maria; Winters, Sinéad; McEvoy, Niall; Mirza, Inam; Lunney, James G.; Duesberg, Georg S.

    2014-03-10

    Spectroscopic ellipsometry (SE) characterization of layered transition metal dichalcogenide (TMD) thin films grown by vapor phase sulfurization is reported. By developing an optical dispersion model, the extinction coefficient and refractive index, as well as the thickness of molybdenum disulfide (MoS{sub 2}) films, were extracted. In addition, the optical band gap was obtained from SE and showed a clear dependence on the MoS{sub 2} film thickness, with thinner films having a larger band gap energy. These results are consistent with theory and observations made on MoS{sub 2} flakes prepared by exfoliation, showing the viability of vapor phase derived TMDs for optical applications.

  4. Dielectric function of sol-gel prepared nano-granular zinc oxide by spectroscopic ellipsometry

    SciTech Connect

    Gilliot, Mickaël Hadjadj, Aomar; Eypert, Céline

    2013-11-14

    ZnO thin films have been prepared by sol gel and deposited by spin coating. The dielectric function has been determined by spectroscopic ellipsometry. Ellipsometric spectra are inverted by a direct numerical method without using the standard fitting procedures. The obtained dielectric function presents a broad excitonic effect. The dielectric function is studied using Elliot excitonic theory including exciton plus band-to-band Coulomb interactions with standard Lorentzian broadening. A modification of this model dielectric function with independent bound and unbound exciton contributions is empirically proposed to improve modelling of the band gap excitonic peak.

  5. Spectroscopic ellipsometry investigations of optical anisotropy in obliquely deposited hafnia thin films

    NASA Astrophysics Data System (ADS)

    Tokas, R. B.; Jena, Shuvendu; Haque, S. Maidul; Rao, K. Divakar; Thakur, S.; Sahoo, N. K.

    2016-05-01

    In present work, HfO2 thin films have been deposited at various oblique incidences on Si substrates by electron beam evaporation. These refractory oxide films exhibited anisotropy in refractive index predictably due to special columnar microstructure. Spectroscopic ellipsometry being a powerful tool for optical characterization has been employed to investigate optical anisotropy. It was observed that the film deposited at glancing angle (80°) exhibits the highest optical anisotropy. Further, anisotropy was noticed to decrease with lower values of deposition angles while effective refractive index depicts opposite trend. Variation in refractive index and anisotropy has been explained in light of atomic shadowing during growth of thin films at oblique angles.

  6. 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.

  7. Study of InGaAs based MODFET structures using variable angle spectroscopic ellipsometry

    NASA Technical Reports Server (NTRS)

    Alterovitz, S. A.; Sieg, R. M.; Yao, H. D.; Snyder, P. G.; Woollam, J. A.; Pamulapati, J.; Bhattacharya, P. K.; Sekula-Moise, P. A.

    1991-01-01

    Variable angle spectroscopic ellipsometry was used to estimate the thicknesses of all layers within the optical penetration depth of InGaAs based MODFET structures. Strained and unstrained InGaAs channels were made by MBE on InP substrates and by MOCVD on GaAs substrates. In most cases, ellipsometrically determined thicknesses were within 10 percent of the growth calibration results. The MBE made InGaAs strained layers showed large strain effects, indicating a probable shift in the critical points of their dielectric function toward the InP lattice matched concentration.

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

    PubMed

    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

    2015-06-17

    The protein-adsorbing and -repelling properties of various smart nanometer-thin polymer brushes containing poly(N-isopropylacrylamide) and poly(acrylic acid) with high potential for biosensing and biomedical applications are studied by in situ infrared-spectroscopic ellipsometry (IRSE). IRSE is a highly sensitive nondestructive technique that allows protein adsorption on polymer brushes to be investigated in an aqueous environment as external stimuli, such as temperature and pH, are varied. These changes are relevant to conditions for regulation of protein adsorption and desorption for biotechnology, biocatalysis, and bioanalytical applications. Here brushes are used as model surfaces for controlling protein adsorption of human serum albumin and human fibrinogen. The important finding of this work is that IRSE in the in situ experiments in protein solutions can distinguish between contributions of polymer brushes and proteins. The vibrational bands of the polymers provide insights into the hydration state of the brushes, whereas the protein-specific amide bands are related to changes of the protein secondary structure. PMID:25668395

  9. 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.

  10. 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.

  11. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    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.

  13. 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

  14. 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

    2016-01-01

    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

  15. Solution of the Inverse Spectroscopic Ellipsometry Problem for an Absorbing Substrate with a Dielectric Layer

    NASA Astrophysics Data System (ADS)

    Stas'kov, N. I.; Shulga, A. V.

    2016-03-01

    An analytical solution of the inverse spectroscopic ellipsometry problem for a transparent layer on an absorbing substrate is obtained based on the envelope function approximation. It is used to determine the spectral dependences of the refractive index n(λ) and absorption k(λ) for model and real silicon substrates with silicon dioxide layers. It was possible to determine analytically the effective optical characteristics of the silicon substrate in the approximation of a layer-substrate model with ideal interface boundaries. This result, together with the relative positions of the spectral curves for the ellipsometric angles tan ψ(λ) and cos Δ(λ) measured for a silicon substrate with a natural surface layer and for a silicon dioxide layer-silicon substrate structure, can be explained by the fact that the silicon dioxide layer is surrounded by transition and surface layers.

  16. 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.

  17. 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.

  18. 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.

  19. Variable angle spectroscopic ellipsometry - Application to GaAs-AlGaAs multilayer homogeneity characterization

    NASA Technical Reports Server (NTRS)

    Alterovitz, Samuel A.; Snyder, Paul G.; Merkel, Kenneth G.; Woollam, John A.; Radulescu, David C.

    1988-01-01

    Variable angle spectroscopic ellipsometry has been applied to a GaAs-AlGaAs multilayer structure to obtain a three-dimensional characterization, using repetitive measurements at several spots on the same sample. The reproducibility of the layer thickness measurements is of order 10 A, while the lateral dimension is limited by beam diameter, presently of order 1 mm. Thus, the three-dimensional result mainly gives the sample homogeneity. In the present case three spots were used to scan the homogeneity over 1 in of a wafer which had molecular-beam epitaxially grown layers. The thickness of the AlGaAs, GaAs, and oxide layers and the Al concentration varied by 1 percent or less from edge to edge. This result was confirmed by two methods of data analysis. No evidence of an interfacial layer was observed on top of the AlGaAs.

  20. Characterization of multilayer GaAs/AlGaAs transistor structures by variable angle spectroscopic ellipsometry

    NASA Technical Reports Server (NTRS)

    Merkel, Kenneth G.; Snyder, Paul G.; Woollam, John A.; Alterovitz, Samuel; Rai, A. K.

    1989-01-01

    Variable angle of incidence spectroscopic ellipsometry (VASE) has been implemented as a means of determining layer thickness, alloy composition, and growth quality of GaAs/AlGaAs samples composed of relatively thick layers as well as superlattices. The structures studied in this work contained GaAs/AlGaAs multilayers with a superlattice 'barrier' and were grown for later formation of modulation-doped field effect transistors (MODFETs). Sample modeling was performed by treating the superlattice as a bulk AlGaAs layer of unknown composition. Extremely good data fits were realized when five layer thicknesses and two alloy ratios were allowed to vary in a regression analysis. Room temperature excitonic effects associated with the e-hh(1), e-lh(1) and e-hh(2) transitions were observed in the VASE data.

  1. Optical properties of post-annealed ZnO:Al thin films studied by spectroscopic ellipsometry

    SciTech Connect

    Hwang, Y.H.; Kim, H.M.; Um, Y.H.; Park, H.Y.

    2012-10-15

    In this paper, effects of the thermal annealing on the structural, electrical, and optical properties of Al-doped ZnO (ZnO:Al) thin films prepared by reactive radio-frequency sputtering were investigated. From the X-ray diffraction observations, the orientation of ZnO:Al films was found to be a c-axis in the hexagonal structure. The optical properties of the films were investigated by optical transmittance and spectroscopic ellipsometry characterization. Based on Tauc–Lorentz model, the optical constants of ZnO:Al films were extracted in the photon energy ranging from 1.0 to 4.5 eV. Our result showed that the refractive index and extinction coefficient of the films changed consistently with annealing temperature.

  2. In situ spectroscopic ellipsometry of pH-responsive polymer brushes on gold substrates.

    PubMed

    Rauch, Sebastian; Uhlmann, Petra; Eichhorn, Klaus-Jochen

    2013-11-01

    The dynamic and reversible switching behaviour of polyelectrolyte brushes of poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) toward changes of the pH value was studied by in situ VIS-spectroscopic ellipsometry (SE). For this, PDMAEMA brushes with three different molecular weights were synthesized via the "grafting from" method using surface initiated atom transfer radical polymerization. In detail, the applicability of different SE data modelling to describe the optical properties of the different brush layers in the swollen and collapsed state was investigated. Especially for the PDMAEMA brushes with a high molecular weight, an improved optical modelling of the experimental data could be achieved and revealed an exponential distribution of the PDMAEMA fraction in the brush layer. PMID:23812852

  3. Optical characteristics of pulsed laser deposited Ge-Sb-Te thin films studied by spectroscopic ellipsometry

    SciTech Connect

    Nemec, P.; Prikryl, J.; Frumar, M.; Nazabal, V.

    2011-04-01

    Pulsed laser deposition technique was used for the fabrication of (GeTe){sub 1-x}(Sb{sub 2}Te{sub 3}){sub x} (x = 0, 0.33, 0.50, 0.66, and 1) amorphous thin films. Scanning electron microscopy with energy-dispersive x-ray analysis, x-ray diffraction, optical reflectivity, and sheet resistance temperature dependences as well as variable angle spectroscopic ellipsometry measurements were used to characterize as-deposited (amorphous) and annealed (rocksaltlike) layers. In order to extract optical functions of the films, the Cody-Lorentz model was applied for the analysis of ellipsometric data. Fitted sets of Cody-Lorentz model parameters are discussed in relation with chemical composition and the structure of the layers. The GeTe component content was found to be responsible for the huge optical functions and thickness changes upon amorphous-to-fcc phase transition.

  4. 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.

  5. Spectroscopic ellipsometry study of Cu2ZnSnSe4 bulk crystals

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

    Using spectroscopic ellipsometry we investigated and analyzed the pseudo-optical constants of Cu2ZnSnSe4 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 E0, E1A, and E1B 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.

  6. HgCdTe Molecular Beam Epitaxy Growth Temperature Calibration Using Spectroscopic Ellipsometry

    NASA Astrophysics Data System (ADS)

    Vilela, M. F.; Pribil, G. K.; Olsson, K. R.; Lofgreen, D. D.

    2012-10-01

    In this work, spectroscopic ellipsometry (SE) is demonstrated as a technique to calibrate growth temperature measurement devices (thermocouples and pyrometers) prior to real mercury cadmium telluride (HgCdTe) growth. A pyrometer is used to control the substrate temperature in molecular beam epitaxy (MBE) for the growth of HgCdTe-based material. It is known that a very narrow optimal growth temperature range exists for HgCdTe, typically ±5°C. A nonoptimal growth temperature will negatively impact on material quality by inducing growth defects, reducing composition uniformity, causing difficulty in controlling doping incorporation, promoting poor electronic properties, and having other adverse effects. Herein, we present a method for measuring and calibrating substrate temperature measurement equipment by using spectroscopic ellipsometry (SE) prior to real HgCdTe growth. This method is easy to implement, nondestructive, and reliable. The proposed method requires one substrate with a surface material with optical properties well known in the temperature range of interest, but not necessarily the same base material as the material to be grown. In the specific case of this work, we use epitaxial CdTe material on top of a Si substrate. This wafer was used to create a database of its optical properties as a function of temperature by using SE. From the collected optical parameters, a model is built and a fit is generated from the SE data collected. The temperature can then be determined by fitting the temperature-dependent SE measurements from this specific CdTe material. The angle offset and surface roughness parameters are also included in the model to account for changes in the average run-to-run angle variations and surface conditions over time. This work does not attempt to obtain an absolute temperature, but rather a reliable and repeatable relative temperature measurement.

  7. 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.

  8. 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

  9. 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. PMID:22524964

  10. 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.

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

    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.

    2015-02-01

    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-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.

  12. Determination of the optical properties of organic thin films by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Sward, Mark L.

    1990-12-01

    This theses demonstrated the feasibility of determining the optical properties of organic and polymer thin films through the use of Spectroscopic Ellipsometry (SE). Tan Psi and cos Delta data from 300 to 800 nanometers (NM) were taken with a Rudolph Research s2000 spectroscopic ellipsometer four samples: indium tin oxide (ITO) coated glass; five layer poly-benzyl-L glutamate (PBLG) organic film on ITO coated glass; eight layer PBLG film on ITO coated glass; and a thiophene polymer film on a microscope slide. The data sets were fit to a choice of four computer models based on a paper written by Dwight Berreman in 1972. The four were written in MATLAB to take advantage of its matrix manipulative capabilities. The models were: a single layer isotropic film on an isotropic substrate; a single layer anisotropic film on an isotropic substrate; two isotropic films on an isotropic substrate; and two anisotropic films on an isotropic substrate. Using only tan Psi data over a restricted wavelength region, all four data sets were fit to variances of 0.01 or less.

  13. Normal-incidence spectroscopic ellipsometry and polarized reflectometry for measurement and control of photoresist critical dimension

    NASA Astrophysics Data System (ADS)

    Holden, James M.; Gubiotti, Thomas; McGahan, William A.; Dusa, Mircea V.; Kiers, Ton

    2002-07-01

    We report here on initial results for the characterization and modeling of 100 nm lithography features based on normal incidence spectroscopic ellipsometry and polarized reflectometry. In this work, a set of wafers was exposed as focus-exposure and separate focus or exposure matrices to create resists patterns with extremely small variations in CD and pattern shape. These variations were generated along scan, within slit and across full wafer. Optical CD scatterometry was used to extract critical feature parameters such as complete shape and associated linear dimensions. Extracted pattern parameters were compared to FIB sections and used to predict lithography process latitudes. We explore effects of using multi normal incidence ellipsometric signals with various profile models to increase accuracy of extracted lithography parameters. We propose a metric for identifying effects of scan-dynamic does and focus variations upon slit-intrafield and scan- intrafield CD errors. This has been tested over ranges of defocus and exposure that are larger than typical FE latitudes of 100 nm features. As a result of spectroscopic scatterometry calculations of pattern shape, we identified pattern shape variations caused by dose and defocus that are clearly coupled to changes in feature size. These could be used for unique determination of dose-focus deviations using scatterometry-extracted information from measurements of a grating structure.

  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.

    1999-06-01

    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.

  15. 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.

  16. 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

  17. Spectroscopic ellipsometry study of N+ ion-implanted ethylene-norbornene films

    NASA Astrophysics Data System (ADS)

    Šiljegović, M.; Kačarević-Popović, Z. M.; Stchakovsky, M.; Radosavljević, A. N.; Korica, S.; Novaković, M.; Popović, M.

    2014-05-01

    The optical properties of 150 keV N+ implanted ethylene-norbornene (TOPAS 6017S-04) copolymer were investigated using phase modulated spectroscopic ellipsometry (PMSE) and ultraviolet-visible (UV-Vis) spectroscopy in the ranges of 0.6-6.5 eV and of 1.5-6.2 eV, respectively. The single-effective-oscillator model was used to fit the calculated data to the experimental ellipsometric spectra. The results show that the oscillator and dispersion energies decrease with increasing ion fluence up to 1015 cm-2, and then these parameters increase with further fluence increasing. Analysis of the UV-Vis absorption spectra revealed the presence of indirect electronic transitions with the band gap energy in the range of 1.3 to 2.8 eV. It was found that both the band gap energy and the energy width of the distribution of localized band tail states decrease, while the values of Tauc coefficient increase with increasing the ion fluence. From the ellipsometric data we found that the real part of the dielectric function increased about 7% after irradiation with 1015 cm-2, and decreased about 10% in samples modified with 1016 cm-2.

  18. Application of Mueller matrix spectroscopic ellipsometry to determine line edge roughness on photomasks

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    We report on Mueller Matrix spectroscopic ellipsometry (MM-SE) to examine undesired asymmetries in structural parameters, i.e. line edge roughness (LER). The investigation was done on a photomask containing line space arrays with intentionally modulated line edges. The Mueller Matrix (MM) elements were measured within the complete azimuth angle range (0 - 360°) and a wavelength range from 300 nm to 980 nm. The results are presented in polar coordinates with the azimuth angle and wavelength as the angular and radial coordinate, respectively. It was found that LER significantly impacts the MM elements, which is indicated by the increase of the isotropic character of the array. The experimental data are confirmed by Rigorous Coupled Wave Analysis (RCWA) simulations on perturbed arrays. Based on RCWA the impact of LER amplitudes in the nm range is determined. It was found that both deviation of critical dimension (CD) and LER amplitude impact the MM elements. Based on the intensity ratios of the elements and their spectral distribution both errors create a characteristic finger print, which allows to separate them. Finally, the required measurement precision for LER in the nm range is estimated at 0.001. This precision is challenging but achievable with today's metrology.

  19. Influence of the graphene substrate on morphology of the gold thin film. Spectroscopic ellipsometry study

    NASA Astrophysics Data System (ADS)

    Kostruba, A. M.

    2013-10-01

    In metal optics gold assumes a special status because of its practical importance in optoelectronic and nanooptical devices, and its role huge increases when occurs combination of gold with two-dimension materials. We performed spectroscopic ellipsometry measurements on evaporated gold, and gold-graphene nanostructures to determine the optical dielectric function across a broad spectral range from 250 to 1000 nm. It was found that the deposition of gold film on the quartz substrate covered by graphene flake leads to significant changes in structural and dielectric properties of thin gold layer. Such changes can be explained by increasing of the gold cluster size. The model fit of the ellipsometric data demonstrates that the bilayer “graphene-gold” nanostructure can be described as a uniform optically homogeneous layer with modified optical properties. We can suggest that graphene flake creates a matrix for epitaxial alignment of the crystalline structure of the gold film during its growing. Effective doping of the graphene by free electrons of the gold clusters tends to decrease the optical contrast at the graphene-gold interface.

  20. Characterization of SiGe/Ge heterostructures and graded layers using variable angle spectroscopic ellipsometry

    NASA Technical Reports Server (NTRS)

    Croke, E. T.; Wang, K. L.; Heyd, A. R.; Alterovitz, S. A.; Lee, C. H.

    1996-01-01

    Variable angle spectroscopic ellipsometry (VASE) has been used to characterize Si(x)Ge(1-x)/Ge superlattices (SLs) grown on Ge substrates and thick Si(x)Ge(1-x)/Ge heterostructures grown on Si substrates. Our VASE analysis yielded the thicknesses and alloy compositions of all layers within the optical penetration depth of the surface. In addition, strain effects were observed in the VASE results for layers under both compressive and tensile strain. Results for the SL structures were found to be in close agreement with high resolution x-ray diffraction measurements made on the same samples. The VASE analysis has been upgraded to characterize linearly graded Si(x)Ge(1-x) buffer layers. The algorithm has been used to determine the total thickness of the buffer layer along with the start and end alloy composition by breaking the total thickness into many (typically more than 20) equal layers. Our ellipsometric results for 1 (mu)m buffer layers graded in the ranges 0.7 less than or = x less than or = 1.0, and 0.5 less than or = x less than or = 1.0 are presented, and compare favorably with the nominal values.

  1. Characterization of High Ge Content SiGe Heterostructures and Graded Alloy Layers Using Spectroscopic Ellipsometry

    NASA Technical Reports Server (NTRS)

    Heyd, A. R.; Alterovitz, S. A.; Croke, E. T.

    1995-01-01

    Si(x)Ge(1-x)heterostructures on Si substrates have been widely studied due to the maturity of Si technology. However, work on Si(x)Ge)1-x) heterostructures on Ge substrates has not received much attention. A Si(x)Ge(1-x) layer on a Si substrate is under compressive strain while Si(x)Ge(1-x) on Ge is under tensile strain; thus the critical points will behave differently. In order to accurately characterize high Ge content Si(x)Ge(1-x) layers the energy shift algorithm used to calculate alloy compositions, has been modified. These results have been used along with variable angle spectroscopic ellipsometry (VASE) measurements to characterize Si(x)Ge(1-x)/Ge superlattices grown on Ge substrates. The results agree closely with high resolution x-ray diffraction measurements made on the same samples. The modified energy shift algorithm also allows the VASE analysis to be upgraded in order to characterize linearly graded layers. In this work VASE has been used to characterize graded Si(x)Ge(1-x) layers in terms of the total thickness, and the start and end alloy composition. Results are presented for a 1 micrometer Si(x)Ge(1-x) layer linearly graded in the range 0.5 less than or equal to x less than or equal to 1.0.

  2. Gate Spacer Width Monitoring Study with Scatterometry Based on Spectroscopic Ellipsometry

    NASA Astrophysics Data System (ADS)

    Vachellerie, V.; Kremer, S.; Elazami, A.; Morin, P.; Julien, C.; Duca, D.; Guiheux, D.; Bicais, N.; Pokrant, S.

    2005-09-01

    Critical Dimension (CD) control of Gate Spacers is key to achieve in well controlled implantations and a tight distribution of Vt for transistors on semiconductors devices. Presently, historical methods for CD control (top-down low-voltage Scanning Electron Microscopy, Atomic Force Microscopy, Transmission Electron Microscopy or Electrical CD measurement) are facing limitations with regards to precision, matching, throughput or sample damage. So, with the reduction of design rules approaching the 65nm technology node, the need for a fast, precise and versatile "in-line" (at the process step) measurement of the spacer width and profile becomes critical, in order to shorten the spacer process development phase and the response time to production excursions. In this paper, we investigate the metrology performances and limitations (sensitivity, precision and accuracy) of Scatterometry (SCD) based on Spectroscopic Ellipsometry (SE) for this application using a KLA-TENCOR SpectraCD system. We show that it will be suitable for, at least, a simple oxide-nitride spacer configuration. We also explore its capability to measure more complex structures like the double-spacer configuration (LDD offset & S/D spacer). Finally, we show how additional information provided by Scatterometry helps in understanding process variations and how they correlate to end of line parametric test results.

  3. High-k dielectric characterization by VUV spectroscopic ellipsometry and X-ray reflection

    NASA Astrophysics Data System (ADS)

    Boher, P.; Evrard, P.; Piel, J. P.; Defranoux, C.; Fouere, J. C.; Bellandi, E.; Bender, H.

    2003-09-01

    In this study, we use vacuum UV spectroscopic ellipsometry (VUVSE) to characterize new high dielectric materials. Indeed, all the candidates for high k dielectrics become strongly absorbent when the wavelength is reduced down to 140nm. So, the correlation between thickness and refractive index is reduced in the VUV range and much more precise structural information can be deduced. HfO2, Al2O3 and mixed HfAlOx layers have been studied with and without thin SiO2 oxide at the interface. X-ray reflectometry (XRR) has been used to measure precisely the layer thickness and roughness. The two techniques are included in the same automated metrology system dedicated to 300mm technology which is also presented. We show in particular that VUVSE can detect the crystalline character of the layers and their composition can be measured in addition to the layer thickness. Results are compared to those obtained by transmission electron microscopy (TEM), x-ray fluorescence analysis (XRF) and x-ray photoemission (XPS).

  4. 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.

  5. 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.

  6. Determination of thicknesses of oxide films grown on titanium under argon irradiation by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    In this article we present a study of the oxidation of pure titanium bulk samples under argon ion irradiation at 500 °C under rarefied air. In particular we follow the dependence of the oxide thickness as a function of the energy of argon ions. The novelty of this study consists in the range of ion energy explored, from 1 to 9 MeV. Until very recently it was commonly accepted that metal surfaces were transparent to ion beams in this low energy range (few MeV), and no surface modifications were expected. In a previous paper by the authors of this work, the formation of shallow craters in the surface of titanium was reported as a result of argon ion bombardment with energies of 2, 4 and 9 MeV under the same environmental conditions. We show here that around 3 MeV the oxide growth is unexpectedly enhanced. We think that an interplay of electronic excitations and nuclear ballistic collisions could possibly explain this enhanced oxide growth. We have used spectroscopic visible ultraviolet ellipsometry and XPS to determine the thickness of the oxide layers and characterize their optical properties. From the optical properties of the oxides we observed that for ion energies below 3-4 MeV the oxides show a dielectric-like behavior, whereas for ion energies above 3-4 MeV the oxides show a metal-like behavior. These findings indicate also that ion bombardment in this energy range may change substantially the oxygen-to-titanium ratio in the oxide films grown under irradiation leading to the formation of titanium sub-oxides.

  7. 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

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

    PubMed

    Losurdo, Maria; 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

    2009-10-01

    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

  9. Variable angle of incidence spectroscopic ellipsometry Application to GaAs-Al(x)Ga(1-x)As multiple heterostructures

    NASA Technical Reports Server (NTRS)

    Snyder, Paul G.; Rost, Martin C.; Bu-Abbud, George H.; Woollam, John A.; Alterovitz, Samuel A.

    1986-01-01

    The sensitivity of spectroscopic ellipsometry data to multilayer model parameters is shown to be a strong function of the angle of incidence. A quantitative study of sensitivity versus angle of incidence is performed for a GaAs-Al(x)Ga(1-x)As-GaAs substrate structure, showing that maximum sensitivity to layer thicknesses and AlGaAs composition occurs near the wavelength-dependent principal angle. These results are verified by experimental measurements on two molecular-beam epitaxy grown samples.

  10. Study of temperature-dependent ultrathin oxide growth on Si(111) using variable-angle spectroscopic ellipsometry

    NASA Technical Reports Server (NTRS)

    De, Bhola N.; Woollam, John A.

    1990-01-01

    The monolayer-sensitive variable-angle spectroscopic ellipsometry technique was used to study the temperature-dependent growth mechanisms of an ultrathin oxide layer on top of silicon. The oxidation was done in atomic oxygen produced in a pure oxygen plasma and driven by an RF power source. The results have been compared with the recently proposed model of Murali and Murarka for ultrathin oxide growth on top of silicon. The activation energies of different growth parameters associated with the oxide growth have also been determined.

  11. Spectroscopic ellipsometry study of hydrogenated amorphous silicon carbon alloy films deposited by plasma enhanced chemical vapor deposition

    SciTech Connect

    Basa, D. K.; Abbate, G.; Ambrosone, G.; Marino, A.; Coscia, U.

    2010-01-15

    The optical properties of the hydrogenated amorphous silicon carbon alloy films, prepared by plasma enhanced chemical vapor deposition technique from silane and methane gas mixture diluted in helium, have been investigated using variable angle spectroscopic ellipsometry in the photon energy range from 0.73 to 4.59 eV. Tauc-Lorentz model has been employed for the analysis of the optical spectra and it has been demonstrated that the model parameters are correlated with the carbon content as well as to the structural properties of the studied films.

  12. Dielectric functions and carrier concentrations of Hg1-xCdxSe films determined by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

    Spectroscopic ellipsometry, ranging from 35 meV to 6 eV, was used to determine the dielectric functions of a series of molecular beam epitaxy-grown Hg1-xCdxSe 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 Hg1-xCdxSe, as expected. Representing the free carrier absorption with a Drude oscillator, we found that the effective masses of Hg1-xCdxSe (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 Hg1-xCdxSe 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.

  13. 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

  14. Spectroscopic Ellipsometry and Fluorescence Study of Thermochromism in an Ultrathin Poly(diacetylene) Film: Reversibility and Transition Kinetics

    SciTech Connect

    CARPICK,R.W.; MAYER,THOMAS M.; SASAKI,DARRYL Y.; BURNS,ALAN R.

    2000-01-18

    We have investigated the thermochromic transition of an ultrathin poly(diacetylene) film. The Langmuir film is composed of three layers of polymerized 10,12-pentacosadiynoic acid [CH{sub 3}(CH{sub 2}){sub 11}C{triple_bond}CC{triple_bond}C(CH{sub 2}){sub 8}COOH] (poly-PCDA) organized into crystalline domains on a silicon substrate. Spectroscopic ellipsometry and fluorescence intensity measurements are obtained with in-situ temperature control. Poly-PCDA films exhibit a reversible thermal transition between the initial blue form and an intermediate ''purple'' form that exists only at elevated temperature (between 303-333 K), followed by an irreversible transition to the red form after annealing above 320 K. We propose that the purple form is thermally distorted blue poly-PCDA, and may represent a transitional configuration in the irreversible conversion to red. This hypothesis is supported by the appearance of unique features in the absorption spectra for each form as derived from the ellipsometry measurements. Significant fluorescence emission occurs only with the red form, and is reduced at elevated temperatures while the absorption remains unchanged. Reduced emission is likely related to thermal fluctuations of the hydrocarbon side chains. Time-resolved fluorescence measurements of the irreversible transition have been performed. Using a first-order kinetic analysis of these measurements we deduce an energy barrier of 17.6 {+-} 1.1 kcal mol{sup -1} between the blue and red forms.

  15. 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

  16. Spectroscopic ellipsometry and electrical characterizations of InGaAs:Mg thin films lattice matched to InP

    NASA Astrophysics Data System (ADS)

    Zeydi, I.; Ezzedini, M.; Sayari, A.; Shalaan, E.; Wageh, S.; Sfaxi, L.; Al-Ghamdi, A. A.; M'Gaieth, R.

    2016-06-01

    Mg-doped InGaAs films were grown at 560 ° C lattice matched to InP semi-insulating substrate by metalorganic vapor phase epitaxy (MOVPE) under various Cp2Mg flow conditions. Hall effect, photoluminescence (PL), high-resolution X-ray diffraction (HR-XRD) and spectroscopic ellipsometry (SE) are the tools used in this work. The crystalline quality and the n-p conversion of the InGaAs:Mg films are described and discussed in relation to the Cp2Mg flow. Distinguishing triple emissions peaks in PL spectra are observed and seem to be strongly dependent on the Cp2Mg flow. SE was used to investigate the interband transitions in InGaAs:Mg/InP heterointerfaces and the different critical point energies were identified.

  17. 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

  18. Investigation of temperature dependent dielectric constant of a sputtered TiN thin film by spectroscopic ellipsometry

    SciTech Connect

    Tripura Sundari, S. Ramaseshan, R.; Jose, Feby; Dash, S.; Tyagi, A. K.

    2014-01-21

    The temperature dependence of optical constants of titanium nitride thin film is investigated using Spectroscopic Ellipsometry (SE) between 1.4 and 5 eV in the temperature range of 300 K to 650 K in steps of 50 K. The real and imaginary parts of the dielectric functions ε{sub 1}(E) and ε{sub 2}(E) marginally increase with increase in temperature. A Drude Lorentz dielectric analysis based on free electron and oscillator model are carried out to describe the temperature behavior. With increase in temperature, the unscreened plasma frequency and broadening marginally decreased and increased, respectively. The parameters of the Lorentz oscillator model also showed that the relaxation time decreased with temperature while the oscillator energies increased. This study shows that owing to the marginal change in the refractive index with temperature, titanium nitride can be employed for surface plasmon sensor applications even in environments where rise in temperature is imminent.

  19. Monitoring Photodeposition of Polymer Films from Diacetylene Monomer Solutions Using In Situ Real-Time Spectroscopic Ellipsometry

    NASA Technical Reports Server (NTRS)

    Hui, Du; Kim, Jin-Sook; Kim, Yeon-Taik; An, Ilsin; Paley, Mark S.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Photodeposition of thin polymer (PDAMNA) films from diacetylene monomer (DAMNA) solutions onto gold coated silica substrates with UV light was studied using the technique of in-situ real time spectroscopic ellipsometry. The dielectric function of PDAMNA was determined; and the thickness of the growing PDAMNA films over a 4 hour time interval was determined using a linear regression fit of the experimental data to a homogeneous four phase optical model. It was found that stirring the solution dramatically lowers the rate of film deposition, suggesting that convection can affect the attachment kinetics of the film to the substrate. Lastly, the morphology of the PDAMNA films was examined using non-contact mode atomic force microscopy.

  20. 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.

  1. 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.

  2. Study of InGaAs-based modulation doped field effect transistor structures using variable-angle spectroscopic ellipsometry

    NASA Technical Reports Server (NTRS)

    Alterovitz, S. A.; Sieg, R. M.; Yao, H. D.; Snyder, P. G.; Woollam, J. A.; Pamulapati, J.; Bhattacharya, P. K.; Sekula-Moise, P. A.

    1991-01-01

    Variable-angle spectroscopic ellipsometry was used to estimate the thicknesses of all layers within the optical penetration depth of InGaAs-based modulation doped field effect transistor structures. Strained and unstrained InGaAs channels were made by molecular beam epitaxy (MBE) on InP substrates and by metal-organic chemical vapor deposition on GaAs substrates. In most cases, ellipsometrically determined thicknesses were within 10% of the growth-calibration results. The MBE-made InGaAs strained layers showed large strain effects, indicating a probable shift in the critical points of their dielectric function toward the InP lattice-matched concentration.

  3. 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.

  4. 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.

  5. Investigation of optical properties of amorphous Ge15Se85-xCux thin films using spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Shaaban, E. R.; Emam-Ismail, M.; Abbady, Gh.; Prakash, Deo; El-Hagary, M.; Afify, N.; Verma, K. D.

    2016-02-01

    Different compositions of amorphous Ge15Se85-xCux thin films were deposited onto glass substrates by the thermal evaporation technique. Their amorphous structural characteristics were studied by X-ray diffraction (XRD). The optical constants (n, k) of amorphous Ge15Se85-xCux thin films were obtained by fitting the ellipsometric parameters (ψ and Δ) data for the first time using three layers model system in the wavelength range 300-1100 nm. It was found that the refractive index, n, increases with the increase of Cu content. The possible optical transition in these films is found to be indirect transitions. The optical energy gap decreases linearly from 1.83 to 1.44 eV with increasing the Cu. The experimental transmittances spectrum can be simulated using the thickness and optical constants modeled by spectroscopic ellipsometry model.

  6. Study of InGaAs-based modulation doped field effect transistor structures using variable-angle spectroscopic ellipsometry

    NASA Technical Reports Server (NTRS)

    Alterovitz, Samuel A.; Sieg, R. M.; Yao, H. D.; Snyder, P. G.; Woollam, J. A.; Pamulapati, J.; Bhattacharya, P. K.; Sekula-Moise, P. A.

    1992-01-01

    Variable-angle spectroscopic ellipsometry was used to estimate the thicknesses of all layers within the optical penetration depth of InGaAs-based modulation doped field effect transistor structures. Strained and unstrained InGaAs channels were made by molecular beam epitaxy (MBE) on InP substrates and by metal organic chemical vapor deposition on GaAs substrates. In most cases, ellipsometrically determined thicknesses were within 10 percent of the growth-calibration results. The MBE-made InGaAs strained layers showed large strain effects, indicating a probable shift in the critical point of their dielectric function toward the InP lattice-matched concentration.

  7. 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)

  8. 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

  9. 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.

  10. Infrared spectroscopic imaging of kidney tumor tissue

    NASA Astrophysics Data System (ADS)

    Sablinskas, V.; Steiner, G.; Koch, E.; Ceponkus, J.; Pucetaite, M.; Strazdaite, S.; Urboniene, V.; Jankevicius, F.

    2011-02-01

    Infrared spectroscopic imaging of cancerous kidney tissue was performed by means of FTIR microscopy. The spectra of thin tissue cryosections were collected with 64x64 MCT FPA detector and imaging area was increased up to 5.4×5.4 mm by mapping by means of PC controlled x,y stage. Chemical images of the samples were constructed using statistical treatment of the raw spectra. Several unsupervised and supervised statistical methods were used. The imaging results are compared with results of the standard histopathological analysis. It was concluded that application of method of cluster analysis ensures the best contrast of the images. It was found that border between cancerous and normal tissues visible in the infrared spectroscopic image corresponds with the border visible in histopathological image. Closer examination of the infrared spectroscopic image reveals that small domains of cancerous cells are found beyond the border in areas distant from the border up to 3 mm. Such domains are not visible in the histopathological images. The smallest domains found in the infrared images are approx. 60 μm.

  11. Study of receptor-chaperone interactions using the optical technique of spectroscopic ellipsometry.

    PubMed

    Kriechbaumer, Verena; Tsargorodskaya, Anna; Mustafa, Mohd K; Vinogradova, Tatiana; Lacey, Joanne; Smith, David P; Abell, Benjamin M; Nabok, Alexei

    2011-07-20

    This work describes a detailed quantitative interaction study between the novel plastidial chaperone receptor OEP61 and isoforms of the chaperone types Hsp70 and Hsp90 using the optical method of total internal reflection ellipsometry (TIRE). The receptor OEP61 was electrostatically immobilized on a gold surface via an intermediate layer of polycations. The TIRE measurements allowed the evaluation of thickness changes in the adsorbed molecular layers as a result of chaperone binding to receptor proteins. Hsp70 chaperone isoforms but not Hsp90 were shown to be capable of binding OEP61. Dynamic TIRE measurements were carried out to evaluate the affinity constants of the above reactions and resulted in clear discrimination between specific and nonspecific binding of chaperones as well as differences in binding properties between the highly similar Hsp70 isoforms. PMID:21767504

  12. 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.

  13. In situ spectroscopic ellipsometry growth studies on the Al-doped ZnO films deposited by remote plasma-enhanced metalorganic chemical vapor deposition

    SciTech Connect

    Volintiru, I.; Creatore, M.; Sanden, M. C. M. van de

    2008-02-01

    In situ spectroscopic ellipsometry (SE) was applied to study the pyramidlike and pillarlike growth of Al doped ZnO (AZO) films deposited by means of remote plasma-enhanced metalorganic chemical vapor deposition for transparent conductive oxide applications. Real time SE studies in the visible region allowed discerning between the two growth modes by addressing the time evolution of the bulk and surface roughness layer thickness. While the pillarlike mode is characterized by a constant growth rate, a slower rate in the initial stage (up to 150-200 nm film thickness), compared to the bulk, is observed for the growth of pyramidlike AZO films. The two modes differ also in terms of surface roughness development: a saturation behavior is observed for film thickness above 150-200 nm in the case of the pyramidlike films, while a slow linear increase with film thickness characterizes the pillarlike mode. By extending the SE analysis of the AZO films to the near infrared region, valuable information about the in grain properties could be extracted: excellent in grain mobility values, i.e., larger than 100 and 50 cm{sup 2}/V s, are determined for the pyramidlike and pillarlike AZO layers, respectively. The comparison between the outcome of the in situ real time SE studies and the ex situ electrical and chemical characterization highlights the limitations in the electron transport occurring in both types of films and allows one to address routes toward further improvement in AZO conductivity.

  14. Spectroscopic ellipsometry and fluorescence study of thermochromism in an ultrathin poly(diacetylene) film: Reversibility and transition kinetics

    SciTech Connect

    Carpick, R.W.; Mayer, T.M.; Sasaki, D.Y.; Burns, A.R.

    2000-05-16

    The authors have investigated the thermochromic transition of an ultrathin poly(diacetylene)film. The Langmuir film is composed of three layers of polymerized 10,12-pentacosadiynoic acid [Ch{sub 3}(CH{sub 2}){sub 11}C{triple_bond}CC{triple_bond}C(CH{sub 2}){sub 8}COOH] (poly-PCDA) organized into crystalline domains on a silicon substrate. Spectroscopic ellipsometry and fluorescence intensity measurements are obtained with in situ temperature control. Poly-PCDA films exhibit a reversible thermal transition between the initial blue form and an intermediate purple form that exists only at elevated temperature (between 303 and 333 K), followed by an irreversible transition to the red form after annealing above 320 K. The authors propose that the purple form is thermally distorted blue poly-PCDA and may represent a transitional configuration in the irreversible conversion to red. This hypothesis is supported by the appearance of unique features in the absorption spectra for each form as derived from the ellipsometry measurements. Significant fluorescence emission occurs only with the red form and is reduced at elevated temperatures while the absorption remains unchanged. Reduced emission is likely related to thermal fluctuations of the hydrocarbon side chains. Time-resolved fluorescence is likely related to thermal fluctuations of the hydrocarbon side chains. Time-resolved fluorescence measurements of the irreversible transition have been performed. Using a first-order kinetic analysis of these measurements, the authors deduce an energy barrier of 17.6 {+-} 1.1 kcal mol{sup {minus}1} between the blue and red forms.

  15. Recent in-situ studies of the evolution of surfaces and interfaces of thin films by spectroscopic phase-modulated ellipsometry

    NASA Astrophysics Data System (ADS)

    Yakovlev, V.; Drevillon, Bernard; Layadi, Nace; Roca i Cabarrocas, Pere

    1993-04-01

    Application of spectroscopic phase modulated ellipsometry (PME) to study both ultrafast and slow processes of interaction of silane (SiH4) with thin film Pd, and to the investigation of the growth kinetics of a-Si:H films deposited by rf glow discharge under UV light irradiation are presented. As compared to other ellipsometric techniques like rotating analyzer ellipsometry (RAE), the phase modulation uses a high frequency of about 50 kHz provided by a photoelastic modulator. Thus, PME allows one to reach 1 - 5 ms time resolution which permits faster real-time measurements than RAE. This remarkable feature of PME makes it particularly suitable for in-situ applications. Changes of optical properties of Pd thin films exposed to SiH4 at different fluxes are monitored by in situ single wavelength ellipsometry in the case of high fluxes which lead to ultrafast process and by in situ spectroscopic ellipsometry at small fluxes and slow kinetics. The study reveals a complicated character of the process which depends on initial flux of silane and leads to formation of Pd disilicide, Pd hydride, and an intrinsic porosity. A qualitative model of the process is proposed.

  16. 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.

  17. 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.

    1988-01-01

    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.

  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. 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.

  20. 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.

  1. Optical properties of Ni(1-x)Mn(2+x)O4 films studied by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Zhang, Leibo; Hou, Yun; Huang, Zhiming; Zhou, Wei; Gao, Yanqing

    2010-10-01

    Transition metal oxide (TMO) has been extensively focused in recent years. In this paper, we investigate the optical properties of a typical TMO material of Ni(1-x)Mn(2+x)O4 (x=0-1) thin films. Different compositions of x=0, 0.1, 0.2, 0.3 thin films are grown on Pt/Ti/SiO2/Si substrates by chemical solution deposition method under annealing temperature of 750°C. X-ray diffraction patterns indicate that Ni(1-x)Mn(2+x)O4 thin films are polycrystalline with spinel structure. The optical properties are investigated using spectroscopic ellipsometry at room temperature in the wavelength range of 400-1700nm. By fitting the measured ellipsometric data with a three-phase model (air/sample/Pt), the optical constants of thin films are determined. The refractive index and extinction coefficient don't show apparent variation with different composition. The obtained optical constants are very significant in the potential applications of optoelectronic devices.

  2. Optical properties of Ni(1-x)Mn(2+x)O4 films studied by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Zhang, Leibo; Hou, Yun; Huang, Zhiming; Zhou, Wei; Gao, Yanqing

    2011-02-01

    Transition metal oxide (TMO) has been extensively focused in recent years. In this paper, we investigate the optical properties of a typical TMO material of Ni(1-x)Mn(2+x)O4 (x=0-1) thin films. Different compositions of x=0, 0.1, 0.2, 0.3 thin films are grown on Pt/Ti/SiO2/Si substrates by chemical solution deposition method under annealing temperature of 750°C. X-ray diffraction patterns indicate that Ni(1-x)Mn(2+x)O4 thin films are polycrystalline with spinel structure. The optical properties are investigated using spectroscopic ellipsometry at room temperature in the wavelength range of 400-1700nm. By fitting the measured ellipsometric data with a three-phase model (air/sample/Pt), the optical constants of thin films are determined. The refractive index and extinction coefficient don't show apparent variation with different composition. The obtained optical constants are very significant in the potential applications of optoelectronic devices.

  3. Spectroscopic Ellipsometry Measurements of Wurtzite Gallium Nitride Surfaces as a Function of Buffered Oxide Etch Substrate Submersion

    NASA Astrophysics Data System (ADS)

    Szwejkowski, Chester; Constantin, Costel; Duda, John; Hopkins, Patrick; Optical Studies of GaN interfaces Collaboration

    2013-03-01

    Gallium nitride (GaN) is considered the most important semiconductor after the discovery of silicon. Understanding the optical properties of GaN surfaces is imperative in determining the utility and applicability of this class of materials to devices. In this work, we present preliminary results of spectroscopic ellipsometry measurements as a function of surface root mean square (RMS). We used commercially available 5mm x 5mm, one side polished GaN (3-7 μm)/Sapphire (430 μm) substrates that have a wurtzite crystal structure and they are slightly n-type doped. The GaN substrates were cleaned with Acetone (20 min)/Isopropanol(20 min)/DI water (20 min) before they were submerged into Buffered Oxide Etch (BOE) for 10s - 60s steps. This BOE treatment produced RMS values of 1-30 nm as measured with an atomic force microscope. Preliminary qualitative ellipsometric measurements show that the complex refractive index and the complex dielectric function decrease with an increase of RMS. More measurements need to be done in order to provide explicit quantitative results. This work was supported by the 4-VA Collaborative effort between James Madison University and University of Virginia.

  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. Surface roughness estimation of MBE grown CdTe/GaAs(211)B by ex-situ spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Karakaya, Merve; Bilgilisoy, Elif; Arı, Ozan; Selamet, Yusuf

    2016-07-01

    Spectroscopic ellipsometry (SE) ranging from 1.24 eV to 5.05 eV is used to obtain the film thickness and optical properties of high index (211) CdTe films. A three-layer optical model (oxide/CdTe/GaAs) was chosen for the ex-situ ellipsometric data analysis. Surface roughness cannot be determined by the optical model if oxide is included. We show that roughness can be accurately estimated, without any optical model, by utilizing the correlation between SE data (namely the imaginary part of the dielectric function, <ɛ2 > or phase angle, ψ) and atomic force microscopy (AFM) roughness. <ɛ2 > and ψ values at 3.31 eV, which corresponds to E1 critical transition energy of CdTe band structure, are chosen for the correlation since E1 gives higher resolution than the other critical transition energies. On the other hand, due to the anisotropic characteristic of (211) oriented CdTe surfaces, SE data (<ɛ2 > and ψ) shows varieties for different azimuthal angle measurements. For this reason, in order to estimate the surface roughness by considering these correlations, it is shown that SE measurements need to be taken at the same surface azimuthal angle. Estimating surface roughness in this manner is an accurate way to eliminate cumbersome surface roughness measurement by AFM.

  6. Spectroscopic Ellipsometry of 3C-SiC Thin Films Grown on Si Substrates Using Organosilane Sources

    NASA Astrophysics Data System (ADS)

    Kubo, Naoki; Moritani, Akihiro; Kitahara, Kuninori; Asahina, Shuichi; Kanayama, Nobuyuki; Tsutsumi, Koichi; Suzuki, Michio; Nishino, Shigehiro

    2005-06-01

    Dielectric function spectra of 3C-SiC films on Si substrates in the energy region of 0.73-6.43 eV were measured by spectroscopic ellipsometry. Hexamethyldisilane (Si2(CH3)6) and tetraethylsilane (Si(C2H5)4) were used as safe organosilane sources for the growth of SiC films. The measured spectra were compared with those of 3C-SiC on a Si(001) substrate grown with disilane (Si2H6). First, the pseudodielectric function spectra gave a shoulder structure corresponding to the direct X5-X1 interband transition in the Brillouin zone. Secondly, the dielectric function of 3C-SiC was determined by applying a four-layer model in which we took into account the surface roughness and mixed crystals of a carbonized interface layer. Finally, the third-derivative lineshape of the imaginary part \\varepsilon2 of the complex-dielectric function provided the values of the interband transition energy Eg and the broadening parameter Γ for the X5-X1 interband transition. The measured values of Γ indicated that the crystalline quality of SiC films grown using organosilane sources is comparable to that of SiC films grown using Si2H6.

  7. 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.

  8. Use of Variable Angle Spectroscopic Ellipsometry in Order to Determine Contaminant Optical Properties

    NASA Technical Reports Server (NTRS)

    Hughes, C.; Workman, G.; Reynolds, J.

    1997-01-01

    In order to measure contaminant levels found in the manufacture of the Redesigned Solid Rocket Motor (RSRM), optical properties of the contaminants are needed to develop standards for calibration purposes. Specific to our efforts is the determination of the complex index of refraction for a hydrocarbon mixture and a commercial methyl siloxane. Using ellipsometric measurements with multiple angles of incident and a range of wavelengths in the near infrared a determination of the index of refraction and the extinction coefficient were made for the contaminants. This paper will present the optical techniques and modeling approach used to determine these optical constants of the hydrocarbon mixture and the methyl siloxane studied.

  9. Ion bombardment effects in low-pressure plasmas: In situ spectroscopic ellipsometry and Monte-Carlo simulation study

    NASA Astrophysics Data System (ADS)

    Amassian, Aram

    Plasma-enhanced chemical vapor deposition (PECVD) is a very versatile, yet highly complex process which has attracted the attention of the optical coatings community for its ability to synthesize thin film materials with a wide and continuous range of optical properties. In this work, we investigate the effects of ion-surface interactions in the case of hyperthermal ions (100 to 103 eV) accelerated at the RF-biased electrode of a PECVD reactor, in order to better understand their effect beneath the substrate surface, on growing films, and on interface formation. We apply in situ real-time spectroscopic ellipsometry (RTSE): (1) to monitor modifications at the surface of model c-Si(001) substrates exposed to low-pressure O2 plasma at the RF-powered electrode as a function of substrate bias voltage (VB), (2) to determine interface broadening during the initial stages of TiO 2 deposition on SiO2, and (3) to monitor the Ar plasma treatment of the interface between porous and dense Si3N4 films, and its effect on the growth of multilayer dense/porous stacks. The first part of this thesis focuses on the modifications of a c-Si substrate resulting from an exposure to an O2 plasma at the RF-powered electrode by using ex situ variable angle spectroscopic ellipsometry (VASE). The study demonstrates the presence of significant sub-surface modifications, giving rise to a top layer oxide (SiO 2) and an interfacial damage layer on c-Si(001). The depth of modifications was found to scale with ˜|VB|½ , increasing from ˜3.4 nm up to ˜9.6 nm for V B ranging between -60 and -600 V after 10 minutes of plasma exposure. Static Monte-Carlo TRIM simulations confirmed that the modifications and scaling can be explained on the basis of depth-dependent O transport by ion implantation. In the second part of this work, we studied the dynamical effects of plasma-surface interactions by using in situ RTSE in combination with TRIDYN (a dynamical version of TRIM) simulations. TRIDYN simulations

  10. 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.

  11. The thickness-dependent band gap and defect features of ultrathin ZrO2 films studied by spectroscopic ellipsometry.

    PubMed

    Xu, Ji-Ping; Zhang, Rong-Jun; Zhang, Yuan; Wang, Zi-Yi; Chen, Lei; Huang, Qing-Hua; Lu, Hong-Liang; Wang, Song-You; Zheng, Yu-Xiang; Chen, Liang-Yao

    2016-01-28

    The band gap and defect features of ultrathin ZrO2 films with varying thicknesses have been investigated by spectroscopic ellipsometry through the point-by-point data inversion method. The ε2-sprectra in the 3-6 eV range are extracted based on an optical model consisting of a Si substrate/effective ZrO2 film/air ambient structure where the effective ZrO2 film is a combination of interfacial layers and ZrO2. Evident widening of the band gap with a reducing size is observed when the effective ZrO2 films are below a critical thickness, somewhere between 8.80 nm and 17.13 nm. This is due to quantum-confinement and amorphous effects. Moreover, the sub-band-gap defects at interfacial layers and in bulk ZrO2 are identified and present strong thickness dependence as well. The interfacial defects at 3.26, 4.13, 4.43, and 4.77 eV mainly exist below the critical thickness and exhibit a significant suppression with increasing film thickness. The bulk defects at 4.15 eV and 4.46 eV dominate in ZrO2 films once they are over the critical thickness. The evolution of the band gap and defects is closely related to variance in the electronic structure of amorphous ZrO2. Our results may be helpful in understanding controversial problems concerning the size effect on ultrathin high-k oxide films and exploring the further miniaturization of electronic devices based on them. PMID:26752103

  12. Developing Spectroscopic Ellipsometry to Study II-Vi and Diluted Magnetic Semiconductors

    NASA Astrophysics Data System (ADS)

    Kim, Young-Dong

    We have constructed a rotating analyzer spectroscopic ellipsometer (RAE) to study effects of magnetic and nonmagnetic doping on the E_1 and E _1 + Delta_1 band gap energies in ZnSe-based II-VI semiconductors. To remove the natural surface oxide overlayer which distorts the intrinsic dielectric response of the sample, a chemical etching technique using dilute NH_4OH solution was developed. The successful removal of the oxide overlayer on ZnSe was confirmed via the XPS technique. For diluted magnetic semiconductors (DMS), we found that the E_1 and E _1 + Delta_1 band gap energies increase with x for Zn_{1-x}Fe _{x}Se and Zn_ {1-x}Co_{x}Se, and decrease with x for Zn_{1-x} Mn_{x}Se. An sp -d direct exchange interaction model which explained the Gamma-point band gap energy of Zn _{1-x}Mn_ {x}Se was applied. The calculated band gap energies at the L-point are only consistent with Zn _{1-x}Mn_ {x}Se data. We showed that an sp-d hybridization model, which includes the location of the energy levels of the magnetic impurity d-levels can account for the concentration dependence of E_1 and E _1 + Delta_1 band gap energies of all three materials. For Zn_{x}Cd _{1-x}Se systems, all spectral features of CdSe were identified as E_0, E_0 + Delta_0, E_1, E_1 + Delta_1, E_2, and E _sp{0}{'} threshold energies from band structure calculations using a nonlocal empirical pseudopotential method. Many-body effect has to be included in the calculation of the dielectric function of CdSe to obtain good agreement with the measured spectrum. Concentration dependent spin-orbit splitting band gap Delta _1(x) is well explained by the statistical fluctuation of the alloy composition.

  13. Use of optical spacers to enhance infrared Mueller ellipsometry sensitivity: application to the characterization of organic thin films.

    PubMed

    Ndong, Gerald; Lizana, Angel; Garcia-Caurel, Enric; Paret, Valerie; Melizzi, Géraldine; Cattelan, Denis; Pelissier, Bernard; Tortai, Jean-Hervé

    2016-04-20

    Mueller ellipsometry in the mid-infrared (IR) spectral range can be used to obtain information about chemical composition through the vibrational spectra of samples. In the case of very thin films (<100  nm), the ellipsometric spectral features due to vibrational absorption are in general quite weak, and sometimes they are hidden by the noise in the measured data. In this work, we present one method based on the use of optical spacers as a tool to enhance the sensitivity of IR Mueller ellipsometry. An optical spacer is a thin film made of a known material which is between the substrate and the layer of interest. We show that, when the thickness of the two layers fulfills a given condition, the spectral features due to vibrational absorptions are enhanced. We explain the enhancement effect in terms of the Airy formula. The theoretical discussion is illustrated with two examples. We analyzed polystyrene thin films deposited on silicon wafers. Some of the wafers were covered by a thin film of thermal silicon dioxide (SiO2), which was used as a spacer. The results show the suitability of the proposed technique to overcome the lack of sensitivity in ellipsometric measurements when it comes to working with either very thin films or materials with low absorption. PMID:27140106

  14. Fourier transform infrared spectroscopic study of truffles

    NASA Astrophysics Data System (ADS)

    Zhao, Dezhang; Liu, Gang; Song, Dingshan; Liu, Jian-hong; Zhou, Yilan; Ou, Jiaming; Sun, Shizhong

    2006-01-01

    Truffles are rare wild growing edible mushrooms belonging to Ascomycetes. In this paper, Fourier transform infrared (FTIR) spectroscopy was used to obtain vibrational spectra of truffles. The results show that the mushrooms exhibit characteristic spectra. The two strongest absorption bands appear at about 1077cm -1 and 1040 cm -1, which were described as C-O stretching in carbohydrate. The vibrational spectra indicate that the main compositions of the truffles are polysaccharide and protein. According to the characteristics bands and absorption ratios of spectra, different species of truffles can be discriminated. It is also found the great changes between moldy and healthy truffles, which the major differences are observed in the bands of protein. In addition, FTIR spectral differences are observed between the same species of truffles from different producing areas. It is showed that the FTIR spectroscopic method is valuable tool for rapid and nondestructive analysis of truffles prior to any extraction method used.

  15. Spectroscopic data for thermal infrared remote sensing

    NASA Technical Reports Server (NTRS)

    Varanasi, P.; Nemtchinov, V.; Li, Z.

    1995-01-01

    There has been extensive world-wide use of chloro-fluoro-carbons (CFC's), especially CFC-11 (CFCl3) and CFC-12 (CF2Cl2), hydro-chloro-fluoro-carbons (HCFC's), HCFC-22 (CHFCl2) in particular, and sulphur hexaflouride (SF6) in numerous many industrial applications. These chemicals possess either a strong ozone-depletion potential or a global-warming potential, or both, and pose a threat to the inhabitability of our planet. Recognition of this fact has led to significant curtailment, if not total banishment, of their use globally. However, as recent satellite observations have shown, decline in their atmospheric concentrations may not be immediate. The marked depletion of ozone which has been observed in recent years at high latitudes has made infrared remote sensing of the atmosphere an activity of high priority. The success of any infrared remote sensing experiment conducted in the atmosphere depends upon the availability of accurate, high-resolution, spectroscopic data that are applicable to that experiment. This paper presents a preliminary phase of a multi-faceted work using a Fourier-transform spectrometer (FTS) which is in progress in our laboratory. The concept of how laboratory-borne measurements can be geared toward obtaining a database that is directly applicable to satellite-borne remote sensing missions is the main thrust of this paper which addresses itself to ongoing or planned international space missions. Spectroscopic data on the unresolvable bands of the above mentioned as well as several other man-made gases and on the individual spectral lines of such naturally present trace gases as CO2, N2O, NH3, and CH4 are presented. There is often significant overlap between the isolated lines of better known bands of the more abundant species and the weaker absorption features identifiable as bands of the currently less abundant CFC's, HCFC's, and SF6.

  16. 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

  17. 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

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. Quantum ellipsometry

    NASA Astrophysics Data System (ADS)

    Toussaint, Kimani Christopher, Jr.

    Ellipsometry is a technique in which the polarization of light is used to determine the optical properties of a material (sample) and infer information such as the thickness of a thin film. Traditional ellipsometric measurements are limited in their accuracy because of the use of an external reference sample for calibration, and because of the quantum noise inherent in the source that becomes important at low light levels. A new technique called quantum ellipsometry is investigated, and is shown to circumvent these limitations by using a non-classical source of light, namely, twin photons generated by the process of spontaneous parametric downconversion (SPDC), in conjunction with a novel polarization interferometer and coincidence-counting detection scheme. Quantum ellipsometry comes in two forms: correlated-photon and entangled-photon ellipsometry. Both ellipsometric techniques yield estimated of the sample reflectance/transmittance with accuracy greater than conventional ellipsometry. Specifically, when the quantum efficiencies of the detectors used are above a certain threshold the signal-to-noise ratio of the measured ellipsometric parameters is larger for quantum ellipsometry than for conventional ellipsometry. This is because the photon pairs generated by SPDC have a fully correlated joint photon counting distribution. Furthermore, both correlated-photon and entangled-photon ellipsometry have the added advantage that they do not require calibration by an external reference sample, which is another limitation on the accuracy for most conventional ellipsometry. Quantum ellipsometry exploits the property of photon number correlation and polarization entanglement. The entanglement property, inherent in entangled-photon ellipsometry, is shown to allow for the movement of the optical elements that precede the sample to the sample-free optical channel in the setup. A theoretical and experimental investigation of quantum ellipsometry was conducted. Both correlated

  4. FIRE near-infrared spectroscopic classifications of SN 2016dag

    NASA Astrophysics Data System (ADS)

    Morrell, N.; Phillips, M. M.; Contreras, C.; Hsia, E. Y.

    2016-07-01

    We report the spectroscopic classification of SN 2016dag, discovered by the Backyard Observatory Supernova Search (BOSS), using a near-infrared spectrum (range 800-2500 nm) obtained on Jul 14.95 UT with the FoldedPort Infrared Echellette (FIRE) spectrograph on the 6.5-m Magellan Baade Telescope at Las Campanas Observatory.

  5. 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.

  6. 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.

  7. 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.

  8. Optical constants of CH3NH3PbBr3 perovskite thin films measured by spectroscopic ellipsometry.

    PubMed

    Alias, Mohd Sharizal; Dursun, Ibrahim; Saidaminov, Makhsud I; Diallo, Elhadj Marwane; Mishra, Pawan; Ng, Tien Khee; Bakr, Osman M; Ooi, Boon S

    2016-07-25

    The lack of optical constants information for hybrid perovskite of CH3NH3PbBr3 in thin films form can delay the progress of efficient LED or laser demonstration. Here, we report on the optical constants (complex refractive index and dielectric function) of CH3NH3PbBr3 perovskite thin films using spectroscopic ellipsometry. Due to the existence of voids, the refractive index of the thin films is around 8% less than the single crystals counterpart. The energy bandgap is around 2.309 eV as obtained from photoluminescence and spectrophotometry spectra, and calculated from the SE analysis. The precise measurement of optical constants will be useful in designing optical devices using CH3NH3PbBr3 thin films. PMID:27464113

  9. Evaluation of thickness and strain of thin planar layers of InAs on GaAs(001) using spectroscopic ellipsometry

    SciTech Connect

    Eyink, K. G.; Szmulowicz, F.; Esposito, D.; Grazulis, L.; Hill, M.; Mahalingam, K.; Aronow, A. J.

    2014-07-21

    We develop a technique for accurately measuring thickness of planar InAs films grown on (001) GaAs by spectroscopic ellipsometry, using bulk optical constants. We observe that the critical point structure for the E{sub 1} and E{sub 1} + Δ{sub 1} transitions extracted from the measured dielectric properties varies with strain in the layer. Transmission electron microscopy confirms the extracted thickness and measures the residual strain based on the dislocation spacing in the film. At small thickness, the E{sub 1} critical point is seen to markedly deviate from the dependence predicted by deformation potential theory and appears to be consistent with additional quantum confinement effects.

  10. Real-Time In Situ Monitoring of GaAs (211) Oxide Desorption and CdTe Growth by Spectroscopic Ellipsometry

    NASA Astrophysics Data System (ADS)

    Lennon, C. M.; Almeida, L. A.; Jacobs, R. N.; Markunas, J. K.; Smith, P. J.; Arias, J.; Brown, A. E.; Pellegrino, J.

    2012-10-01

    We describe the growth of CdTe (211)B by molecular beam epitaxy on large-area epiready GaAs (211)B substrates. Prior to CdTe growth, GaAs substrates were thermally cleaned under an As4 flux. Oxide desorption was verified by in situ spectroscopic ellipsometry (SE) and reflection high-energy electron diffraction. The use of in situ SE played a significant role in the study of CdTe-on-GaAs growth and annealing processes. An effective medium approximation (EMA) was used to model the overlayer thickness variation of CdTe epilayers throughout growth and in situ annealing cycles. A correlation between SE-derived EMA thickness values and surface defect formation mitigation is discussed. All annealed samples (11.5 μm to 13 μm thick) exhibited excellent crystalline quality with average double crystal rocking curve full-width at half-maximum (FWHM) values of ~60 arcsec.

  11. Spectroscopic Ellipsometry Studies of Thin Film a-Si:H Solar Cell Fabrication by Multichamber Deposition in the n-i-p Substrate Configuration

    NASA Astrophysics Data System (ADS)

    Dahal, Lila Raj

    Real time spectroscopic ellipsometry (RTSE), and ex-situ mapping spectroscopic ellipsometry (SE) are powerful characterization techniques capable of performance optimization and scale-up evaluation of thin film solar cells used in various photovoltaics technologies. These non-invasive optical probes employ multichannel spectral detection for high speed and provide high precision parameters that describe (i) thin film structure, such as layer thicknesses, and (ii) thin film optical properties, such as oscillator variables in analytical expressions for the complex dielectric function. These parameters are critical for evaluating the electronic performance of materials in thin film solar cells and also can be used as inputs for simulating their multilayer optical performance. In this Thesis, the component layers of thin film hydrogenated silicon (Si:H) solar cells in the n-i-p or substrate configuration on rigid and flexible substrate materials have been studied by RTSE and ex-situ mapping SE. Depositions were performed by magnetron sputtering for the metal and transparent conducting oxide contacts and by plasma enhanced chemical vapor deposition (PECVD) for the semiconductor doped contacts and intrinsic absorber layers. The motivations are first to optimize the thin film Si:H solar cell in n-i-p substrate configuration for single-junction small-area dot cells and ultimately to scale-up the optimized process to larger areas with minimum loss in device performance. Deposition phase diagrams for both i- and p -layers on 2" x 2" rigid borosilicate glass substrate were developed as functions of the hydrogen-to-silane flow ratio in PECVD. These phase diagrams were correlated with the performance parameters of the corresponding solar cells, fabricated in the Cr/Ag/ZnO/n/i/ p/ITO structure. In both cases, optimization was achieved when the layers were deposited in the protocrystalline phase. Identical solar cell structures were fabricated on 6" x 6" borosilicate glass with

  12. Infrared spectroscopic diagnosis of thyroid tumors

    NASA Astrophysics Data System (ADS)

    Liu, K. Z.; Schultz, C. P.; Salamon, E. A.; Man, A.; Mantsch, H. H.

    2003-12-01

    The objective of this study was to assess the feasibility of infrared spectroscopy as an alternative means of screening for the diagnosis of thyroid tumors. A total of 89 fine-needle aspirates were obtained from patients with various thyroid disorders. Infrared spectra were recorded from original aspirates as well as from cell pellets obtained after centrifugation. The spectra were analyzed by two different multivariate statistical methods using the clinical data as reference. An unsupervised cluster analysis of cell pellet spectra revealed a good separation of normal cells from tumor cells with an accuracy of 94.7%. When using spectra of the original aspirates, the separation of normal and tumor was only 65.3%. However, by using a supervised methodology, such as the linear discriminant analysis, the partition of the original aspirates into normal and tumor groups was highly successful; the accuracy for the training set was 96.6%, while that for the validation set was as high as 90.2%. These results suggest that this new methodology, after appropriate refinement, has the potential of screening for thyroid tumors from fine-needle aspirate samples.

  13. Complex Refractive Index Spectra of CH3NH3PbI3 Perovskite Thin Films Determined by Spectroscopic Ellipsometry and Spectrophotometry.

    PubMed

    Löper, Philipp; Stuckelberger, Michael; Niesen, Bjoern; Werner, Jérémie; Filipič, Miha; Moon, Soo-Jin; Yum, Jun-Ho; Topič, Marko; De Wolf, Stefaan; Ballif, Christophe

    2015-01-01

    The complex refractive index (dielectric function) of planar CH3NH3PbI3 thin films at room temperature is investigated by variable angle spectroscopic ellipsometry and spectrophotometry. Knowledge of the complex refractive index is essential for designing photonic devices based on CH3NH3PbI3 thin films such as solar cells, light-emitting diodes, or lasers. Because the directly measured quantities (reflectance, transmittance, and ellipsometric spectra) are inherently affected by multiple reflections, the complex refractive index has to be determined indirectly by fitting a model dielectric function to the experimental spectra. We model the dielectric function according to the Forouhi-Bloomer formulation with oscillators positioned at 1.597, 2.418, and 3.392 eV and achieve excellent agreement with the experimental spectra. Our results agree well with previously reported data of the absorption coefficient and are consistent with Kramers-Kronig transformations. The real part of the refractive index assumes a value of 2.611 at 633 nm, implying that CH3NH3PbI3-based solar cells are ideally suited for the top cell in monolithic silicon-based tandem solar cells. PMID:26263093

  14. 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.

  15. 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.

  16. Spectroscopic ellipsometry and x-ray photoelectron spectroscopy of La{sub 2}O{sub 3} thin films deposited by reactive magnetron sputtering

    SciTech Connect

    Atuchin, V. V.; Kalinkin, A. V.; Kochubey, V. A.; Kruchinin, V. N.; Vemuri, R. S.; Ramana, C. V.

    2011-03-15

    Lanthanum oxide (La{sub 2}O{sub 3}) films were grown by the reactive dc magnetron sputtering and studied their structural, chemical and optical parameters. La{sub 2}O{sub 3} films were deposited onto Si substrates by sputtering La-metal in a reactive gas (Ar+O{sub 2}) mixture at a substrate temperature of 200 deg. C Reflection high-energy electron diffraction measurements confirm the amorphous state of La{sub 2}O{sub 3} films. Chemical analysis of the top-surface layers evaluated with x-ray photoelectron spectroscopy indicates the presence of a layer modified by hydroxylation due to interaction with atmosphere. Optical parameters of a-La{sub 2}O{sub 3} were determined with spectroscopic ellipsometry (SE). There is no optical absorption over spectral range {lambda}=250-1100 nm. Dispersion of refractive index of a-La{sub 2}O{sub 3} was defined by fitting of SE parameters over {lambda}=250-1100 nm.

  17. Atmospheric and Spectroscopic Research in the Far Infrared

    NASA Technical Reports Server (NTRS)

    Park, Kwangjai

    2001-01-01

    The University of Oregon (UO) was a participant in a number of far infrared spectroscopic projects over the past three decades. These include Sub-millimeter Infrared Balloon Experiment (SIBEX), the Balloon Intercomparison Campaign (BIC), and the Infrared Balloon Experiment (IBEX). In addition to these field studies, the UO program contained a detector research component and a laboratory spectroscopy element. Through a productive collaboration with Dr. Carli's group in Italy, with Prof. Ade's group in England and with Dr. Chance of Harvard-Smithsonian, we have made substantial contributions to the development of far infrared spectroscopy as a mature measurement technology for the atmospheric science. This report summarizes the activities during the latest grant period, covering the span from February 22, 1998 to February 21, 2002.

  18. Atmospheric and spectroscopic research in the far infrared

    NASA Technical Reports Server (NTRS)

    Park, Kwangjai; Radostitz, James V.

    1992-01-01

    The University of Oregon (UO) has been a major participant in the development of far infrared spectroscopic research of the stratosphere for the purpose of understanding the ozone layer processes. The UO has had a 15-year collaboration with the Italian group of B. Carli, and have participated in the 1978/79 Sub-millimeter Infrared Balloon Experiment (SIBEX), in the Balloon Intercomparison Campaign, (BIC), in the Infrared Balloon Experiment (IBEX), and in the recently concluded Far Infrared Experiment for UARS Correlative Measurements (FIREX). Both IBEX and FIREX programs were conducted in collaboration with NASA Langley, and were designed as validation flights in support of the Upper Atmosphere Research Satellite (UARS) Program. The technique of atmospheric far infrared spectroscopy offers two important advantages. First, many chemically important species can be measured simultaneously and co-spatially in the atmosphere. Second, far infrared atmospheric spectra can be obtained in thermal emission without reference to the sun's position, enabling full diurnal and global coverage. Recent improvements in instrumentation, field measurements, and molecular concentration retrieval techniques are now making the far infrared a mature measurement technology. This work to date has largely focused on balloon-based studies, but the future efforts will focus also on satellite-based experiments. A program of research in the following general areas was proposed: Laboratory Pressure broadening coefficient studies; specialized detector system assembly and testing; and consultation and assistance with instrument and field support. The proposal was approved and a three-year research grant titled 'Atmospheric and Spectroscopic Research in the Far Infrared' was awarded. A summary of technical accomplishments attained during the grant period are presented.

  19. 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

  20. [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

  1. Infrared-spectroscopic nanoimaging with a thermal source.

    PubMed

    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. PMID:21499314

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. Spectroscopic ellipsometry study of the effect of illumination and thermal annealing on the optical constants of thin Ge-As-S films

    NASA Astrophysics Data System (ADS)

    Pamukchieva, V.; Szekeres, A.; Arsova, D.

    2011-02-01

    The effects of illumination and post-illumination thermal annealing on the optical properties of chalcogenide thin (~150 nm) films were studied by spectroscopic ellipsometry. The films were thermally evaporated from Ge30.8As5.7S63.5 and Ge32As5S63 glasses. They were exposed to illumination with an HBO 500 lamp and to subsequent thermal annealing at a temperature of 350 °C. Ellipsometric measurements in the spectral range 300-820 nm were carried out after each technological step. From the ellipsometric data analysis the optical constants (n, k, ɛ), optical band gap energy Eog and film thickness have been determined, while the oscillator energies E0 and Ed have been estimated applying the single-oscillator approximation theory. In the ɛ2 spectra three peaks, denoted by E1, E2 and E3, have appeared, which are attributed to interband transitions. By illumination, the values of the complex refractive index (\\tilde n = n - {\\rm{i}}k), dielectric function (\\skew3\\tilde \\varepsilon = \\varepsilon _1 - {\\rm{i}}\\varepsilon _{\\rm{2}} ) and dispersion energy Ed decrease, whereas the band gap energy (Eog) and the oscillator energy (E0) values increase. All these are accompanied by a ~12-13% enhancement of film thickness. Thermal annealing leads to a further increase of the energetic parameters values, but causes a ~14-15% decrease of film thickness in comparison to that of illuminated films. The E1 and E2 peaks diminish on illumination and post-illumination annealing, whereas the magnitude of the E3 peak decreases on illumination and increases by annealing, approaching its initial value for the as-deposited state.

  8. 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

  9. 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.

  10. Spectroscopic ellipsometry analysis of nanoporous low dielectric constant films processed via supercritical carbon dioxide for next-generation microelectronic devices

    NASA Astrophysics Data System (ADS)

    Othman, Maslina T.

    My research will address issues at the back-end-of-line in microelectronics fabrication, specifically the need for Low-k extendibility. The International Roadmap for Semiconductors (2005) suggested that interconnect insulation must be replaced with a material having an ultra-low dielectric constant (k) of < 2.0 and can withstand rigorous current process integration for the 65 nm technology. Creating porosity in the films produces k-values as low (1.0) air. In this research, supercritical CO2 (SCCO2) process is utilized to create pores, remove water, repair plasma-damaged sample and seal pores. These multi-step processing does not only produce low-k film but also create device reliability. Spectroscopy ellipsometric (SE) analysis is used to evaluate the performance of each process on porous film. In SE analysis, Cauchy, Bruggeman Effective Medium Approximation and graded models are used to model the processed samples. The depth profile SE analysis demonstrates the individual process performance based on its changes of refractive index (n) throughout the film thickness. SE also provide important film properties like thickness, porosity etc. In addition to SE, Fourier Transform Infra-red (FT-IR), Scanning Electron Microscopy (SEM) and electrical characterizations are used. Results show that SCCO2/co-solvents can extract porogens and remove water effectively at a significantly shorter time (≤1 hr) and at a low temperature (≤160°C) without thickness shrinkage in contrast with thermal annealing which uses 450°C and 5 hours without significantly shrinkage. SCCO2/TMCS removes water and terminates silanol group with methyl group, and hence preventing water re-adsorption which increases k. The dense layer on the sample surface that formed through the vapor treatment/HMDS helps to seal pores and prevent metal diffusion. This research also shows that patterning samples prior to porogen/water removal can minimize plasma damages on porous sample.

  11. Infrared spectroscopic study of sputtered tungsten oxide films

    SciTech Connect

    Paul, J.L.; Lassegues, J.C. )

    1993-10-01

    Recent infrared and Raman spectroscopic studies of various tungsten oxide films concluded either the formation of W=O terminal bonds or the transformation of such bonds into W-OH groups upon proton insertion. The infrared transmission and reflection spectra of bleached and colored sputtered films were reinvestigated in order to resolve the previous contradictory interpretations and for better insight into the mechanism of electrochromism at the molecular level. The new results confirm the first interpretation and allow us to show that H[sup +] or Li[sup +] insertion creates shorter ([approximately]1.7[angstrom]) and longer ([approximately]2 [angstrom]) W-O bonds around the W[sup 5+] centers. These results are in agreement with the concepts of small polaron and of intervalence charge transfer mechanism. They illustrate the local lattice distortion around a W[sup 5+] site. Aging of the initial films has also been followed and characterized by H/D in situ isotopic exchange.

  12. Atmospheric and Spectroscopic Research in the Far Infrared

    NASA Technical Reports Server (NTRS)

    Park, Kwangjai

    1998-01-01

    The spectroscopic measurements of molecular parameters constitute one of the major areas of our research program. This part of our program has been conducted in close collaboration with Smithsonian Astrophysical Observatory (SAO) and National Institute of Standards and Technology (NIST). The references on HO2, OH, and O2 that appear on the publication list are examples of this type of work completed during the grant period. These pressure-broadening studies have provided the kind of improvements needed in the database for retrieving atmospheric profiles from far infrared limb sensing data. Authors summarized the laboratory spectroscopic studies conducted during the grant period. We attempted to measure the pressure broadening coefficients of the O2 lines in the 50 and 117/ cm regions. An accurate characterization of these lines using the IBEX detector system was needed to analyze the flight data. These are difficult lines to measure because they arise from weak magnetic dipole transitions. We used a 4-meter absorption cell to obtain the pressure broadening coefficients for the 50 and 83 /cm lines. We also completed the pressure broadening studies including the temperature dependence of two lines of OH at 83 and 118 /cm. These two lines are important not only for the balloon data retrieval work but also for the future project proposals.Another area of focus in our program is the far infrared detector research. The third area of focus deals with data distribution and dissemination.

  13. Interband electronic transitions and phase transformation of multiferroic Bi1-xLaxFe1-yTiyO3 ceramics revealed by temperature-dependent spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    Optical properties and phase transition of Bi1-xLaxFe1-yTiyO3 (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 ɛ1 increases with the temperature. Meanwhile, the imaginary part ɛ2 in the low-energy region decreases with the temperature and has an opposite trend in the high-energy side. Four typical interband transitions (Ea ˜ 2.50 eV, Eb ˜ 2.70 eV, Ec ˜ 3.60 eV, and Ed ˜ 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 Fe3+ ions with nonmagnetic Ti4+ ions can reduce the exchange interaction between adjacent magnetic moments. Therefore, SE technique can be sensitive for detecting the phase/structural transitions of multiferroic oxides.

  14. 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}.

  15. 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

  16. 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

  17. 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

  18. 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. PMID:26927101

  19. Denoising and deblurring of Fourier transform infrared spectroscopic imaging data

    NASA Astrophysics Data System (ADS)

    Nguyen, Tan H.; Reddy, Rohith K.; Walsh, Michael J.; Schulmerich, Matthew; Popescu, Gabriel; Do, Minh N.; Bhargava, Rohit

    2012-03-01

    Fourier transform infrared (FT-IR) spectroscopic imaging is a powerful tool to obtain chemical information from images of heterogeneous, chemically diverse samples. Significant advances in instrumentation and data processing in the recent past have led to improved instrument design and relatively widespread use of FT-IR imaging, in a variety of systems ranging from biomedical tissue to polymer composites. Various techniques for improving signal to noise ratio (SNR), data collection time and spatial resolution have been proposed previously. In this paper we present an integrated framework that addresses all these factors comprehensively. We utilize the low-rank nature of the data and model the instrument point spread function to denoise data, and then simultaneously deblurr and estimate unknown information from images, using a Bayesian variational approach. We show that more spatial detail and improved image quality can be obtained using the proposed framework. The proposed technique is validated through experiments on a standard USAF target and on prostate tissue specimens.

  20. Infrared spectroscopic near-field mapping of single nanotransistors.

    PubMed

    Huber, A J; Wittborn, J; Hillenbrand, R

    2010-06-11

    We demonstrate the application of scattering-type scanning near-field optical microscopy (s-SNOM) for infrared (IR) spectroscopic material recognition in state-of-the-art semiconductor devices. In particular, we employ s-SNOM for imaging of industrial CMOS transistors with a resolution better than 20 nm, which allows for the first time IR spectroscopic recognition of amorphous SiO(2) and Si(3)N(4) components in a single transistor device. The experimentally recorded near-field spectral signature of amorphous SiO(2) shows excellent agreement with model calculations based on literature dielectric values, verifying that the characteristic near-field contrasts of SiO(2) stem from a phonon-polariton resonant near-field interaction between the probing tip and the SiO(2) nanostructures. Local material recognition by s-SNOM in combination with its capabilities of contact-free and non-invasive conductivity- and strain-mapping makes IR near-field microscopy a versatile metrology technique for nanoscale material characterization and semiconductor device analysis with application potential in research and development, failure analysis and reverse engineering. PMID:20463381

  1. 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

  2. The molecular structure of chloritoid: A mid-infrared and near-infrared spectroscopic study

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    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.

  3. 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. PMID:25828887

  4. 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

  5. Infrared Spectroscopic Studies with the Stratospheric Observatory for Infrared Astronomy (sofia)

    NASA Astrophysics Data System (ADS)

    Gehrz, R. D.; Becklin, E. E.

    2011-06-01

    The joint U.S. and German Stratospheric Observatory for Infrared Astronomy (SOFIA) will be a premier facility for studying the physics and chemistry of the interstellar medium and the stellar evolution process for many decades. SOFIA's first-generation instrument complement includes broadband imagers, moderate resolution spectrographs capable of resolving broad features due to dust and large molecules, and high resolution spectrometers suitable for kinematic studies of molecular and atomic gas lines at km/s resolution. SOFIA spectroscopic science applications will be discussed, with special emphasis on investigations related to infrared spectroscopy of astrophysical gas, grains, and ices. First light images and early science results related to these topics will be presented.

  6. Analysis of Urinary Calculi Using Infrared Spectroscopic Imaging

    NASA Astrophysics Data System (ADS)

    Sablinskas, Valdas; Lesciute, Daiva; Hendrixson, Vaiva

    2009-06-01

    Kidney stone disease is a cosmopolitan disease, occurring in both industrialized and developing countries and mainly affecting adults aged 2060 years. The formation of kidney stones is a process that includes many factors. Its primary and contributing pathogenic factors are genetic, nutritional and environmental, but also include personal habits. Information about the chemical structure of kidney stones is of great importance to the treatment of the kidney diseases. The usefulness of such information was first recognized in early 1950s. Analysis of urinary stones by various chemical methods, polarization microscopy, x-ray diffraction, porosity determination, solid phase NMR, and thermo analytical procedures have been widely used. Unfortunately, no one method is sufficient to provide all the clinically useful information about the structure and composition of the stones. Infrared spectroscopy can be considered a relatively new method of kidney stone analysis. It allows to identify any organic or inorganic molecules the constituents of kidney stones. So far this method had never been used to collect information about kidney stone component patterns in Lithuania. Since no epidemiological studies have been performed in this field, the medical treatment of kidney stone disease is empirical and often ineffective in hospitals around the country. The aim of this paper is to present some results of analysis of kidney stones extracted from local patients using FTIR spectroscopical microscopy.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. Infrared imaging spectroscopic system based on a PGP spectrograph and a monochrome infrared camera

    NASA Astrophysics Data System (ADS)

    Garcia-Allende, Pilar Beatriz; Anabitarte, Francisco; Conde, Olga M.; Madruga, Francisco J.; Lomer, Mauro; Lopez-Higuera, Jose M.

    2008-04-01

    Hyperspectral imaging spectroscopy has been widely used in remote sensing. However, its potential for applications in industrial and biological fields is enormous. Observation line spectrographs, based on the reflectance of the material under study in each field, can be obtained by means of an imaging spectrometer. In this way, imaging spectroscopy allows the simultaneous determination of the optical spectrum components and the spatial location of an object in a surface. A simple, small and low-cost spectrometer, such as those ones based on passive Prism-Grating-Prism (PGP) devices, is required for the abovementioned application fields. In this paper a non-intrusive and non-contact near infrared acquisition system based on a PGP spectrometer is presented. An extension to the whole near infrared range of the spectrum of a previously designed system in the Vis-NIR range has been performed. The reason under this investigation is to improve material characterization. To our knowledge, no imaging spectroscopic system based on a PGP device working in this range has been previously reported. The components of the system, its assembling, alignment and calibration procedures will be described in detail. This system can be generalized for a wide variety of applications employing a specific and adequate data processing

  12. Measurement of organic/polymer material by phase modulation ellipsometry

    NASA Astrophysics Data System (ADS)

    Ji, Yong; Teboul, Eric; Kramer, Alan R.

    2004-06-01

    Due to they can be tailored to provide a wide range of physical properties and their easiness of processing and fabrication, polymeric materials have found widespread use in the manufacture of microwave, electronics, photonics and bio-tech systems. This paper presents the basic principle of phase modulation spectroscopic ellipsometer (PMSE) and its advantages over other ellipsometry in measuring polymer film. Used for thin film measurements ultra-thin dielectric, meal film and organic film, the PMSE technique is now used over a wide spectral range from the vacuum ultraviolet to the mid infrared. Film thickness ranging from Angstrom up to 50um can be measured by PMSE. Applications of PMSE on measurement and characterization of polymer/organic material are given in the paper.

  13. Modeling ellipsometry and electron energy loss spectroscopy of graphene

    SciTech Connect

    Lyon, Keenan A.; Miskovic, Zoran L.; Diebold, Alain C.; Idrobo, Juan-Carlos

    2014-03-31

    Recent studies of electronic excitations in graphene by Electron Energy Loss Spectroscopy (EELS) have revealed massive high-frequency peaks assigned to the π and σ+π plasmons [1], which were semi-quantitatively modeled with a two-dimensional, two-fluid hydrodynamic (HD) model [2]. On the other hand, Spectroscopic Ellipsometry (SE) of graphene covers the region of nearly constant absorbance due to graphene’s universal optical conductivity at infrared frequencies, which is not clearly resolved by EELS, and goes up to cover the π-plasmon peak at ultraviolet frequencies [3]. To attempt to model both the SE and EELS, we amend the HD model by including a low-frequency contribution of graphene’s inter-band transitions, while monitoring the fulfillment of the f-sum rule [4] up to frequencies that cover excitations of all valence electrons.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. Near- and mid-infrared spectroscopic determination of algal composition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to investigate the feasibility of using near-infrared reflectance spectroscopy (NIRS) and mid-infrared reflectance spectroscopy (MIRS) to determine the composition of algal samples. We assayed a set of algal biomass samples (n=117), collected from algae turf scrubber...

  19. 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).

  20. Infrared Spectroscopic Identification of Chosen Dental Materials and Natural Teeth

    NASA Astrophysics Data System (ADS)

    Hędzelek, W.; Marcinkowska, A.; Domka, L.; Wachowiak, R.

    2008-08-01

    Studies using solid phase infrared spectroscopy in the range of 400 to 4000 wave numbers were conducted in order to quickly identify solid tooth fragments and differentiate them from dental materials used in the dental practice. The frequently employed dental materials were evaluated. Natural chemical structure of permanent teeth obtained from donors of various ages provided the reference material. The infrared vibrations detected in infrared transmission spectra depended on the chemical structure of examined compound. Comparable distinctive peaks in infrared spectra of natural teeth and inorganic dental materials (porcelain) were exhibited. Analogous infrared spectra of dental materials consisting of organic matrix with inorganic fillers were found. In the case of acrylic materials specific organic groups were enhanced. The prepared database of infrared transmission spectra included 23 dental materials, facilitating their appropriate identification. Application of infrared spectroscopy allowed for a quick differential identification of typical dental materials produced from organic compounds for inorganic restorations (porcelain) and of tooth structure-resembling hydroxyapatite and its contaminate forms with fluoride and carbonate ions.

  1. Infrared micro-spectroscopic studies of epithelial cells

    PubMed Central

    Romeo, Melissa; Mohlenhoff, Brian; Jennings, Michael; Diem, Max

    2009-01-01

    We report results from a study of human and canine mucosal cells, investigated by infrared micro-spectroscopy, and analyzed by methods of multivariate statistics. We demonstrate that the infrared spectra of individual cells are sensitive to the stage of maturation, and that a distinction between healthy and diseased cells will be possible. Since this report is written for an audience not familiar with infrared micro-spectroscopy, a short introduction into this field is presented along with a summary of principal component analysis. PMID:16797481

  2. Spectroscopic ellipsometry studies on the m-plane Al1‑ x In x N epilayers grown by metalorganic vapor phase epitaxy on a freestanding GaN substrate

    NASA Astrophysics Data System (ADS)

    Kojima, Kazunobu; Kagaya, Daiki; Yamazaki, Yoshiki; Ikeda, Hirotaka; Fujito, Kenji; Chichibu, Shigefusa F.

    2016-05-01

    Dispersion relationships of the refractive index and extinction coefficient of m-plane Al1‑ x In x N epitaxial films (x = 0.00, 0.23, and 0.30) grown on a freestanding m-plane GaN substrate were determined by spectroscopic ellipsometry measurement. The experimentally obtained ellipsometric parameters tan Ψ and cos Δ, which represent the differences in the p- and s-polarized amplitudes and phases of the incident light, respectively, were well fitted using the standard analytical functions. As the measurement was carried out at photon energies between 1.55 and 5.40 eV, the dispersion curves of the extinction coefficient k exhibited local maxima at approximately the Al1‑ x In x N bandgap energies of x = 0.23 and 0.30, and the sample with x = 0.00 showed an ordinal absorption spectrum with a bandtail formed owing to high-concentration residual impurities. A large and x-dependent energy difference between the absorption and emission spectra (Stokes’ shift) was observed for the Al1‑ x In x N films, suggesting the presence of carrier localization phenomena.

  3. 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

  4. 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.

  5. Near-infrared spectroscopic observations of Comets by Japanese Infrared Satellite

    NASA Astrophysics Data System (ADS)

    Kobayashi, Hitomi; Yamaguchi, Mitsuru; Ootsubo, Takafumi; Kawakita, Hideyo; Hamada, Saki

    Comets are thought to be one of the primeordial bodies in the solar system. Chemical abun-dances of the cometary icy materials are precious clue to the conditions in the early solar system. H2O is the most abundant species of the cometry nucleus, but CO and CO2 are also abundant with diversities. Especially, CO2 cannot be directly observed by ground-based ob-servations because of the strong absorption by telluric CO2. Thus, only the space observatory (or spacecraft) can access CO2 in comets directly. We observed some comets by "AKARI", Japanese infrared satellite. It has 68.5 cm telescope with InfraRed Camera (IRC). The IRC also has a spectroscopic capability (both grism and prism were available for disperser). The data we present were taken by the IRC in the grism mode. The IRC with grism can cover the wavelength range from 2.5 to 5 microns where vibrational fundamental bands of H2O, CO2, and CO (at 2.7, 4.3, and 4.7 microns) are usually recognized as emission in cometary spectra. We determined the mixng ratios of CO and CO2 relative to H2O for 5 comets: C/2006 W3, C/2006 OF2, C/2006 W3, /2007 N3, and C/2007 W1. These comets were observed at various heliocetric distances, so their mixing ratios can not be compared directly among these comets. We tried to convert the obtained mixing ratios at various heliocentric distancees to the mixing ratios at 1 AU from the Sun. Previous studies of mixing ratios of CO2 and CO relative to H2O were carried out by the Vega space craft (1P/Halley), ISO (C/1995 O1 and 103P/Hartley 2) and Deep Impcat spacecraft (9P/Tempel 1). We also applied the conversion factors to those prvious works. We will discuss about the diversity of mixing ratios of CO2 and CO in these comets.

  6. Ellipsometry: a sophisticated tool for optical metrology

    NASA Astrophysics Data System (ADS)

    Azzam, Rasheed M. A.

    2000-11-01

    Ellipsometry is a sensitive optical technique for non- invasive in-situ (in any optically transparent environment) and ex-situ (in air) characterization of surfaces, interfaces, and thin films which is based on measurement of the polarization of light before and after reflection from a given sample at different angles of incidence and as a function of wavelength. The spectral range of spectroscopic ellipsometry (SE) -typically 1-6eV of photon energy- has been extended to the mid and far IR on one side and to the VUV, EUV, and X-ray region on the other. Significant advances and sophistication of available instrumentation and supportive software have resulted in extensive use of ellipsometry in biology, chemistry, physics, materials science and engineering, and industrial applications over the past two decades. Fast ellipsometers are used for real- time on-line monitoring and feedback process control of various thin films and for the fabrication of pre-engineered multilayer and graded-composition structures. As a metrology tool, ellipsometry yields information on dielectric functions of layered optically isotropic or anisotropic materials, film thicknesses, interface roughnesses, and compositions (void and alloy fractions) and depth profiles of inhomogeneous thin films.

  7. Infrared spectroscopic parameters of COF2, SF6, ClO, N2, and O2

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Goldman, Aaron; Flaud, Jean-Marie

    1992-01-01

    The status of the middle infrared spectroscopy of selected atmospheric trace gases, COF2, SF6, ClO, N2, and O2 is reviewed. Emphasis is placed on improved sets of spectroscopic parameters that have been included in the 1991 and 1992 versions of the HITRAN database.

  8. Structural and bonding environments derived from infrared spectroscopic studies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infrared spectroscopy, generally in the form of FTIR, has been used to characterize the organic matter in animal manure and relevant materials or fractions. The FT-IR spectra of most manure samples resemble the Type III spectra of humic substances with strong aliphatic characters. However, the absor...

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

    PubMed

    Sigrist, Markus W

    2015-05-01

    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

  10. 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

  11. 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.

  12. 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

  13. Near infrared spectroscopic transmittance measurements for pharmaceutical powder mixtures.

    PubMed

    Sánchez-Paternina, Adriluz; Román-Ospino, Andrés D; Martínez, Mirna; Mercado, Joseph; Alonso, Camila; Romañach, Rodolfo J

    2016-05-10

    This study describes the development of near infrared (NIR) calibration models using transmittance measurements in powder samples and compares the results obtained with those of tablet transmittance and diffuse reflectance of powders. Transmission near infrared spectroscopy is a method widely used for the analysis of tablets in the evaluation of drug concentration due to the larger sample volume analyzed, but not commonly used for the analysis of powder samples. Diffuse reflection near infrared spectroscopy is a method used in both powder and tablets for the evaluation of quality attributes. In this initial study NIR transmittance measurements were obtained using an off-line spectrometer equipped with a high intensity light source. Spectra were obtained with three different resolutions for the analysis of powder and tablet samples of 7.50-22.50% (w/w) acetaminophen. The Partial Least Squares (PLS) calibration models developed include pretreatments such as Standard Normal Variate (SNV) and first derivative in the region from 9500-7500 cm(-1). Transmittance in powder presented low Root Mean Square Error of Prediction (RMSEP) values that varied from 0.23-1.15% (w/w) APAP with resolution of 64 and 16 cm(-1). The lowest RMSEP values (0.23-0.39% (w/w) APAP) were obtained using a resolution of 64 cm(-1). The RMSEP values for powder transmittance measurements were 2.4-5.6 times lower than the diffuse reflectance measurements of the powder mixtures. PMID:26895497

  14. Spectroscopic studies of superconductors. Part A: Infrared and Raman spectra

    SciTech Connect

    Bozovic, I.; Marel, D. van der

    1996-12-31

    During the ten years that followed the discovery of superconductivity above 30 K in lanthanum barium cuprate by Bednorz and Mueller, the condensed matter physics community has been engaged in an unprecedented worldwide effort in materials processing, characterization of physical properties, and theoretical modeling of superconductors. The present conference has brought together a group of researchers who are actively involved in the experimental determination of the physical properties of high-{Tc} superconductors, the quest for the microscopic mechanism (or mechanisms) of superconductivity, the search for new physical phenomena in these materials, or the search for new classes of superconducting materials. The distinguishing feature and the unifying theme of this conference was the use of spectroscopic techniques as the primary tools in pursuing these goals. Separate abstracts were prepared for 32 papers in this conference.

  15. Non-destructive infrared spectroscopic analysis of IMPROVE aerosol samples

    NASA Astrophysics Data System (ADS)

    Ruthenburg, T. C.; Dillner, A. M.

    2011-12-01

    The use of mid-infrared (MIR) spectroscopy is of increasing interest for determining organic functional group composition of aerosols. The organic fraction of aerosols is thought to affect visibility, climate and toxicity. Organic functional group composition can provide insights into aerosol sources and aging. The Interagency Monitoring of Protected Visual Environments (IMPROVE) program, established in 1985, operates a long term particulate matter monitoring network primarily in National Parks and Wilderness Areas. IMRPROVE samples collected on polytetrafluoroethylene (PTFE) filters are analyzed via IR spectroscopy to determine organic functional group composition. Organic carbon (OC) mass determined by MIR spectroscopy is compared to OC derived from a thermal-optical method.

  16. 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.

  17. 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.

  18. Optical properties of Cd{sub 0.9}Zn{sub 0.1}Te studied by variable angle spectroscopic ellipsometry between 0.75 and 6.24 eV

    SciTech Connect

    Ralph B. James

    2000-01-07

    Optical properties of Cd{sub 0.9}Zn{sub 0.1}Te (CZT) were studied by variable angle spectroscopic ellipsometry (VASE). Measurements made by VASE were performed on CZT and CdTe samples in air at room temperature at multiple angles of incidence. A parametric function model was employed in the VASE analysis to determine the dielectric functions {var_epsilon}={var_epsilon}{sub 1} + i{var_epsilon}{sub 2} in the range of 0.75 to 6.24 eV. A two-oscillator analytical model was used to describe the dielectric response of native oxides on CZT. Surface oxide optical properties and thickness on CZT were also determined in conjunction with the VASE measurement and analysis of a CdTe sample. Two samples of CZT of different oxide thicknesses were measured and their optical constants were coupled together in a multiple-sample, multiple-model VASE analysis to resolve correlations between fitting parameters. Effective medium approximation (EMA) was used to describe the optical properties of the CZT oxide with roughness. A Kramers-Kronig self-consistency check of the real and imaginary parts of the Cd{sub 0.9}Zn{sub 0.1} dielectric functions was performed over the energy range 0.75 to 6.24 eV. A five-Lorentz-oscillator model was employed to describe the dielectric response of CZT in the range of 1.6 to 6.24 eV. Intensity transmission measurements were made on the Cd{sub 0.9}Zn{sub 0.1}Te and CdTe, showing the absorption energy band edges of {approximately} 1.58 and 1.46 eV, respectively.

  19. 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.

  20. Spectroscopic ellipsometry of Zn(1-x)Cu(x)O thin films based on a modified sol-gel dip-coating technique.

    PubMed

    Al-Khanbashi, Hibah A; Shirbeeny, W; Al-Ghamdi, A A; Bronstein, Lyudmila M; Mahmoud, Waleed E

    2014-01-24

    Nanocrystalline Zn(1-x)Cu(x)O thin films (x=0, 0.01, 0.02, 0.03, 0.04 and 0.05) were synthesized by sol-gel dip-coating technique on a quartz substrate. These films were annealed at 350°C for 2 h. The X-ray diffraction showed a hexagonal crystal structure with high intensity peak for the (002) reflection plane indicating preferential growth along the c-axis of the crystal lattice. The peak position related to the (002) peak was shifted as a result of the copper ion incorporation, confirming the interstitial substitution of the zinc ions by the copper ions. This interstitial substitution leads to a decrease of an average crystallite size and lattice constants and an increase of the micro-strain up to 2 at.% of the copper amount. The surface morphology was explored by scanning electron microscopy which confirmed the homogenous distribution of nanoparticles in the deposited films along the quartz substrates. The energy dispersion X-ray spectroscopy revealed absence of impurities in the as-deposited films. The high resolution electron microscopy and selected area electron diffraction depicted that the films have polycrystalline nature. The film thickness and optical constants of the Zn(1-x)Cu(x)O thin films were estimated by fitting the spectroscopic ellipsometric data (ψ and Δ) using three different models. The refractive index was fitted using harmonic oscillator model from which the oscillator and the dispersive energies were found. The dielectric constant, dielectric loss, energy loss functions were also determined. PMID:24157332

  1. 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.

  2. Visible and Infrared Spectroscopic Evolution of Nova V2467 Cygni

    NASA Astrophysics Data System (ADS)

    Lynch, David K.; Russell, R. W.; Rudy, R. J.; Woodward, C. E.

    2009-01-01

    We present a nineteen-spectrum time series that documents the visible and infrared (0.8 - 5.0 microns) evolution of novae V2467 Cygni. Observations were made using SpeX on the IRTF, and VNIRIS at Lick and spanned the period from 30 Apr 2007 to 12 Aug 2008 UT. Peak brightness (discovery) was mag 7.4 on 15 Mar 2007 UT. The decline rates t2 and t3 were 7.3 and 15.1 days, respectively. Except for some early, low amplitude periodic oscillations, the light curve declined monotonically and showed no evidence of dust formation as of this writing (Oct 1, 2008). The spectrum quickly moved from low excitation on 7 May 2007 UT to showing coronal lines of [Si VI], [Si VII], [Ca VIII], [S VIII] and [S IX] by May 31 2007. At least 5 Rydberg emission lines were present in the latter spectrum and all of the coronal lines had complex profiles. An interstellar reddening of E(B-V) = 1.5. was derived from the Lyman beta-fluoresced OI lines. By 14 Dec 2007 the object displayed many high-excitation emission lines. Coronal lines of [SI VII], [Ca VIII], [Si X], and [S XI] showed notched, doubled line profiles and lines of H I, He I, He II, weak OI, and Rydberg lines were still present. On June 15, 2008 the spectrum was dominated by coronal lines. [Mg VIII] at 3.03 microns was the brightest emission line in the infrared spectrum, and lines from four separate ionization states of silicon were present: [Si VI], [Si VII], [Si IX], [Si X]. Other species displaying coronal emission lines included [P VIII], [S VIII], [S IX], [Ca VII], [Ca VIII] and possibly [Ni X]. The 12 Aug 2008 spectrum was virtually identical to the 15 June 2008 spectrum only fainter.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. Spectroscopic Investigation of the Effects of Environment on Newly-Developed Near Infrared Emitting Dyes

    NASA Astrophysics Data System (ADS)

    McNamara, Louis E.; Liyanage, Nalaka; Delcamp, Jared; Hammer, Nathan I.

    2015-06-01

    The effects of environment on the photophysical properties of a series of newly-developed near infrared emitting dyes was studied spectroscopically. Properties of interest include fluorescence emission, fluorescence lifetime, and quantum yield. Tracking how the photophysics of these compounds are affected in the solid phase, in thin films, in solution, and at the single molecule level with changing environment will provide a deeper insight into how dye structure affects their function.

  8. 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.

  9. Mid-Infrared and Near-Infrared Spectroscopic Properties of Fusarium Isolates: Effects of Culture Conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Fusarium genus includes soil saprobes as well as pathogenic or toxin-producing species. Traditional classification of Fusarium isolates is slow and requires a high level of expertise. The objective of this project is to describe culture condition effects on mid-infrared (MidIR) and near-infrared...

  10. Acidic properties of sulfated zirconia: An infrared spectroscopic study

    SciTech Connect

    Babou, F.; Coudurier, G.; Vedrine, J.C.

    1995-04-01

    Sulfated zirconia with S content of 2 wt.% equivalent to complete coverage of its surface was studied by infrared spectroscopy. At least four sulfated species were identified and exhibited an important and reversible sensitivity to water. These equilibria were demonstrated to exist by the study of adsorption of incremental amounts of water. D{sub 2}O and H{sub 2}{sup 18}O isotopically enriched water molecules were used to assist interpretation of IR spectra. To characterize acidity features, the probe molecules butane, CO, and H{sub 2}O (as weak bases) or pyridine (as a strong base) were adsorbed. Two Lewis acid sites (L{sub 1} and L{sub 2}) were observed and one Bronsted site (B) related to the zirconia support (L{sub 1}) and the sulfated species (L{sub 2}, B). They were evidenced by pyridine adsorption which was shown to partly displace adsorbed sulfate species. With the help of previous theoretical calculations using an ab initio method and representing the zirconia surface by a mononuclear zirconium complex, it is emphasized that the sulfated zirconia can be visualized as a H{sub 2}SO{sub 4} compound grafted onto the surface of zirconia in a way which makes it very sensitive to water but in a reversible way. Its acidity is similar to that of sulfuric acid but it is not really superacidic. Comparison with other oxides leads us to suggest that the cationic charge borne by the metallic cation is of prime importance for the acidity strength. The role of water on the acidic and catalytic properties for n-butane isomerization reaction is emphasized. 33 refs., 11 figs., 2 tabs.

  11. 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

  12. Fourier transform infrared and Raman spectroscopic characterization of homogeneous solution concentration gradients near a container wall at different temperatures

    NASA Technical Reports Server (NTRS)

    Loo, B. H.; Burns, D. H.; Lee, Y. G. L.; Emerson, M. T.

    1991-01-01

    Fourier transform infrared (FTIR) and Raman spectroscopic techniques were used to study the solution concentration gradient in succino nitrile-rich and water-rich homogeneous solutions. The spectroscopic data shows significant concentration dependency. Although FTIR-attenuated total reflectance could not yield surface spectra since the evanescent infrared wave penetrated deep into the bulk solution, it showed that water-rich clusters were decreased at higher temperatures. This result is consistent with the calorimetric results reported earlier.

  13. 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

  14. Advanced ellipsometry for very thin films and multilayers

    NASA Astrophysics Data System (ADS)

    Paduschek, Peter; Tamme, Michael; Hankey, Thomas D.

    1995-09-01

    In an introduction, problems of modern thin film research and production of thin films are discussed. Possible solutions with different measurement methods like nulling ellipsometers, RAE-ellipsometry, spectroscopic ellipsometry, and interferometry are compared. RAE- ellipsometry with respect to precision for thin films below 100 angstrom are discussed. Repeatabilities of below 0.1 angstrom are shown. Thicker films even above a few microns can be evaluated with multi-wavelength measurements at distinct wavelengths at 543 nm, HeNe, 790 nm, IR 1.3 micrometers , and IR 1.5 micrometers . This interferometer emulation concept is practically free of order ambiguity--a problem with traditional ellipsometry. Multiple wavelengths are also used to characterize multilayers such as ONO, OPO, etc. with multiple results. Multiple wavelength ellipsometry is compared to multiple incidence angle ellipsometry. For multilayer stacks (transparent or absorbing) the SPI program was developed and is shown. In this program the known parameters as well as the to-be-measured parameters can be selected (substrate value, refractive index, k-value, thickness). Measurement spotsize effects are discussed--high lateral resolution measurements are presented.

  15. A NEAR-INFRARED SPECTROSCOPIC SURVEY OF COOL WHITE DWARFS IN THE SLOAN DIGITAL SKY SURVEY

    SciTech Connect

    Kilic, Mukremin; Kowalski, Piotr M.; Von Hippel, Ted

    2009-07-15

    We present near-infrared photometric observations of 15 and spectroscopic observations of 38 cool white dwarfs (WDs). This is the largest near-infrared spectroscopic survey of cool WDs to date. Combining the Sloan Digital Sky Survey photometry and our near-infrared data, we perform a detailed model atmosphere analysis. The spectral energy distributions of our objects are explained fairly well by model atmospheres with temperatures ranging from 6300 K down to 4200 K. Two WDs show significant absorption in the infrared, and are best explained with mixed H/He atmosphere models. Based on the up-to-date model atmosphere calculations by Kowalski and Saumon, we find that the majority of the stars in our sample have hydrogen-rich atmospheres. We do not find any pure helium atmosphere WDs below 5000 K, and we find a trend of increasing hydrogen to helium ratio with decreasing temperature. These findings present an important challenge to understanding the spectral evolution of WDs.

  16. Feasibility Demonstration of Wide-Field Fourier-Spectroscopic-Imaging in Infrared Region

    NASA Astrophysics Data System (ADS)

    Qi, Wei; Takuma, Takashi; Tsutsumi, Ryosuke; Inui, Asuka; Kagiyama, Hiroyasu; Kojima, Daisuke; Nishiyama, Akira; Ishimaru, Ichirou

    We are aiming at the realization of living-environment sensor and non-invasive blood-sugar sensor by the proposed imaging type 2-D Fourier spectroscopy. This method is based on the phase-shift interference between the object beams. As a result, even if the object beams are spatially incoherent, we can observe the phase-shift interference phenomena. In the near infrared region, we can obtain the high-contrast blood vessel image of mouse's ear in the deeper part by InGaAs camera. Furthermore, in the mid-infrared region, we have successfully measured the radiation spectroscopic-imaging with wild field of view by the infrared module, such as the house plants.

  17. 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

  18. 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

    NASA Astrophysics Data System (ADS)

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

    2006-09-01

    Low-pressure O2 plasma exposures were performed on c-Si(001) at a radio frequency (rf)-powered electrode in the presence of substrate self-biasing (VB) from VB=-60to-600V, 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 (≪1s ) to a depth of a few nanometers below the surface after exposure to a low oxygen ion fluence (˜5×1014Ocm-2). Oxide growth is detected at intermediate fluence (˜1015-1016Ocm-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 (>1017cm-2) as oxide and DL thicknesses reach bias-dependent steady-state values, determined by the maximum ion penetration depth, which increases from ˜3.6to9.5nm for VB=-60to-600V. 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+ ions in the plasma environment, capable of penetrating and damaging up to 3nm deeper than the majority ion population (O2+), and (2) because of important surface motion resulting from oxidation

  19. Thin film characterization using spectroscopic ellipsometry

    NASA Technical Reports Server (NTRS)

    Alterovitz, Samuel A.

    1990-01-01

    The application of the multiple angle and wavelength (MAW) technique to measure the dielectric function of semiconducting films is discussed. This technique evaluates unambiguously the complex dielectric function, epsilon (E), of the film without any pre-assumptions. In some cases the effective medium approximation (EMA) was used to determine the volume fraction of the film components. Application of the MAW technique to several semiconducting films was published previously. Different applications and examples are given, including metal and insulator films.

  20. [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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. Identification and classification of human neural stem cells by infrared spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Steiner, G.; Küchler, S.; Koch, E.; Salzer, R.; Schackert, G.; Kirsch, M.

    2009-02-01

    Human neural stem were cultivated and characterized using infrared spectroscopic imaging. A classification algorithm based on linear discriminate analysis was developed to distinguish the differentiation of the stem cells to neurons, astrocytes and stem cells without labeling. The classification is based upon spectral features which mainly arise from proteins, nucleic acids. A spectral training set was formed with spectra from cells which were identified by a subsequently staining according to a standard histological protocol. Differentiated cells could be classified with a high accuracy whereas not differentiated stem cells did exhibit some misclassifications

  7. 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

  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. PMID:24076459

  9. 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.

  10. Near-Infrared Spectroscopic Study of AA Tau: Water and OH Observations

    NASA Astrophysics Data System (ADS)

    Brown, Logan Ryan; Gibb, Erika

    2014-06-01

    To understand our own solar origins, we must investigate the composition of the protoplanetary disk from which the solar system formed. To infer this, we study analogs to the early solar system called T Tauri stars. These objects are low-mass, pre-main sequence stars surrounded by circumstellar disks of material from which planets are believed to form. We present high-resolution (λ/Δλ˜25,000), near-infrared spectroscopic data from the T Tauri star AA Tau using NIRSPEC at the Keck II telescope, located on Mauna Kea, HI, taken in 2009 and 2010. AA Tau has a close to edge-on geometry, with an inclination of 70° ± 10° (Donati et al. 2010). Objects must have a nearly edge-on inclination for the disk to be sampled via absorption line spectroscopy. We observed strong absorption lines of both water and OH to which a spectroscopic model was fit in order for us to determine column density and rotational temperature. These near-infrared observations complement the work being done with ALMA, allowing us to probe the inner most disk regions and the chemistry contained within while ALMA primarily samples and is most sensitive to the outer disk.

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. Ground-based infrared solar spectroscopic measurements of carbon monoxide during 1994 Measurement of Air Pollution From Space flights

    NASA Astrophysics Data System (ADS)

    Pougatchev, N. S.; Sen, B.; Steele, L. P.; Toon, G. C.; Yurganov, L. N.; Zander, R.; Zhao, Y.

    1998-08-01

    Results of the comparison of carbon monoxide ground-based infrared solar spectroscopic measurements with data obtained during 1994 Measurement of Air Pollution From Space (MAPS) flights are presented. Spectroscopic measurements were performed correlatively with April and October MAPS flights by nine research groups from Belgium, Canada, Germany, Japan, New Zealand, Russia, and the United States. Characterization of the techniques and error analysis were performed. The role of the CO a priori profile used in the retrieval was estimated. In most cases an agreement between spectroscopic and MAPS data is within estimated MAPS accuracy of +/-10%.

  16. 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

  17. Superconducting energy gap and c-axis plasma frequency of (Nd,Sm)FeAsO0.82F0.18 superconductors from infrared ellipsometry.

    PubMed

    Dubroka, A; Kim, K W; Rössle, M; Malik, V K; Drew, A J; Liu, R H; Wu, G; Chen, X H; Bernhard, C

    2008-08-29

    We present far-infrared ellipsometric measurements of polycrystalline samples of the pnictide superconductor RFeAsO0.82F0.18 (R=Nd and Sm). We find evidence that the electronic properties are strongly anisotropic such that the optical spectra are dominated by the weakly conducting c-axis response similar to the cuprate high-temperature superconductors. We deduce an upper limit of the c-axis superconducting plasma frequency of omega pl,c(SC)< or =260 cm(-1) corresponding to a lower limit of the c-axis magnetic penetration depth of lambda c > or =6 microm and lambda c/lambda ab > or =30 as compared to lambda ab=185 nm from muon spin rotation [A. Drew, arXiv:0805.1042 [Phys. Rev. Lett. (to be published)

  18. Infrared spectroscopic analysis of skin tumor of mice treated with several medicinal plants

    PubMed Central

    Ali, Huma; Dixit, Savita

    2013-01-01

    Objective To evaluate the differences between cancerous tissue, drug treated tissue and its corresponding normal tissue by infrared spectroscopic analysis. Methods Methanolic extracts of Azadirachta indica, Ocimum sanctum, Aloe barbandesis, Tinospora cordifolia and Triticum aestivum were assessed for the isolation and purification of active compound. After that, combine crude and combine isolated samples were prepared. Skin tumor was induced by topical application of 7, 12-dimethyl benz (a) anthracene and promoted by croton oil in Swiss albino mice. To assess the chemopreventive potential of different drugs, it was administered at a concentration of 400 mg/kg body weight daily up to 16 weeks. Fourier transform infrared spectroscopy analysis was used to differentiate the drug treated tissues with the normal and cancerous tissue. In the present study, spectra of different tissues were recorded in the range of 400-4 000 cm−1. Results The results of the present study have shown that the remarkable difference exists between the IR spectra of normal, drugs treated and cancerous tissue in terms of frequencies and intensities of prominent bands of cellular biomolecules. Conclusions Fourier transform infrared spectroscopy analysis suggests the chemopreventive effect of above treated drugs and the best result was observed in combine crude sample and in combine isolated sample or synergistic effect of individual crude and isolated extract in 7, 12-dimethyl benz (a) anthracene croton oil induced skin carcinogenesis in Swiss albino mice.

  19. A broadband silicon quarter-wave retarder for far-infrared spectroscopic circular dichroism

    NASA Astrophysics Data System (ADS)

    Xi, Xiaoxiang; Smith, R. J.; Stanislavchuk, T. N.; Sirenko, A. A.; Gilbert, S. N.; Tu, J. J.; Carr, G. L.

    2014-11-01

    The high brightness, broad spectral coverage and pulsed characteristics of infrared synchrotron radiation enable time-resolved spectroscopy under throughput-limited optical systems, as can occur with the high-field magnet cryostat systems used to study electron dynamics and cyclotron resonance by far-infrared techniques. A natural extension for magnetospectroscopy is to sense circular dichroism, i.e. the difference in a material's optical response for left and right circularly polarized light. A key component for spectroscopic circular dichroism is an achromatic 1 4 wave retarder functioning over the spectral range of interest. We report here the development of an in-line retarder using total internal reflection in high-resistivity silicon. We demonstrate its performance by distinguishing electronic excitations of differing handedness for GaAs in a magnetic field. This 1 4 wave retarder is expected to be useful for far-infrared spectroscopy of circular dichroism in many materials.

  20. 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.

  1. SEM, EDX, infrared and Raman spectroscopic characterization of the silicate mineral yuksporite.

    PubMed

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

    2015-02-25

    The mineral yuksporite (K,Ba)NaCa2(Si,Ti)4O11(F,OH)⋅H2O 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. PMID:25240833

  2. Recent Developments in Solid-Phase Extraction for Near and Attenuated Total Reflection Infrared Spectroscopic Analysis.

    PubMed

    Huck, Christian W

    2016-01-01

    A review with more than 100 references on the principles and recent developments in the solid-phase extraction (SPE) prior and for in situ near and attenuated total reflection (ATR) infrared spectroscopic analysis is presented. New materials, chromatographic modalities, experimental setups and configurations are described. Their advantages for fast sample preparation for distinct classes of compounds containing different functional groups in order to enhance selectivity and sensitivity are discussed and compared. This is the first review highlighting both the fundamentals of SPE, near and ATR spectroscopy with a view to real sample applicability and routine analysis. Most of real sample analyses examples are found in environmental research, followed by food- and bioanalysis. In this contribution a comprehensive overview of the most potent SPE-NIR and SPE-ATR approaches is summarized and provided. PMID:27187347

  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. A Herschel Spectroscopic Survey of Warm Molecular Gas in Local Infrared Luminous Galaxies

    NASA Astrophysics Data System (ADS)

    Lu, N.; Zhao, Y.; Xu, C. K.; Gao, Y.; GOALS FTS Team

    2013-03-01

    We describe an on-going 194-671 μm spectroscopic survey of a flux-limited sample of 125 local luminous infrared galaxies (LIRGs) with Herschel SPIRE Fourier Transform Spectrometer (FTS). The survey targets primarily the CO spectral line energy distribution (SLED), from J = 4-3 up to J = 13-12, to probe dense and warm molecular gas that should play an intimate role in star formation and/or active galactic nuclear activities in these galaxies. The program is about 75% finished. At S/N > 5, besides the CO lines, we also detected [N ii] 205 μm and [C i] 370 μm (3 P 2 - 3P1) lines in every target observed. In about half of the observed targets, we also detected [C i] 609 μm (3 P 1 - 3P0).

  5. A Herschel Spectroscopic Survey of Warm Molecular Gas in Local Luminous Infrared Galaxies

    NASA Astrophysics Data System (ADS)

    Lu, Nanyao Y.; Zhao, Y.; Xu, C. K.; Gao, Y.; Armus, L.; Appleton, P. N.; Charmandaris, V.; Diaz Santos, T.; Evans, A. S.; Howell, J.; Issak, K.; Iwasawa, K.; Leech, J.; Lord, S. D.; Mazzarella, J. M.; Petric, A.; Sanders, D. B.; Schulz, B.; Surace, J. A.; Van der Werf, P.

    2013-01-01

    We describe an on-going Herschel 194-671 micron spectroscopic survey of a flux-limited sample of 125 local luminous infrared galaxies (LIRGs), targeting primarily at the spectral line energy distribution (SLED) of the CO rotational line emission (from J=4-3 up to J=13-12) from warm and dense molecular gas, the [NII] 205 micron line from ionized gas, and the [CI] 370 and 609 micron lines arising mainly from less dense and colder molecular gas where the CO (J=1-0) line is also strong. We present observational results for the first set of 65 sample galaxies that are more or less point sources with respect to the Herschel beams, and show statistical correlations among the shape of the CO SLED, CO line luminosities, IR dust luminosity, and whether a target is known to harbor AGN or not.

  6. 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.

  7. 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.

  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. 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.

  10. Fourier transform infrared spectroscopic analysis of sperm chromatin structure and DNA stability.

    PubMed

    Oldenhof, H; Schütze, S; Wolkers, W F; Sieme, H

    2016-05-01

    Sperm chromatin structure and condensation determine accessibility for damage, and hence success of fertilization and development. The aim of this study was to reveal characteristic spectral features coinciding with abnormal sperm chromatin packing (i.e., DNA-protein interactions) and decreased fertility, using Fourier transform infrared spectroscopy. Chromatin structure in spermatozoa obtained from different stallions was investigated. Furthermore, spermatozoa were exposed to oxidative stress, or treated with thiol-oxidizing and disulfide-reducing agents, to alter chromatin structure and packing. Spectroscopic studies were corroborated with flow cytometric analyses using the DNA-intercalating fluorescent dye acridine orange. Decreased fertility of individuals correlated with increased abnormal sperm morphology and decreased stability toward induced DNA damage. Treatment with the disulfide reducing agent dithiothreitol resulted in increased sperm chromatin decondensation and DNA accessibility, similar as found for less mature epididymal spermatozoa. In situ infrared spectroscopic analysis revealed that characteristic bands arising from the DNA backbone (ν1230, ν1086, ν1051 cm(-1) ) changed in response to induced oxidative damage, water removal, and decondensation. This coincided with changes in the amide-I region (intensity at ν1620 vs. ν1640 cm(-1) ) denoting concomitant changes in protein secondary structure. Reduction in protein disulfide bonds resulted in a decreased value of the asymmetric to symmetric phosphate band intensity (ν1230/ν1086 cm(-1) ), suggesting that this band ratio is sensitive for the degree of chromatin condensation. Moreover, when analyzing spermatozoa from different individuals, it was found that the asymmetric/symmetric phosphate band ratio negatively correlated with the percentage of morphologically abnormal spermatozoa. PMID:26916383

  11. Label free molecular sexing of monomorphic birds using infrared spectroscopic imaging.

    PubMed

    Steiner, Gerald; Preusse, Grit; Zimmerer, Cordelia; Krautwald-Junghanns, Maria-Elisabeth; Sablinskas, Valdas; Fuhrmann, Herbert; Koch, Edmund; Bartels, Thomas

    2016-04-01

    The absence of sexual dimorphism in many birds often makes sex determination difficult. In particular immature birds and adults of monomorphic species show no external sex characteristics. Molecular techniques based on DNA hybridization or polymerase chain reaction (PCR) are standard methods for sex identification. However, these methods are expensive and time consuming procedures and require special sample preparation. Noninvasive methods for a rapid determination of bird's gender are of increasing importance for ornithologists, breeders as well as for successful captive-breeding programs. Fourier transform infrared (FT-IR) spectroscopy is one such technique that can provide gender specific information. In this study, using the example of domestic pigeons (Columba livia f. dom.) we demonstrate that only a small amount of the feather pulp is needed to determine the gender. FT-IR spectroscopic images of feather pulp suspensions were recorded in transmission mode. Principal component analysis (PCA) and linear discriminant analysis (LDA) were performed to identify the sex. The gender related information are described by 2nd and 4th principal component principle component (PC). The 2nd PC represents different amounts of proteins while the 4th PC shows variations within the amide I and amide II bands as well as in the region of phosphate vibrations of nucleic acids. Blood cells of male pigeons exhibit a significantly higher amount of proteins and nucleic acids than those of female pigeons. Feather pulp samples of male species were assigned with 100% accuracy. Seven from eight female samples were assigned correctly while one sample could not be classified. This study demonstrates that the sex of domestic pigeons can be accurately and and rapidly identified by infrared spectroscopic imaging. PMID:26838394

  12. 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.

  13. 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.

  14. Spectroscopic infrared extinction mapping as a probe of grain growth in IRDCs

    NASA Astrophysics Data System (ADS)

    Lim, Wanggi; Carey, Sean J.

    2014-07-01

    We present photometric and spectroscopic tests of MIR to FIR extinction laws toward IRDC G028.36+00.07, a potential site of massive star formation. Lim & Tan (2014, hereafter LT14) developed methods of FIR extinction mapping of this source using Spitzer-MIPS 24 micron and Herschel-PACS 70 micron images, and extending the MIR 8 micron mapping methods of (Butler & Tan 2012, hereafter BT12), finding evidence for grain growth in the highest mass surface density regions. Here we present initial results of spectroscopic infrared extinction (SIREX) mapping using Spitzer-IRS (14 to 38 micron) data of the same IRDC. These methods allow us to measure the SED of the diffuse Galactic ISM, which we compare to theoretical models of Draine & Li (2007), as well as to search for opacity law variations with mass surface density within the IRDC. By comparison with theoretical dust models, e.g., Ossenkopf & Henning (1994) and Ormel et al. (2011), we are able to search for compositional signatures of the grain ices, such as water and methanol. We 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.

  15. Spectroscopic Capabilities and Possibilities of the Far Infrared and Submillimeter Telescope Mission

    NASA Technical Reports Server (NTRS)

    Pearson, J. C.

    2000-01-01

    The Far Infrared and Submillimeter Telescope (FIRST) mission is the fourth European Space Agency corner stone mission. FIRST will be an observatory with a passively cooled (80 Kelvin) 3.5 meter class telescope and three cryogenic instruments covering the 670 to 80 mm spectral region. The mission is slated for a 4.5 year operational lifetime in an L2 orbit. It will share an Arian 5 launch with PLANCK in early 2007. The three payload instruments include the Spectral and Photometric Imaging Receiver (SPIRE), which is a bolometer array with Martin-Puplett FTS for 200-670 microns, the Photoconductor Array Camera and Spectrometer (PACS), which is a photoconductor array with a grating spectrometer for 80-210 microns and the Heterodyne Instrument for FIRST (HIFI), which is a series of seven heterodyne receivers covering 480-1250 GHz and portions of 1410-1910 GHz and 2400-2700 GHz. FIRST will make many detailed spectral surveys of a wide variety of objects previously obscured by the atmosphere and in regions of the spectrum seldom used for astronomical observations, With all of the spectroscopic capability on FIRST a great deal of laboratory spectroscopic support will be needed for accurate interpretation of the spectral data.

  16. Two-dimensional infrared study of 3-azidopyridine as a potential spectroscopic reporter of protonation state

    SciTech Connect

    Nydegger, Michael W.; Dutta, Samrat; Cheatum, Christopher M.

    2010-10-07

    The lack of general spectroscopic probes that can be used in a range of systems to probe kinetics and dynamics is a major obstacle to the widespread application of two-dimensional infrared (2D IR) spectroscopy. We have studied 3-azidopyridine to characterize its potential as a probe of the protonation state of the pyridine ring. We find that the azido-stretching vibration is split by accidental Fermi resonance interactions with one or more overtones and combination states. Using 2D IR spectroscopy, we determine the state structure of the resulting eigenstates for complexes of 3-azidopyridine with formic acid and trifluoroacetic acid in which the pyridine ring is unprotonated and protonated, respectively. Based on the measurements, we develop a two-oscillator depurturbation model to determine the energies and couplings of the zeroth-order azido-stretching state and the perturbing dark state that couples to it. Based on these results, we conclude that the azido-stretching vibration is, in fact, sensitive to the protonation state of the pyridine shifting up in frequency by 8 cm{sup -1} in the complex with trifluoroacetic acid relative to the formic acid complex. These results suggest that, although 3-azidopyridine is not suitable as a spectroscopic probe, the approach of employing an organic azide as a remote probe of protonation state holds significant promise.

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

    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.

  18. 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.

  19. A near-infrared high-resolution spectroscopic survey of Galactic bulge stars . - JASMINE prestudy -

    NASA Astrophysics Data System (ADS)

    Tsujimoto, T.; Kobayashi, N.; Ikeda, Y.; Kondo, S.; Yasui, C.; Minami, A.; Motohara, K.; Gouda, N.

    We are developing a new near-infrared high-resolution (R_max= 100,000) and high-sensitive spectrograph WINERED, which is specifically customized for short NIR bands at 0.9-1.35 mu m. WINERED employs the novelty in the optical system; a portable design with a near-infrared immersion grating and warm optics without any cold stops. The planned astrometric space mission JASMINE will provide the exact positions, distances, and proper motions of the Galactic bulge stars. The missing components, the radial velocity and chemical compositions, will be measured by WINERED with high accuracies (delta V< 10km/s). These combined data brought by JASMINE and WINERED will certainly reveal the nature of the Galactic bulge. We plan to complete this instrument with a single slit by the end of 2008 and hope to attach it to various 4-10 m telescopes as a PI-type instrument. In succession, we plan to develop a similar spectrograph but with a simultaneous multi-object spectroscopic capability for full-fledged bulge survey.

  20. 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

    2016-01-01

    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. A Near-Infrared Spectroscopic Survey of 886 Nearby M Dwarfs

    NASA Astrophysics Data System (ADS)

    Terrien, Ryan C.; Mahadevan, Suvrath; Deshpande, Rohit; Bender, Chad F.

    2015-09-01

    We present a catalog of near-infrared (NIR) spectra and associated measurements for 886 nearby M dwarfs. The spectra were obtained with the NASA-Infrared Telescope Facility SpeX Spectrograph during a two-year observing campaign; they have high signal-to-noise ratios (S/N > 100-150), span 0.8-2.4 μm, and have R˜ 2000. Our catalog of measured values contains useful Teff and composition-sensitive features, empirical stellar parameter measurements, and kinematic, photometric, and astrometric properties compiled from the literature. We focus on measurements of M dwarf abundances ([Fe/H] and [M/H]), capitalizing on the precision of recently published empirical NIR spectroscopic calibrations. We explore systematic differences between different abundance calibrations, and from other similar M dwarf catalogs. We confirm that the M dwarf abundances we measure show the expected inverse dependence with kinematic-, activity-, and color-based age indicators. Finally, we provide updated [Fe/H] and [M/H] for 16 M dwarf planet hosts. This catalog represents the largest published compilation of NIR spectra and associated parameters for M dwarfs. It provides a rich and uniform resource for nearby M dwarfs, and will be especially valuable for measuring Habitable Zone locations and comparative abundances of the M dwarf planet hosts that will be uncovered by upcoming exoplanet surveys.

  2. 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.

  3. 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.

  4. 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

  5. Infrared spectroscopic signatures of (NH4)2SO4 aerosols

    NASA Astrophysics Data System (ADS)

    Weis, David D.; Ewing, George E.

    1996-08-01

    Ammonium sulfate particles in air with average diameters ranging from 0.1 to 0.5-μm have been generated by atomizing aqueous solutions of (NH4)2SO4 of various concentrations at ambient temperatures and pressures. The infrared spectra from 4000 to 600 cm-1 of the resulting aerosols have been investigated. This spectral region has allowed us to study the four infrared-active vibrational modes of this salt: ν3(NH4+), ν4(NH4+), ν3(SO42-), and ν4(SO42-). The frequencies of these modes are similar to published results obtained from infrared studies of the single crystal but are displaced to higher wavenumbers. Depending on relative humidity, the aerosol particles are crystalline or supersaturated aqueous droplets. These phase identifications are possible because liquid water absorption features are found in the droplets but not in the crystals. Extensive Mie theory calculations have been performed for spheres of diameters ranging from 0.1-μm to 2.0-μm to explore frequency shifts and the relative contributions to extinction of scattering and absorption with particle size. We show that, for the smaller particles, the molecular cross section in the ν3(SO42-) region can be used to determine the number of (NH4)2SO4 molecules in an aerosol sample. The (small) frequency shifts in this region provide information on the aerosol particle size. A Mie theory calculation of extinction for a model polydisperse aerosol, believed to approximate that of an experimental aerosol, gives reasonable agreement with the observed spectrum. While calculated band centers of the four modes are within 1% of those observed, values of extinction can differ by as much as 50%. We discuss possible reasons for the discrepancies. Spectroscopic changes observed for an aerosol as the particles settle are discussed in terms of kinetic models and Mie theory. We discuss the potential of spectroscopic signatures of tropospheric (NH4)2SO4 aerosols for the characterization of their size, morphology, phase

  6. 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

  7. 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

  8. 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

  9. 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

  10. High-dispersion infrared spectroscopic observations of comet 8P/Tuttle with VLT/CRIRES

    NASA Astrophysics Data System (ADS)

    Kobayashi, H.; Bockelée-Morvan, D.; Kawakita, H.; Dello Russo, N.; Jehin, E.; Manfroid, J.; Smette, A.; Hutsemékers, D.; Stüwe, J.; Weiler, M.; Arpigny, C.; Biver, N.; Cochran, A.; Crovisier, J.; Magain, P.; Sana, H.; Schulz, R.; Vervack, R. J.; Weaver, H.; Zucconi, J.-M.

    2010-01-01

    We report on the composition of the Halley-family comet (HFC) 8P/Tuttle investigated with high-dispersion near-infrared spectroscopic observations. The observations were carried out at the ESO VLT (Very Large Telescope) with the CRIRES instrument as part of a multi-wavelength observation campaign of 8P/Tuttle performed in late January and early February 2008. Radar observations suggested that 8P/Tuttle is a contact binary, and it was proposed that these components might be heterogeneous in chemistry. We determined mixing ratios of organic volatiles with respect to H2O and found that mixing ratios were consistent with previous near infrared spectroscopic observations obtained in late December 2007 and in late January 2008. It has been suggested that because 8P/Tuttle is a contact binary, it might be chemically heterogeneous. However, we find no evidence for chemical heterogeneity within the nucleus of 8P/Tuttle. We also compared the mixing ratios of organic molecules in 8P/Tuttle with those of both other HFCs and long period comets (LPCs) and found that HCN, C2H2, and C2H6 are depleted whereas CH4 and CH3OH have normal abundances. This may indicate that 8P/Tuttle was formed in a different region of the early solar nebula than other HFCs and LPCs. We estimated the conversion efficiency from C2H2 to C2H6 by hydrogen addition reactions on cold grains by employing the C2H6/(C2H6+C2H2) ratio. The C2H6/(C2H6+C2H2) ratio in 8P/Tuttle is consistent with the ratios found in other HFCs and LPCs within the error bars. We also discuss the source of C2 and CN based on our observations and conclude that the abundances of C2H2 and C2H6 are insufficient to explain the C2 abundances in comet 8P/Tuttle and that the abundance of HCN is insufficient to explain the CN abundances in the comet, so at least one additional parent is needed for each species, as pointed out in previous study. Based on observations collected at the European Southern Observatory, Paranal, Chile (ESO Prog. 080.C

  11. Combining sequence-based prediction methods and circular dichroism and infrared spectroscopic data to improve protein secondary structure determinations

    PubMed Central

    Lees, Jonathan G; Janes, Robert W

    2008-01-01

    Background A number of sequence-based methods exist for protein secondary structure prediction. Protein secondary structures can also be determined experimentally from circular dichroism, and infrared spectroscopic data using empirical analysis methods. It has been proposed that comparable accuracy can be obtained from sequence-based predictions as from these biophysical measurements. Here we have examined the secondary structure determination accuracies of sequence prediction methods with the empirically determined values from the spectroscopic data on datasets of proteins for which both crystal structures and spectroscopic data are available. Results In this study we show that the sequence prediction methods have accuracies nearly comparable to those of spectroscopic methods. However, we also demonstrate that combining the spectroscopic and sequences techniques produces significant overall improvements in secondary structure determinations. In addition, combining the extra information content available from synchrotron radiation circular dichroism data with sequence methods also shows improvements. Conclusion Combining sequence prediction with experimentally determined spectroscopic methods for protein secondary structure content significantly enhances the accuracy of the overall results obtained. PMID:18197968

  12. GEMINI near-infrared spectroscopic observations of young massive stars embedded in molecular clouds

    NASA Astrophysics Data System (ADS)

    Roman-Lopes, A.; Abraham, Z.; Ortiz, R.; Rodriguez-Ardila, A.

    2009-03-01

    K-band spectra of young stellar candidates in four Southern hemisphere clusters have been obtained with the Gemini Near-Infrared Spectrograph in Gemini South. The clusters are associated with IRAS sources that have colours characteristic of ultracompact HII regions. Spectral types were obtained by comparison of the observed spectra with those of a near-infrared (NIR) library; the results include the spectral classification of nine massive stars and seven objects confirmed as background late-type stars. Two of the studied sources have K-band spectra compatible with those characteristic of very hot stars, as inferred from the presence of CIV, NIII and NV emission lines at 2.078, 2.116 and 2.100 μm, respectively. One of them, I16177_IRS1, has a K-band spectrum similar to that of Cyg OB2 7, an O3If* supergiant star. The nebular K-band spectrum of the associated Ultra-Compact (UC) HII region shows the s-process [KrIII] and [SeIV] high excitation emission lines, previously identified only in planetary nebula. One young stellar object was found in each cluster, associated with either the main IRAS source or a nearby resolved Midecourse Space eXperiment (MSX) component, confirming the results obtained from previous NIR photometric surveys. The distances to the stars were derived from their spectral types and previously determined JHK magnitudes; they agree well with the values obtained from the kinematic method, except in the case of IRAS 15408-5356, for which the spectroscopic distance is about a factor of 2 smaller than the kinematic value.

  13. 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.

  14. 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}.

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. Red to Near-Infrared Isoindole BODIPY Fluorophores: Synthesis, Crystal Structures, and Spectroscopic and Electrochemical Properties.

    PubMed

    Yu, Changjiang; Wu, Qinghua; Wang, Jun; Wei, Yun; Hao, Erhong; Jiao, Lijuan

    2016-05-01

    A series of high-performance fluorophores named isoindole boron dipyrromethenes (BODIPYs) containing either symmetrical or unsymmetrical alkyl substitution patterns on pyrrole rings were synthesized by an efficient process and were characterized by X-ray diffraction and spectroscopic and electrochemical analyses. Most of these dyes show strong, sharp absorption and bright fluorescence emission in the red to near-infrared (NIR) region (up to 805 nm in acetonitrile). Pyrrolic alkyl substitutions lead to increases in the HOMO and LUMO energy levels and an overall decrease in the energy band gaps of the dye. Among the 23 isoindole BODIPY dyes synthesized, solvent-dependent fluorescence emission and lifetime decay were only observed for those containing a 3-methyl substituent on the uncoordinated pyrrole ring, whereas little variation in the fluorescence intensity was observed for the rest of the dyes upon changing the polarity of the solvent. These resultant dyes can be further functionalized via the Knoevenagel condensation on the α-methyl substituent of the chromophore to install a variety of functionalities, including a dimethylamine group demonstrated in this work. This dimethylamine-functionalized isoindole BODIPY shows weak fluorescence at 805 nm in acetonitrile and a ratiometric "turn-on" NIR fluorescence response to decreasing pH. PMID:27031115

  20. Identification of primary tumors of brain metastases by infrared spectroscopic imaging and linear discriminant analysis.

    PubMed

    Krafft, Christoph; Shapoval, Larysa; Sobottka, Stephan B; Schackert, Gabriele; Salzer, Reiner

    2006-06-01

    This study applies infrared (IR) spectroscopy to distinguish normal brain tissue from brain metastases and to determine the primary tumor of four frequent brain metastases such as lung cancer, colorectal cancer, breast cancer, and renal cell carcinoma. Standard methods sometimes fail to identify the origin of brain metastases. As metastatic cells contain the molecular information of the primary tissue cells and IR spectroscopy probes the molecular fingerprint of cells, IR spectroscopy based methods constitute a new approach to determine the primary tumor of a brain metastasis. IR spectroscopic images were recorded by a FTIR spectrometer equipped with a macro sample chamber and coupled to a focal plane array detector. Unsupervised cluster analysis of IR images revealed variances within each sample and between samples of the same tissue type. Cluster averaged IR spectra of tissue classes with known diagnoses were selected to develop a metric with eight variables. These data trained a supervised classification model based on linear discriminant analysis that was used to identify the origin of 20 cryosections including one brain metastasis with an unknown primary tumor. PMID:16700626

  1. Infrared spectroscopic studies of galvanic effect influence on surface modification of sulfide minerals by surfactant adsorption.

    PubMed

    Mielczarski, Ela; Mielczarski, Jerzy A

    2005-08-15

    The influence of interaction between mineral components in natural mixtures on the adsorption of organic and inorganic species on the mineral surfaces is recognized. However, the surface phenomena have been meagerly investigated. In this study the formation of different surface species of surfactant (amyl xanthate, C5H11OC(S)S-) adsorbed on FeS2, PbS, and CuFeS2 has been spectroscopically investigated in single-mineral and complex systems. The type and amount of adsorbed species were determined directly on each mineral surface by infrared external reflection spectroscopy. Galvanic interaction between grains of different minerals could have tremendous consequence on the adsorption of surfactants on each mineral component and their future reactivity. The detected changes are dramatic, from no adsorption to the formation of several layers of hydrophobic or hydrophilic surface products depending on which minerals are in contact. It has been documented that even very short contact time between different mineral grains by collision is sufficient to produce dramatic modification of the surface composition and structure. The results obtained indicate clearly that the observations and conclusions aboutthe surfactant adsorption made in a single mineral system cannot be simply extrapolated to describe the real situation in natural multicomponent mineral systems. The obtained information on sulfide mineral interaction in complex systems is indispensable to understand processes taking place in nature at mineral-water interfaces (dissolution of heavy metals). An additional benefit is the improved ability to design efficient separation processes of these minerals. PMID:16173571

  2. 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.

  3. 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

  4. A spectroscopic and theoretical study in the near-infrared region of low concentration aliphatic alcohols.

    PubMed

    Beć, Krzysztof B; Futami, Yoshisuke; Wójcik, Marek J; Ozaki, Yukihiro

    2016-05-11

    The near-infrared (NIR) spectra of low-concentration (5 × 10(-3) M) solutions in CCl4 of basic aliphatic alcohols, methanol, ethanol, and 1-propanol were, for the first time, calculated by second-order vibrational perturbation theory computations and were compared with the corresponding experimental data. Density functional theory (DFT) using single hybrid (B3LYP) and double hybrid (B2PLYP) density functionals and their derivatives with additional empirical dispersion correction (B3LYP-D3 and B2PLYP-D, respectively) and second order Møller-Plesset perturbation theory were used in combination with selected basis sets including fairly new basis sets from the "spectroscopic" SNS family, double-ζ SNSD and triple-ζ SNST basis sets. Each time, anharmonic vibrational modes and intensities were calculated by using second-order vibrational perturbation theory. The effect of solvent cavity on the calculated results was included by the application of a self-consistent reaction field with a polarized continuum model. Ethanol and 1-propanol have conformational isomerism; following a conformational analysis, theoretical spectra of all isomers were calculated and their final predicted NIR spectra were obtained as Boltzmann-averaged spectra of resolved conformers. For ethanol and 1-propanol, the observed broadening of the overtone band of the OH stretching mode was well reflected by the differences in the position of the relevant band among conformational isomers of these alcohols; the effect of solvent on broadening was also discussed. Detailed band assignments in the experimental NIR spectra of the studied alcohols were proposed based on the calculation of potential energy distributions. The final accuracy of the predicted NIR spectra for each of the theoretical methods was estimated based on the errors in calculated frequencies of overtones and combination bands. PMID:27137865

  5. Spectroscopic Line Parameters in the Infrared Bands of CH3CN and C2H6

    NASA Astrophysics Data System (ADS)

    Devi, V. Malathy

    2010-10-01

    In this paper, measurements of critical spectroscopic line parameters such as positions, absolute intensities and pressure broadened (self- and N2) half-width coefficients for transitions in the ν4 band of CH3CN (acetonitile, ethanenitrile, methyl cyanide) and the ν9 band of C2H6 (ethane) are presented. CH3CN has been measured by remote sensing in the earth's atmosphere, in comets and in interstellar molecular clouds. It is also a constituent in the atmospheres of Titan, Saturn's largest moon. Likewise, C2H6 is also an important constituent in the atmosphere of earth, the giant planets and comets. The 12- μm(˜720-850 cm-1) emission features of this molecule have been observed in spectra from outer solar system bodies of Jupiter, Saturn, Neptune and Titan. Because of their importance in remote sensing measurements, we recently recorded and analyzed a large number of laboratory infrared absorption spectra of pure and N2-broadened spectra of both these molecular bands. Spectra used in these analyses were recorded using either the Bruker IFS 125HR or the Bruker IFS 120HR FTS located at the Pacific Northwest National Laboratory (PNNL), in Richland Washington. To retrieve the various spectral line parameters, a multispectrum nonlinear least squares fitting algorithm was employed and all spectra belonging to each band were fitted simultaneously. Using this fitting technique, the same spectral regions from multiple spectra were fit all at once to maximize the accuracy of the retrieved parameters. The results obtained from present analyses are briefly discussed. In the case of C2H6 both room- and low temperature (˜210-296 K) spectra were recorded, but results from analyzing only room-temperature spectra will be discussed in this work.

  6. 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

  7. 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

  8. Ellipsometry of diffractive insect reflectors

    NASA Astrophysics Data System (ADS)

    Brink, D. J.; Lee, M. E.

    1996-04-01

    Scales on the wings of certain insects, such as Trichoplusia orichalcea, exhibit a surface microstructure resembling a fine diffraction grating. Diffraction of incident light by this structure is responsible for many of the optical properties of the wings of this moth, such as the metallic yellow color and the almost-specular reflection and polarization properties of the scattered radiation. It is shown that by the use of null ellipsometry the polarization characteristics can be used to obtain the optical constants of the scale material. Theoretical considerations and suitable experimental conditions are discussed and evaluated.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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

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

    PubMed

    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. PMID:27370501

  15. Exploring the early dust-obscured phase of galaxy formation with blind mid-/far-infrared spectroscopic surveys

    NASA Astrophysics Data System (ADS)

    Bonato, M.; Negrello, M.; Cai, Z.-Y.; De Zotti, G.; Bressan, A.; Lapi, A.; Gruppioni, C.; Spinoglio, L.; Danese, L.

    2014-03-01

    While continuum imaging data at far-infrared to submillimetre wavelengths have provided tight constraints on the population properties of dusty star-forming galaxies up to high redshifts, future space missions like the Space Infrared Telescope for Cosmology and Astrophysics (SPICA) and ground-based facilities like the Cerro Chajnantor Atacama Telescope (CCAT) will allow detailed investigations of their physical properties via their mid-/far-infrared line emission. We present updated predictions for the number counts and the redshift distributions of star-forming galaxies spectroscopically detectable by these future missions. These predictions exploit a recent upgrade of evolutionary models, that include the effect of strong gravitational lensing, in the light of the most recent Herschel and South Pole Telescope data. Moreover the relations between line and continuum infrared luminosity are re-assessed, considering also differences among source populations, with the support of extensive simulations that take into account dust obscuration. The derived line luminosity functions are found to be highly sensitive to the spread of the line to continuum luminosity ratios. Estimates of the expected numbers of detections per spectral line by SPICA/SpicA FAR-infrared Instrument (SAFARI) and by CCAT surveys for different integration times per field of view at fixed total observing time are presented. Comparing with the earlier estimates by Spinoglio et al. we find, in the case of SPICA/SAFARI, differences within a factor of 2 in most cases, but occasionally much larger. More substantial differences are found for CCAT.

  16. 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.

  17. 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,...

  18. Northern and Southern Hemisphere Ground-Based Infrared Spectroscopic Measurements of Tropospheric Carbon Monoxide and Ethane

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Jones, Nicholas B.; Connor, Brian J.; Logan, Jennifer A.; Pougatchev, Nikita S.; Goldman, Aaron; Murcray, Frank J.; Stephen, Thomas M.; Pine, Alan S.; Zander, Rodolphe

    1998-01-01

    Time series of CO and C2H, measurements have been derived from high-resolution infrared solar spectra recorded in Lauder, New Zealand (45.0 degrees S, 169.7 degrees E, altitude 0.37 km), and at the U.S. National Solar Observatory (31.9 degrees N, 11, 1.6 degrees W, altitude 2.09 km) on Kitt Peak. Lauder observations were obtained between July 1993 and November 1997, while the Kitt Peak measurements were recorded between May 1977 and December 1997. Both databases were analyzed with spectroscopic parameters that included significant improvements for C2H6 relative to previous studies. Target CO and C2H6 lines were selected to achieve similar vertical samplings based on averaging kernels. These calculations show that partial columns from layers extending from the surface to the mean tropopause and from the mean tropopause to 100 km are nearly independent. Retrievals based on a semiempirical application of the Rodgers optimal estimation technique are reported for the lower layer, which has a broad maximum in sensitivity in the upper troposphere. The Lauder CO and C2H, partial columns exhibit highly asymmetrical seasonal cycles with minima in austral autumn and sharp peaks in austral spring. The spring maxima are the result of tropical biomass burning emissions followed by deep convective vertical transport to the upper troposphere and long-range horizontal transport. Significant year-to-year variations are observed for both CO and C2H6, but the measured trends, (+0.37 +/- 0.57)% yr(exp -1) and (-0.64 +/- 0.79)% yr(exp -1), I sigma, respectively, indicate no significant long-term changes. The Kitt Peak data also exhibit CO and C2H6, seasonal variations in the lower layer with trends equal to (-0.27 +/- 0.17)% yr(exp -1) and (-1.20 +/- 0.35)% yr(exp -1), 1 sigma, respectively. Hence a decrease in the Kitt Peak tropospheric C2H6 column has been detected, though the CO trend is not significant. Both measurement sets are compared with previous observations, reported trends

  19. Northern and Southern Hemisphere Ground-Based Infrared Spectroscopic Measurements of Tropospheric Carbon Monoxide and Ethane

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Jones, Nicholas B.; Connor, Brian J.; Logan, Jennifer A.; Pougatchev, Nikita; Goldman, Aaron; Murcray, Frank J.; Stephen, Thomas M.; Pine, Alan S.; Zander, Rodolphe; Mahieu, Emmanual; Demoulin, Philippe

    1998-01-01

    Time series of CO and C2H6 measurements have been derived from high resolution infrared solar spectra recorded in Lauder, New Zealand (45.0 deg S, 169.7 deg E, altitude 0.37 km) and at the U. S. National Solar Observatory (31.90 deg N, 111.6 deg W, altitude 2.09 km) on Kitt Peak. Lauder observations were obtained between July 1993 and November 1997 while the Kitt Peak measurements were recorded between May 1977 and December 1997. Both databases were analyzed with spectroscopic parameters that included significant improvements for C2H6 relative to previous studies. Target CO and C2H6 lines were selected to achieve similar vertical samplings based on averaging kernels. These calculations show that partial columns from layers extending from the surface to the mean tropopause and from the mean tropopause to 100 km are nearly independent. Retrievals based on a semiempirical application of the Rodgers optimal estimation technique are reported for the lower layer, which has a broad maximum in sensitivity in the upper troposphere. The Lauder CO and C2H6 partial columns exhibit highly asymmetrical seasonal cycles with minima in austral autumn and sharp peaks in austral spring. The spring maxima are the result of tropical biomass burning emissions followed by deep convective vertical transport to the upper troposphere and long-range horizontal transport. Significant year-to-year variations are observed for both CO and C2H6, but the measured trends, (+0.37 +/- 0.57)%/ yr and (-0.64 +/- 0.79)%/ yr, 1 sigma, respectively, indicate no significant long-term changes. The Kitt Peak data also exhibit CO and C2H6 seasonal variations in the lower layer with trends equal to (-0.27 +/- 0.17)%/ yr and (-1.20 +/- 0.35)%/ yr, 1 sigma, respectively. Hence, a decrease in the Kitt Peak tropospheric C2H6 column has been detected, though the CO trend is not significant. Both measurement sets are compared with previous observations, reported trends, and three-dimensional model calculations.

  20. 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

  1. 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

  2. Birefringence characterization using transmission ellipsometry

    NASA Astrophysics Data System (ADS)

    Nee, Soe-Mie F.

    1992-12-01

    Birefringence can be obtained from the phase difference (Delta) between the ordinary and the extraordinary rays for normal transmission through a birefringent slab. Rotating analyzer ellipsometry (RAE) and null ellipsometry (NE) were used to measure (Delta) . NE gives accurate phase spectrum which shows linear dependence of phase on wave-number. The phase spectrum by RAE looks like a damped oscillatory curve. The calibration of RAE against NE shows that the extrema of RAE phase spectrum correspond to (Delta) equals m(pi) of NE spectrum, where m equals integer; the phases near m (pi) + (pi) /2 are about the same from both methods. Error caused by partially coherent interference of the multiple reflected waves within the slab consists basically of the sinusoidal functions of (Delta) and its harmonics, and is zero at (Delta) equals m(pi) . These errors can be suppressed by the least-square fit of m to a quadratic function of 1/(lambda) . The birefringence spectrum measured for a sapphire sample in the 0.4 to 0.9 micrometers wavelength region agrees with the handbook values.

  3. 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.

  4. 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

  5. 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.

  6. A near-infrared spectroscopic survey of massive jets towards extended green objects

    NASA Astrophysics Data System (ADS)

    Caratti o Garatti, A.; Stecklum, B.; Linz, H.; Garcia Lopez, R.; Sanna, A.

    2015-01-01

    Context. Protostellar jets and outflows are the main outcome of the star formation process, and their analysis can provide us with major clues about the ejection and accretion history of young stellar objects (YSOs). Aims: We aim at deriving the main physical properties of massive jets from near-infrared (NIR) observations, comparing them to those of a large sample of jets from low-mass YSOs, and relating them to the main features of their driving sources. Methods: We present a NIR imaging (H2 and Ks) and low-resolution spectroscopic (0.95-2.50 μm) survey of 18 massive jets towards GLIMPSE extended green objects (EGOs), driven by intermediate- and high-mass YSOs, which have bolometric luminosities (Lbol) between 4 × 102 and 1.3 × 105 L⊙. Results: As in low-mass jets, H2 is the primary NIR coolant, detected in all the analysed flows, whereas the most important ionic tracer is [Fe ii], detected in half of the sampled jets. Our analysis indicates that the emission lines originate from shocks at high temperatures and densities. No fluorescent emission is detected along the flows, regardless of the source bolometric luminosity. On average, the physical parameters of these massive jets (i.e. visual extinction, temperature, column density, mass, and luminosity) have higher values than those measured in their low-mass counterparts. The morphology of the H2 flows is varied, mostly depending on the complex, dynamic, and inhomogeneous environment in which these massive jets form and propagate. All flows and jets in our sample are collimated, showing large precession angles. Additionally, the presence of both knots and jets suggests that the ejection process is continuous with burst episodes, as in low-mass YSOs. We compare the flow H2 luminosity with the source bolometric luminosity confirming the tight correlation between these two quantities. Five sources, however, display a lower LH2/Lbol efficiency, which might be related to YSO evolution. Most important, the

  7. ELLIPSOMETRY IN THE STUDY OF DYNAMIC MATERIAL PROPERTIES

    SciTech Connect

    Obst, A. W.; Alrick, K.R.; Boboridis, K.; Buttler, William T.; Lamoreaux, Steve Keith; Montgomery, S. L.; Payton, J. R.; Wilke, M. D.

    2001-01-01

    Measurements of the time-dependent absolute temperature of surfaces shocked using high explosives (HE) provide valuable constraints on the equations-of-state (EOS) of materials and on the state of ejecta from those surfaces. In support of these dynamic surface temperature measurements, techniques for measuring the dynamic surface emissivity of shocked metals in the near infrared (IR) are being developed. These consist of time-dependent laser ellipsometric measurements, using several approaches. A discussion of these ellipsometric techniques is included here. Ellipsometry permits an accurate determination of the dynamic emissivity at a given wavelength, and may also provide a signature of melt in shocked metals.

  8. 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

  9. Photoelectron, nuclear gamma-ray and infrared absorption spectroscopic studies of neptunium in sodium silicate glass

    SciTech Connect

    Veal, B.W.; Carnall, W.T.; Dunlap, B.D.; Mitchell, A.W.; Lam, D.J.

    1986-04-01

    The valence state of neptunium ions in sodium silicate glasses prepared under reducing and oxidizing conditions has been investigated by the x-ray photoelectron, Moessbauer and optical absorption spectroscopic techniques. Results indicate that the Np ions are tetravalent in glasses prepared under reducing conditions and pentavalent in glasses prepared under oxidizing conditions.

  10. 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.

  11. 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.

  12. 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.

  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. 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.

  15. Near Infrared photometric and spectroscopic observations of the bright optical transient J212444.87+321738.3

    NASA Astrophysics Data System (ADS)

    Mondal, Soumen; Das, Ramkrishna; Ashok, N. M.; Banerjee, D. P. K.; Dutta, Somnath; Ghosh, Supriyo; Mondal, Anindita

    2013-04-01

    We report near infrared JHK-band photometry and spectroscopic observations of the recently reported bright optical transient J212444.87+321738.3 using the Near-IR Imager cum spectrograph (NICMOS-3) installed on the Mount Abu 1.2-m telescope of the Physical Research Laboratory, India following the outburst announcement by Tiurina et al. in ATel #4888. The photometric observations were carried out on 2013 March 21.020 UT and 23.010 UT yielding magnitudes of J = 5.85 +/- 0.06, H = 4.47 +/- 0.06, K = 3.77 +/- 0.05; and J= 5.64 +/- 0.04, H= 4.48 +/- 0.04, K = 3.77 +/- 0.03 respectively.

  16. 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/

  17. 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

  18. Infrared and Raman Spectroscopic Studies of the Antimicrobial Effects of Garlic Concentrates and Diallyl Constituents on Foodborne Pathogens

    PubMed Central

    Lu, Xiaonan; Rasco, Barbara A.; Kang, Dong-Hyun; Jabal, Jamie M.F.; Aston, D. Eric; Konkel, Michael E.

    2012-01-01

    The antimicrobial effects of garlic (Allium sativum) extract (25, 50, 75, 100, and 200 μl/ml) and diallyl sulfide (5, 10 and 20 μM) on Listeria monocytogenes and Escherichia coli O157:H7 cultivated in tryptic soy broth at 4, 22 and 35°C for up to 7 days were investigated. L. monocytogenes was more resistant to garlic extract and diallyl compounds treatment than E. coli O157:H7. Fourier transform Infrared (FT-IR) spectroscopy indicated that diallyl constituents contributed more to the antimicrobial effect than phenolic compounds. This effect was verified by Raman spectroscopy and Raman mapping on single bacteria. Scanning electron microscope (SEM) and transmission electron microscope (TEM) showed cell membrane damage consistent with spectroscopic observation. The degree of bacterial cell injury could be quantified using chemometric methods. PMID:21553849

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. Design and spectroscopic characterization of novel series of near infrared indocyanine dyes

    NASA Astrophysics Data System (ADS)

    Abd-El-Aziz, Alaa S.; Strohm, Elizabeth A.; Okasha, Rawda M.

    2015-07-01

    A novel series of near infrared heptamethine indocyanine dyes bearing various aromatic chromophores has been synthesized. The synthetic methodology was achieved via ester condensation reactions of heptamethine indocyanine parent dye with carboxylic moiety and aromatic compounds such as anthracene, pyrene and thiophene derivatives. Structural analysis of the newly prepared dyes was accomplished using one- and two-dimensional nuclear magnetic resonance, infrared spectroscopy and electrospray ionization mass spectrometry. These dyes exhibited high molar absorptivity based on the UV-visible/near-infrared spectral data. Fluorescence emission spectral data was used to determine the relative quantum yield. The new dyes displayed formation of H-aggregates in water at low concentrations, while this behavior was not observed in methanol.

  6. Microsampling techniques for infrared spectroscopic analysis of lunar and terrestrial minerals

    NASA Technical Reports Server (NTRS)

    Estep, P. A.; Kovach, J. J.; Karr, C.

    1973-01-01

    Microsampling techniques have been developed for infrared analysis of single mineral grains from lunar rocks and dusts, allowing a detailed molecular structure characterization of these complex fine-grained samples. The methods include special devices for isolating single grains, preparing micropellets from the grains, and obtaining in situ microspecular reflectance spectra from grains in polished rock samples. Although specifically developed for the work on lunar samples, the special techniques for single grain infrared analysis were found to be equally useful in studies of complex terrestrial mineral samples. For example, infrared microanalysis has contributed substantially in solving problems concerned with our natural resources, such as the structural characterization of minerals from commercial iron ores, marine deposits, coal, and fly ash derived from coal.

  7. 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...

  8. 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…

  9. Mid-Infrared Spectroscopic Properties of Humic Acid and Fulvic Acid-Soil Mixtures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The detection of humic materials in soils is essential in order to determine organic matter (SOM) stability and C sequestration on agricultural land. Mid-Infrared (MidIR) spectroscopy has been used to characterize SOM quality [1], study extracted soil humic acids [2], develop calibrations for quanti...

  10. Mid-Infrared Spectroscopic Properties of Humic Acid and Fulvic Acid-Soil Mixtures.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The detection of humic materials in soils is essential in order to determine organic matter (SOM) stability and C sequestration on agricultural land. Mid-Infrared (MidIR) spectroscopy has been used to characterize SOM quality [1], study extracted soil humic acids [2], develop calibrations for quanti...

  11. 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

  12. 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.

  13. Mid-Infrared Spectroscopic Method for the Identification and Quantification of Dissolved Oil Components in Marine Environments.

    PubMed

    Stach, Robert; Pejcic, Bobby; Crooke, Emma; Myers, Matthew; Mizaikoff, Boris

    2015-12-15

    The use of mid-infrared sensors based on conventional spectroscopic equipment for oil spill monitoring and fingerprinting in aqueous systems has to date been mainly confined to laboratory environments. This paper presents a portable-based mid-infrared attenuated total reflectance (MIR-ATR) sensor system that was used to quantify a number of environmentally relevant hydrocarbon contaminants in marine water. The sensor comprises a polymer-coated diamond waveguide in combination with a room-temperature operated pyroelectric detector, and the analytical performance was optimized by evaluating the influence of polymer composition, polymer film thickness, and solution flow rate on the sensor response. Uncertainties regarding the analytical performance and instrument specifications for dissolved oil detection were investigated using real-world seawater matrices. The reliability of the sensor was tested by exposition to known volumes of different oils; crude oil and diesel samples were equilibrated with seawater and then analyzed using the developed MIR-ATR sensor system. For validation, gas chromatographic measurements were performed revealing that the MIR-ATR sensor is a promising on-site monitoring tool for determining the concentration of a range of dissolved oil components in seawater at ppb to ppm levels. PMID:26599809

  14. 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.

  15. Design and performance of a wide-bandwidth and sensitive instrument for near-infrared spectroscopic measurements on human tissue

    NASA Astrophysics Data System (ADS)

    Rovati, Luigi; Bandera, Andrea; Donini, Maurizio; Salvatori, Giorgia; Pollonini, Luca

    2004-12-01

    The article describes an instrument designed to perform in vivo near-infrared spectroscopic measurements on human tissues. The system integrates five continuous-wave laser diode sources emitting in the near-infrared spectral region and a low-noise detection system based on an avalanche photodiode. The optical probe is based on a compact, reliable, and low-cost fiber based system with four quantitative measuring points. The excellent sensitivity of the instrument allows one to perform quantitative assessments of the hemoglobin concentration exploiting precise absorption measurements close to the absorption peak of the water: 975 nm. Moreover, a good signal to noise ratio is obtained also at a high acquisition rate, allowing us to follow rapid changes in oxidative metabolism. The system bandwidth is selectable within the range 2.3-27 Hz, i.e., 20 channels (five chromatic and four spatial channels) can be acquired 27 times for each measuring second, whereas the system amplification can be set to measure optical density ranging from 3.5 to 8.5. A prototype version of the instrument has been realized and characterized.

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

    PubMed

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

    2014-07-28

    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

  17. Spectroscopic investigation on cocrystal formation between adenine and fumaric acid based on infrared and Raman techniques

    NASA Astrophysics Data System (ADS)

    Du, Yong; Fang, Hong Xia; Zhang, Qi; Zhang, Hui Li; Hong, Zhi

    2016-01-01

    As an important component of double-stranded DNA, adenine has powerful hydrogen-bond capability, due to rich hydrogen bond donors and acceptors existing within its molecular structure. Therefore, it is easy to form cocrystal between adenine and other small molecules with intermolecular hydrogen-bond effect. In this work, cocrystal of adenine and fumaric acid has been characterized as model system by FT-IR and FT-Raman spectral techniques. The experimental results show that the cocrystal formed between adenine and fumaric acid possesses unique spectroscopical characteristic compared with that of starting materials. Density functional theory (DFT) calculation has been performed to optimize the molecular structures and simulate vibrational modes of adenine, fumaric acid and the corresponding cocrystal. Combining the theoretical and experimental vibrational results, the characteristic bands corresponding to bending and stretching vibrations of amino and carbonyl groups within cocrystal are shifted into lower frequencies upon cocrystal formation, and the corresponding bond lengths show some increase due to the effect of intermolecular hydrogen bonding. Different vibrational modes shown in the experimental spectra have been assigned based on the simulation DFT results. The study could provide experimental and theoretical benchmarks to characterize cocrystal formed between active ingredients and cocrystal formers and also the intermolecular hydrogen-bond effect within cocrystal formation process by vibrational spectroscopic techniques.

  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. 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

  20. Infrared-faint radio sources are at high redshifts. Spectroscopic redshift determination of infrared-faint radio sources using the Very Large Telescope

    NASA Astrophysics Data System (ADS)

    Herzog, A.; Middelberg, E.; Norris, R. P.; Sharp, R.; Spitler, L. R.; Parker, Q. A.

    2014-07-01

    Context. Infrared-faint radio sources (IFRS) are characterised by relatively high radio flux densities and associated faint or even absent infrared and optical counterparts. The resulting extremely high radio-to-infrared flux density ratios up to several thousands were previously known only for high-redshift radio galaxies (HzRGs), suggesting a link between the two classes of object. However, the optical and infrared faintness of IFRS makes their study difficult. Prior to this work, no redshift was known for any IFRS in the Australia Telescope Large Area Survey (ATLAS) fields which would help to put IFRS in the context of other classes of object, especially of HzRGs. Aims: This work aims at measuring the first redshifts of IFRS in the ATLAS fields. Furthermore, we test the hypothesis that IFRS are similar to HzRGs, that they are higher-redshift or dust-obscured versions of these massive galaxies. Methods: A sample of IFRS was spectroscopically observed using the Focal Reducer and Low Dispersion Spectrograph 2 (FORS2) at the Very Large Telescope (VLT). The data were calibrated based on the Image Reduction and Analysis Facility (IRAF) and redshifts extracted from the final spectra, where possible. This information was then used to calculate rest-frame luminosities, and to perform the first spectral energy distribution modelling of IFRS based on redshifts. Results: We found redshifts of 1.84, 2.13, and 2.76, for three IFRS, confirming the suggested high-redshift character of this class of object. These redshifts and the resulting luminosities show IFRS to be similar to HzRGs, supporting our hypothesis. We found further evidence that fainter IFRS are at even higher redshifts. Conclusions: Considering the similarities between IFRS and HzRGs substantiated in this work, the detection of IFRS, which have a significantly higher sky density than HzRGs, increases the number of active galactic nuclei in the early universe and adds to the problems of explaining the formation of

  1. Exploring the relationship between black hole accretion and star formation with blind mid-/far-infrared spectroscopic surveys

    NASA Astrophysics Data System (ADS)

    Bonato, M.; Negrello, M.; Cai, Z.-Y.; De Zotti, G.; Bressan, A.; Lapi, A.; Pozzi, F.; Gruppioni, C.; Danese, L.

    2014-11-01

    We present new estimates of redshift-dependent luminosity functions of IR lines detectable by SPICA/SAFARI (SPace InfraRed telescope for Cosmology and Astrophysics/SpicA FAR infrared Instrument) and excited both by star formation and by AGN activity. The new estimates improve over previous work by using updated evolutionary models and dealing in a self-consistent way with emission of galaxies as a whole, including both the starburst and the AGN component. New relationships between line and AGN bolometric luminosity have been derived and those between line and IR luminosities of the starburst component have been updated. These ingredients were used to work out predictions for the source counts in 11 mid-/far-IR emission lines partially or entirely excited by AGN activity. We find that the statistics of the emission line detection of galaxies as a whole is mainly determined by the star formation rate, because of the rarity of bright AGNs. We also find that the slope of the line integral number counts is flatter than two implying that the number of detections at fixed observing time increases more by extending the survey area than by going deeper. We thus propose a wide spectroscopic survey of 1 h integration per field of view over an area of 5 deg2 to detect (at 5σ) ˜760 AGNs in [O IV]25.89 μm - the brightest AGN mid-infrared line - out to z ˜ 2. Pointed observations of strongly lensed or hyperluminous galaxies previously detected by large area surveys such as those by Herschel and by the South Pole Telescope can provide key information on the galaxy-AGN co-evolution out to higher redshifts.

  2. 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.

  3. 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

  4. 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.

  5. Automated high-pressure titration system with in situ infrared spectroscopic detection.

    PubMed

    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

  6. 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

  7. 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

  8. 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

  9. Carbonate associated with hydroxide sol-gel processing of yttria: An infrared spectroscopic study

    SciTech Connect

    Seaverson, L.M.; Luo, S.Q.; Chien, P.L.; McClelland, J.F.

    1986-05-01

    Yttrium hydroxide gel was dried by five techniques to study their influences on the sintering behavior of yttria. Dried precursors, calcined and sintered oxides, and the initial gel were examined via Fourier transform infrared photoacoustic and/or attenuated total reflection spectroscopies. Carbonate was found to be in unidentate coordination to surface yttrium on both the dried hydroxide precursor and calcined oxide particles. An inverse correlation was found between the normalized surface carbonate concentration (carbonate concentration (wt%)/surface area (m/sup 2//g)) of precursors and calcined oxides and the density of their corresponding sintered bodies. Carbonate affects sintered density during the calcination and sintering steps.

  10. 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. PMID:21911018

  11. 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.

  12. The H2O-CH3F Complex: a Combined Microwave and Infrared Spectroscopic Study Supported by Structure Calculations

    NASA Astrophysics Data System (ADS)

    Gnanasekar, Sharon Priya; Goubet, Manuel; Arunan, Elangannan; Georges, Robert; Soulard, Pascale; Asselin, Pierre; Huet, T. R.; Pirali, Olivier

    2015-06-01

    The H2O-CH3F complex could have two geometries, one with a hydrogen bond and one with the newly proposed carbon bond. While in general carbon bonds are weaker than hydrogen bonds, this complex appears to have comparable energies for the two structures. Infrared (IR) and microwave (MW) spectroscopic measurements using, respectively, the Jet-AILES apparatus and the FTMW spectrometer at the PhLAM laboratory, have been carried out to determine the structure of this complex. The IR spectrum shows the formation of the CH3F- H2O hydrogen bonded complex and small red-shifts in OH frequency most probably due to (CH3F)m-(H2O)n clusters. Noticeably, addition of CH_3F in the mixture promotes the formation of small water clusters. Preliminary MW spectroscopic measurements indicate the formation of the hydrogen bonded complex. So far, we have no experimental evidence for the carbon bonded structure. However, calculations of the Ar-CH3F complex show three energetically equivalent structures: a T-shape, a "fluorine" bond and a carbon bond. The MW spectrum of the (Ar)n-CH3F complexes is currently under analysis. Mani, D; Arunan, E. Phys. Chem. Chem. Phys. 2013, 15, 14377. Cirtog, M; Asselin, P; Soulard, P; Tremblay, B; Madebene, B; Alikhani, M. E; Georges, R; Moudens, A; Goubet, M; Huet, T.R; Pirali, O; Roy, P. J. Phys. Chem. A. 2011, 115, 2523 Kassi, S; Petitprez, D; Wlodarczak, G. J. Mol. Struct. 2000, 517-518, 375

  13. 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.

  14. An infrared spectroscopic study of Li2B4O7

    NASA Astrophysics Data System (ADS)

    Zhigadlo, N. D.; Zhang, M.; Salje, E. K. H.

    2001-07-01

    The temperature evolution of the infrared powder spectra of lithium tetraborate Li2B4O7 has been measured in the infrared region 50-1600 cm-1 and over a temperature range between 20 K and 680 K. In contrast to the sharp B-O bands, the Li-related bands in the region between 300 cm-1 and 510 cm-1 are rather broad even at 20 K. With increasing temperature these bands show a stronger thermal response than in the higher-frequency region: the bands at 350 cm-1 and 424 cm-1 shift significantly in frequency and become very broad above 500 K. The 508 cm-1 band appears to split into two individual bands near 500 K. The broadening of the Li-related bands is probably due to the thermally induced Li disorder. The temperature dependence of the B-O bending and stretching vibrations does not show clear evidence of structural phase transitions in Li2B4O7 occurring in the temperature range between 20 K and 680 K.

  15. Chemical fingerprinting of Arabidopsis using Fourier transform infrared (FT-IR) spectroscopic approaches.

    PubMed

    Gorzsás, András; Sundberg, Björn

    2014-01-01

    Fourier transform infrared (FT-IR) spectroscopy is a fast, sensitive, inexpensive, and nondestructive technique for chemical profiling of plant materials. In this chapter we discuss the instrumental setup, the basic principles of analysis, and the possibilities for and limitations of obtaining qualitative and semiquantitative information by FT-IR spectroscopy. We provide detailed protocols for four fully customizable techniques: (1) Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS): a sensitive and high-throughput technique for powders; (2) attenuated total reflectance (ATR) spectroscopy: a technique that requires no sample preparation and can be used for solid samples as well as for cell cultures; (3) microspectroscopy using a single element (SE) detector: a technique used for analyzing sections at low spatial resolution; and (4) microspectroscopy using a focal plane array (FPA) detector: a technique for rapid chemical profiling of plant sections at cellular resolution. Sample preparation, measurement, and data analysis steps are listed for each of the techniques to help the user collect the best quality spectra and prepare them for subsequent multivariate analysis. PMID:24057375

  16. 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.).

  17. 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.

  18. 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

  19. 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.

  20. A Pre-Main Sequence Spectroscopic Binary Revealed through Infrared Spectroscopy with Phoenix on Gemini.

    NASA Astrophysics Data System (ADS)

    Doppmann, G.; White, R.; Charbonneau, D.

    2005-12-01

    Empirical measurements of basic stellar and substellar properties in pre-main sequence (PMS) objects are critical to our understanding of how and when these objects evolve toward the main sequence. Dynamical measurements of PMS binary systems are beginning to provide these fundamental data, if they can be accurately placed on an H-R diagram for comparison with PMS evolutionary models. A recent high-precision near-IR radial velocity survey with Phoenix at Gemini South has lead to the new discovery of one double-line spectroscopic binary in Chamaeleon. With the high spectral resolution (R=50,000) provided by Phoenix we have successfully measured the orbital period and determined the dynamical mass ratio (from the relative velocity amplitudes) with our spectra taken over nine epochs (29 April - 23 June, 2005). In two epochs where we have near maximum velocity separation at the 2-0 CO bandhead, we use spectral synthesis templates to fit the primary and secondary bandheads (both evident in the spectrum) to accurately determine the component spectral types. Our multicomponent spectral fits also set constraints on gravity, assumed to be equal for both components in this low mass ( M2) co-evol PMS binary system. With the placement of this system in the H-R diagram by the properties we determine from spectroscopy, we will test the accuracy of theoretical model tracks using the independent mass information obtained from the orbital motion.

  1. 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.

  2. 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. PMID:27064742

  3. Near-infrared spectroscopic measurements of blood analytes using multi-layer perceptron neural networks.

    PubMed

    Kalamatianos, Dimitrios; Liatsis, Panos; Wellstead, Peter E

    2006-01-01

    Near-infrared (NIR) spectroscopy is being applied to the solution of problems in many areas of biomedical and pharmaceutical research. In this paper we investigate the use of NIR spectroscopy as an analytical tool to quantify concentrations of urea, creatinine, glucose and oxyhemoglobin (HbO2). Measurements have been made in vitro with a portable spectrometer developed in our labs that consists of a two beam interferometer operating in the range of 800-2300 nm. For the data analysis a pattern recognition philosophy was used with a preprocessing stage and a multi-layer perceptron (MLP) neural network for the measurement stage. Results show that the interferogram signatures of the above compounds are sufficiently strong in that spectral range. Measurements of three different concentrations were possible with mean squared error (MSE) of the order of 10(-6). PMID:17947035

  4. Infrared spectroscopic characterization of [2]rotaxane molecular switch tunnel junction devices.

    PubMed

    DeIonno, Erica; Tseng, Hsian-Rong; Harvey, Desmond D; Stoddart, J Fraser; Heath, James R

    2006-04-20

    Langmuir-Blodgett monolayers of a bistable [2]rotaxane were prepared at packing densities of 118, 73, and 54 A(2)/molecule. The monolayers were both characterized via infrared spectroscopy before and after evaporation of a 2 nm film of titanium and incorporated into molecular switch tunnel junction devices. The study suggests that the evaporation process primarily affects portions of the molecule exposed to the metal atom source. Thus, in tightly packed monolayers (73 and 54 A(2)/molecule), only the portions of the [2]rotaxane that are present at the molecule/air interface are clearly affected, leaving key functionality necessary for switching intact. Monolayers transferred at a lower pressure (118 A(2)/molecule) exhibit nonspecific damage and poor switching behavior following Ti deposition. These results indicate that tightly packed monolayers and sacrificial functionality displayed at the molecule/air interface are important design principles for molecular electronic devices. PMID:16610848

  5. 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.

  6. Blood compatibility of artificial blood vessels probed by infrared spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Steiner, Gerald; Maitz, Manfred; Tunc, Sibel; Salzer, Reiner

    2006-02-01

    The determination of protein structure and function plays an important role in biomedical and biochemical research. Common techniques that give full structural information do not permit in-vivo measurements. Infrared spectroscopy has a sufficient sensitivity to examine the structure of proteins solution under in-situ conditions and even on surfaces. However, measurements at few spots on the surface are not suitable to find out the blood compatibility of the protein layer, because the changes in conformation occur often in small domains. Here we report on the investigations of adsorbed fibrinogen with FTIR imaging. FTIR imaging permits an identification of coagulation spots in the micrometer range and the identification of coagulation spots on the implant material.

  7. 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.

  8. Fourier transform infrared spectroscopic study of Br 2O and OBrO

    NASA Astrophysics Data System (ADS)

    Chu, Liang T.; Li, Zhuangjie

    2000-11-01

    Vibrational frequencies of gaseous Br 2O and OBrO were observed using the Fourier transform infrared spectrometer. For the first time, bands at 629.0 cm -1 ( ν3) and 532.9 cm -1 ( ν1) were recorded for both Br-O asymmetric and symmetric stretching vibrations of gaseous Br 2O. Two fundamental vibrations were observed at 798.7 cm-1 (ν 1) and 846.3 cm-1 (ν 3) for the O 18BrO radical. In addition, two new peaks at 2333 cm -1 and 668 cm -1 were observed in a HOBr spectrum. They are tentatively assigned to the H-Br and Br-O stretching vibrations of a HOBr isomer on the basis of ab initio computational results.

  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. PMID:26702948

  10. Raman and mid-infrared spectroscopic study of geometrically frustrated hydroxyl cobalt halides at room temperature

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-Dong; Meng, Dong-Dong; Hagihala, Masato; Zheng, Xu-Guang; Guo, Qi-Xin

    2011-07-01

    Mid-infrared absorption and Raman spectra of the geometrically frustrated material series, hydroxyl cobalt halides ß-Co2(OH)3Cl and ß-Co2(OH)3Br, are first, to the best of our knowledge, measured at room temperature, to study the corresponding relationship between their vibrational spectral properties and crystal microstructures. Through the comparative analysis of the four spectra we have categorically assigned the OH-related vibration modes of hydroxyl groups in the trimeric hydrogen bond environment (Co3 ≡OH)3 ... Cl/Br, and tentatively suggested vibration modes of O-Co-O, Co-O and Cl/Br-Co-Cl/Br units. These results can also become the basis for analysing their low-temperature spectral properties, which can help to understand the underlying physics of their exotic geometric frustration phenomena around phase transition temperatures.

  11. Mid-infrared spectroscopic assessment of nanotoxicity in gram-negative vs. gram-positive bacteria.

    PubMed

    Heys, Kelly A; Riding, Matthew J; Strong, Rebecca J; Shore, Richard F; Pereira, M Glória; Jones, Kevin C; Semple, Kirk T; Martin, Francis L

    2014-03-01

    Nanoparticles appear to induce toxic effects through a variety of mechanisms including generation of reactive oxygen species (ROS), physical contact with the cell membrane and indirect catalysis due to remnants from manufacture. The development and subsequent increasing usage of nanomaterials has highlighted a growing need to characterize and assess the toxicity of nanoparticles, particularly those that may have detrimental health effects such as carbon-based nanomaterials (CBNs). Due to interactions of nanoparticles with some reagents, many traditional toxicity tests are unsuitable for use with CBNs. Infrared (IR) spectroscopy is a non-destructive, high throughput technique, which is unhindered by such problems. We explored the application of IR spectroscopy to investigate the effects of CBNs on Gram-negative (Pseudomonas fluorescens) and Gram-positive (Mycobacterium vanbaalenii PYR-1) bacteria. Two types of IR spectroscopy were compared: attenuated total reflection Fourier-transform infrared (ATR-FTIR) and synchrotron radiation-based FTIR (SR-FTIR) spectroscopy. This showed that Gram-positive and Gram-negative bacteria exhibit differing alterations when exposed to CBNs. Gram-positive bacteria appear more resistant to these agents and this may be due to the protection afforded by their more sturdy cell wall. Markers of exposure also vary according to Gram status; Amide II was consistently altered in Gram-negative bacteria and carbohydrate altered in Gram-positive bacteria. ATR-FTIR and SR-FTIR spectroscopy could both be applied to extract biochemical alterations induced by each CBN that were consistent across the two bacterial species; these may represent potential biomarkers of nanoparticle-induced alterations. Vibrational spectroscopy approaches may provide a novel means of fingerprinting the effects of CBNs in target cells. PMID:24162371

  12. Pb+ irradiation of synthetic zircon (ZrSiO4): Infrared spectroscopic investigation

    SciTech Connect

    Zhang, Ming; Boatner, Lynn A; Salje, Ekhard K.H.; Honda, Shin-ichi; Ewing, Rodney C.

    2008-01-01

    The structural variations of synthetic zircon (ZrSiO{sub 4}) single crystals irradiated at room temperature by 280 keV Pb{sup +} ions (with fluences up to 1 x 10{sup 15} ions/cm{sup 2}) were investigated using infrared (IR) spectroscopy. Like metamict zircon whose crystal structure is damaged and amorphized by naturally occurring {alpha}-decay events, the Pb{sup +}-irradiated zircon crystals show a dramatic decrease in reflectivity. However, no significant decrease in wavenumbers of the stretching vibrations of SiO{sub 4} tetrahedra in zircon was detected. The Pb{sup +}-implanted zircon exhibits new IR bands, indicating irradiation-induced new vibrations or domains, clusters or phases in addition to SiO{sub 2} and ZrO{sub 2}. IR features consistent with those of Pb silicates (with a divalent state, i.e., Pb{sup 2+}) are also found in the irradiated sample. This finding implies that some of the radiogenic Pb in natural zircon might not actually reside in the zircon lattice or in ZrSiO{sub 4} phases, but form new local domains or clusters. Infrared bands of OH-stretching vibrations were also detected in the irradiated synthetic zircon, which was originally free from OH features prior to the irradiation. These results indicate that H can easily diffuse into the irradiated layer or into irradiated-induced phases to form OH or and hydrous species after the irradiated material is damaged. The type and content of hydrous species vary with irradiation fluences.

  13. 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.

  14. 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.

  15. 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.

  16. Fourier-transform infrared spectroscopic comparison of cultured human fibroblast and fibrosarcoma cells

    NASA Astrophysics Data System (ADS)

    Yang, Difei; Castro, Dan J.; El-Sayed, Ivan H.; El-Sayed, Mostafa A.; Saxton, Romaine E.; Zhang, Nancy Y.

    1995-05-01

    Infrared vibration spectroscopy appears to be a more powerful technique for diagnosis than visible or UV spectroscopy. Advantages of IR spectra include: 1) vibrational motion has a smaller tissue absorption coefficient than electronic motion, 2) scattering of infrared radiation has a lower cross section than visible or UV light, (these two facts allow deeper penetration of IR radiation) and 3) vibration spectra provide a better fingerprint of chemical groups present in cells than the unresolved broad electronic spectrum of biological molecules. In the present work, Fourier-transform IR spectroscopy was used to compare cultured human fibroblast and malignant fibrosarcoma cells. Significant differences were observed by comparing the spectra of the normal cells with that of the cancer cells. the PO2 symmetric stretching mode at 1082cm-1 in the cancer cell is reduced in intensity. These observations are similar to those reported previously by Wong et al in comparing the IR spectra of pairs of normal and cancerous cells from the colon and cervix. However, the observed increase in the relative intensity of the symmetric to antisymmetric CH3 bending mode are only found in fibrosarcoma and basal cell carcinoma. The decrease in intensity of the CH2 bending mode relative to that of CH3 mode was observed only for fibrosarcoma cells. This finding with paired human fibroblast and fibrosarcoma cells suggests that fatty acid chains or side chains of protein in the cancer cells are partially degraded leading to more terminal carbon. It is also possible that changes in the environment upon carcinogenesis induces a change in the relative absorption cross sections for the CH3 and CH2 bending vibrations.

  17. 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

  18. A rapid method for peroxide value determination in edible oils based on flow analysis with Fourier transform infrared spectroscopic detection.

    PubMed

    Ruíz, A; Ayora Cañada, M J; Lendl, B

    2001-02-01

    The development of an automated, rapid and highly precise method for determination of the peroxide value in edible oils based on a continuous flow system and Fourier transform infrared (FTIR) spectroscopic detection is described. The sample stream was mixed with a solvent mixture consisting of 25% (v/v) toluene in hexanol which contained triphenylphosphine (TPP). The hydroperoxides present in the sample reacted stoichiometrically with TPP to give triphenylphosphine oxide (TPPO) which has a characteristic and intense absorption band at 542 cm-1. A 10% (m/v) TPP solution in the solvent mixture and a 100 cm reaction coil were necessary for complete reaction. FTIR transmission spectra were recorded using a flow cell equipped with CsI windows having an optical pathlength of 100 microns. By using tert-butyl hydroperoxide spiked oil standards and evaluation of the band formed at 542 cm-1 a linear calibration graph covering the range 1-100 PV (peroxide value; mequiv O2 kg-1 oil) was obtained. The relative standard deviation was 0.23% (n = 11) and the throughput 24 samples h-1. The developed system was also applied to the determination of PV in olive, sunflower and corn oils, showing good agreement with the official reference method of the European Community which is based on titration using organic solvents. The results obtained clearly show that the developed method is superior to the standard wet chemical method, hence suggesting its application in routine analysis and quality control. PMID:11235111

  19. Near-infrared spectroscopic and photometric evolution of nova V476 Scuti - a nova that formed optically thin dust

    NASA Astrophysics Data System (ADS)

    Das, R. K.; Banerjee, D. P. K.; Ashok, N. M.; Mondal, Soumen

    2013-09-01

    We present results of near-infrared (near-IR) JHK (1.07 - 2.5 μm) spectroscopic and photometric observations of Nova V476 Scuti (V476 Sct) which was discovered in outburst in 2005 September. The near-IR observations of the nova presents the evolution of the post-maxima spectra and near-IR light curve. The spectra of V476 Sct, observed on 9 different epochs, show prominent lines due to HI, OI, CI and NI. Based on the IR spectral signatures we independently identify it as a Fe II type of nova, consistent with the same classification obtained from optical spectra. A detailed identification of the observed spectral lines is presented. The near-IR JHK light curve extending for a period of about 59 days after outburst clearly shows the formation of a optically thin dust shell, a phenomenon which is not commonly observed in novae. By fitting black body curves to the spectral energy distributions (SEDs) the temperatures of the dust shell on different epochs have been estimated. Dust formation in V476 Sct is consistent with the presence of lines of elements with low-ionization potential like Na and Mg in the early spectra which had earlier been suggested by us to be potential indicators of dust formation at a later phase in a nova's development.

  20. 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.

  1. Development of a practical spatial-spectral analysis protocol for breast histopathology using Fourier transform infrared spectroscopic imaging.

    PubMed

    Pounder, F Nell; Reddy, Rohith K; Bhargava, Rohit

    2016-06-23

    Breast cancer screening provides sensitive tumor identification, but low specificity implies that a vast majority of biopsies are not ultimately diagnosed as cancer. Automated techniques to evaluate biopsies can prevent errors, reduce pathologist workload and provide objective analysis. Fourier transform infrared (FT-IR) spectroscopic imaging provides both molecular signatures and spatial information that may be applicable for pathology. Here, we utilize both the spectral and spatial information to develop a combined classifier that provides rapid tissue assessment. First, we evaluated the potential of IR imaging to provide a diagnosis using spectral data alone. While highly accurate histologic [epithelium, stroma] recognition could be achieved, the same was not possible for disease [cancer, no-cancer] due to the diversity of spectral signals. Hence, we employed spatial data, developing and evaluating increasingly complex models, to detect cancers. Sub-mm tumors could be very confidently predicted as indicated by the quantitative measurement of accuracy via receiver operating characteristic (ROC) curve analyses. The developed protocol was validated with a small set and statistical performance used to develop a model that predicts study design for a large scale, definitive validation. The results of evaluation on different instruments, at higher noise levels, under a coarser spectral resolution and two sampling modes [transmission and transflection], indicate that the protocol is highly accurate under a variety of conditions. The study paves the way to validating IR imaging for rapid breast tumor detection, its statistical validation and potential directions for optimization of the speed and sampling for clinical deployment. PMID:27095431

  2. Infra-red spectroscopic characteristics of naphthalocyanine in bis(naphthalocyaninato) rare earth complexes peripherally substituted with thiophenyl derivatives

    NASA Astrophysics Data System (ADS)

    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]rad - 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]rad -. In addition, both the Q-bands of electronic absorption spectra and the typical IR absorption bands of naphthalocyanine radical anion [Nc(SPh)8]rad - 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.

  3. 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. PMID:18242826

  4. Feasibility of analysis of polar compounds by high performance liquid chromatography with Fourier transform infrared spectroscopic detection

    SciTech Connect

    Amateis, P.G.

    1984-01-01

    High performance liquid chromatographic separations employing on-line flow cell Fourier transform infrared spectroscopic detection were developed for polar compounds including phenols, alcohols, amines and azaarenes. Detection by FTIR gave information concerning hydrogen bonding and solvent effects occurring during the separations in addition to giving structural information about eluted species to aid in identification. Both analytical size and microbore normal phase columns were employed. Such experimental considerations as column overload, injected minimum detectable quantities, the use of analytical vs. microbore columns and flow cell pathlength were examined. The developed HPLC-FTIR systems were applied to the analysis of several coal liquefaction samples for heteroatom content. Confirmatory and additional information concerning the samples were provided by field ionization mass spectrometry, gas chromatography/mass spectrometry and reversed phase liquid chromatography employing UV detection. An equation relating reversed phase retention times to structural parameters was developed and applied to the analysis of the coal-derived samples. Two process solvents were found to contain primarily alkyl-substituted phenols in addition to azaarenes such as pyridine and quinoline. Some non-distillable coal-derived samples were found to contain azaarenes such as alkyl quinolines. Evidence was also found concerning the presence of hydroxy-pyridine type compounds and the incorporation of process solvent molecules into the coal structure during liquefaction.

  5. 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.

  6. Infrared spectroscopic studies of detergent-solubilized uncoupling protein from brown-adipose-tissue mitochondria.

    PubMed

    Rial, E; Muga, A; Valpuesta, J M; Arrondo, J L; Goñi, F M

    1990-02-22

    The uncoupling protein of brown-adipose-tissue mitochondria has been purified in the form of mixed micelles with lipid and reduced Triton X-100. This surfactant has the advantage over conventional Triton X-100, that it does not interfere with amide bands in infrared spectra. The structure of the uncoupling protein in micellar form has been examined by Fourier-transform infrared spectroscopy (FTIR). In order to decompose the amide I contour into its components, band-narrowing (Fourier derivation and deconvolution) and band-decomposition techniques have been used. Combining data from spectra taken in H2O and 2H2O media, the following percentage distribution of secondary structure patterns has been obtained: 50% alpha-helix, 28-30% beta-structure; 13-15% beta-turns and 7% unordered. Thermal denaturation of the uncoupling protein has also been monitored by FTIR. In accordance with previous observations of different proteins, thermal denaturation is marked by a shift in the amide I maximum and the appearance of two new peaks in 2H2O, at around 1620 cm-1 and 1685 cm-1. Denaturation occurs in the 40-50 degrees C temperature range, in agreement with studies of GDP-binding capacity. Cooling down the thermally denatured protein produces a new change in its secondary structure; however, the original conformation is not restored. The uncoupling protein possesses a nucleotide-binding site. On addition of GDP, small changes in protein conformation occur, attributable to changes in tertiary structure. However, no detectable effects are seen in the presence or absence of the other physiological regulators, the free fatty acids. The uncoupling protein shares important similarities in its primary structure with other anion carriers of the mitochondrial membrane; one of these, the adenine-nucleotide translocator, has been used in a comparative study, applying the same FTIR techniques described above for the uncoupling protein. Both proteins have a similar proportion of alpha

  7. 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.

  8. Organic matter characterization by infrared spectroscopic methods in lake sediment records from boreal and subarctic Sweden: Implications for long-term carbon cycling

    NASA Astrophysics Data System (ADS)

    Meyer-Jacob, Carsten; Rosén, Peter; Bindler, Richard

    2013-04-01

    Freshwater systems play an important role in the global carbon cycle. In this dynamic system, inorganic and organic carbon can be incorporated into biota, effluxed to the atmosphere or accumulated in sediments. The amount and composition of the carbon, derived from both aquatic and terrestrial sources, accumulated in sediments depend on the climatic and environmental conditions present in the lake and its catchment, and are thus sensitive to changes in, e.g., temperature, precipitation, vegetation and hydrological flow patterns. In this study, we show the application of infrared spectroscopic methods to qualitatively and quantitatively characterize organic matter stored in lake sediments with a focus on changes in the source of terrestrial-derived organic matter. Infrared spectroscopic methods facilitate a fast, cost-efficient and non-destructive analysis of minerogenic as well as organic sediment components. We applied three different infrared spectroscopic analyses - visible-near infrared spectroscopy (VNIRS; 25000-4000 cm-1), Fourier-transform infrared spectroscopy in the mid-IR region (FTIR; 3750-400 cm-1) and a combined Fourier-transformed infrared - thermal programmed desorption technique (FTIR-TPD; 3750-400 cm-1) - to Holocene sediment records from two Swedish lakes, Lång-Älgsjön and Lake Koukkel, to reconstruct past changes in the organic matter composition. The infrared spectral information of these records indicate sections of different organic matter composition reflecting varying stages of the lake and landscape development. An early-Holocene mire development around the boreal lake Lång-Älgsjön led to an increased input of organic matter from the catchment into the lake initiating an early natural lake acidification, whereas the subarctic Lake Koukkel has been affected by mire and potentially late-Holocene permafrost dynamics, which caused an increased and less variable input of allochthonous organic matter. Overall, variations in organic matter

  9. 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.

  10. Stardust Interstellar Preliminary Examination III: Infrared spectroscopic analysis of interstellar dust candidates

    NASA Astrophysics Data System (ADS)

    Bechtel, Hans A.; Flynn, George J.; Allen, Carlton; Anderson, David; Ansari, Asna; Bajt, SašA.; Bastien, Ron K.; Bassim, Nabil; Borg, Janet; Brenker, Frank E.; Bridges, John; Brownlee, Donald E.; Burchell, Mark; Burghammer, Manfred; Butterworth, Anna L.; Changela, Hitesh; Cloetens, Peter; Davis, Andrew M.; Doll, Ryan; Floss, Christine; Frank, David R.; Gainsforth, Zack; Grün, Eberhard; Heck, Philipp R.; Hillier, Jon K.; Hoppe, Peter; Hudson, Bruce; Huth, Joachim; Hvide, Brit; Kearsley, Anton; King, Ashley J.; Lai, Barry; Leitner, Jan; Lemelle, Laurence; Leroux, Hugues; Leonard, Ariel; Lettieri, Robert; Marchant, William; Nittler, Larry R.; Ogliore, Ryan; Ong, Wei Ja; Postberg, Frank; Price, Mark C.; Sandford, Scott A.; Tresseras, Juan-Angel Sans; Schmitz, Sylvia; Schoonjans, Tom; Silversmit, Geert; Simionovici, Alexandre S.; Solé, Vicente A.; Srama, Ralf; Stadermann, Frank J.; Stephan, Thomas; Sterken, Veerle J.; Stodolna, Julien; Stroud, Rhonda M.; Sutton, Steven; Trieloff, Mario; Tsou, Peter; Tsuchiyama, Akira; Tyliszczak, Tolek; Vekemans, Bart; Vincze, Laszlo; von Korff, Joshua; Westphal, Andrew J.; Wordsworth, Naomi; Zevin, Daniel; Zolensky, Michael E.

    2014-09-01

    Under the auspices of the Stardust Interstellar Preliminary Examination, picokeystones extracted from the Stardust Interstellar Dust Collector were examined with synchrotron Fourier transform infrared (FTIR) microscopy to establish whether they contained extraterrestrial organic material. The picokeystones were found to be contaminated with varying concentrations and speciation of organics in the native aerogel, which hindered the search for organics in the interstellar dust candidates. Furthermore, examination of the picokeystones prior to and post X-ray microprobe analyses yielded evidence of beam damage in the form of organic deposition or modification, particularly with hard X-ray synchrotron X-ray fluorescence. From these results, it is clear that considerable care must be taken to interpret any organics that might be in interstellar dust particles. For the interstellar candidates examined thus far, however, there is no clear evidence of extraterrestrial organics associated with the track and/or terminal particles. However, we detected organic matter associated with the terminal particle in Track 37, likely a secondary impact from the Al-deck of the sample return capsule, demonstrating the ability of synchrotron FTIR to detect organic matter in small particles within picokeystones from the Stardust interstellar dust collector.

  11. 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.

  12. A near-infrared high-resolution spectroscopic survey of bulge stars - JASMINE prestudy

    NASA Astrophysics Data System (ADS)

    Tsujimoto, T.; Gouda, N.; Kobayashi, N.; Yasui, C.; Kondo, S.; Minami, A.; Motohara, K.; Ikeda, Y.

    2006-08-01

    We are developing a new near-infrared high-resolution (R[max]= 100,000) and high-sensitive spectrograph WINERED, which is specifically customized for short NIR bands at 0.9-1.35 μm. WINERED employs the novelty in the optical system; a potable design and a warm optics without any cold stops. The planned astrometric space mission JASMINE will provide the exact positions, distances, and proper motions of the bulge stars. The missing components, the radial velocity and chemical compositions will be measured by WINERED with high accuracies (δV< 1km/s). These combined data brought by JASMINE and WINERED will certainly reveal the nature of the Galactic bulge. We plan to complete this instrument for the observation of a single object by the end of 2008 and hope to attach it to various 4-10m telescopes as a PI-type instrument. In succession, we will develop it to the design for a simultaneous multi-object spectroscopy.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Fourier Transform Infrared Spectroscopic Studies on Modulation of N-Nitrosodiethylamine-Induced Hepatocarcinogenesis by Azadirachta indica.

    PubMed

    Bharati, Sanjay; Rishi, Parveen; Koul, Ashwani

    2015-01-01

    Fourier transform infrared spectroscopy was employed in the present study to obtain information about the molecular composition of hepatic tumor versus hepatic tissue. A hepatic cancer model was developed by administering N-nitrosodiethylamine (NDEA) to male Balb/c mice. The results revealed that NDEA-induced hepatic cancer tumor tissue had altered molecular composition compared with normal liver tissue. Compared with the normal tissue, the saturation level of membrane phospholipids was observed to be decreased in tumors along with an abnormal distribution of protein secondary structures. A significant decrease in glycogen and a significant increase in total nucleic acid content were also observed in tumor cells. The administration of aqueous Azadirachta indica leaf extract (AAILE) prior to NDEA treatment resulted in the normalization of saturation levels in phospholipids and total nucleic acid content and in the distribution of protein secondary structures in tumors. A significant increase in the amount of stored glycogen was observed in AAILE cotreated tumors compared with NDEA-induced tumors, which might indicate that AAILE cotreatment impeded the ability of tumor cells to consume glucose at a faster rate. The normalization of molecular composition upon AAILE cotreatment in hepatic tumors might indicate that AAILE hampered the process of evolution of tumors, which could be responsible for its observed chemopreventive action. PMID:26349605

  18. Attenuated total reflectance Fourier-transform infrared spectroscopic investigation of silicon heterojunction solar cells.

    PubMed

    Holovský, Jakub; De Wolf, Stefaan; Jiříček, Petr; Ballif, Christophe

    2015-07-01

    Silicon heterojunction solar cells critically depend on the detailed properties of their amorphous/crystalline silicon interfaces. We report here on the use of attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy to gain precise insight into the vibrational properties of the surfaces and ultrathin layers present in such solar cells. We fabricate ATR prisms from standard silicon wafers similar to those used for device fabrication. In this fashion, we acquire very-high sensitivity FTIR information on device-relevant structures. Our method has no requirement for minimum layer thickness, enabling the study of the impact of the different fabrication process steps on the film microstructure. We discuss the necessary requirements for the method implementation and give a comprehensive overview of all observed vibration modes. In particular, we study vibrational signatures of Si-H(X), Si-H(X)(Si(Y)O(Z)), B-H, hydroxyl groups, and hydrocarbons on the Si(111) surface. We observe subtle effects in the evolution of the chemical state of the surface during sample storage and process-related wafer handling and discuss their effect on the electronic properties of the involved interfaces. PMID:26233357

  19. 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.

  20. In situ infrared spectroscopic study of forsterite carbonation in wet supercritical CO2.

    PubMed

    Loring, John S; Thompson, Christopher J; Wang, Zheming; Joly, Alan G; Sklarew, Deborah S; Schaef, H Todd; Ilton, Eugene S; Rosso, Kevin M; Felmy, Andrew R

    2011-07-15

    Carbonation reactions are central to the prospect of CO(2) trapping by mineralization in geologic reservoirs. In contrast to the relevant aqueous-mediated reactions, little is known about the propensity for carbonation in the key partner fluid: supercritical carbon dioxide containing dissolved water ("wet" scCO(2)). We employed in situ mid-infrared spectroscopy to follow the reaction of a model silicate mineral (forsterite, Mg(2)SiO(4)) for 24 h with wet scCO(2) at 50 °C and 180 atm. The results show a dramatic dependence of reactivity on water concentration and the presence of liquid water on the forsterite particles. Exposure to neat scCO(2) showed no detectable carbonation reaction. At 47% and 81% water saturation, an Ångstrom-thick liquid-like water film was detected on the forsterite particles and less than 1% of the forsterite transformed. Most of the reaction occurred within the first 3 h of exposure to the fluid. In experiments at 95% saturation and with an excess of water (36% above water saturation), a nanometer-thick water film was detected, and the carbonation reaction proceeded continuously with approximately 2% and 10% conversion, respectively. Our collective results suggest constitutive links between water concentration, water film formation, reaction rate and extent, and reaction products in wet scCO(2). PMID:21699182

  1. Infrared spectroscopic characterization of carbonated apatite: a combined experimental and computational study.

    PubMed

    Ren, Fuzeng; Ding, Yonghui; Leng, Yang

    2014-02-01

    A combined experimental and computational approach was employed to investigate the feasibility and effectiveness of characterizing carbonated apatite (CAp) by infrared (IR) spectroscopy. First, an experimental comparative study was conducted to identify characteristic IR vibrational bands of carbonate substitution in the apatite lattice. The IR spectra of pure hydroxyapatite (HA), carbonate adsorbed on the HA surface, a physical mixture of HA and sodium carbonate monohydrate, a physical mixture of HA and calcite, synthetic CAps prepared using three methods (precipitation method, hydrothermal route, and solid-gas reaction at high temperature) and biological apatites (human enamel, human cortical bone, and two animal bones) were compared. Then, the IR vibrational bands of carbonate in CAp were calculated with density functional theory. The experimental study identified characteristic IR bands of carbonate that cannot be generated from surface adsorption or physical mixtures and the results show that the bands at ∼880, 1413, and 1450 cm(-1) should not be used as characteristic bands of CAp since they could result from carbonate adsorbed on the apatite crystals surface or present as a separate phase. The combined experimental and computational study reveals that the carbonate v3 bands at ∼1546 and 1465 cm(-1) are, respectively, the IR signature bands for type A CAp and type B CAp. PMID:23533194

  2. 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.

  3. 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.

  4. Infrared spectroscopic demonstration of a conformational change in bacteriorhodopsin involved in proton pumping.

    PubMed Central

    Ormos, P

    1991-01-01

    Infrared spectral changes in bacteriorhodopsin (bR) were followed during the slow decay of the M intermediate in the temperature region 240-260 K. The decay of the M form is characterized by the disappearance of the ethylenic bands and the bands indicating the reprotonation of the Schiff base. The route of Schiff-base reprotonation completely changes between 240 K and 260 K. At 240 K reprotonation occurs from Asp-85, the group to which the proton was released during M formation, and there is no pumping. At 260 K Schiff-base reprotonation takes place through Asp-96 from the cytoplasmic side, in the normal sequence assumed for proton pumping. The dramatic change in the route of Schiff-base reprotonation is coupled to a protein conformational change characterized by the change of the ratio of the two amide I bands at 1658 cm-1 and 1669 cm-1. This conformational change is interpreted as the conformational switch crucial for proton pumping: a protein relaxation following M formation results in a local rearrangement of the group, in the vicinity of the Schiff base. The rearrangement changes the accessibility of the Schiff base and provides that its deprotonation and reprotonation occur on different sides. The conformational change has characteristics typical for relaxations in proteins. In addition, it is shown that at 260 K an equilibrium exists between the M and N forms. Images PMID:1846442

  5. 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.

  6. 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.

  7. [Infrared spectroscopic study on the component and vigor analysis of Cistanche deserticola seeds].

    PubMed

    Xu, Rong; Sun, Su-Qin; Chen, Jun; Chen, Shi-Lin; Zhou, Feng

    2009-01-01

    Comparative study of the different parts of cistanche deserticola seeds and their changes after different processing were examined by Fourier transform infrared spectroscopy spectra (FTIR). The results of the analysis showed that components in the cistanche deserticola seeds were abundant, which contained characteristic absorption peaks of protein, fat and carbohydrate. As well, pectin and aromatic compound can be also found in the seeds. However, the components were different in different parts of cistanche deserticola seeds. The characteristic absorption peak intensities of fat at 2,926, 1,746, 1,161 and 721 cm(-1) were the strongest in the seed kernels. However, the seed coats mainly consisted of carbohydrate and pectin, which were showed at 1,054 cm(-1). The contents of protein and carbohydrate were decreased distinctly in the moldy and dead seeds after processing. The characteristic absorption peak intensity ratio of protein to fat (I1,630/I1,745 ) was all higher than 1.05 in the live seeds. The characteristic absorption peak intensity ratio of amido link I of protein to fat (11,653/I1,745) in the dead seed kernels of the cistanche deserticola was decreased from 0.31 to 0. 23, which was 25.8% less than that in vital seed kernels. The results suggest that FTIR not only can be used in fast comprehensive analysis of seed components, but also can be used in the seed vigor analysis, seed longevity determination and seed quality evaluation. PMID:19385214

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Near-infrared spectroscopic imaging of stimulus-related hemodynamic responses on the neonatal auditory cortices

    NASA Astrophysics Data System (ADS)

    Kotilahti, Kalle; Nissila, Ilkka; Makela, Riikka; Noponen, Tommi; Lipiainen, Lauri; Gavrielides, Nasia; Kajava, Timo; Huotilainen, Minna; Fellman, Vineta; Merilainen, Pekka; Katila, Toivo

    2005-04-01

    We have used near-infrared spectroscopy (NIRS) to study hemodynamic auditory evoked responses on 7 full-term neonates. Measurements were done simultaneously above both auditory cortices to study the distribution of speech and music processing between hemispheres using a 16-channel frequency-domain instrument. The stimulation consisted of 5-second samples of music and speech with a 25-second silent interval. In response to stimulation, a significant increase in the concentration of oxygenated hemoglobin ([HbO2]) was detected in 6 out of 7 subjects. The strongest responses in [HbO2] were seen near the measurement location above the ear on both hemispheres. The mean latency of the maximum responses was 9.42+/-1.51 s. On the left hemisphere (LH), the maximum amplitude of the average [HbO2] response to the music stimuli was 0.76+/- 0.38 μ M (mean+/-std.) and to the speech stimuli 1.00+/- 0.45 μ+/- μM. On the right hemisphere (RH), the maximum amplitude of the average [HbO2] response was 1.29+/- 0.85 μM to the music stimuli and 1.23+/- 0.93 μM to the speech stimuli. The results indicate that auditory information is processed on both auditory cortices, but LH is more concentrated to process speech than music information. No significant differences in the locations and the latencies of the maximum responses relative to the stimulus type were found.

  13. [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

  14. 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?

  15. 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.

  16. Infrared Spectroscopic Studies of Water and Organics in Protoplanetary Disks around Young Stars

    NASA Astrophysics Data System (ADS)

    Sargent, Benjamin; Forrest, William; Watson, Dan M.; Calvet, Nuria; Furlan, Elise; Kim, Kyoung-Hee; Green, Joel; Pontoppidan, Klaus Martin; Tayrien, Cyprian

    2015-08-01

    The building blocks of planets in planet-forming ("protoplanetary") disks are assembled early in the lifetime of a young star. The gas disks are relatively short-lived, with a half-life of about 3 million years, as chemical reactions modify the reservoir of material from the natal molecular cloud. 5 - 7.5 μm wavelength Spitzer Space Telescope Infrared Spectrograph (IRS) spectra of about a dozen T Tauri stars in the Taurus-Auriga star-forming region showing emission from water vapor and absorption from other gases in these stars' protoplanetary disks will be presented. Some of these stars' spectra show a strong emission manifold at 6.6 μm due to the nu2 = 1 - 0 bending mode of water vapor, with the shape of the spectrum suggesting water vapor temperatures > 500 K. Other stars' spectra show a strong absorption band, peaking in strength at 5.6 - 5.7 μm, which appears consistent in some cases with gaseous formaldehyde (H2CO) and in other cases with formic acid (HCOOH). Modeling of these stars' spectra suggests these gases are present in the inner few AU -- i.e., in the planet-forming regions -- of their disks. How the gaseous features observed between 5 - 7.5 μm relate to those at other wavelengths will be discussed. Future directions for this research, including both pursuing confirmation of HCOOH and H2CO features at these and other wavelengths and modeling of the gas features at these wavelengths in other Spitzer-IRS spectra of protoplanetary disks around young stars, will also be discussed. This work suggests that water and organic molecules, which are crucial for life as we know it, are present in the habitable zones of stars at a very early age [of 1-3 million years].

  17. 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

  18. Predictions for imaging and spectroscopic surveys of galaxies and Active Galactic Nuclei in the mid-/far-Infrared

    NASA Astrophysics Data System (ADS)

    Bonato, Matteo

    2015-02-01

    While continuum imaging data at far-infrared to sub-millimeter wavelengths have provided tight constraints on the population properties of dusty star-forming galaxies up to high redshifts, future space missions like the Space Infra-Red Telescope for Cosmology and Astrophysics (SPICA) and ground based facilities like the Atacama Large Millimeter/submillimeter Array (ALMA) and the Cerro Chajnantor Atacama Telescope (CCAT) will allow detailed investigations of their physical properties via their mid-/far-infrared line emission. The goal of this thesis project was to carry out predictions for these spectroscopic surveys using both a phenomenological approach and physically grounded models. These predictions are useful to optimize the planning of the surveys. In the first part of the work, I present updated predictions for the number counts and the redshift distributions of star-forming galaxies spectroscopically detectable by these future missions. These predictions exploit a recent upgrade of evolutionary models, that includes the effect of strong gravitational lensing, in the light of the most recent Herschel and South Pole Telescope (SPT) data. Moreover the relations between line and continuum infrared luminosity are re-assessed, considering also differences among source populations, with the support of extensive simulations that take into account dust obscuration. My reference model for the redshift dependent IR luminosity functions is the one worked out by Cai et al. (2013) based on a comprehensive hybrid approach combining a physical model for the progenitors of early-type galaxies with a phenomenological one for late-type galaxies. The derived line luminosity functions are found to be highly sensitive to the spread of the line to continuum luminosity ratios. Estimates of the expected numbers of detections per spectral line by the SpicA FAR infrared Instrument (SAFARI) and by CCAT surveys for different integration times per field of view at fixed total observing

  19. 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.

  20. 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.

  1. Infrared spectroscopic and mutational studies on putidaredoxin-induced conformational changes in ferrous CO-P450cam.

    PubMed

    Nagano, Shingo; Shimada, Hideo; Tarumi, Akiko; Hishiki, Takako; Kimata-Ariga, Yoko; Egawa, Tsuyoshi; Suematsu, Makoto; Park, Sam-Yong; Adachi, Shin-ichi; Shiro, Yoshitsugu; Ishimura, Yuzuru

    2003-12-16

    Ferrous-carbon monoxide bound form of cytochrome P450cam (CO-P450cam) has two infrared (IR) CO stretching bands at 1940 and 1932 cm(-1). The former band is dominant (>95% in area) for CO-P450cam free of putidaredoxin (Pdx), while the latter band is dominant (>95% in area) in the complex of CO-P450cam with reduced Pdx. The binding of Pdx to CO-P450cam thus evokes a conformational change in the heme active site. To study the mechanism involved in the conformational change, surface amino acid residues Arg79, Arg109, and Arg112 in P450cam were replaced with Lys, Gln, and Met. IR spectroscopic and kinetic analyses of the mutants revealed that an enzyme that has a larger 1932 cm(-1) band area upon Pdx-binding has a larger catalytic activity. Examination of the crystal structures of R109K and R112K suggested that the interaction between the guanidium group of Arg112 and Pdx is important for the conformational change. The mutations did not change a coupling ratio between the hydroxylation product and oxygen consumed. We interpret these findings to mean that the interaction of P450cam with Pdx through Arg112 enhances electron donation from the proximal ligand (Cys357) to the O-O bond of iron-bound O(2) and, possibly, promotes electron transfer from reduced Pdx to oxyP450cam, thereby facilitating the O-O bond splitting. PMID:14661963

  2. In Situ Ellipsometry for Shock Compression Measurements

    NASA Astrophysics Data System (ADS)

    Bakshi, L.; Eliezer, S.; Appelbaum, G.; Nissim, N.; Perelmutter, L.; Mond, M.

    2009-12-01

    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 α→ɛ phase transition.

  3. 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.

  4. 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.

  5. Visible and near infrared spectroscopic investigation of E-type asteroids, including 2867 Steins, a target of the Rosetta mission

    NASA Astrophysics Data System (ADS)

    Fornasier, S.; Migliorini, A.; Dotto, E.; Barucci, M. A.

    2008-07-01

    We present the results of a visible spectroscopic survey of igneous asteroids belonging to the small and intriguing E-class, including 2867 Steins, a target of the Rosetta mission. The survey was carried out at the 3.5 m Telescopio Nazionale Galileo (TNG), and at the 3.5 m New Technology Telescope (NTT) of the European Southern Observatory. We obtained new visible spectra for eighteen E-type asteroids, and near infrared spectra for eight of them. We confirm the presence of three different mineralogies in the small E-type populations. We classify each object in the E[I], E[II] or E[III] subgroups [Gaffey, M.J., Kelley, M.S., 2004. Lunar Planet. Sci. XXXV. Abstract 1812] on the basis of the spectral behavior and of the eventual presence of absorption features attributed to sulfides (such the 0.49 μm band, on E[II]), or to iron bearing silicates (0.9 μm band, on E[III]). We suggest that some asteroids (i.e. 64 Angelina, 317 Roxane, and 434 Hungaria), which show different spectral behavior comparing our data with those available in literature, have an inhomogeneous surface composition. 2867 Steins, a target of the Rosetta mission, shows a spectral behavior typical of the E[II] subgroup, as already suggested by Barucci et al. [Barucci, M.A., Fulchignoni, M., Fornasier, S., Dotto, E., Vernazza, P., Birlan, M., Binzel, R.P., Carvano, J., Merlin, F., Barbieri, C., Belskaya, I., 2005. Astron. Astrophys. 430, 313-317] and Fornasier et al. [Fornasier, S., Marzari, F., Dotto, E., Barucci, M.A., Migliorini, A., 2007. Astron. Astrophys. 474, 29-32]. Litva and 1990 TN1, initially classified as E-types, show a visible and near infrared behavior consistent with the olivine rich A-class asteroids, while 5806 Archieroy, also supposed to belong to the E-class, has a spectral behavior consistent with the S(V) classification following the Gaffey et al. [Gaffey, M.J., Burbine, T.H., Piatek, J.L., Reed, K.L., Chaky, D.A., Bell, J.F., Brown, R.H., 1993. Icarus 106, 573

  6. 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

  7. 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

  8. 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

  9. Use of rotating compensator spectroscoic ellipsometry for monitoring the photoresist etching on Si wafer

    NASA Astrophysics Data System (ADS)

    Choi, Yong-Seok; Kim, Yun-Hwan; Kim, Gon-Ho; Oh, Hye-Keun; An, Ilsin

    2003-05-01

    Etching is one of the important processes of semiconductor production. In this study, we monitored surface etching process, which is used for dielectric barrier discharge (DBD) at atmospheric pressure and room temperature, of photoresist (PR) on Si wafer by using rotating compensator spectroscopic ellipsometry (RCSE). Ellipsometry has mono-layer sensitivity and we can use it in a severe atmosphere such as a reactive gas, plasma and high temperature etc. Also, it is possible to perform non-destructive, real-time, and in-situ measurement. DBD reactor used 20 kV pulse power. We used alumina as dielectric material. The atmosphere of DBD plasma was operated without dark period in optimal frequency. We used 248 nm PR as sample. The PR is coated by spin coater on Si wafer with 248 nm anti-reflection coating (ARC), and wafer is baked after that. Samples are not exposed and are not developed, but are etched after bake. The PR is removed linearly with respect to time and temperature. We obtained several results at various experimental conditions - temperature, gas flow, process time and frequency. On the assumption that PR is removed homogeneously, we can calculate the etching rate by continuous measurement of thickness of PR by ellipsometry.

  10. 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.

  11. 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

  12. 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.

  13. Infrared and Raman spectroscopic analyses and theoretical computation of 4-butyl-1-(4-hydroxyphenyl)-2-phenyl-3,5-pyrazolidinedione

    NASA Astrophysics Data System (ADS)

    Binil, P. S.; Mary, Y. Sheena; Varghese, Hema Tresa; Panicker, C. Yohannan; Anoop, M. R.; Manojkumar, T. K.

    Infrared and Raman spectroscopic analyses were carried out on 4-butyl-1-(4-hydroxyphenyl)-2-phenyl-3,5-pyrazolidinedione. The interpretation of the spectra was aided by DFT calculation of the molecule. The vibrational wavenumbers were examined theoretically using the Gaussian03 set of quantum chemistry codes and the normal modes were assigned by potential energy distribution calculations. A computation of the first hyperpolarizability of the compound indicates that the compound may be a good candidate as a NLO material. Optimized geometrical parameters are in agreement with the reported XRD results. The RMS error of the observed Raman bands and IR bands are found to be 35.09 and 39.57 for HF method and 14.31 and 17.17 for DFT method. The predicted infrared intensities and Raman activities are reported.

  14. Analyzing biomolecular interactions by variable angle ellipsometry

    NASA Astrophysics Data System (ADS)

    Wu, Jiun-Yan; Lee, Chih-Kung; Lee, J. H.; Shiue, Shuen-Chen; Lee, Shu-Sheng; Lin, Shiming

    2001-10-01

    In this paper, an innovative ellipsometer is developed and applied to metrology of the biomolecular interaction on a protein biochip. Both the theory, optical and opto-mechanical configurations of this newly developed ellipsometer and methodologies adopted in system design to improve the system performance are presented. It will be shown that by measuring the ellipsometric parameters, the corresponding concentration variation in biochemical reaction can be calculated according to stoichiometry analysis. By applying the variable angle ellipsometry to analysis of a multi-layered sample, the thickness and concentration are resolved. It is believed that the newly developed ellipsometer biosensor is able to undertake an accurate measurement on biomedical interaction.

  15. Accurate spectroscopic characterization of oxirane: A valuable route to its identification in Titan's atmosphere and the assignment of unidentified infrared bands

    SciTech Connect

    Puzzarini, Cristina; Biczysko, Malgorzata; Bloino, Julien; Barone, Vincenzo

    2014-04-20

    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{sup –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).

  16. 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

  17. 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.

  18. ''A Time-Resolved Infrared Spectroscopic Study of Reactive Acyl Intermediates Relevant to Cobalt-Catalyzed Hydroformylation''

    SciTech Connect

    Ford, Peter C.; S.M. Massick; J.Rabor; S.Elbers; J.Marhanke; S.Bernhard; J.R. Schoonover

    2000-12-31

    OAK-B135 Mechanisms of the homogeneous catalytic and photocatalytic activation of small molecules such as carbon monoxide, dihydrogen and various hydrocarbons. Time-resolved spectroscopic investigations of rhodium and iridium haol cabonyl complex intermediates proposed in methanol carbonylation catalysts.

  19. In situ mid-infrared spectroscopic titration of forsterite with water in supercritical CO2: Dependence of mineral carbonation on quantitative water speciation

    NASA Astrophysics Data System (ADS)

    Loring, J. S.; Thompson, C. J.; Wang, Z.; Schaef, H. T.; Martin, P.; Qafoku, O.; Felmy, A. R.; Rosso, K. M.

    2011-12-01

    Geologic sequestration of carbon dioxide holds promise for helping mitigate CO2 emissions generated from the burning of fossil fuels. Supercritical CO2 (scCO2) plumes containing variable water concentrations (wet scCO2) will displace aqueous solution and dominate the pore space adjacent to caprocks. It is important to understand possible mineral reactions with wet scCO2 to better predict long-term caprock integrity. We introduce novel in situ instrumentation that enables quantitative titrations of reactant minerals with water in scCO2 at temperatures and pressures relevant to target geologic reservoirs. The system includes both transmission and attenuated total reflection mid-infrared optics. Transmission infrared spectroscopy is used to measure concentrations of water dissolved in the scCO2, adsorbed on mineral surfaces, and incorporated into precipitated carbonates. Single-reflection attenuated total reflection infrared spectroscopy is used to monitor water adsorption, mineral dissolution, and carbonate precipitation reactions. Results are presented for the infrared spectroscopic titration of forsterite (Mg2SiO4), a model divalent metal silicate, with water in scCO2 at 100 bar and at both 50 and 75°C. The spectral data demonstrate that the quantitative speciation of water as either dissolved or adsorbed is important for understanding the types, growth rates, and amounts of carbonate precipitates formed. Relationships between dissolved/adsorbed water, water concentrations, and the role of liquid-like adsorbed water are discussed. Our results unify previous in situ studies from our laboratory based on infrared spectroscopy, nuclear magnetic resonance spectroscopy and X-ray diffraction.

  20. 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.

  1. 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

  2. Automatic null ellipsometry with an interferometer

    SciTech Connect

    Watkins, Lionel R.

    2009-11-10

    A new approach to automatic null ellipsometry is described in which the analyzer of a traditional polarizer compensator sample analyzer (PCSA) null ellipsometer is replaced with a heterodyne Michelson interferometer. One arm of this interferometer is modified such that it produces a fixed, linearly polarized reference beam, irrespective of the input polarization state. This beam is recombined interferometrically with the measurement beam and spatially separated into its p and s polarizations. The relative phase of the resulting temporal fringes is a linear function of the polarizer azimuthal angle P, and thus this component can be driven to its null position without iteration. Once at null, the azimuthal angle of the reflected, linearly polarized light is trivially determined from the relative amplitude of the fringes. Measurements made with this instrument on a native oxide film on a silicon wafer were in excellent agreement with those made with a traditional PCSA null ellipsometer.

  3. 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.

  4. 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.

  5. 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.

  6. Imaging and spectroscopic analysis of single microdroplets containing p-cresol using the near-infrared laser tweezers/Raman microprobe system

    NASA Astrophysics Data System (ADS)

    Ajito, Katsuhiro; Morita, Masao

    1999-06-01

    The near-infrared (NIR) laser tweezers/Raman microprobe system features two charge-coupled device (CCD) cameras with holographic notch filters (HNFs) for the imaging and spectroscopic analysis of molecules in a single microdroplet (MD). One CCD camera and a HNF are used to record an image of the laser microprobe in a trapped MD. The other CCD camera and two HNFs are used with a polychromator to obtain a Raman spectrum of molecules in the MD. A dielectric multilayer coated beam splitter divides the scattered NIR light into two optical paths for the cameras. The system provides sufficient sensitivity to obtain a Raman spectrum of p-cresol contained in a single picoliter toluene MD and sufficient spatial resolution to record an image of the laser microprobe in a trapped MD simultaneously. Furthermore, a difference in the solubility for the p-cresol in bulk solvent and in the MD solvent was clearly observed using this system.

  7. Study of surfaces using near infrared optical fiber spectrometry

    NASA Technical Reports Server (NTRS)

    Workman, G. L.; Arendale, W. A.; Hughes, C.

    1995-01-01

    The measurement and control of cleanliness for critical surfaces during manufacturing and in service provides a unique challenge for fulfillment of environmentally benign operations. Of particular interest has been work performed in maintaining quality in the production of bondline surfaces in propulsion systems and the identification of possible contaminants. This work requires an in-depth study of the possible sources of contamination, methodologies to identify contaminants, discrimination between contaminants and chemical species caused by environment, and the effect of particular contaminants on the bondline integrity of the critical surfaces. This presentation will provide an introduction to the use of optical fiber spectrometry in a nondestructive measurement system for process monitoring and how it can be used to help clarify issues concerning surface chemistry. Correlation of the Near Infrared (NIR) spectroscopic results with Optical Stimulated Electron Emission (OSEE) and ellipsometry will also be presented.

  8. 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.

  9. 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. PMID:25467664

  10. 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.

  11. Fiber Optic Fourier Transform Infrared Spectroscopic Techniques for Advanced On-Line Chemical Analysis in Semiconductor Fabrication Tools

    NASA Astrophysics Data System (ADS)

    Kester, Michael; Trygstad, Marc; Chabot, Paul

    2003-09-01

    A unique analytical methodology has recently been developed to perform real-time, on-line chemical analysis of bath solutions in semiconductor fabrication tools. A novel, patented fiber optic sensor is used to transmit infrared light directly through the tube walls of the circulating bath solutions within the fabrication tool in a completely non-invasive, non-extractive way. The sensor simply "clips" onto the tubing, thus permitting immediate analysis of the bath composition by Fourier Transform infrared (FTIR) spectroscopy. The infrared spectrometer is capable of multiplexing up to eight "Clippir™" sensor heads to a single interferometer using fiber optic cables. The instrument can analyze almost any bath solution utilized today. The analysis is performed using the near-infrared (NIR) portion of the electromagnetic spectrum, where absorption bands related to molecular vibrations can be found. The Fourier Transform infrared spectrometer gives access to absorption bands over a wide range of frequencies (or wavelengths), and the absorptions are correlated to concentrations using a chemometric approach employing a partial least-squares algorithm. Models are generated from this approach for each chemistry to be analyzed. This paper will review the analytical technology necessary to make such measurements, and discuss the instrument performance criteria required to achieve accurate and precise measurements of bath chemistries. The ability to measure non-infrared absorbing compounds will be discussed, as will the nature of the influence of sample temperature on measurement. Issues critical to the development of robust models and their direct implementation on multiple channels and even different instruments will be considered.

  12. 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

  13. 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.

  14. 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

  15. 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.…

  16. 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...

  17. A Fourier transform infrared spectroscopic study of yeast hexokinase: conformational changes under interaction with substrates and inhibitors

    NASA Astrophysics Data System (ADS)

    Trinquier-Dinet, Murielle; Boisdon, Marie-Thérèse; Perie, Jacques; Willson, Michèle

    1998-02-01

    The infrared (FTIR) spectroscopy study of several complexes of yeast hexokinase with substrates and inhibitors allows the determination of open and closed conformations of the protein. The analysis is based on a correlation between FTIR and X-ray data for one of the inhibitor-enzyme complexes of the study and from that reference, the features of the amide I band hydration component.

  18. 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}.

  19. Determination of MBT-waste reactivity - An infrared spectroscopic and multivariate statistical approach to identify and avoid failures of biological tests.

    PubMed

    Böhm, K; Smidt, E; Binner, E; Schwanninger, M; Tintner, J; Lechner, P

    2010-04-01

    The Austrian Landfill Ordinance provides limit values regarding the reactivity for the disposal of mechanically biologically treated (MBT) waste before landfilling. The potential reactivity determined by biological tests according to the Austrian Standards (OENORM S 2027 1-2) can be underestimated if the microbial community is affected by environmental conditions. New analytical tools have been developed as an alternative to error-prone and time-consuming biological tests. Fourier Transform Infrared (FT-IR) spectroscopy in association with Partial Least Squares Regression (PLS-R) was used to predict the reactivity parameters respiration activity (RA(4)) and gas generation sum (GS(21)) as well as to detect errors resulting from inhibiting effects on biological tests. For this purpose 250 MBT-waste samples from different Austrian MBT-plants were investigated using FT-IR spectroscopy in the mid (MIR) and near infrared (NIR) area and biological tests. Spectroscopic results were compared with those from biological tests. Arising problems caused by interferences of RA(4) and GS(21) are discussed. It is shown that FT-IR spectroscopy predicts RA(4) and GS(21) reliably to assess stability of MBT-waste materials and to detect errors. PMID:19854633

  20. 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.

  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. An Analysis on Lyapunov Spectrum of Hemodynamic Response in Functional Near Infrared Spectroscopic Measurement during Different Imaginary Motor Tasks

    NASA Astrophysics Data System (ADS)

    Soe, Ni Ni; Nakagawa, Masahiro

    2008-03-01

    This paper presents the novel approach to evaluate the effects of different motor activation tasks of functional near infrared spectroscopy signal (fNIRS). Functional near infrared spectroscopy is a practical non-invasive optical technique to detect characteristic of hemodynamic response during functional activation of the cerebral cortex. In this paper, fNIRS measurements were made in the area of motor cortex. Three subjects, aged 23-30 years, participated in the experiment. The application of the Lyapunov analysis which is a method of nonlinear analysis to analyze and to quantify the chaotic property in the time series of the hemoglobin dynamics of the various motor imagery tasks of fNIRS signal was presented. The strength of chaos was estimated by the Kolmogorov entropy which is related to Lyapunov spectrum. Experimental results show that these nonlinear measures are good discriminators of NIRS signals. The Lyapunov spectra, Lyapunov dimension (DL), and Kolmogorov entropy (K) all indicated chaotic behavior.

  3. Infrared spectroscopic studies on the cluster size dependence of charge carrier structure in nitrous oxide cluster anions.

    PubMed

    Thompson, Michael C; Weber, J Mathias

    2016-03-14

    We report infrared photodissociation spectra of nitrous oxide cluster anions of the form (N2O)nO(-) (n = 1-12) and (N2O)n (-) (n = 7-15) in the region 800-1600 cm(-1). The charge carriers in these ions are NNO2 (-) and O(-) for (N2O)nO(-) clusters with a solvation induced core ion switch, and N2O(-) for (N2O)n (-) clusters. The N-N and N-O stretching vibrations of N2O(-) (solvated by N2O) are reported for the first time, and they are found at (1595 ± 3) cm(-1) and (894 ± 5) cm(-1), respectively. We interpret our infrared spectra by comparison with the existing photoelectron spectroscopy data and with computational data in the framework of density functional theory. PMID:26979688

  4. Infrared spectroscopic studies on the cluster size dependence of charge carrier structure in nitrous oxide cluster anions

    NASA Astrophysics Data System (ADS)

    Thompson, Michael C.; Weber, J. Mathias

    2016-03-01

    We report infrared photodissociation spectra of nitrous oxide cluster anions of the form (N2O)nO- (n = 1-12) and (N2O)n- (n = 7-15) in the region 800-1600 cm-1. The charge carriers in these ions are NNO2- and O- for (N2O)nO- clusters with a solvation induced core ion switch, and N2O- for (N2O)n- clusters. The N-N and N-O stretching vibrations of N2O- (solvated by N2O) are reported for the first time, and they are found at (1595 ± 3) cm-1 and (894 ± 5) cm-1, respectively. We interpret our infrared spectra by comparison with the existing photoelectron spectroscopy data and with computational data in the framework of density functional theory.

  5. 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.

  6. 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.

  7. Infrared and nuclear magnetic resonance spectroscopic study of secondary amide hydrogen bonding in benzoyl PABA derivatives (retinoids).

    PubMed

    Dalterio, Richard; Huang, Xiaohua Stella; Yu, Kuo-Long

    2007-06-01

    Attenuated total reflection (ATR) Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) data are used to characterize the hydrogen bonding of the secondary amide N-H group of several structurally similar benzoyl derivatives of p-aminobenzoic acid esters (retinoids) in chloroform solution. The amide N-H can form intermolecular hydrogen bonds to several proton acceptors in these molecules or it can form an intramolecular hydrogen bond to a fluorine or oxygen atom in some of the molecules. The concentration dependence of the solution N-H infrared absorption bands is used to determine the formation of intramolecular and/or intermolecular H-bonds. Proton NMR spectra were obtained from deuterated chloroform solutions and the sec-amide N-H resonance was assigned for each compound. The downfield shift in the N-H resonance is correlated to intramolecular H-bond formation. Also, the NMR spectra of fluorine-containing compounds provide J(F-H) through-space coupling values. Using infrared and NMR data, the relative intramolecular hydrogen bond strengths (N-H...F or N-H...O) of the compounds are approximately ranked. PMID:17650370

  8. Preliminary study on near-infrared spectroscopic measurement of urine hippuric acid for the screening of biological exposure index

    NASA Astrophysics Data System (ADS)

    Ogawa, Mitsuhiro; Yamakoshi, Yasuhiro; Motoi, Kosuke; Yamakoshi, Takehiro; Yamakoshi, Ken-Ichi

    2008-10-01

    Biological Exposure Indices (BEIs) are reference for a chemical or its metabolite in the biological specimen. BEIs give guidelines for the evaluation of potential health hazards or for diagnosis of occupational illnesses. Among them, urine hippuric acid (HA) that is a metabolites of toluene is considered as the BEIs of toluene exposure for human and measured from workers using toluene. In this study, we attempted to develop a brief measurement of urine HA by using near-infrared spectroscopy. As the first step, water solutions of hippuric acid of several concentrations (0-250mg/dl) are measured. Afterward, artificial urines conditioned by adding glucose and urine to HA solutions were measured and analyzed. The solvents are optically measured within near infrared region (750-2500nm) obtaining optical absorption. Then, differential absorbance were calculated by subtraction of analyte absorbance from ion-exchange water absorbance and analyzed. As a result, for HA solutions, a calibration equation from absorbance in two wavelengths can be obtained by using multiple regression (R2=0.935). However, this calibration cannot provide a good estimation for artificial urines. Secondary, another calibration from three wavelengths was obtained and providing a good regression (R2=0.934). This result suggests that a brief urine constituents measurement using near-infrared spectroscopy can be developed.

  9. Probing Physical and Chemical Properties of Laser Shocked Materials using Ultrafast Dynamic Ellipsometry and Spectroscopies

    NASA Astrophysics Data System (ADS)

    Dang, Nhan

    2013-06-01

    Ultrafast laser techniques allow resolution of shock induced physics and chemistry picoseconds behind the shock front. In this presentation, the 350 ps sustained laser-generated shocks will be shown to combine with ultrafast dynamic ellipsometry to measure the shock state and transient absorption to measure the molecular electronic response to shock loading. Experimental data will be presented on shocked explosive crystals and liquids. Ultrafast dynamic ellipsometry was used to measure the shock and particle velocity as well as the shocked refractive index. Transient absorption spectra of RDX and simple molecular liquids in the spectral region from 440 to 780 nm were measured to map out shock reactivity during the first 350 ps, over shock stress states from 7 to 20 GPa. Additionally, nonlinear spectroscopic probes will be demonstrated to offer the potential to measure even more details of the molecular shock response, such as evolution of chemical species and vibrational temperature. Preliminary results of shocked phenylacetylene obtained using vibrational coherent anti-Stokes Raman spectroscopy (CARS) and the capability of femtosecond stimulated Raman scattering (FSRS) data to measure the nonequilibrium time evolution of mode specific vibrational temperatures on picosecond time scales will be discussed.

  10. 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.

  11. 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.

  12. 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

  13. Variable-temperature diffuse reflectance Fourier transform infrared spectroscopic studies of amine desorption from a siliceous surface

    SciTech Connect

    Leyden, D.E.; Proctor, K.G.

    1994-12-31

    Variable-temperature diffuse reflectance infrared Fourier transform spectroscopy was used in conjunction with pyridine desorption studies to assess the acidity of a siliceous surface. An amorphous, porous silica substrate was investigated. The results contribute to an understanding of the acidic strength and the distribution of acidic sites on this material. A hydrogen-bonding interaction was observed between pyridine and the surface. Isothermal rate constants and an activation energy for the desorption process are reported and can be used as direct measures of surface site acidity. 23 refs., 7 figs.

  14. 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.

  15. 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. PMID:26946935

  16. 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.

  17. Quantitative infrared spectroscopic analysis of SF 6 decomposition products obtained by electrical partial discharges and sparks using PLS-calibrations

    NASA Astrophysics Data System (ADS)

    Kurte, R.; Heise, H. M.; Klockow, D.

    2001-05-01

    Infrared spectroscopy is a powerful tool for the analysis of gaseous by-products in sulfur hexafluoride gas used as an insulator in high-voltage equipment. Sparks and electrical partial discharges were generated between different point-plane configurations within a custom-made discharge chamber constructed from stainless steel and Teflon ®. Various electrode materials were used such as stainless steel, copper, aluminium, silver, tungsten and tungsten/copper alloy. Owing to the different electrical conditions, a wide concentration range of the decomposition products existed. The main-products found were the sulfuroxyfluorides SOF 4 and SOF 2, as well as HF following experiments with partial discharges and sparking with energies around 1.0 J/spark. All infrared spectra were recorded using an FTIR-spectrometer equipped with a 10 cm gas cell. Quantification was carried out using classical least-squares and partial least-squares (PLS) with multivariate spectral data from selected intervals. PLS calibration models were also optimised under the constraint of a minimum number of spectral variables with a view to developing simple photometers based on a restricted number of laser wavelengths. Standard errors of prediction obtained by cross-validation of different PLS calibration models are reported for the compounds mentioned, as well as for SF 4, SO 2F 2 and SiF 4.

  18. Spectroscopic investigation in the mid- and far-infrared regions of phosphorus fertilizers derived from thermochemically treated sewage sludge ash.

    PubMed

    Vogel, Christian; Kohl, Anka; Adam, Christian

    2011-03-01

    Inorganic phosphorus and nitrogen-phosphorus-potassium (NPK) fertilizers based on phosphates from thermochemically treated sewage sludge ash were analyzed using mid-infrared (mid-IR) and far-infrared (FIR) spectroscopy. The different compounds present in the fertilizers were qualitatively determined with the help of recorded reference spectra of pure substances. Differentiation between various phosphates and other compounds such as sulfates, nitrates, and oxides was possible using combined interpretation of the mid-IR and FIR spectra. The results are in agreement with previous X-ray diffraction (XRD) measurements of the same samples. The main phosphate phases detected were NH(4)H(2)PO(4), MgHPO(4)·3H(2)O, Mg(3)(PO(4))(2), Ca(5)(PO(4))(5)Cl, CaHPO(4)·2H(2)O, Ca(H(2-)PO(4))(2)·H(2)O, and AlPO(4). Furthermore, K(2)SO(4), NH(4)NO(3), Fe(2)O(3), and SiO(2) were identified in the IR spectra. However, ammonium and sulfate compounds were only identified in the mid-IR region but were not detectable in the FIR region. PMID:21352646

  19. 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. PMID:21397245

  20. 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.