Science.gov

Sample records for ac-impedance spectroscopy ac-is

  1. AC impedance spectroscopy and conductivity studies of Dy doped Bi4V2O11 ceramics

    NASA Astrophysics Data System (ADS)

    Bag, Sasmitarani; Das, Parthasarathi; Behera, Banarji

    2017-03-01

    The ac impedance and conductivity properties of Dy doped Bi4V2 - x Dy x O11 (x = 0.05, 0.10, 0.15 and 0.20) ceramics prepared by solid-state reaction technique, in a wide frequency range at different temperatures have been studied. All the samples exhibited β-type phase orthorhombic structure at room temperature. The Nyquist plot confirmed the presence of both grain and grain boundary effects for all Dy doped samples. Double relaxation behavior was also observed. The grain and grain boundary resistance decreases with rise in temperature for all the concentration and exhibits a typical negative temperature co-efficient of resistance (NTCR) behavior. An analysis of the electric modulus suggests the possible hopping mechanism for electrical transport processes of all the materials. The ac conductivity spectrum obeys Jonscher's universal power law. DC conductivity of the materials were also studied and values of the activation energy found to be 0.40, 0.49, 0.73 and 0.78 eV for the compositions x = 0.05, 0.10, 0.15 and 0.20, respectively, at different temperatures (150-375 °C).

  2. Microfabricated AC impedance sensor

    DOEpatents

    Krulevitch, Peter; Ackler, Harold D.; Becker, Frederick; Boser, Bernhard E.; Eldredge, Adam B.; Fuller, Christopher K.; Gascoyne, Peter R. C.; Hamilton, Julie K.; Swierkowski, Stefan P.; Wang, Xiao-Bo

    2002-01-01

    A microfabricated instrument for detecting and identifying cells and other particles based on alternating current (AC) impedance measurements. The microfabricated AC impedance sensor includes two critical elements: 1) a microfluidic chip, preferably of glass substrates, having at least one microchannel therein and with electrodes patterned on both substrates, and 2) electrical circuits that connect to the electrodes on the microfluidic chip and detect signals associated with particles traveling down the microchannels. These circuits enable multiple AC impedance measurements of individual particles at high throughput rates with sufficient resolution to identify different particle and cell types as appropriate for environmental detection and clinical diagnostic applications.

  3. Influence of Dopants on Electrical Properties of ZnO-V2O5 Varistors Deduced from AC Impedance and Variable-Temperature Dielectric Spectroscopy

    NASA Astrophysics Data System (ADS)

    Wu, Jun; Li, Taotao; Qi, Ting; Qin, Qingwei; Li, Guangqiang; Zhu, Bailin; Wu, Run; Xie, Changsheng

    2012-07-01

    The influence of MnO2, PbO, and a mixture of MnO2, PbO, and B2O3 on the electrical and dielectric properties of ZnO-V2O5 ceramics was studied by alternating-current (AC) impedance and variable-temperature dielectric spectroscopy. The results show that, compared with the resistivity of the intervening layer at the grain boundary, the Schottky barrier present at the grain boundary is much more important for varistor performance, which can be significantly improved by using a mixture of MnO2, PbO, and B2O3. Consequently, better varistor performance is achieved for 94.5 mol.% ZnO + 0.5 mol.% V2O5 + 1.0 mol.% MnO2 + 2.0 mol.% PbO + 2.0 mol.% B2O3 (ZVMPB), i.e., nonlinear coefficient α = 35.3 and leakage current density I l = 2.72 μA/cm2. The activation energy for the characteristic dielectric relaxation process is in the range of 0.339 eV to 0.365 eV, indicating that it is only associated with oxygen vacancy V{O/·}.

  4. AC impedance analysis of polypyrrole thin films

    NASA Technical Reports Server (NTRS)

    Penner, Reginald M.; Martin, Charles R.

    1987-01-01

    The AC impedance spectra of thin polypyrrole films were obtained at open circuit potentials from -0.4 to 0.4 V vs SCE. Two limiting cases are discussed for which simplified equivalent circuits are applicable. At very positive potentials, the predominantly nonfaradaic AC impedance of polypyrrole is very similar to that observed previously for finite porous metallic films. Modeling of the data with the appropriate equivalent circuit permits effective pore diameter and pore number densities of the oxidized film to be estimated. At potentials from -0.4 to -0.3 V, the polypyrrole film is essentially nonelectronically conductive and diffusion of polymer oxidized sites with their associated counterions can be assumed to be linear from the film/substrate electrode interface. The equivalent circuit for the polypyrrole film at these potentials is that previously described for metal oxide, lithium intercalation thin films. Using this model, counterion diffusion coefficients are determined for both semi-infinite and finite diffusion domains. In addition, the limiting low frequency resistance and capacitance of the polypyrrole thin fims was determined and compared to that obtained previously for thicker films of the polymer. The origin of the observed potential dependence of these low frequency circuit components is discussed.

  5. AC impedance electrochemical modeling of lithium-ion positive electrodes.

    SciTech Connect

    Dees, D.; Gunen, E.; Abraham, D.; Jansen, A.; Prakash, J.; Chemical Engineering; IIT

    2004-01-01

    Under Department of Energy's Advanced Technology Development Program,various analytical diagnostic studies are being carried out to examine the lithium-ion battery technology for hybrid electric vehicle applications, and a series of electrochemical studies are being conducted to examine the performance of these batteries. An electrochemical model was developed to associate changes that were observed in the post-test analytical diagnostic studies with the electrochemical performance loss during testing of lithium ion batteries. While both electrodes in the lithium-ion cell have been studied using a similar electrochemical model, the discussion here is limited to modeling of the positive electrode. The positive electrode under study has a composite structure made of a layered nickel oxide (LiNi{sub 0.8}Co{sub 0.15}Al{sub 0.05}O{sub 2}) active material, a carbon black and graphite additive for distributing current, and a PVDF binder all on an aluminum current collector. The electrolyte is 1.2M LiPF{sub 6} dissolved in a mixture of EC and EMC and a Celgard micro-porous membrane is used as the separator. Planar test cells (positive/separator/negative) were constructed with a special fixture and two separator membranes that allowed the placement of a micro-reference electrode between the separator membranes [1]. Electrochemical studies including AC impedance spectroscopy were then conducted on the individual electrodes to examine the performance and ageing effects in the cell. The model was developed by following the work of Professor Newman at Berkeley [2]. The solid electrolyte interface (SEI) region, based on post-test analytical results, was assumed to be a film on the oxide and an oxide layer at the surface of the oxide. A double layer capacity was added in parallel with the Butler-Volmer kinetic expression. The pertinent reaction, thermodynamic, and transport equations were linearized for a small sinusoidal perturbation [3]. The resulting system of differential

  6. Laser Raman and ac impedance spectroscopic studies of PVA: NH 4NO 3 polymer electrolyte

    NASA Astrophysics Data System (ADS)

    Hema, M.; Selvasekarapandian, S.; Hirankumar, G.; Sakunthala, A.; Arunkumar, D.; Nithya, H.

    2010-01-01

    Ion conducting polymer electrolyte PVA:NH 4NO 3 has been prepared by solution casting technique and characterized using XRD, Raman and ac impedance spectroscopic analyses. The amorphous nature of the polymer films has been confirmed by XRD and Raman spectroscopy. An insight into the deconvoluted Raman peaks of υ1 vibration of NO 3- anion for the polymer electrolyte reveals the dominancy of ion aggregates at higher NH 4NO 3 concentration. From the ac impedance studies, the highest ion conductivity at 303 K has been found to be 7.5 × 10 -3 S cm -1 for 80PVA:20NH 4NO 3. The conductivity of the polymer electrolytes has been found to depend on the degree of dissociation of the salt in the host polymer matrix. The combination of the above-mentioned analyses has proven worth while and in fact necessary in order to achieve better understanding of these complex systems.

  7. Equivalent Circuits For AC-Impedance Analysis Of Corrosion

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1992-01-01

    Report presents investigation of equivalent circuits for ac-impedance analysis of corrosion. Impedance between specimen and electrolyte measured as function of frequency. Data used to characterize corrosion electrochemical system in terms of equivalent circuit. Eleven resistor/capacitor equivalent-circuit models were analyzed.

  8. AC impedance study of degradation of porous nickel battery electrodes

    NASA Technical Reports Server (NTRS)

    Lenhart, Stephen J.; Macdonald, D. D.; Pound, B. G.

    1987-01-01

    AC impedance spectra of porous nickel battery electrodes were recorded periodically during charge/discharge cycling in concentrated KOH solution at various temperatures. A transmission line model (TLM) was adopted to represent the impedance of the porous electrodes, and various model parameters were adjusted in a curve fitting routine to reproduce the experimental impedances. Degradation processes were deduced from changes in model parameters with electrode cycling time. In developing the TLM, impedance spectra of planar (nonporous) electrodes were used to represent the pore wall and backing plate interfacial impedances. These data were measured over a range of potentials and temperatures, and an equivalent circuit model was adopted to represent the planar electrode data. Cyclic voltammetry was used to study the characteristics of the oxygen evolution reaction on planar nickel electrodes during charging, since oxygen evolution can affect battery electrode charging efficiency and ultimately electrode cycle life if the overpotential for oxygen evolution is sufficiently low.

  9. Laser Raman, XRD, DSC and Ac-Impedance Analysis of Polymer Blend Electrolyte Based on Eco-Friendly Pva-Pvp Blend with NH4NO3

    NASA Astrophysics Data System (ADS)

    Rajeswari, N.; Selvasekarapandian, S.; Prabaharan, S. R. S.; Kawamura, J.; Iwai, Y.; Karthikeyan, S.

    2013-07-01

    Proton conducting polymer blend electrolytes have attractive interest because of their advantages such as processability, flexibility, electrochemical stability, easy handling and their applications to a variety of electrochemical devices such as fuel cells, chemical sensor and electrochemical displays. In the present work, the films of 50PVA-50PVP blend with different MWt% concentrations of NH4NO3 have been prepared by solution casting techniques using distilled water as a solvent. The prepared films have been investigated by different techniques such as XRD, DSC, Laser Raman and AC Impedance spectroscopy. XRD studies reveal the amorphous nature of the polymer blend-salt complexes. The glass transition temperature has been calculated from the DSC analysis. From the AC Impedance spectroscopy, the high conductivity of the 30MWt% of NH4NO3 doped 50PVA-50PVP polymer complex has been found to be the order of 1.41 × 10-3S cm-1 at room temperature.

  10. Potentiostatic and ac impedance studies of the hydrogen electrodes used in Ni/H2 batteries

    NASA Technical Reports Server (NTRS)

    Le Helloco, Jean-Guy; Bojkov, Hristo; Parthasarathy, Arvind; Srinivasan, Supramaniam; Appleby, A. J.

    1992-01-01

    In a study of electrode activity for hydrogen evolution and hydrogen ionization, knowledge of the detailed kinetics and of the surface coverage by adsorbed hydrogen is essential. In the Ni/H2 battery, the hydrogen electrode is subjected to high hydrogen pressure; elucidation of the variation of kinetic parameters with hydrogen pressure is therefore of interest. Potentiostatic and ac impedance spectroscopic techniques were used in the present study. The equivalent circuit of the reaction, the kinetic parameters, and their pressure dependence have been determined.

  11. Investigation of water and ice by ac impedance using electrochemical properties cup.

    PubMed

    Chin, K B; Buehler, M G; Seshadri, S; Keymeulen, D; Anderson, R C; Dutz, S; Narayanan, S R

    2007-01-01

    Water and ice were investigated by ac impedance with the electrochemical properties cup in an effort to develop an in situ instrument for water characterization. In liquid water, the impedance modulus decreased with the increase in charge carriers. In the ice, the impedance measurements were characterized by the dielectric relaxation and its corresponding activation energy. The activation energy of 0.400 eV was determined for pure ice. With ice containing Cl(-) anions, the activation energy was 0.24 eV. H(+) and OH(-) doped ice has the lowest activation energy for dielectric relaxation. Results from previous works are similar to the results reported in this study.

  12. Development of AC impedance methods for evaluating corroding metal surfaces and coatings

    NASA Technical Reports Server (NTRS)

    Knockemus, Ward

    1986-01-01

    In an effort to investigate metal surface corrosion and the breakdown of metal protective coatings the AC Impedance Method was applied to zinc chromate primer coated 2219-T87 aluminum. The model 368-1 AC Impedance Measurement System recently acquired by the MSFC Corrosion Research Branch was used to monitor changing properties of coated aluminum disks immersed in 3.5% NaCl buffered at ph 5.5 over three to four weeks. The DC polarization resistance runs were performed on the same samples. The corrosion system can be represented by an electronic analog called an equivalent circuit that consists of transistors and capacitors in specific arrangements. This equivalent circuit parallels the impedance behavior of the corrosion system during a frequency scan. Values for resistances and capacities that can be assigned in the equivalent circuit following a least squares analysis of the data describe changes that occur on the corroding metal surface and in the protective coating. A suitable equivalent circuit was determined that predicts the correct Bode phase and magnitude for the experimental sample. The DC corrosion current density data are related to equivalent circuit element parameters.

  13. Study of metal corrosion using ac impedance techniques in the STS launch environment

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.

    1989-01-01

    AC impedance measurements were performed to investigate the corrosion resistance of 19 alloys under conditions similar to the STS launch environment. The alloys were: Zirconium 702, Hastelloy C-22, Inconel 625, Hastelloy C-276, Hastelloy C-4, Inconel 600, 7Mo + N, Ferralium 255, Inco Alloy G-3, 20Cb-3, SS 904L, Inconel 825, SS 304LN, SS 316L, SS 317L, ES 2205, SS 304L, Hastelloy B-2, and Monel 400. AC impedance data were gathered for each alloy after one hour immersion time in each of the following three electrolyte solutions: 3.55 percent NaCl, 3.55 percent NaCl-0.1N HCl, and 3.55 percent NaCl-1.0N HCl. The data were analyzed qualitatively using the Nyquist plot and quantitatively using the Bode plot. Polarization resistance, Rp, values were obtained using the Bode plot. Zirconium 702 was the most corrosion resistant alloy in the three electrolytes. The ordering of the other alloys according the their resistance to corrosion varied as the concentration of hydrochloric acid in the electrolyte increased. The corrosion resistance of Zirconium 702 and Ferralium 255 increased as the concentration of hydrochloric acid in the electrolyte increased. The corrosion resistance of the other 17 alloys decreased as the concentration of the hyrdochloric acid in the electrolyte increased.

  14. AC Impedance Studies on Metal/Nanoporous Silicon/ p-Silicon Structures

    NASA Astrophysics Data System (ADS)

    Mabrook, M. F.; Ray, A. K.

    2017-04-01

    Alternating current (AC) impedance measurements have been performed on 10- to 15- μm thick porous silicon layers on a (100) p-type silicon ( p(+)Si) substrate with the aluminium (Al) top electrode in a sandwich configuration in the range of 20 Hz-1 MHz and in the temperature ranging between 152 K and 292 K. The ac conductivity σ ac was found to increase with frequency f according to the universal power law: σ_{{ac}} = Afs where the exponent s is a frequency and temperature-dependent quantity. A hopping process is found to be dominant at low temperatures and high frequencies, while a thermally activated free band process is responsible for conduction at higher temperatures. Capacitance is found to decrease with frequency but increase with temperature. Frequency dependence of the loss tangent is observed with a temperature-dependent minimum value.

  15. AC Impedance Studies on Metal/Nanoporous Silicon/p-Silicon Structures

    NASA Astrophysics Data System (ADS)

    Mabrook, M. F.; Ray, A. K.

    2016-11-01

    Alternating current (AC) impedance measurements have been performed on 10- to 15-μm thick porous silicon layers on a (100) p-type silicon (p(+)Si) substrate with the aluminium (Al) top electrode in a sandwich configuration in the range of 20 Hz-1 MHz and in the temperature ranging between 152 K and 292 K. The ac conductivity σ ac was found to increase with frequency f according to the universal power law: σ_{ac} = Afs where the exponent s is a frequency and temperature-dependent quantity. A hopping process is found to be dominant at low temperatures and high frequencies, while a thermally activated free band process is responsible for conduction at higher temperatures. Capacitance is found to decrease with frequency but increase with temperature. Frequency dependence of the loss tangent is observed with a temperature-dependent minimum value.

  16. An electrochemical study of corrosion protection by primer-topcoat systems on 4130 steel with ac impedance and dc methods

    NASA Technical Reports Server (NTRS)

    Mendrek, M. J.; Higgins, R. H.; Danford, M. D.

    1988-01-01

    To investigate metal surface corrosion and the breakdown of metal protective coatings, the ac impedance method is applied to six systems of primer coated and primer topcoated 4130 steel. Two primers were used: a zinc-rich epoxy primer and a red lead oxide epoxy primer. The epoxy-polyamine topcoat was used in four of the systems. The EG and G-PARC Model 368 ac impedance measurement system, along with dc measurements with the same system using the polarization resistance method, were used to monitor changing properties of coated 4230 steel disks immersed in 3.5 percent NaCl solutions buffered at pH 5.4 over periods of 40 to 60 days. The corrosion system can be represented by an electronic analog called an equivalent circuit consisting of resistors and capacitors in specific arrangements. This equivalent circuit parallels the impedance behavior of the corrosion system during a frequency scan. Values for the resistors and capacitors, that can be assigned in the equivalent circuit following a least-squares analysis of the data, describe changes that occur on the corroding metal surface and in the protective coatings. Two equivalent circuits have been determined that predict the correct Bode phase and magnitude of the experimental sample at different immersion times. The dc corrosion current density data are related to equivalent circuit element parameters. Methods for determining corrosion rate with ac impedance parameters are verified by the dc method.

  17. Evaluation of the electrode performance for PAFC by using acid absorption, acceleration and ac-impedance measurement

    SciTech Connect

    Kim, Chang-Soo; Song, Rak-Hyun; Choi, Byung-Woo

    1996-12-31

    In PAFC, the degradation on cathode electrode caused by carbon corrosion, platinum dissolution and growth is especially severe. An acceleration test is a good technique for evaluating the degradation of electrode performance, because it does not need long time. Coleman et al used thermal cycling and on-off cycling as an acceleration test. Song et al showed that hydrogen shortage decreased the electrode performance more rapidly than that of air shortage in gas shortage test. Honji et al reported that the rate of coarsening of Pt particle is rapid in open circuit potential and this is one of major causes on the performance degradation of electrode. The cathode performance has been studied by using acid absorption, acceleration and ac-impedance measurements as functions of the polytetrafluoroethylene (PTFE) contents and sintering temperatures of the electrode.

  18. AC impedance modelling study on porous electrodes of proton exchange membrane fuel cells using an agglomerate model

    NASA Astrophysics Data System (ADS)

    Gerteisen, Dietmar; Hakenjos, Alex; Schumacher, Jürgen O.

    A one-dimensional model of the PEM fuel cell cathode is developed to analyse ac impedance spectra and polarisation curves. The porous gas diffusion electrode is assumed to consist of a network of dispersed catalyst (Pt/C) forming spherically shaped agglomerated zones that are filled with electrolyte. The coupled differential equation system describes: ternary gas diffusion in the backing (O2 , N2 , water vapour), Fickian diffusion and Tafel kinetics for the oxygen reduction reaction (ORR) inside the agglomerates, proton migration with ohmic losses and double-layer charging in the electrode. Measurements are made of a temperature-controlled fuel cell with a geometric area of 1.4 cm × 1.4 cm. Lateral homogeneity is ensured by using a high stoichiometry of λmin . The model predicts the behaviour of measured polarisation curves and impedance spectra. It is found that a better humidification of the electrode leads to a higher volumetric double-layer capacity. The catalyst layer resistance shows the same behaviour depending on the humidification as the membrane resistance. Model parameters, e.g. Tafel slope, ionic resistance and agglomerate radius are varied. A sensitivity analysis of the model parameters is conducted.

  19. Oxygen diffusion in niobia-doped zirconia as surrogate for oxide film on Zr-Nb alloy: AC impedance analysis

    NASA Astrophysics Data System (ADS)

    Yamana, Teppei; Arima, Tatsumi; Yoshihara, Takatoshi; Inagaki, Yaohiro; Idemitsu, Kazuya

    2013-11-01

    The oxygen conductivities and crystallographic properties of niobia-doped yttria-stabilized tetragonal zirconia with 0.0-2.6 wt% Nb2O5 were evaluated by the AC impedance analysis and the X-ray diffraction measurement, respectively. The tetragonality of zirconia increased with niobia content and approached ˜1.017 while the tetragonal-to-monoclinic phase transition occurred above ca. 1 wt% Nb2O5. On the other hand, oxygen conductivities of bulk and grain-boundary (GB) decreased with increasing niobia content. The bulk conductivity controlled the total ionic conductivity at high temperatures, and its activation energy had smaller dependence on temperature than that of GB. In addition to the effect of [VO] depletion by niobia addition, the behaviors of bulk and GB conductivities might be explained by the decrease of mobility of oxygen ion due to Coulomb repulsion between Nb5+ and VO and by no segregation of Nb ions in the space-charge layers, respectively.

  20. AC impedance spectroscopy studies on solid-state sintered zinc aluminum oxide (ZnAl2O4) ceramics

    NASA Astrophysics Data System (ADS)

    Kumar, B. Rajesh; Rao, T. Subba

    2012-07-01

    In the present investigation Zinc Aluminum Oxide (ZnAl2O4) is prepared by solid-state reaction technique. Dielectric constant (ɛ'), dielectric loss(tan δ), ac conductivity (σac) as a function of temperature are studied by varying frequencies from 100 Hz to 1MHz using an impedance analyzer. The dielectric constant and dielectric loss increases gradually with an increase of temperature, but it decreases with increase of frequency. The ac conductivity (σac) also increases with increases of frequency. The transition peaks for ZnAl2O4 are observed at 490°C, 510°C, 520°C for the frequencies 1 KHz, 10 KHz and 100 KHz. No transition peaks are found for the frequency 100 Hz and 1 MHz because of high conductive loss.

  1. AC impedance analysis of ionic and electronic conductivities in electrode mixture layers for an all-solid-state lithium-ion battery

    NASA Astrophysics Data System (ADS)

    Siroma, Zyun; Sato, Tomohiro; Takeuchi, Tomonari; Nagai, Ryo; Ota, Akira; Ioroi, Tsutomu

    2016-06-01

    The ionic and electronic effective conductivities of an electrode mixture layers for all-solid-state lithium-ion batteries containing Li2Ssbnd P2S5 as a solid electrolyte were investigated by AC impedance measurements and analysis using a transmission-line model (TLM). Samples containing graphite (graphite electrodes) or LiNi0.5Co0.2Mn0.3O2 (NCM electrodes) as the active material were measured under a "substrate | sample | bulk electrolyte | sample | substrate" configuration (ion-electron connection) and a "substrate | sample | substrate" configuration (electron-electron connection). Theoretically, if the electronic resistance is negligibly small, which is the case with our graphite electrodes, measurement with the ion-electron connection should be effective for evaluating ionic conductivity. However, if the electronic resistance is comparable to the ionic resistance, which is the case with our NCM electrodes, the results with the ion-electron connection may contain some inherent inaccuracy. In this report, we theoretically and practically demonstrate the advantage of analyzing the results with the electron-electron connection, which gives both the ionic and electronic conductivities. The similarity of the behavior of ionic conductivity with the graphite and NCM electrodes confirms the reliability of this analysis.

  2. Synthesis and characterization of cancrinite-type zeolite, and its ionic conductivity study by AC impedance analysis

    NASA Astrophysics Data System (ADS)

    Kriaa, A.; Ben Saad, K.; Hamzaoui, A. H.

    2012-12-01

    The synthesis of cancrinite in the system NaOH-SiO2-Al2O3-NaHCO3-H2O was performed, according to methods described in the literature, in an autoclave under hydrothermal conditions at T = 473 K. The electrical properties of cancrinite-type zeolite pellets were investigated by complex impedance spectroscopy in the temperature range 465-800°C. The effect of temperature on impedance parameters was studied using an impedance analyzer in a wide frequency range (1 Hz to 13 MHz). The real and imaginary parts of complex impedance trace semicircles in the complex plane are plotted. The bulk resistance of the material decreases with rise in temperature. This exhibits a typical negative temperature coefficient of resistance (NTCR) behavior of the material. The results of bulk electrical conductivity and its activation energy are presented. The modulus analysis suggests that the electrical transport processes in the material are very likely to be of electronic nature. Relaxation frequencies follow an Arrhenius behavior with activation energy values not comparable to those found for the electrical conductivity.

  3. Electrochemical Performance and Stability of the Cathode for Solid Oxide Fuel Cells. I. Cross Validation of Polarization Measurements by Impedance Spectroscopy and Current-Potential Sweep

    SciTech Connect

    Zhou, Xiao Dong; Pederson, Larry R.; Templeton, Jared W.; Stevenson, Jeffry W.

    2009-12-09

    The aim of this paper is to address three issues in solid oxide fuel cells: (1) cross-validation of the polarization of a single cell measured using both dc and ac approaches, (2) the precise determination of the total areal specific resistance (ASR), and (3) understanding cathode polarization with LSCF cathodes. The ASR of a solid oxide fuel cell is a dynamic property, meaning that it changes with current density. The ASR measured using ac impedance spectroscopy (low frequency interception with real Z´ axis of ac impedance spectrum) matches with that measured from a dc IV sweep (the tangent of dc i-V curve). Due to the dynamic nature of ASR, we found that an ac impedance spectrum measured under open circuit voltage or on a half cell may not represent cathode performance under real operating conditions, particularly at high current density. In this work, the electrode polarization was governed by the cathode activation polarization; the anode contribution was negligible.

  4. A study of optothermal and AC impedance properties of Cr-doped Mn{sub 3}O{sub 4} sprayed thin films

    SciTech Connect

    Larbi, T.; Amara, A.; Ben Said, L.; Ouni, B.; Haj Lakhdar, M.; Amlouk, M.

    2015-10-15

    Highlights: • Outlining adequacy an original combination of several characterization means. • Structural, optical, thermal and electrical properties have been studied. • Opto- thermal analysis shows that band gap can be tuned through Cr doping. • Outlining physical properties for an eventual development of sensing components. - Abstract: Chrome-doped Mn{sub 3}O{sub 4} thin films were grown on the glass substrates by the spray pyrolysis technique at 350 °C. XRD diffraction and Raman spectroscopy analysis revealed that all samples have tetragonal spinel structure with a preferred orientation along the direction (1 0 1). Absorption coefficient has been measured using both transmission and mirage effect. The band gap energy decreases from 2.2 to 1.9 eV with Cr content while Urbach energy value increases from 354 to 473 meV. Also, thermal conductivity was evaluated. Finally, physical properties have been evaluated and discussed in terms of alteration of the band gap edges, electrical patterns and mirage effect.

  5. A new monitoring method for electrochemical aggregates by impedance spectroscopy

    NASA Astrophysics Data System (ADS)

    Kurzweil, P.; Fischle, H.-J.

    A variant of ac impedance spectroscopy is applied to monitor and control electrochemical cells and appliances without need for reference values and knowledge of control points in advance. Electrolyzers, fuels cells, energy stores, sensors and electrochemical reactors are steered to an optimum operating state by continuous evaluation of capacitance and the derivatives thereof. Dry and humid electrode-electrolyte interfaces are distinguished with the aid of the low-frequency impedance. The problem is solved in order to determine electrolyte concentrations unambiguously from electrolyte resistance, although the conductivity of the solution has a maximum and changes nonlinearly with the concentration.

  6. H3K36ac Is an Evolutionary Conserved Plant Histone Modification That Marks Active Genes1[OPEN

    PubMed Central

    Arellano, Minerva Susana Trejo; Shu, Huan; Gruissem, Wilhelm

    2016-01-01

    In eukaryotic cells, histones are subject to a large number of posttranslational modifications whose sequential or combinatorial action affects chromatin structure and genome function. We identified acetylation at Lys-36 in histone H3 (H3K36ac) as a new chromatin modification in plants. The H3K36ac modification is evolutionary conserved in seed plants, including the gymnosperm Norway spruce (Picea abies) and the angiosperms rice (Oryza sativa), tobacco (Nicotiana tabacum), and Arabidopsis (Arabidopsis thaliana). In Arabidopsis, H3K36ac is highly enriched in euchromatin but not in heterochromatin. Genome-wide chromatin immunoprecipitation sequencing experiments revealed that H3K36ac peaks at the 5′ end of genes, mainly on the two nucleosomes immediately distal to the transcription start site, independently of gene length. H3K36ac overlaps with H3K4me3 and the H2A.Z histone variant. The histone acetyl transferase GCN5 and the histone deacetylase HDA19 are required for H3K36ac homeostasis. H3K36ac and H3K36me3 show negative crosstalk, which is mediated by GCN5 and the histone methyl transferase SDG8. Although H3K36ac is associated with gene activity, we did not find a linear relationship between H3K36ac and transcript levels, suggesting that H3K36ac is a binary indicator of transcription. PMID:26764380

  7. AC Impedance Behavior of LaNi3.55Mn0.4Al0.3Co0.6Fe0.15 Hydrogen-Storage Alloy: Effect of Surface Area

    NASA Astrophysics Data System (ADS)

    Tliha, M.; Khaldi, C.; Lamloumi, J.

    2016-04-01

    The decrease of Cobalt content in alloy is very beneficial to reduce the production cost of the alloy, whereas the effect of Co on cycle life of the AB5-type hydrogen-storage alloys is extremely important. Therefore, it is interesting to investigate low-Co and/or Co-free AB5-type alloys in which Co was substituted by other elements. Iron is a key element in the development of low-Co AB5-type alloys. The aim of this work is to systematically investigate the effect of the real surface area on the all kinetic properties of a low-Co LaNi3.55Mn0.4Al0.3Co0.6Fe0.15 alloy under cycling using electrochemical impedance spectroscopy (EIS) technique. All kinetic properties of the electrode, such as exchange density, limiting current density, high-rate charge/discharge ability, cycle life time, electrocatalytic activity, and diffusion rate are related to the real surface area. During the EIS analysis, interestingly, we found that with increasing number of charge/discharge cycles, the metal hydride alloy powders undergo micro-cracking into smaller particles, and thus the real surface area of the alloy increases, which then influences the kinetic properties of the electrode reactions.

  8. Electron transfer at the contact between Al electrode and gold nanoparticles of polymer: Nanoparticle resistive switching devices studied by alternating current impedance spectroscopy

    SciTech Connect

    Ouyang, Jianyong

    2013-12-02

    Electron transfer at the contact between an Al electrode and Au nanoparticles of polymer:nanoparticle devices is studied by ac impedance spectroscopy. The devices have a polystyrene layer embedded with Au nanoparticles capped with conjugated 2-naphthalenethiol sandwiched between Al and MoO{sub 3}/Al electrodes, and they exhibit electrode-sensitive resistive switches. The devices in the pristine or high resistance state have high capacitance. The capacitance decreases after the devices switch to a low resistance state by a voltage scan. The change in the capacitance is attributed to the voltage-induced change on the electronic structure of the contact between the Al electrode and Au nanoparticles.

  9. Electrochemical impedance spectroscopy of metal alloys in the space transportation system launch environment

    NASA Technical Reports Server (NTRS)

    Calle, Luz

    1990-01-01

    AC impedance measurements were performed to investigate the corrosion resistance of 18 alloys under conditions similar to the Space Transportation System (STS) launch environment. The alloys were: (1) zirconium 702; (2) Hastelloy C-22, C-276, C-4, and B-2; (3) Inconel 600 and 825; (4) Ferralium 255; (5) Inco Alloy G-3; (6) 20Cb-3; (7) SS 904L, 304LN, 316L, 317L, and 304L; (8) ES 2205; and (9) Monel 400. AC impedance data were gathered for each alloy at various immersion times in 3.55 percent NaCl-0.1N HCl. Polarization resistance values were obtained for the Nyguist plots at each immersion time using the EQUIVALENT CIRCUIT software package available with the 388 electrochemical impedance software. Hastelloy C-22 showed the highest overall values for polarization resistance while Monel 400 and Inconel 600 had the lowest overall values. There was good general correlation between the corrosion performance of the alloys at the beach corrosion testing site, and the expected rate of corrosion as predicted based on the polarization resistance values obtained. The data indicate that electrochemical impedance spectroscopy can be used to predict the corrosion performance of metal alloys.

  10. An AC impedance study of steel in concrete

    NASA Astrophysics Data System (ADS)

    Lay, P.; Lawrence, P. F.; Wilkins, N. J. M.; Williams, D. E.

    1984-01-01

    Impedance measurements executed between both steel and platinum electrodes embedded in both porous and non-porous concretes were used to explore the physical characteristics of the system. A simple method is described for measuring high impedances (up to 500 M) in which the unknown impedance is compared with the imput impedance of the measuring instrument, previously calibrated. Impedance measurements on concrete immersed in an electrolyte were used to quantify concrete quality, and the dynamics of wetting, drying and electrolyte exchange were explored: the dynamics of such processes are considered to be among the factors determining the rate of corrosion of steel reinforcement under some conditions, since intermittent wetting is an efficient method for transporting oxygen and salt into the concrete. The existence of cracks along the electrode-concrete interface was inferred. Impedance changes consequent on the initiation of corrosion of steel electrodes were noted, but the changes were small and not clear-cut.

  11. AC Impedance Analysis of Corrosion Fatigue in Naval Aircraft Alloys.

    DTIC Science & Technology

    1987-05-01

    bridge. 2.3 Inhibitor Systems A saturated xylene solution of tri-alkyl (C8-CI0) ammonium complexes of the inhibiting anions borate, molybdate, dichromate ...dedThs the electrochemical rate of oxidation in hite crack tip by a factor of 100. The role of aqueous and organic phase dichrom &’e, nitrite, borate and...UNCLASSIFIED NADC 87183-60 SI 4NITY CLASSIFICATI ON 0 THIS PACE 𔃺.01 M borate reduces the cathodically aerated CF. The molybdate and dichromate inhibitors at

  12. Study of Influence of Electrode Geometry on Impedance Spectroscopy

    SciTech Connect

    Ahmed, Riaz; Reifsnider, Kenneth L

    2011-01-01

    Electrochemical Impedance Spectroscopy (EIS) is a powerful and proven tool for analyzing AC impedance response. A conventional three electrode EIS method was used to perform the investigation in the present study. Saturated potassium chloride solution was used as the electrolyte and three different material rods were used as working electrodes. Different configurations of electrode area were exposed to the electrolyte as an active area to investigate electrode geometry effects. Counter to working electrode distance was also altered while keeping the working electrode effective area constant to explore the AC response dependence on the variation of ion travel distance. Some controlled experiments were done to validate the experimental setup and to provide a control condition for comparison with experimental results. A frequency range of 100 mHz to 1 MHz was used for all experiments. In our analysis, we have found a noteworthy influence of electrode geometry on AC impedance response. For all electrodes, impedance decreases with the increase of effective area of the electrolyte. High frequency impedance is not as dependent on geometry as low frequency response. The observed phase shift angle drops in the high frequency region with increased working electrode area, whereas at low frequency the reverse is true. Resistance and capacitive reactance both decrease with an increase of area, but resistance response is more pronounce than reactance. For lower frequencies, small changes in working area produce very distinctive EIS variations. Electrode material as well as geometry was systematically varied in the present study. From these and other studies, we hope to develop a fundamental foundation for understanding specific changes in local geometry in fuel cell (and other) electrodes as a method of designing local morphology for specific performance.

  13. Domain III of the Bacillus thuringiensis delta-endotoxin Cry1Ac is involved in binding to Manduca sexta brush border membranes and to its purified aminopeptidase N.

    PubMed

    de Maagd, R A; Bakker, P L; Masson, L; Adang, M J; Sangadala, S; Stiekema, W; Bosch, D

    1999-01-01

    Three types of binding assays were used to study the binding of Bacillus thuringiensis delta-endotoxin Cry1Ac to brush border membrane vesicle (BBMV) membranes and a purified putative receptor of the target insect Manduca sexta. Using hybrid proteins consisting of Cry1Ac and the related Cry1C protein, it was shown that domain III of Cry1Ac is involved in specificity of binding as observed by all three techniques. In ligand blotting experiments using SDS-PAGE-separated BBMV proteins as well as the purified putative receptor aminopeptidase N (APN), the presence of domain III of Cry1Ac in a hybrid with Cry1C was necessary and sufficient for specific binding to APN. Using the surface plasmon resonance (SPR) technique with immobilized APN, it was shown that the presence of domain III of Cry1Ac in a hybrid is sufficient for binding to one of the two previously identified Cry1Ac binding sites, whereas the second site requires the full Cry1Ac toxin for binding. In addition, the role of domain III in the very specific inhibition of Cry1Ac binding by the amino sugar N-acetylgalactosamine (GalNac) was determined. Both in ligand blotting and in surface plasmon resonance experiments, as well as in binding assays using intact BBMVs, it was shown that the presence of domain III of Cry1Ac in a toxin molecule is sufficient for the inhibition of binding by GalNAc. These and other results strongly suggest that domain III of delta-endotoxins play a role in insect specificity through their involvement in specific binding to insect gut epithelial receptors.

  14. Interactions of the baicalin and baicalein with bilayer lipid membranes investigated by cyclic voltammetry and UV-Vis spectroscopy.

    PubMed

    Zhang, Ying; Wang, Xuejing; Wang, Lei; Yu, Miao; Han, Xiaojun

    2014-02-01

    The baicalin and baicalein are the major flavonoids found in Radix Scutellariae, an essential herb in traditional Chinese medicine for thousands of years. The interactions of the baicalin and baicalein with lipid bilayer membranes were studied using cyclic voltammetry and UV-Vis spectroscopy. The thickness d of supported bilayer lipid membranes was calculated as d=4.59(±0.36) nm using AC impedance spectroscopy. The baicalein interacted with egg PC bilayer membranes in a dose-dependent manner. The responses of K3Fe(CN)6 on lipid bilayer membrane modified Pt electrode linearly increased in a concentration range of baicalein from 6.25μM to 25μM with a detection limit of 0.1μM and current-concentration sensitivity of 0.11(±0.01) μA/μM, and then reached a plateau from 25μM to 50μM. However the baicalin showed much weaker interactions with egg PC bilayer membranes. UV-Vis spectroscopy also confirmed that the baicalein could interact with egg PC membranes noticeably, but the interaction of baicalin with membranes was hard to be detected. The results provide useful information on understanding the mechanism of action of Radix Scutellariae in vivo.

  15. Frequency-dependent impedance spectroscopy on the 0.925(Bi0.5Na0.40K0.10)TiO3-0.075(Ba0.70Sr0.30)TiO3 ceramic

    NASA Astrophysics Data System (ADS)

    Ullah, Amir; Rahman, Muneeb-ur; Iqbal, Muhammad Javid; Ahn, Chang Won; Kim, Ill Won; Ullah, Aman

    2016-06-01

    The electrical properties of the 0.925(Bi0.5(Na0.40K0.10)TiO3-0.075(Ba0.70Sr0.30)TiO3 (0.925BNKT-0.075BST) ceramic were investigated by using AC impedance spectroscopy over a wide range of frequencies (10 -2 ~ 105 Hz). The X-ray diffraction patterns confirmed the formation of a single-phase compound. A single semicircular arc in the impedance spectrum indicates that the main contribution of the bulk resistance ( R b ) were due to grain effects, with Rb decreasing with increasing temperature. The conductivity of the ceramics increased with increasing temperature, and the activation energy resulting from the DC conductivity was 0.86 eV. The ceramic displayed a typical negative temperature coefficient of resistance (NTCR) behavior, like that of a semiconductor.

  16. Electrical transport properties of Mn-Ni-Zn ferrite using complex impedance spectroscopy

    NASA Astrophysics Data System (ADS)

    Azizar Rahman, M.; Hossain, A. K. M. Akther

    2014-02-01

    Polycrystalline Mn0.45Ni0.05Zn0.50Fe2O4 was prepared by a standard solid state reaction technique. We report the electrical properties of this ferrite using ac impedance spectroscopy as a function of frequency (20 Hz-10 MHz) at different temperatures (50-350 °C). X-ray diffraction patterns reveal the formation of cubic spinel structure. Complex impedance analysis has been used to separate the grain and grain boundary resistance of this ferrite. The variation of grain and grain boundary conductivities with temperature confirms semiconducting behavior. The dielectric permittivity shows dielectric dispersion at lower frequency and reveals that it has almost the same value on the high-frequency side. The non-coincidence of peaks corresponding to modulus and impedance indicates deviation from Debye-type relaxation. A similar value of activation energy is obtained from impedance and modulus spectra, indicating that charge carriers overcome the same energy barrier during relaxation. Electron hopping is responsible for ac conduction in this ferrite. The electron hopping shifts toward higher frequency with increasing temperature, below which the conductivity is frequency independent. The frequency-independent ac conductivity has been observed at and above 300 °C in the frequency range 20 Hz-1 MHz. This frequency-independent ac conductivity is due to the long-range movement of the mobile charge carriers.

  17. Failure of thin organic films by a combination of shearography and electrochemical impedance spectroscopy: the new concept of resistivity

    NASA Astrophysics Data System (ADS)

    Habib, Khaled

    2012-04-01

    A critical (steady state) value of the resistivity of different organic coatings was determined by a combination of optical shearography and electrochemical impedance spectroscopy (EIS). The behavior of organic coatings, i.e., ACE premiumgray enamel, white enamel, beige enamel (spray coatings), a yellow acrylic lacquer, and a gold nail polish on a metallic alloy, i.e., a carbon steel, was investigated over a temperature range of 20-60 °C. The value of the resistivity of coatings was determined by correlating the in-plan displacement of the coating (by shearography over a temperature range of 20- 60 °C) and the value of the alternating current (A.C) impedance of the coating by EIS in 3% NaCl solution. The integrity of the coatings with respect to time was assessed by comparison the measured value of resistivity to the critical (steady state) or asymptotic value of resistivity. In other words, by shearography, measurement of coating properties could be performed independent of parameters such as UV exposure, humidity, presence of chemical species, and other parameters which may normally interfere with conventional methods of the assessing of the integrity of coatings. Therefore, one may measure the resistivity of coatings, regardless of the history of the coating, in order to assess the integrity of coatings. Also, the obtained shearography data were found to be in a reasonable trend with the data of electrochemical impedance spectroscopy (EIS) in 3%NaCl solution.

  18. AC-impedance measurements during thermal runaway process in several lithium/polymer batteries

    NASA Astrophysics Data System (ADS)

    Uchida, I.; Ishikawa, H.; Mohamedi, M.; Umeda, M.

    In this work, we present a set of thermal characterization experiments of charged prismatic polymer lithium-ion battery (PLB) comparatively with those of a lithium-ion battery (LIB). These cells at different state of charge (SOC) were tested inside an accelerated rate calorimeter (ARC) to determine the onset-of-thermal runaway (OTR) temperatures. In addition, the thermally activated components of these cells were followed by monitoring the impedance (at 1 kHz) and the open-circuit voltage (OCV) as a function of temperature. An increase in the impedance was observed at around 133 °C corresponding to the polyethylene separator shutdown. Above 140 °C, the OCV dropped to zero indicating an internal short-circuit due the separator meltdown suggesting that the pinholes created in the separator at meltdown are large enough to create an internal short-circuit.

  19. Quarkonium spectroscopy

    SciTech Connect

    Scharre, D.L.

    1981-06-01

    Recent experimental investigations of heavy quark-antiquark bound state systems are reviewed. Results from SPEAR on charmonium spectroscopy and from DORIS and CESR on bottomonium spectroscopy are presented. The current status of the search for top is also discussed.

  20. Chiroptical spectroscopy

    NASA Astrophysics Data System (ADS)

    Gunde, Kevin Edward

    1997-09-01

    The research presented here is of chiroptical spectroscopy. A new type of non-linear chiroptical spectroscopy, two-photon circular dichroism, is developed experimentally and theoretically. A theoretical formalism is developed to describe another new chiroptical spectroscopy, second-harmonic generation circular dichroism. An established type of chiroptical spectroscopy, time-resolved chiroptical luminescence, is applied to two new sets of subject systems. Journal articles related to these topics, as well as other research to which the author has contributed, are reproduced and included as appendices.

  1. Electrical transport properties of CoMn0.2-xGaxFe1.8O4 ferrites using complex impedance spectroscopy

    NASA Astrophysics Data System (ADS)

    Tsay, Chien-Yie; Lin, Yi-Hsiang; Wang, Yao-Ming; Chang, Horng-Yi; Lei, Chien-Ming; Jen, Shien-Uang

    2016-05-01

    In this study, we report the influence of Ga content on the microstructural, magnetic, and AC impedance properties of Co-based ferrites with compositions of CoMn0.2-xGaxFe1.8O4 (x=0, 0.1, and 0.2) prepared by the solid-state reaction method. Experimental results showed that the as-prepared Co-based ferrites had a single-phase spinel structure; the Curie temperature of Co-based ferrites decreased with increasing Ga content. All ferrite samples exhibited a typical hysteresis behavior with good values of saturation magnetization at room temperature. The electrical properties of Co-based ferrites were investigated using complex impedance spectroscopy analysis in the frequency range of 100 kHz-50 MHz at temperatures of 150 to 250 oC. The impedance analysis revealed that the magnitudes of the real part (Z') and the imaginary part (Z") of complex impedance decreased with increasing temperature. Only one semicircle was observed in each complex impedance plane plot, which revealed that the contribution to conductivity was from the grain boundaries. It was found that the relaxation time for the grain boundary (τgb) also decreased with increasing temperature. The values of resistance for the grain boundary (Rgb) significantly increased with increasing Ga content, which indicated that the incorporation of Ga into Co-based ferrites enhanced the electrical resistivity.

  2. Raman Spectroscopy.

    ERIC Educational Resources Information Center

    Gerrard, Donald L.

    1984-01-01

    Reviews literature on Raman spectroscopy from late 1981 to late 1983. Topic areas include: instrumentation and sampling; liquids and solutions; gases and matrix isolation; biological molecules; polymers; high-temperature and high-pressure studies; Raman microscopy; thin films and surfaces; resonance-enhanced and surface-enhanced spectroscopy; and…

  3. Amateur Spectroscopy

    NASA Astrophysics Data System (ADS)

    Gavin, M.; Murdin, P.

    2003-04-01

    Spectroscopy (see ASTRONOMICAL SPECTROSCOPY) has seen a revival of late. Pioneers in the 19th century such as Angelo Secchi and William Huggins observed spectra visually via large refractors under pristine skies. While the eye can comprehend the brilliant solar spectrum and a few brighter stars aided by a telescope, even low spectral dispersion greatly dilutes starlight. Photo-film can marginally ...

  4. Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Gleeson, Helen F.

    Raman spectroscopy has been used as a tool to study liquid crystals for several decades. There are several features that make Raman spectroscopy an important characterisation method. It is bond-specific, so can provide information about the interaction of liquid crystals with colloidal systems and can offer an insight into phase transitions. The polarization dependence of the scattering can be used to determine order parameters in liquid crystal systems. Finally, the relatively high spatial resolution of the technique (∽1 μm) can be used to explore spatiallydependent order in soft matter systems. This chapter describes the most important ways in which Raman spectroscopy can be used to reveal information about liquid crystal systems, illustrated by examples. Both the theoretical background and experimental considerations are described, providing a comprehensive introduction to anybody interested in using the technique to understand liquid crystal systems.

  5. Cometary spectroscopy

    NASA Astrophysics Data System (ADS)

    Biver, N.

    2011-04-01

    Cometary spectroscopy from the ultraviolet to the radio wavelength domain provides us with insights on the composition of the gases that are released by the cometary nuclei. While infrared to millimeter spectroscopy give access to the parent molecules that are released directly from the nucleus, visible spectroscopy enables observation of daughter species. Those "radicals" observable in the visible domain have more complex spectroscopic band-like structures and are mainly CN, C2, C3, NH2. Their spectroscopic signatures are easily accessible to amateur astronomers class equipment. Provided that carefully calibrated data are acquired, some simple calculation can readily be done to convert the line intensities into comet molecular outgassing rates and thus provide interesting physical data on comets. In addition to broadband dust measurements, the interested amateur can produce valuable scientific data on comets that will always be welcome from the professional community and certainly useful as the monitoring of comets activity is always essential.

  6. Modern Spectroscopy

    ERIC Educational Resources Information Center

    Barrow, Gordon M.

    1970-01-01

    Presents the basic ideas of modern spectroscopy. Both the angular momenta and wave-nature approaches to the determination of energy level patterns for atomic and molecular systems are discussed. The interpretation of spectra, based on atomic and molecular models, is considered. (LC)

  7. Grain Spectroscopy

    NASA Technical Reports Server (NTRS)

    Allamandola, L. J.

    1992-01-01

    Our fundamental knowledge of interstellar grain composition has grown substantially during the past two decades thanks to significant advances in two areas: astronomical infrared spectroscopy and laboratory astrophysics. The opening of the mid-infrared, the spectral range from 4000-400 cm(sup -1) (2.5-25 microns), to spectroscopic study has been critical to this progress because spectroscopy in this region reveals more about a materials molecular composition and structure than any other physical property. Infrared spectra which are diagnostic of interstellar grain composition fall into two categories: absorption spectra of the dense and diffuse interstellar media, and emission spectra from UV-Vis rich dusty regions. The former will be presented in some detail, with the latter only very briefly mentioned. This paper summarized what we have learned from these spectra and presents 'doorway' references into the literature. Detailed reviews of many aspects of interstellar dust are given.

  8. Kinetics of electrochemically controlled surface reactions on bulk and thin film metals studied with Fourier transform impedance spectroscopy and surface plasmon resonance techniques

    NASA Astrophysics Data System (ADS)

    Assiongbon, Kankoe A.

    2005-07-01

    In the work presented in this thesis, the surface sensitive electrochemical techniques of cyclic voltametry (CV), potential step (PS) and Fourier transform impedance spectroscopy (FT-EIS), as well as the optical technique of surface plasmon resonance (SPR), were used to probe a wide variety of surface processes at various metal/liquid interface. Three polycrystalline metals (Au, Ta and Cu) and a Cr-coated gold film were used for these studies in different aqueous environments. A combination of CV with FT-EIS and PS was used to investigate electronic and structural proprieties of a modified bulk electrode of Au. This experimental system involved under potential deposition (UPD) of Bi3+ on Au in a supporting aqueous electrolyte containing ClO-4 . UPD range of Bi3+ was determined, and adsorption kinetics of Bi3+ in the presence of coadsorbing anion, ClO-4 were quantified. Potentiodynamic growth of oxide films of Ta in the following electrolytes NaNO3, NaNO3 + 5wt% H2O2, NaOH and NaOH + 5wt% H2O2 had been investigated. The oxide films were grown in the range -0.1 → +0.4V (high electric field) at a scan rate of 10 mV/s. Time resolved A.C. impedance spectroscopy measurements in the frequency range (0.1--20 KHz) were performed to characterize the surface reactions of oxide formation. The results are interpreted in terms of charge conductivity O2- through the oxide film, and disintegration of H2O2 into OH-. In a high pH medium (pH 12), dissociation of H2O2 was catalytically enhanced. This led to destabilization of the electrogenerated tantalum oxide surface film in the form of a soluble hexatantalate species. In contrast with the electrolytes, NaNO3, NaNO3 + 5wt% H2O2, NaOH, where only the oxide growth was observed, the A.C. impedance spectroscopy measurements in NaOH + 5wt% H 2O2 showed competition between oxide formation and its removal. These results are relevant for chemical slurry design in chemical mechanical polishing (CMP) of Ta. Further investigations were

  9. Laser Spectroscopy

    NASA Astrophysics Data System (ADS)

    Katori, H.; Yoneda, H.; Nakagawa, K.; Shimizu, F.

    2010-02-01

    Anderson localization of matter-waves in a controlled disorder: a quantum simulator? / A. Aspect ... [et al.] -- Squeezing and entanglement in a Bose-Einstein condensate / C. Gross ... [et al.] -- New physics in dipolar Bose-Einstein condensates / Y. Kawaguchi, H. Saito, and M. Ueda -- Observation of vacuum fluctuations in a spinor Bose-Einstein condensate / C. Klempt ... [et al.] -- Negative-index media for matter waves / F. Perales ... [et al.] -- Entanglement of two individual atoms using the Rydberg blockade / A. Browaeys ... [et al.] -- Array of mesoscopic ensembles on a magnetic atom chip / A. F. Tauschinsky ... [et al.] -- Stability of the proton-to-electron mass ratio tested with molecules using an optical link to primary clock / A. Amy-Klein ... [et al.] -- Metastable helium: lifetime measurements using cold atoms as a test of QED / K. G. H. Baldwin ... [et al.] -- Optical lattice clocks with single occupancy bosons and spin-polarized fermions toward 10[symbol] accuracy / M. Takamoto ... [et al.] -- Frequency measurements of Al[symbol] and Hg[symbol] optical standards / W. M. Itano ... [et al.] -- Switching of light with light using cold atoms inside a hollow optical fiber / M. Bajcsy ... [et al.] -- Room-temperature atomic ensembles for quantum memory and magnetometry / K. Jensen ... [et al.] -- Components for multi-photon non-classical state preparation and measurement / G. Puentes ... [et al.] -- Quantum field state measurement and reconstruction in a cavity by quantum nondemolition photon counting / M. Brune ... [et al.] -- XUV frequency comb spectroscopy / C. Gohle ... [et al.] -- Ultrahigh-repetition-rate pulse train with absolute-phase control produced by an adiabatic raman process / M. Katsuragawa ... [et al.] -- Strongly correlated bosons and fermions in optical lattices / S. Will ... [et al.] -- Bragg spectroscopy of ultracold bose gases in optical lattices / L. Fallani ... [et al.] -- Synthetic quantum many-body systems / C. Guerlin ... [et al

  10. Raman spectroscopy

    SciTech Connect

    Gerrard, D.L.; Bowley, H.J.

    1988-06-15

    The period of this review is from late 1985 to late 1987. During this time over 6000 papers have been published in the scientific literature dealing with many applications of Raman spectroscopy and extending its use to new areas of study. This article covers only those papers that are relevant to the analytical chemist and this necessitates a highly selective approach. There are some areas that have been the subject of many papers with relatively few being of analytical interest. In such cases the reader is referred to appropriate reviews which are detailed in this section.

  11. Laser Spectroscopy

    NASA Astrophysics Data System (ADS)

    Hollberg, Leo; Bergquist, James Charles; Kasevich, Mark A.

    2008-04-01

    Degenerate gases. Probing vortex pair sizes in the Berezinskii-Kosterlitz-Thouless regime on a two-dimensional lattice of Bose-Einstein condensates / V. Schweikhard ... [et al.]. Interacting Bose-Einstein condensates in random potentials / P. Bouyer ... [et al.]. Towards quantum magnetism with ultracold atoms in optical lattices / I. Bloch -- Precision measurement and fundamental physics. T-violation and the search for a permanent electric dipole moment of the mercury atom / E. N. Fortson -- Quantum information and control I. Quantum information processing and ramsey spectroscopy with trapped ions / C. F. Roos ... [et al.]. Quantum non-demolition counting of photons in a cavity / S. Haroche ... [et al.] -- Ultra-fast control and spectroscopy. Frequency-Comb- assisted mid-infrared spectroscopy / P. de Natale ... [et al.] -- Precision measurement and applications. Precision gravity tests by atom interferometry / G. M. Tino ... [et al.] -- Novel spectroscopic applications. On a variation of the proton-electron mass ratio / W. Ubachs ... [et al.] -- Quantum information and control II. Quantum interface between light and atomic ensembles / H. Krauter ... [et al.] -- Degenerate Fermi gases. An atomic Fermi gas near a P-wave Feshbach resonance / D. S. Jin, J. P. Gaebler and J. T. Stewart. Bragg scattering of correlated atoms from a degenerate Fermi gas / R. J. Ballagh, K. J. Challis and C. W. Gardiner -- Spectroscopy and control of atoms and molecules. Stark and Zeeman deceleration of neutral atoms and molecules / S. D. Hogan ... [et al.]. Generation of coherent, broadband and tunable soft x-ray continuum at the leading edge of the driver laser pulse / A. Jullien ... [et al.]. Controlling neural atoms and photons with optical conveyor belts and ultrathin optical fibers / D. Meschede. W. Alt and A. Rauschenbeutel -- Spectroscopy on the small scale. Wide-field cars-microscopy / C. Heinrich ... [et al.]. Atom nano-optics and nano-lithography / V. I. Balykin ... [et al

  12. Amateur spectroscopy

    NASA Astrophysics Data System (ADS)

    Gavin, M. V.

    1998-06-01

    (The 1997 Presidential Address to the British Astronomical Association.) Auguste Comte is remembered for an unfortunate remark. In 1825 he said the chemical composition of stars would never be revealed. Within a decade or so the heart of the atom was being explored in remote stars through the science of spectroscopy. In simplistic terms one can regard the atom as a miniature solar system, but with the novel option that electrons (representing planets) having the ability to 'jump' from one orbit to another. In 'falling' to a lower orbit a photon of light of precise wavelength is released to travel outwards. When the electron 'jumps' to a higher orbit a photon of light is absorbed. This is taking place on a vast scale which we observe as lines in the spectrum - their position and prominence relates to the particular atomic element, temperature and pressure within the stellar atmosphere. It is beyond the scope of this Address to discuss the various processes that affect spectra, or to provide a mathematical explanation which can be found elsewhere. In any case the lack of a deep understanding does not preclude enjoyable or useful observations. Methods and results from amateurs conducting such observations are discussed in this paper.

  13. MHD Spectroscopy

    SciTech Connect

    Heeter, R F; Fasoli, A; Testa, D; Sharapov, S; Berk, H L; Breizman, B; Gondhalekar, A; Mantsinen, M

    2004-03-23

    Experiments are conducted on the JET tokamak to assess the diagnostic potential of MHD active and passive spectroscopy, for the plasma bulk and its suprathermal components, using Alfv{acute e}n Eigenmodes (AEs) excited by external antennas and by energetic particles. The measurements of AE frequencies and mode numbers give information on the bulk plasma. Improved equilibrium reconstruction, in particular in terms of radial profiles of density and safety factor, is possible from the comparison between the antenna driven spectrum and that calculated theoretically. Details of the time evolution of the non-monotonic safety factor profile in advanced scenarios can be reconstructed from the frequency of ICRH-driven energetic particle modes. The plasma effective mass can be inferred from the resonant frequency of externally driven AEs in discharges with similar equilibrium profiles. The stability thresholds and the nonlinear development of the instabilities can give clues on energy and spatial distribution of the fast particle population. The presence of unstable AEs provides lower limits in the energy of ICRH generated fast ion tails. Fast ion pressure gradients and their evolution can be inferred from the stability of AEs at different plasma radial positions. Finally, the details of the AE spectrum in the nonlinear stage can be used to obtain information about the fast particle velocity space diffusion.

  14. SIMP spectroscopy

    NASA Astrophysics Data System (ADS)

    Hochberg, Yonit; Kuflik, Eric; Murayama, Hitoshi

    2016-05-01

    We study the interactions between strongly interacting massive particle dark matter and the Standard Model via a massive vector boson that is kinetically mixed with the hypercharge gauge boson. The relic abundance is set by 3 → 2 self-interactions of the dark matter, while the interactions with the vector mediator enable kinetic equilibrium between the dark and visible sectors. We show that a wide range of parameters is phenomenologically viable and can be probed in various ways. Astrophysical and cosmological constraints are evaded due to the p-wave nature of dark matter annihilation into visible particles, while direct detection methods using electron recoils can be sensitive to parts of the parameter space. In addition, we propose performing spectroscopy of the strongly coupled dark sector at e + e - colliders, where the energy of a mono-photon can track the resonance structure of the dark sector. Alternatively, some resonances may decay back into Standard Model leptons or jets, realizing `hidden valley' phenomenology at the LHC and ILC in a concrete fashion.

  15. Chiroptical Spectroscopy

    NASA Astrophysics Data System (ADS)

    Gurst, Jerome E.

    1995-09-01

    A brief review of the literature, and Chemical and Engineering News in particular, reveals that the determination and use of optical activity is of increasing importance in today's commercial and research laboratories. The classical technique is to measure [alpha]D using a manual or recording polarimeter to provide a single value, the specific rotation at 589 nm. A spectropolarimeter can be used to determine optical activity through the UV-Visible spectrum (Optical Rotatory Dispersion [ORD]). At wavelengths far removed from electronic absorption bands, optical activity arises from circular birefringence, or the difference in the refractive index for left- and right-circularly polarized light; i.e., nL - nR does not equal zero for chiral materials. If the optical activity is measured through an absorption band, complex behavior is observed (a Cotton Effect curve). At an absorption band, chiral materials exhibit circular dichroism (CD), or a difference in the absorption of left- and right-circularly polarized light; epsilon L minus epsilon R does not equal zero. If the spectropolarimeter is set for the measurement of CD spectra, one observes what appears to be a UV-Vis spectrum except that some absorption bands are positive while others may be negative. Just as enantiomers have specific rotations that are equal and opposite at 589 nm (sodium D line), rotations are equal and opposite at all wavelengths, and CD measurements are equal and opposite at all wavelengths. Figure 1 shows the ORD curves for the enantiomeric carvones while Figure 2 contains the CD curves. The enantiomer of carvone that has the positive [alpha]D is obtained from caraway seeds and is known to have the S-configuration while the R-enantiomer is found in spearmint oil. Figure 1. ORD of S-(+)- and R-(-)-carvones Figure 2. CD of S-(+)- and R-(-)-carvones While little can be done to correlate stereochemistry with [alpha]D values, chiroptical spectroscopy (ORD and/or CD) often can be used to assign

  16. Heterodyne laser spectroscopy system

    DOEpatents

    Wyeth, Richard W.; Paisner, Jeffrey A.; Story, Thomas

    1989-01-01

    A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency and the like, and provides spectral analysis of a laser beam.

  17. Heterodyne laser spectroscopy system

    DOEpatents

    Wyeth, Richard W.; Paisner, Jeffrey A.; Story, Thomas

    1990-01-01

    A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency, and provides spectral analysis of a laser beam.

  18. BATSE spectroscopy analysis system

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.; Bansal, Sandhia; Basu, Anju; Brisco, Phil; Cline, Thomas L.; Friend, Elliott; Laubenthal, Nancy; Panduranga, E. S.; Parkar, Nuru; Rust, Brad

    1992-01-01

    The Burst and Transient Source Experiment (BATSE) Spectroscopy Analysis System (BSAS) is the software system which is the primary tool for the analysis of spectral data from BATSE. As such, Guest Investigators and the community as a whole need to know its basic properties and characteristics. Described here are the characteristics of the BATSE spectroscopy detectors and the BSAS.

  19. Laser Spectroscopy of Plasmas.

    DTIC Science & Technology

    1987-03-15

    AD-F161 00? LASER SPECTROSCOPY OF PLASMASMU CALIFORNIA NIY 1/1 BEKEEY J N DAILY 15 MAR 6? AFOSit-TR-6?-9?44 AFOSi-OS-0E? UNL SIFIF Z F//G2/9 M 22.5...TITLE (Inluded Secuity Clusifeation) 61102F 2308 I A3 Laser Spectroscopy of Plasmas ____________ % 12. PERSONAL AUTHOR(hI John W. Daily 13.. TYPE OF...Con Eanue on everse if neceuary and idenety by bioc* numInboen During the past year, work was initiated to develop novel advanced laser spectroscopy

  20. Charmonium spectroscopy, 1987

    SciTech Connect

    Cahn, R.N.

    1987-07-30

    The state of charmonium spectroscopy is reviewed. All analyses proceed from a spin-dependent, non-relativistic Schroedinger equation. Many of the possible branching ratios for charm like states are investigated. 17 refs.

  1. Beam-foil spectroscopy

    SciTech Connect

    Berry, H.G.; Hass, M.

    1982-01-01

    A brief survey of some applications of beam-foil spectroscopy is presented. Among the topics covered are lifetime and magnetic moment measurements, nuclear alignment, and polarized light production. (AIP)

  2. Spectroscopy - so what?

    NASA Astrophysics Data System (ADS)

    Stanley, Matthew

    2010-07-01

    The development of astronomical spectroscopy allowed amazing achievements in investigating the composition and motion of celestial bodies. But even beyond specific measurements and results, the fruitfulness and practice of spectroscopy had important ramifications on a more abstract level. This paper will discuss ways in which spectroscopy inspired or boosted new theories of the atom, life, and the Universe; redrew the boundaries among scientific disciplines; demonstrated the unity of terrestrial and celestial physical laws; changed what counted as scientific knowledge; and even revealed divine mysteries. Scientists and science writers from the first half-century of astronomical spectroscopy will be discussed, including James Clerk Maxwell, William Crookes, John Tyndall, Agnes Clerke, William Huggins and Norman Lockyer.

  3. Spectroscopy - so what?

    NASA Astrophysics Data System (ADS)

    Stanley, Matthew

    2010-01-01

    The development of astronomical spectroscopy allowed amazing achievements in investigating the composition and motion of celestial bodies. But even beyond specific measurements and results, the fruitfulness and practice of spectroscopy had important ramifications on a more abstract level. This paper will discuss ways in which spectroscopy inspired or boosted new theories of the atom, life, and the universe; redrew the boundaries among scientific disciplines; demonstrated the unity of terrestrial and celestial physical laws; changed what counted as scientific knowledge; and even revealed divine mysteries. Scientists and science writers from the first half-century of astronomical spectroscopy will be discussed, including James Clerk Maxwell, William Thomson (Lord Kelvin), John Tyndall, Agnes Clerke, William Huggins, and Norman Lockyer.

  4. EDITORIAL: Nano Meets Spectroscopy Nano Meets Spectroscopy

    NASA Astrophysics Data System (ADS)

    Birch, David J. S.

    2012-08-01

    The multidisciplinary two-day Nano Meets Spectroscopy (NMS) event was held at the National Physical Laboratory (NPL), Teddington, UK, in September 2011. The event was planned from the outset to be at the interface of several areas—in particular, spectroscopy and nanoscience, and to bring together topics and people with different approaches to achieving common goals in biomolecular science. Hence the meeting cut across traditional boundaries and brought together researchers using diverse techniques, particularly fluorescence and Raman spectroscopy. Despite engaging common problems, these techniques are frequently seen as mutually exclusive with the two communities rarely interacting at conferences. The meeting was widely seen to have lived up to its billing in good measure. It attracted the maximum capacity of ~120 participants, including 22 distinguished speakers (9 from outside the UK), over 50 posters and a vibrant corporate exhibition comprising 10 leading instrument companies and IOP Publishing. The organizers were Professor David Birch (Chair), Dr Karen Faulds and Professor Duncan Graham of the University of Strathclyde, Professor Cait MacPhee of the University of Edinburgh and Dr Alex Knight of NPL. The event was sponsored by the European Science Foundation, the Institute of Physics, the Royal Society of Chemistry, NPL and the Scottish Universities Physics Alliance. The full programme and abstracts are available at http://sensor.phys.strath.ac.uk/nms/program.php. The programme was quite ambitious in terms of the breadth and depth of scope. The interdisciplinary and synergistic concept of 'X meets Y' played well, cross-fertilization between different fields often being a source of inspiration and progress. Fluorescence and Raman spectroscopy provided the core, but the meeting had little repetition and also attracted contributions on more specialist techniques such as CARS, super-resolution, single molecule and chiral methods. In terms of application the

  5. Nuclear Magnetic Resonance Spectroscopy

    DTIC Science & Technology

    1992-04-23

    and find new applications. A SENO 3 maturi ig undz:uanding of spin physics has allowed the de- 11 velopment of sophisticated techniques for assigning...structure of a fullerene Dist i S poial i9 derivative was determined. PAR" SENO3 I NMR spectroscopy continues to be invaluable as a routine 1i technique ...and SEN30 1s nucleic acids in solutions. The coverage of imaging and 7 spatially localized spectroscopy emphasizes technique de- 12 velopment and

  6. Spectroscopy of divertor plasmas

    SciTech Connect

    Isler, R.C.

    1995-12-31

    The requirements for divertor spectroscopy are treated with respect to instrumentation and observations on present machines. Emphasis is placed on quantitative measurements.of impurity concentrations from the interpretation of spectral line intensities. The possible influence of non-Maxwellian electron distributions on spectral line excitation in the divertor is discussed. Finally the use of spectroscopy for determining plasma temperature, density, and flows is examined.

  7. Spectroscopy of D Mesons

    SciTech Connect

    Bianco, Stefano

    2006-02-11

    The scenario of heavy quark meson spectroscopy underwent recently a major revolution, after the observation of BABAR and CLEO, confirmed by BELLE, of DsJ L=1 excited states, and by further evidences by SELEX. These experimental results have cast doubts on the incarnations of the ideas of Heavy Quark Effective Theory in heavy quark spectroscopy. I shall review the status of experimental data, discuss implications and sketch an outlook.

  8. Electronic Spectroscopy & Dynamics

    SciTech Connect

    Mark Maroncelli, Nancy Ryan Gray

    2010-06-08

    The Gordon Research Conference (GRC) on Electronic Spectroscopy and Dynamics was held at Colby College, Waterville, NH from 07/19/2009 thru 07/24/2009. The Conference was well-attended with participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. The GRC on Electronic Spectroscopy & Dynamics showcases some of the most recent experimental and theoretical developments in electronic spectroscopy that probes the structure and dynamics of isolated molecules, molecules embedded in clusters and condensed phases, and bulk materials. Electronic spectroscopy is an important tool in many fields of research, and this GRC brings together experts having diverse backgrounds in physics, chemistry, biophysics, and materials science, making the meeting an excellent opportunity for the interdisciplinary exchange of ideas and techniques. Topics covered in this GRC include high-resolution spectroscopy, biological molecules in the gas phase, electronic structure theory for excited states, multi-chromophore and single-molecule spectroscopies, and excited state dynamics in chemical and biological systems.

  9. Effect of antimony on the semiconducting properties of the anodic plumbous oxide film formed in sulfuric acid solution I. Studies with alternating-current (a.c.) impedance

    NASA Astrophysics Data System (ADS)

    He, Zhuo-Li; Pu, Cong; Zhou, Wei-Fang

    The semiconducting properties of the anodic plumbous oxide films formed on lead and leadantimony alloys in 4.5 M H 2SO 4 (20 °C) at 0.9 V (versus Hg/Hg 2SO 4) for 2 h have been studied using the a.c. method. From the Mott-Schottky plots, the films are demonstrated to be n-type semiconductors. The flat-band potentials of the films on Pb, Pb—1at.%Sb, Pb—3at.%Sb and Pb—9at.%Sb are -0.95, -1.0, -0.69 and -0.70 V (versus Hg/Hg 2SO 4), respectively; while the corresponding donor densities are 0.82×10 16, 1.2×10 17, 5.5×10 17 and 6.3×10 17 cm -3. The shift of the flat-band potential to more positive values with increase in the antimony content is probably due to the occlusion of a Sb 2O 3 phase in the film. The effect of antimony on the donor density and the lattice-defect density of the n-type semiconductor oxide both conform to the Hauffe Rules.

  10. Microstructure, AC impedance and DC electrical conductivity characteristics of NiFe2-xGdxO4 (x = 0, 0.05 and 0.075)

    NASA Astrophysics Data System (ADS)

    Kamala Bharathi, K.; Markandeyulu, G.; Ramana, C. V.

    2012-03-01

    The structure and electrical characteristics of Gd doped Ni ferrite materials, namely NiFe1.95Gd0.05O4 and NiFe1.925Gd0.075O4, are reported to demonstrate their improved electrical properties compared to that of pure NiFe2O4. NiFe1.95Gd0.05O4 and NiFe1.925Gd0.075O4 compounds crystallize in the cubic inverse spinel phase with a very small amount of GdFeO3 additional phase while pure NiFe2O4 crystallize in inverse spinel phase without any impurity phase. The back scattered electron imaging analysis indicate the primary and secondary formation in NiFe1.95Gd0.05O4 and NiFe1.925Gd0.075O4 compounds. Atomic force microscopy measurements indicate that the bulk grains are ˜2-5 micron size while the grain boundaries are thin compared to bulk grains. Impedance spectroscopic analysis at different temperature indicates the different relaxation mechanisms and their variation with temperature, bulk grain and grain-boundary contributions to the electrical conductivity (Rg) and capacitance (Cg) of these materials. The conductivity in pure NiFeO4 is found to be predominantly due to intrinsic bulk contribution (Rg=213 kΩ and Cg=4.5 x 10-8 F). In the case of NiFe1.95Gd0.05O4 and NiFe1.925Gd0.075O4 compounds, grain and grain-boundary contributions to the conductivity are clearly observed. The DC conductivity values (at 300 K) of NiFe2O4, NiFe1.95Gd0.05O4 and NiFe1.925Gd0.075O4 compounds are found to be 1.06 x 10-7 Ω-1 cm-1, 5.73 x 10-8 Ω-1 cm-1 and 1.28 x 10-8 Ω-1 cm-1 respectively.

  11. Structural and complex AC impedance spectroscopic studies of A 2CoNbO 6 (A = Sr, Ba) ordered double perovskites

    NASA Astrophysics Data System (ADS)

    Bashir, J.; Shaheen, R.

    2011-05-01

    Powder X-ray diffraction has been employed to study the crystal structures of Sr 2CoNbO 6 ( SCNO) and Ba 2CoNbO 6 ( BCNO) double perovskites. Rietveld fit to the X-ray diffraction data showed that Ba 2CoNbO 6 perovskites was monoclinic with space group P2 1/ n whereas Sr 2CoNbO 6 was found to be tetragonal with space group I4/ m. Like other cobalt based perovskites, both materials exhibit high values of dielectric constant at room temperature and low frequencies. Room temperature impedance and modulus spectra, measured over the 1 Hz to 10 MHz, reveal two relaxation processes with different relaxation times which were attributed to the grain and grain boundaries.

  12. Holographic tissue dynamics spectroscopy

    NASA Astrophysics Data System (ADS)

    Nolte, David D.; An, Ran; Turek, John; Jeong, Kwan

    2011-08-01

    Tissue dynamics spectroscopy uses digital holography as a coherence gate to extract depth-resolved quasi-elastic dynamic light scattering from inside multicellular tumor spheroids. The temporal speckle contrast provides endogenous dynamical images of proliferating and hypoxic or necrotic tissues. Fluctuation spectroscopy similar to diffusing wave spectroscopy is performed on the dynamic speckle to generate tissue-response spectrograms that track time-resolved changes in intracellular motility in response to environmental perturbations. The spectrograms consist of several frequency bands that range from 0.005 to 5 Hz. The fluctuation spectral density and temporal autocorrelations show the signature of constrained anomalous diffusion, but with large fluctuation amplitudes caused by active processes far from equilibrium. Differences in the tissue-response spectrograms between the proliferating outer shell and the hypoxic inner core differentiate normal from starved conditions. The differential spectrograms provide an initial library of tissue-response signatures to environmental conditions of temperature, osmolarity, pH, and serum growth factors.

  13. Holographic tissue dynamics spectroscopy.

    PubMed

    Nolte, David D; An, Ran; Turek, John; Jeong, Kwan

    2011-08-01

    Tissue dynamics spectroscopy uses digital holography as a coherence gate to extract depth-resolved quasi-elastic dynamic light scattering from inside multicellular tumor spheroids. The temporal speckle contrast provides endogenous dynamical images of proliferating and hypoxic or necrotic tissues. Fluctuation spectroscopy similar to diffusing wave spectroscopy is performed on the dynamic speckle to generate tissue-response spectrograms that track time-resolved changes in intracellular motility in response to environmental perturbations. The spectrograms consist of several frequency bands that range from 0.005 to 5 Hz. The fluctuation spectral density and temporal autocorrelations show the signature of constrained anomalous diffusion, but with large fluctuation amplitudes caused by active processes far from equilibrium. Differences in the tissue-response spectrograms between the proliferating outer shell and the hypoxic inner core differentiate normal from starved conditions. The differential spectrograms provide an initial library of tissue-response signatures to environmental conditions of temperature, osmolarity, pH, and serum growth factors.

  14. Spectroscopy of francium

    SciTech Connect

    Simsarian, J. E.; Grossman, J. S.; Orozco, L. A.; Pearson, M.; Sprouse, G. D.; Zhao, W. Z.

    1999-01-15

    Francium is the least studied of the alkali atoms because it has no stable isotopes. We have performed precision spectroscopy on cold Fr atoms in a magneto optical trap. We have determined the location of the first two excited states of the S series by two-photon spectroscopy. We have measured the lifetimes of the 7p levels with a precision better than 0.5%. Our measurements test the many-body perturbation theory ab initio calculations of the dipole matrix element to very high accuracy in this relativistic alkali.

  15. Practical Amateur Spectroscopy

    NASA Astrophysics Data System (ADS)

    Tonkin, Stephen F.

    Because today's amateur astronomical telescopes are both powerful and affordable, spectroscopy - once the province of professionals - is becoming more and more popular. Various spectroscopes, at prices to suit everyone, are now available "off the shelf". Practical Amateur Spectroscopy contains everything an amateur needs to grasp the basic principles, to begin observing, and to understand just what the spectra show. Contributions by leading practical amateurs from America and Europe cover a very wide range of amateur equipment and techniques. One even describes how an audio CD can be used to show solar emission and absorption lines!

  16. Advanced Spectroscopy Technique for Biomedicine

    NASA Astrophysics Data System (ADS)

    Zhao, Jianhua; Zeng, Haishan

    This chapter presents an overview of the applications of optical spectroscopy in biomedicine. We focus on the optical design aspects of advanced biomedical spectroscopy systems, Raman spectroscopy system in particular. Detailed components and system integration are provided. As examples, two real-time in vivo Raman spectroscopy systems, one for skin cancer detection and the other for endoscopic lung cancer detection, and an in vivo confocal Raman spectroscopy system for skin assessment are presented. The applications of Raman spectroscopy in cancer diagnosis of the skin, lung, colon, oral cavity, gastrointestinal tract, breast, and cervix are summarized.

  17. Mössbauer Spectroscopy

    NASA Astrophysics Data System (ADS)

    Dickson, Dominic P. E.; Berry, Frank J.

    1986-12-01

    Preface; 1. Principles of Mössbauer spectroscopy Dominic P. E. Dickson and Frank J. Berry; 2. Mössbauer spectroscopy and the chemical bond R. V. Parish; 3. Mössbauer spectroscopy as a structural probe Gary J. Long; 4. Mössbauer spectroscopy of magnetic solids M. F. Thomas and C. E. Johnson; 5. Time-dependent effects and relaxation in Mössbauer spectroscopy S. Dattagupta; 6. The dynamics of nuclei studied by Mössbauer spectroscopy E. R. Bauminger and I. Nowik; References; Index.

  18. Spectroscopy with Supersonic Jets.

    ERIC Educational Resources Information Center

    Skinner, Anne R.; Chandler, Dean W.

    1980-01-01

    Discusses a new technique that enables spectroscopists to study gas phase molecules at temperatures below 1 K, without traditional cryogenic apparatus. This technique uses supersonic jets as samples for gas molecular spectroscopy. Highlighted are points in the theory of supersonic flow which are important for applications in molecular…

  19. FTIR Rotational Spectroscopy.

    ERIC Educational Resources Information Center

    Woods, Ron; Henderson, Giles

    1987-01-01

    Presented are representative examples of the spectra and the analyses for a linear molecule (HC1), a symmetric top molecule (NH3), and an asymmetric top (H2O). Any combination of these projects could be incorporated in a physical chemistry or molecular spectroscopy laboratory. (RH)

  20. Broadband Rotational Spectroscopy

    NASA Astrophysics Data System (ADS)

    Pate, Brooks

    2014-06-01

    The past decade has seen several major technology advances in electronics operating at microwave frequencies making it possible to develop a new generation of spectrometers for molecular rotational spectroscopy. High-speed digital electronics, both arbitrary waveform generators and digitizers, continue on a Moore's Law-like development cycle that started around 1993 with device bandwidth doubling about every 36 months. These enabling technologies were the key to designing chirped-pulse Fourier transform microwave (CP-FTMW) spectrometers which offer significant sensitivity enhancements for broadband spectrum acquisition in molecular rotational spectroscopy. A special feature of the chirped-pulse spectrometer design is that it is easily implemented at low frequency (below 8 GHz) where Balle-Flygare type spectrometers with Fabry-Perot cavity designs become technologically challenging due to the mirror size requirements. The capabilities of CP-FTMW spectrometers for studies of molecular structure will be illustrated by the collaborative research effort we have been a part of to determine the structures of water clusters - a project which has identified clusters up to the pentadecamer. A second technology trend that impacts molecular rotational spectroscopy is the development of high power, solid state sources in the mm-wave/THz regions. Results from the field of mm-wave chirped-pulse Fourier transform spectroscopy will be described with an emphasis on new problems in chemical dynamics and analytical chemistry that these methods can tackle. The third (and potentially most important) technological trend is the reduction of microwave components to chip level using monolithic microwave integrated circuits (MMIC) - a technology driven by an enormous mass market in communications. Some recent advances in rotational spectrometer designs that incorporate low-cost components will be highlighted. The challenge to the high-resolution spectroscopy community - as posed by Frank De

  1. High resolution hypernuclear spectroscopy

    SciTech Connect

    F. Garibaldi

    2005-02-01

    Hypernuclear spectroscopy provides fundamental information for understanding the effective ?-Nucleon interaction. Jefferson Laboratory experiment E94-107 was designed to perform high resolution hypernuclear spectroscopy by electroproduction of strangeness in four 1p-shell nuclei: 12C, 9Be, 16O, and 7Li. The first part of the experiment on 12C and 9Be has been performed in January and April-May 2004 in Hall A at Jefferson Lab. Significant modifications were made to the standard Hall A apparatus for this challenging experiment: two septum magnets and a RICH detector have been added to get reasonable counting rates and excellent particle identification, as required for the experiment. A description of the apparatus and the preliminary analysis results are presented here.

  2. Raman spectroscopy in astrobiology.

    PubMed

    Jorge Villar, Susana E; Edwards, Howell G M

    2006-01-01

    Raman spectroscopy is proposed as a valuable analytical technique for planetary exploration because it is sensitive to organic and inorganic compounds and able to unambiguously identify key spectral markers in a mixture of biological and geological components; furthermore, sample manipulation is not required and any size of sample can be studied without chemical or mechanical pretreatment. NASA and ESA are considering the adoption of miniaturised Raman spectrometers for inclusion in suites of analytical instrumentation to be placed on robotic landers on Mars in the near future to search for extinct or extant life signals. In this paper we review the advantages and limitations of Raman spectroscopy for the analysis of complex specimens with relevance to the detection of bio- and geomarkers in extremophilic organisms which are considered to be terrestrial analogues of possible extraterrestial life that could have developed on planetary surfaces.

  3. Precision Muonium Spectroscopy

    NASA Astrophysics Data System (ADS)

    Jungmann, Klaus P.

    2016-09-01

    The muonium atom is the purely leptonic bound state of a positive muon and an electron. It has a lifetime of 2.2 µs. The absence of any known internal structure provides for precision experiments to test fundamental physics theories and to determine accurate values of fundamental constants. In particular ground state hyperfine structure transitions can be measured by microwave spectroscopy to deliver the muon magnetic moment. The frequency of the 1s-2s transition in the hydrogen-like atom can be determined with laser spectroscopy to obtain the muon mass. With such measurements fundamental physical interactions, in particular quantum electrodynamics, can also be tested at highest precision. The results are important input parameters for experiments on the muon magnetic anomaly. The simplicity of the atom enables further precise experiments, such as a search for muonium-antimuonium conversion for testing charged lepton number conservation and searches for possible antigravity of muons and dark matter.

  4. BATSE spectroscopy detector calibration

    NASA Technical Reports Server (NTRS)

    Band, D.; Ford, L.; Matteson, J.; Lestrade, J. P.; Teegarden, B.; Schaefer, B.; Cline, T.; Briggs, M.; Paciesas, W.; Pendleton, G.

    1992-01-01

    We describe the channel-to-energy calibration of the Spectroscopy Detectors of the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (GRO). These detectors consist of NaI(TI) crystals viewed by photomultiplier tubes whose output in turn is measured by a pulse height analyzer. The calibration of these detectors has been complicated by frequent gain changes and by nonlinearities specific to the BATSE detectors. Nonlinearities in the light output from the NaI crystal and in the pulse height analyzer are shifted relative to each other by changes in the gain of the photomultiplier tube. We present the analytical model which is the basis of our calibration methodology, and outline how the empirical coefficients in this approach were determined. We also describe the complications peculiar to the Spectroscopy Detectors, and how our understanding of the detectors' operation led us to a solution to these problems.

  5. Inelastic electron tunneling spectroscopy

    NASA Technical Reports Server (NTRS)

    Khanna, S. K.; Lambe, J.

    1983-01-01

    Inelastic electron tunneling spectroscopy is a useful technique for the study of vibrational modes of molecules adsorbed on the surface of oxide layers in a metal-insulator-metal tunnel junction. The technique involves studying the effects of adsorbed molecules on the tunneling spectrum of such junctions. The data give useful information about the structure, bonding, and orientation of adsorbed molecules. One of the major advantages of inelastic electron tunneling spectroscopy is its sensitivity. It is capable of detecting on the order of 10 to the 10th molecules (a fraction of a monolayer) on a 1 sq mm junction. It has been successfully used in studies of catalysis, biology, trace impurity detection, and electronic excitations. Because of its high sensitivity, this technique shows great promise in the area of solid-state electronic chemical sensing.

  6. Plasma Spectroscopy in ISTTOK

    NASA Astrophysics Data System (ADS)

    Figueiredo, J.; Gomes, R. B.; Pereira, T.; Fernandes, H.; Sharakovski, A.

    2008-04-01

    Plasma spectroscopy is a well established technique for impurities study in fusion plasmas. A brief description of the several spectroscopic systems which have been in operation at ISTTOK is given. In ISTTOK a passive spectroscopy diagnostic system is being used to perform spectral and spatial characterization in the 300-850 nm wavelength range. The system used to perform that work consist essentially of a cooled CCD camera coupled to a half a meter imaging spectrograph with collection optics based on a multi-fiber set to allow for enhanced spatial resolution. Experimental data is shown underlining typical plasma fusion spectral lines and specific ISTTOK characteristics. A web based data access tool is presented that allows the spectral plasma survey in specific wavelength ranges. The information provided by this survey has been used to select suitable transmission filters for a diagnostic, currently under development, to measure Zeff parameter for ISTTOK plasmas. A description of this diagnostic is also presented.

  7. Chiral rotational spectroscopy

    NASA Astrophysics Data System (ADS)

    Cameron, Robert P.; Götte, Jörg B.; Barnett, Stephen M.

    2016-09-01

    We introduce chiral rotational spectroscopy, a technique that enables the determination of the orientated optical activity pseudotensor components BX X, BY Y, and BZ Z of chiral molecules, in a manner that reveals the enantiomeric constitution of a sample and provides an incisive signal even for a racemate. Chiral rotational spectroscopy could find particular use in the analysis of molecules that are chiral solely by virtue of their isotopic constitution and molecules with multiple chiral centers. A basic design for a chiral rotational spectrometer together with a model of its functionality is given. Our proposed technique offers the more familiar polarizability components αX X, αY Y, and αZ Z as by-products, which could see it find use even for achiral molecules.

  8. Charm Baryon Spectroscopy

    NASA Astrophysics Data System (ADS)

    Chistov, R.

    2016-02-01

    B-factories Belle and BaBar during its operation made not only measurements connected with B-meson decays but also numerous observation and measurements in charm physics. In particular, their results on charm baryon decays and spectroscopy have enlarged and enriched the current picture of heavy flavour hadrons. In this talk we overview current status of charm baryons and their excited states.

  9. Coherent spectroscopy of semiconductors.

    PubMed

    Cundiff, Steven T

    2008-03-31

    The coherent optical response of semiconductors has been the subject of substantial research over the last couple of decades. The interest has been motivated by unique aspects of the interaction between light and semiconductors that are revealed by coherent techniques. The ability to probe the dynamics of charge carriers has been a significant driver. This paper presents a review of selected results in coherent optical spectroscopy of semiconductors.

  10. Applications in Photoacoustic Spectroscopy.

    DTIC Science & Technology

    1979-08-01

    25 Chopping frequency vs. PA signal ... ..... 30 Concentration vs. PA signal .. ........ .. 35 III Photoacoustic Detection of Thin Films ...1,21, researchers today utilize PA spectroscopy to investigate the optical and thermal properties of solids (3,4] and solutions (5]. Reviews of the basic... optical properties , the thermal properties and the physical dimensions of the 2 sample, the cell, and the coupling gas. Studies to date have been somewhat

  11. Quantum Gravitational Spectroscopy

    SciTech Connect

    Nesvizhevsky, Valery V.; Antoniadis, Ignatios; Baessler, Stefan; Pignol, Guillaume

    2015-01-01

    We report that one of the main goals for improving the accuracy of quantum gravitational spectroscopy with neutrons is searches for extra short-range fundamental forces. We discuss also any progress in all competing nonneutron methods as well as constraints at other characteristic distances. Among major methodical developments related to the phenomenon of gravitational quantum states are the detailed theoretical analysis and the planning experiments on observation of gravitational quantum states of antihydrogen atoms.

  12. 2008 Vibrational Spectroscopy

    SciTech Connect

    Philip J. Reid

    2009-09-21

    The conference focuses on using vibrational spectroscopy to probe structure and dynamics of molecules in gases, liquids, and interfaces. The goal is to bring together a collection of researchers who share common interests and who will gain from discussing work at the forefront of several connected areas. The intent is to emphasize the insights and understanding that studies of vibrations provide about a variety of systems.

  13. Dielectric spectroscopy of polyaniline

    SciTech Connect

    Calleja, R.D.; Matveeva, E.M.

    1993-12-31

    Polyaniline films (PANI) are being considered as attractive new galvanic sources, electrochromic displays, chemical sensors, etc. So far much work has been done to study their optical, electrochemical and electrical properties. However, there are still doubts about the basic electric conductivity mechanisms of PANI. The aim of this paper is to study the influence of water molecules and acid anions on the properties of PANI films by dielectric spectroscopy.

  14. Theory and spectroscopy

    NASA Astrophysics Data System (ADS)

    Stanton, John F.

    2015-05-01

    The interaction between quantum-mechanical theory and spectroscopy is one of the most fertile interfaces in all of science, and has a richly storied history. Of course it was spectroscopy that provided essentially all of the evidence that not all was well (or, perhaps more correctly put, complete) with the world of 19th century classical physics. From the discoveries of the dark lines in the solar spectrum by Fraunhöfer in 1814 to the curiously simple geometric formula discovered seventy years later that described the hydrogen atom spectrum, spectroscopy and spectroscopists have consistently identified the areas of atomic and molecular science that are most in need of hard thinking by theoreticians. The rest of the story, of course, is well-known: spectroscopic results were used to understand and motivate the theory of radioactivity and ultimately the quantum theory, first in its immature form that was roughly contemporaneous with the first World War, and then the Heisenberg-Schrödinger-Dirac version that has withstood the test of time. Since the basic principles of quantum mechanics ware first understood, the subject has been successfully used to understand the patterns found in spectra, and how these relate to molecular structure, symmetry, energy levels, and dynamics. But further understanding required to attain these intellectual achievements has often come only as a result of vital and productive interactions between theoreticians and spectroscopists (of course, many people have strengths in both areas). And indeed, a field that might be termed "theoretical spectroscopy" was cultivated and is now an important part of modern molecular science.

  15. Colloquium: Graphene spectroscopy

    NASA Astrophysics Data System (ADS)

    Basov, D. N.; Fogler, M. M.; Lanzara, A.; Wang, Feng; Zhang, Yuanbo

    2014-07-01

    Spectroscopic studies of electronic phenomena in graphene are reviewed. A variety of methods and techniques are surveyed, from quasiparticle spectroscopies (tunneling, photoemission) to methods probing density and current response (infrared optics, Raman) to scanning probe nanoscopy and ultrafast pump-probe experiments. Vast complimentary information derived from these investigations is shown to highlight unusual properties of Dirac quasiparticles and many-body interaction effects in the physics of graphene.

  16. Layman friendly spectroscopy

    NASA Astrophysics Data System (ADS)

    Sentic, Stipo; Sessions, Sharon

    Affordable consumer grade spectroscopes (e.g. SCiO, Qualcomm Tricorder XPRIZE) are becoming more available to the general public. We introduce the concepts of spectroscopy to the public and K12 students and motivate them to delve deeper into spectroscopy in a dramatic participatory presentation and play. We use diffraction gratings, lasers, and light sources of different spectral properties to provide a direct experience of spectroscopy techniques. Finally, we invite the audience to build their own spectroscope--utilizing the APS SpectraSnapp cell phone application--and study light sources surrounding them in everyday life. We recontextualize the stigma that science is hard (e.g. ``Math, Science Popular Until Students Realize They're Hard,'' The Wall Street Journal) by presenting the material in such a way that it demonstrates the scientific method, and aiming to make failure an impersonal scientific tool--rather than a measure of one's ability, which is often a reason for shying away from science. We will present lessons we have learned in doing our outreach to audiences of different ages. This work is funded by the APS Outreach Grant ``Captain, we have matter matters!'' We thank New Mexico Tech Physics Department and Physics Club for help and technical equipment.

  17. High Resolution Laboratory Spectroscopy

    NASA Astrophysics Data System (ADS)

    Brünken, S.; Schlemmer, S.

    2016-05-01

    In this short review we will highlight some of the recent advancements in the field of high-resolution laboratory spectroscopy that meet the needs dictated by the advent of highly sensitive and broadband telescopes like ALMA and SOFIA. Among these is the development of broadband techniques for the study of complex organic molecules, like fast scanning conventional absorption spectroscopy based on multiplier chains, chirped pulse instrumentation, or the use of synchrotron facilities. Of similar importance is the extension of the accessible frequency range to THz frequencies, where many light hydrides have their ground state rotational transitions. Another key experimental challenge is the production of sufficiently high number densities of refractory and transient species in the laboratory, where discharges have proven to be efficient sources that can also be coupled to molecular jets. For ionic molecular species sensitive action spectroscopic schemes have recently been developed to overcome some of the limitations of conventional absorption spectroscopy. Throughout this review examples demonstrating the strong interplay between laboratory and observational studies will be given.

  18. Single nanowire extinction spectroscopy.

    PubMed

    Giblin, Jay; Vietmeyer, Felix; McDonald, Matthew P; Kuno, Masaru

    2011-08-10

    Here we show the first direct extinction spectra of single one-dimensional (1D) semiconductor nanostructures obtained at room temperature utilizing a spatial modulation approach. (1) For these materials, ensemble averaging in conventional extinction spectroscopy has limited our understanding of the interplay between carrier confinement and their electrostatic interactions. (2-4) By probing individual CdSe nanowires (NWs), we have identified and assigned size-dependent exciton transitions occurring across the visible. In turn, we have revealed the existence of room temperature 1D excitons in the narrowest NWs.

  19. Spectroscopy of Stellar Coronae

    NASA Astrophysics Data System (ADS)

    Laming, J. Martin

    I review the important spectroscopic results that have come from observations of stellar coronae, mainly by EUVE and ASCA, but also from HST. The plasma parameters that can be determined from such spectra include the electron density and temperature distributions, and relative element abundances. With high resolution spectra dynamical information can be obtained. Such parameters can then be used to put constraints on models of the heating and structure of stellar coronae. Throughout, I try to emphasise the similarities and differences between stellar coronal spectroscopy and that of the solar corona.

  20. Resonance Raman spectroscopy.

    PubMed

    Robert, Bruno

    2009-01-01

    Resonance Raman spectroscopy may yield precise information on the conformation of, and on the interactions assumed by, the chromophores involved in the first steps of the photosynthetic process, whether isolated in solvents, embedded in soluble or membrane proteins, or, as shown recently, in vivo. By making use of this technique, it is possible, for instance, to relate the electronic properties of these molecules to their structure and/or the physical properties of their environment, or to determine subtle changes of their conformation associated with regulatory processes. After a short introduction to the physical principles that govern resonance Raman spectroscopy, the information content of resonance Raman spectra of chlorophyll and carotenoid molecules is described in this review, together with the experiments which helped in determining which structural parameter each Raman band is sensitive to. A selection of applications of this technique is then presented, in order to give a fair and precise idea of which type of information can be obtained from its use in the field of photosynthesis.

  1. Nanowire Electron Scattering Spectroscopy

    NASA Technical Reports Server (NTRS)

    Hunt, Brian; Bronikowsky, Michael; Wong, Eric; VonAllmen, Paul; Oyafuso, Fablano

    2009-01-01

    Nanowire electron scattering spectroscopy (NESS) has been proposed as the basis of a class of ultra-small, ultralow-power sensors that could be used to detect and identify chemical compounds present in extremely small quantities. State-of-the-art nanowire chemical sensors have already been demonstrated to be capable of detecting a variety of compounds in femtomolar quantities. However, to date, chemically specific sensing of molecules using these sensors has required the use of chemically functionalized nanowires with receptors tailored to individual molecules of interest. While potentially effective, this functionalization requires labor-intensive treatment of many nanowires to sense a broad spectrum of molecules. In contrast, NESS would eliminate the need for chemical functionalization of nanowires and would enable the use of the same sensor to detect and identify multiple compounds. NESS is analogous to Raman spectroscopy, the main difference being that in NESS, one would utilize inelastic scattering of electrons instead of photons to determine molecular vibrational energy levels. More specifically, in NESS, one would exploit inelastic scattering of electrons by low-lying vibrational quantum states of molecules attached to a nanowire or nanotube.

  2. Vibronic Spectroscopy of Phenylvinylnitrile

    NASA Astrophysics Data System (ADS)

    Mehta, Deepali N.; Navotnaya, Polina; Parobek, Alex; Clayton, Rachel; Vara, Vanesa Vaquero; Zwier, Timothy S.

    2012-06-01

    This talk will present results of a gas phase, jet-cooled vibronic spectroscopy study of phenylvinylnitrile (C_6H_5-CH=CH-C≡N, PVN). This molecule is seen as a potential photochemical precursor to nitrogen heteroaromatics, and therefore is particularly relevant to Titan's atmosphere, where nitriles exist in significant abundance. As a first step towards such photochemical studies, a fluorescence excitation spectrum of PVN spanning the range 33,500-35,840 cm- 1 (298.5-279.0 nm) has been recorded, and dispersed fluorescence spectra that uncover and characterize the vibronic activity have been acquired. The S_0-S_1 origin is a prominent band located at 33,826 cm- 1, and the excitation spectrum is characterized by significant vibronic activity leading to spectral congestion. Hole-burning in the region of 33,500-35,840 cm- 1 has also been completed, and the excitation spectrum can be assigned solely to (E)-PVN. As PVN is the nitrogen-containing counterpart to phenylvinylacetylene (PVA), a comparison of the vibronic spectroscopy between the two molecules will be made.

  3. Photothermal spectroscopy of aerosols

    SciTech Connect

    Campillo, A.J.; Lin, H.B.

    1981-04-01

    In situ aerosol absorption spectroscopy was performed using two novel photothermal detection schemes. The first, based on a photorefractive effect and coherent detection, called phase fluctuation optical heterodyne (PFLOH) spectroscopy, could, depending on the geometry employed, yield particle specific or particle and gas absorption data. Single particles of graphite as small as 1 ..mu..m were detected in the particle specific mode. In another geometrical configuration, the total absorption (both gas and particle) of submicron sized aerosols of ammonium sulfate particles in equilibrium with gaseous ammonia and water vapor were measured at varying CO/sub 2/ laser frequencies. The specific absorption coefficient for the sulfate ion was measured to be 0.5 m/sup 2//g at 1087 cm/sup -1/. The absorption coefficient sensitivity of this scheme was less than or equal to 10/sup -8/ cm/sup -1/. The second scheme is a hybrid visible Mie scattering scheme incorporating photothermal modulation. Particle specific data on ammonium sulfate droplets were obtained. For chemically identical species, the relative absorption spectrum versus laser frequency can be obtained for polydisperse aerosol distributions directly from the data without the need for complex inverse scattering calculations.

  4. Atmospheric trace molecule spectroscopy

    NASA Technical Reports Server (NTRS)

    Farmer, C. B.

    1982-01-01

    The Spacelab investigation entitled Atmospheric Trace Molecule Spectroscopy (ATMOS) is designed to obtain fundamental information related to the chemistry and physics of the Earth's upper atmosphere using the techniques of infrared absorption spectroscopy. There are two principal objectives to be met. The first is the determination, on a global scale, of the compositional structure of the upper atmosphere and its spatial variability. The establishment of this variability represents the first step toward determining the characteristic residence times for the upper atmospheric constituents; the magnitudes of their sources and sinks; and, ultimately, an understanding of their effects on the stability of the stratosphere. The second objective is to provide the high-resolution, calibrated spectral information which is essential for the detailed design of advanced instrumentation for subsequent global monitoring of specific species found to be critical to atmospheric stability. This information will be disseminated in the form of a three dimensional atlas of solar absorption spectra obtained over a range of latitudes, longitudes, and altitudes.

  5. Wave mixing spectroscopy

    SciTech Connect

    Smith, R.W.

    1980-08-01

    Several new aspects of nonlinear or wave mixing spectroscopy were investigated utilizing the polarization properties of the nonlinear output field and the dependence of this field upon the occurrence of multiple resonances in the nonlinear susceptibility. First, it is shown theoretically that polarization-sensitive detection may be used to either eliminate or controllably reduce the nonresonant background in coherent anti-Stokes Raman spectroscopy, allowing weaker Raman resonances to be studied. The features of multi-resonant four-wave mixing are examined in the case of an inhomogeneously broadened medium. It is found that the linewidth of the nonlinear output narrows considerably (approaching the homogeneous width) when the quantum mechanical expressions for the doubly- and triply-resonant susceptibilities are averaged over a Doppler or strain broadened profile. Experimental studies of nonlinear processes in Pr/sup +3/:LaF/sub 3/ verify this linewidth narrowing, but indicate that this strain broadened system cannot be treated with a single broadening parameter as in the case of Doppler broadening in a gas. Several susceptibilities are measured from which are deduced dipole matrix elements and Raman polarizabilities related to the /sup 3/H/sub 4/, /sup 3/H/sub 6/, and /sup 3/P/sub 0/ levels of the praseodymium ions.

  6. Array-based photoacoustic spectroscopy

    DOEpatents

    Autrey, S. Thomas; Posakony, Gerald J.; Chen, Yu

    2005-03-22

    Methods and apparatus for simultaneous or sequential, rapid analysis of multiple samples by photoacoustic spectroscopy are disclosed. A photoacoustic spectroscopy sample array including a body having at least three recesses or affinity masses connected thereto is used in conjunction with a photoacoustic spectroscopy system. At least one acoustic detector is positioned near the recesses or affinity masses for detection of acoustic waves emitted from species of interest within the recesses or affinity masses.

  7. Photoelectron photoion molecular beam spectroscopy

    SciTech Connect

    Trevor, D.J.

    1980-12-01

    The use of supersonic molecular beams in photoionization mass spectroscopy and photoelectron spectroscopy to assist in the understanding of photoexcitation in the vacuum ultraviolet is described. Rotational relaxation and condensation due to supersonic expansion were shown to offer new possibilities for molecular photoionization studies. Molecular beam photoionization mass spectroscopy has been extended above 21 eV photon energy by the use of Stanford Synchrotron Radiation Laboratory (SSRL) facilities. Design considerations are discussed that have advanced the state-of-the-art in high resolution vuv photoelectron spectroscopy. To extend gas-phase studies to 160 eV photon energy, a windowless vuv-xuv beam line design is proposed.

  8. Development of Electro Supercapacitors

    DTIC Science & Technology

    1991-11-01

    The highly hygroscopic nature of these polymers yielding deliquescent films has precluded their use in supercapacitors. Fluorinated analogs of these...polymer was 2.17 x 10-2 Scm- 1, as measured by ac impedance spectroscopy using stainless steel electrodes. However, this 6 film was highiy deliquescent

  9. Resonant ultrasound spectroscopy

    DOEpatents

    Migliori, Albert

    1991-01-01

    A resonant ultrasound spectroscopy method provides a unique characterization of an object for use in distinguishing similar objects having physical differences greater than a predetermined tolerance. A resonant response spectrum is obtained for a reference object by placing excitation and detection transducers at any accessible location on the object. The spectrum is analyzed to determine the number of resonant response peaks in a predetermined frequency interval. The distribution of the resonance frequencies is then characterized in a manner effective to form a unique signature of the object. In one characterization, a small frequency interval is defined and stepped though the spectrum frequency range. Subsequent objects are similarly characterized where the characterizations serve as signatures effective to distinguish objects that differ from the reference object by more than the predetermined tolerance.

  10. Soliton absorption spectroscopy

    PubMed Central

    Kalashnikov, V. L.; Sorokin, E.

    2010-01-01

    We analyze optical soliton propagation in the presence of weak absorption lines with much narrower linewidths as compared to the soliton spectrum width using the novel perturbation analysis technique based on an integral representation in the spectral domain. The stable soliton acquires spectral modulation that follows the associated index of refraction of the absorber. The model can be applied to ordinary soliton propagation and to an absorber inside a passively modelocked laser. In the latter case, a comparison with water vapor absorption in a femtosecond Cr:ZnSe laser yields a very good agreement with experiment. Compared to the conventional absorption measurement in a cell of the same length, the signal is increased by an order of magnitude. The obtained analytical expressions allow further improving of the sensitivity and spectroscopic accuracy making the soliton absorption spectroscopy a promising novel measurement technique. PMID:21151755

  11. Broadband local dielectric spectroscopy

    NASA Astrophysics Data System (ADS)

    Labardi, M.; Lucchesi, M.; Prevosto, D.; Capaccioli, S.

    2016-05-01

    A route to extend the measurement bandwidth of local dielectric spectroscopy up to the MHz range has been devised. The method is based on a slow amplitude modulation at a frequency Ω of the excitation field oscillating at a frequency ω and the coherent detection of the modulated average electric force or force gradient at Ω. The cantilever mechanical response does not affect the measurement if Ω is well below its resonant frequency; therefore, limitations on the excitation field frequency are strongly reduced. Demonstration on a thin poly(vinyl acetate) film is provided, showing its structural relaxation spectrum on the local scale up to 45 °C higher than glass temperature, and nanoscale resolution dielectric relaxation imaging near conductive nanowires embedded in the polymer matrix was obtained up to 5 MHz frequency, with no physical reason to hinder further bandwidth extension.

  12. Femtosecond Stimulated Raman Spectroscopy.

    PubMed

    Dietze, Daniel R; Mathies, Richard A

    2016-05-04

    Femtosecond stimulated Raman spectroscopy (FSRS) is an ultrafast nonlinear optical technique that provides vibrational structural information with high temporal (sub-50 fs) precision and high spectral (10 cm(-1) ) resolution. Since the first full demonstration of its capabilities ≈15 years ago, FSRS has evolved into a mature technique, giving deep insights into chemical and biochemical reaction dynamics that would be inaccessible with any other technique. It is now being routinely applied to virtually all possible photochemical reactions and systems spanning from single molecules in solution to thin films, bulk crystals and macromolecular proteins. This review starts with an historic overview and discusses the theoretical and experimental concepts behind this technology. Emphasis is put on the current state-of-the-art experimental realization and several variations of FSRS that have been developed. The unique capabilities of FSRS are illustrated through a comprehensive presentation of experiments to date followed by prospects.

  13. Computational multiheterodyne spectroscopy

    PubMed Central

    Burghoff, David; Yang, Yang; Hu, Qing

    2016-01-01

    Dual-comb spectroscopy allows for high-resolution spectra to be measured over broad bandwidths, but an essential requirement for coherent integration is the availability of a phase reference. Usually, this means that the combs’ phase and timing errors must be measured and either minimized by stabilization or removed by correction, limiting the technique’s applicability. We demonstrate that it is possible to extract the phase and timing signals of a multiheterodyne spectrum completely computationally, without any extra measurements or optical elements. These techniques are viable even when the relative linewidth exceeds the repetition rate difference and can tremendously simplify any dual-comb system. By reconceptualizing frequency combs in terms of the temporal structure of their phase noise, not their frequency stability, we can greatly expand the scope of multiheterodyne techniques. PMID:27847870

  14. Protected subspace Ramsey spectroscopy

    NASA Astrophysics Data System (ADS)

    Ostermann, L.; Plankensteiner, D.; Ritsch, H.; Genes, C.

    2014-11-01

    We study a modified Ramsey spectroscopy technique employing slowly decaying states for quantum metrology applications using dense ensembles. While closely positioned atoms exhibit super-radiant collective decay and dipole-dipole induced frequency shifts, recent results [L. Ostermann, H. Ritsch, and C. Genes, Phys. Rev. Lett. 111, 123601 (2013), 10.1103/PhysRevLett.111.123601] suggest the possibility to suppress such detrimental effects and achieve an even better scaling of the frequency sensitivity with interrogation time than for noninteracting particles. Here we present an in-depth analysis of this "protected subspace Ramsey technique" using improved analytical modeling and numerical simulations including larger three-dimensional (3D) samples. Surprisingly we find that using subradiant states of N particles to encode the atomic coherence yields a scaling of the optimal sensitivity better than 1 /√{N } . Applied to ultracold atoms in 3D optical lattices we predict a precision beyond the single atom linewidth.

  15. Infrared spectroscopy of aerosols

    NASA Astrophysics Data System (ADS)

    Mentel, Th.; Sebald, H.

    2003-04-01

    In our large Aerosol Chamber at the FZ Jülich we apply HR FTIR absorption spectroscopy for the determination of trace gases. In the FTIR spectra we also observe broad absorptions of several 10 to a few 100 cm-1 widths that arise from species in the condensed aerosol phase: liquid H_2O, NO_3^-, SO_42-, HSO_4^-, or dicarboxylic acids. Moreover, the aerosol droplets caused extinctions over several 1000 cm-1 by IR scattering. This allows for in-situ observation of changes in the condensed aerosol phase e.g. on HNO_3 uptake, like the shift of the sulfate/bisulfate equilibrium or the growth by water condensation. The IR absorptions of the condensed aerosol phase provide useful extra information in process studies, if they can be quantified. Therefore the absorption cross section, respective, the absorption index which is the imaginary part of the complex refractive index is needed. We set up an aerosol flow tube in which IR spectroscopy on a 8 m light path and aerosol size distribution measurements in the range from 20 nm - 10 μm can be performed simultaneously. We measured sulfate aerosols at several relative humidities (dry, metastable, deliquescent). We will demonstrate an iterative procedure based on Mie calculations and Kramers Kronig transformation to retrieve the absorption index from the observed IR spectra and the corresponding size distribution (for dry ammonium sulfate). We will compare resulting absorption indices for aqueous sodium bisulfate aerosols at several relative humidties with thermodynamic model calculations for the Na^+/H^+/HSO_4^-/SO_42-/H_2O system.

  16. Electron spectroscopy analysis

    NASA Technical Reports Server (NTRS)

    Gregory, John C.

    1992-01-01

    The Surface Science Laboratories at the University of Alabama in Huntsville (UAH) are equipped with x-ray photoelectron spectroscopy (XPS or ESCA) and Auger electron spectroscopy (AES) facilities. These techniques provide information from the uppermost atomic layers of a sample, and are thus truly surface sensitive. XPS provides both elemental and chemical state information without restriction on the type of material that can be analyzed. The sample is placed into an ultra high vacuum (UHV) chamber and irradiated with x-rays which cause the ejection of photoelectrons from the sample surface. Since x-rays do not normally cause charging problems or beam damage, XPS is applicable to a wide range of samples including metals, polymers, catalysts, and fibers. AES uses a beam of high energy electrons as a surface probe. Following electronic rearrangements within excited atoms by this probe, Auger electrons characteristic of each element present are emitted from the sample. The main advantage of electron induced AES is that the electron beam can be focused down to a small diameter and localized analysis can be carried out. On the rastering of this beam synchronously with a video display using established scanning electron microscopy techniques, physical images and chemical distribution maps of the surface can be produced. Thus very small features, such as electronic circuit elements or corrosion pits in metals, can be investigated. Facilities are available on both XPS and AES instruments for depth-profiling of materials, using a beam of argon ions to sputter away consecutive layers of material to reveal sub-surface (and even semi-bulk) analyses.

  17. An Introductory Infrared Spectroscopy Experiment.

    ERIC Educational Resources Information Center

    Hess, Kenneth R.; Smith, Wendy D.; Thomsen, Marcus W.; Yoder, Claude H.

    1995-01-01

    Describes a project designed to introduce infrared spectroscopy as a structure-determination technique. Students are introduced to infrared spectroscopy fundamentals then try to determine the identity of an unknown liquid from its infrared spectrum and molecular weight. The project demonstrates that only rarely can the identity of even simple…

  18. The light meson spectroscopy program

    SciTech Connect

    Smith, Elton S.

    2014-06-01

    Recent discoveries of a number of unexpected new charmomium-like meson states at the BaBar and Belle B-factories have demonstrated how little is still known about meson spectroscopy. In this talk we will review recent highlights of the light quark spectroscopy from collider and fixed target experiments.

  19. Industrial applications of Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Grasselli, J. G.; Walder, F.; Petty, C.; Kemeny, G.

    1993-03-01

    In the last two decades, Raman spectroscopy has matured as an important method for the study of molecules and complex molecular systems. This is evident from the number of fine texts and the many review articles which have been published describing theory and applications of Raman spectroscopy over a very broad range of subjects (1-10). Raman spectroscopy is the essential partner to infrared spectroscopy for a complete vibrational analysis of a molecule in structure determinations. From the understanding developed on small molecules, theory was extended to interpret the spectra of larger systems such as polymers, biological molecules, and ordered condensed phases. The contribution of Raman spectroscopy to these areas has been significant. It was the development of commercial lasers in the 1960s which spurred the renewed interest in the Raman technique. But applications were still limited for highly fluorescing or intensely colored systems. In 1986, a breakthrough paper by Hirschfeld and Chase (11) described the use of near-infrared laser excitation and a commercial interferometer-based FT-IR spectrometer to record FT-Raman spectra. Significant advantages included the inherent multiplex, throughput and data processing features of the FT interferometers and the use of a ND:YAG laser (1.064 μm) which dramatically decreased problems with sample fluorescence and decomposition. A deluge of papers describing applications of FT-Raman spectroscopy can be found in the Journal of Raman Spectroscopy, Spectrochimica Acta (special issues 40A ad 47A), and Applied Spectroscopy since then.

  20. Spectroscopy, Understanding the Atom Series.

    ERIC Educational Resources Information Center

    Hellman, Hal

    This booklet is one of the "Understanding the Atom" Series. The science of spectroscopy is presented by a number of topics dealing with (1) the uses of spectroscopy, (2) its origin and background, (3) the basic optical systems of spectroscopes, spectrometers, and spectrophotometers, (4) the characteristics of wave motion, (5) the…

  1. Wavelength-modulated photocapacitance spectroscopy

    NASA Technical Reports Server (NTRS)

    Kamieniecki, E.; Lagowski, J.; Gatos, H. C.

    1980-01-01

    Derivative deep-level spectroscopy was achieved with wavelength-modulated photocapacitance employing MOS structures and Schottky barriers. The energy position and photoionization characteristics of deep levels of melt-grown GaAs and the Cr level in high-resistivity GaAs were determined. The advantages of this method over existing methods for deep-level spectroscopy are discussed.

  2. Infrared heterodyne spectroscopy in astronomy

    NASA Technical Reports Server (NTRS)

    Betz, A.

    1980-01-01

    A heterodyne spectrometer was constructed and applied to problems in infrared astronomical spectroscopy. The instrument offers distinct observational advantages for the detection and analysis of individual spectral lines at Doppler-limited resolution. Observations of carbon dioxide in planetary atmospheres and ammonia in circumstellar environments demonstrate the substantial role that infrared heterodyne techniques will play in the astronomical spectroscopy of the future.

  3. Laser Spectroscopy and Frequency Combs

    NASA Astrophysics Data System (ADS)

    Hänsch, Theodor W.; Picqué, Nathalie

    2013-12-01

    The spectrum of a frequency comb, commonly generated by a mode-locked femtosecond laser consists of several hundred thousand precisely evenly spaced spectral lines. Such laser frequency combs have revolutionized the art measuring the frequency of light, and they provide the long-missing clockwork for optical atomic clocks. The invention of the frequency comb technique has been motivated by precision laser spectroscopy of the simple hydrogen atom. The availability of commercial instruments is facilitating the evolution of new applications far beyond the original purpose. Laser combs are becoming powerful instruments for broadband molecular spectroscopy by dramatically improving the resolution and recording speed of Fourier spectrometers and by creating new opportunities for highly multiplexed nonlinear spectroscopy, such as two-photon spectroscopy or coherent Raman spectroscopy. Other emerging applications of frequency combs range from fundamental research in astronomy, chemistry, or attosecond science to telecommunications and satellite navigation.

  4. Operando fuel cell spectroscopy

    NASA Astrophysics Data System (ADS)

    Kendrick, Ian Michael

    The active state of a catalyst only exists during catalysis (1) provided the motivation for developing operando spectroscopic techniques. A polymer electrolyte membrane fuel cell (PEMFC) was designed to interface with commercially available instruments for acquisition of infrared spectra of the catalytic surface of the membrane electrode assembly (MEA) during normal operation. This technique has provided insight of the complex processes occurring at the electrode surface. Nafion, the solid electrolyte used in most modern-day polymer electrolyte membrane fuel cells (PEMFC), serves many purposes in fuel cell operation. However, there is little known of the interface between Nafion and the electrode surface. Previous studies of complex Stark tuning curves of carbon monoxide on the surface of a platinum electrode were attributed the co-adsorption of bisulfite ions originating from the 0.5M H2SO4 electrolyte used in the study(2). Similar tuning curves obtained on a fuel cell MEA despite the absence of supplemental electrolytes suggest the adsorption of Nafion onto platinum (3). The correlation of spectra obtained using attenuated total reflectance spectroscopy (ATR) and polarization modulated IR reflection-absorption spectroscopy (PM-IRRAS) to a theoretical spectrum generated using density functional theory (DFT) lead to development of a model of Nafion and platinum interaction which identified participation of the SO3- and CF3 groups in Nafion adsorption. The use of ethanol as a fuel stream in proton exchange membrane fuel cells provides a promising alternative to methanol. Relative to methanol, ethanol has a greater energy density, lower toxicity and can be made from the fermentation of biomass(4). Operando IR spectroscopy was used to study the oxidation pathway of ethanol and Stark tuning behavior of carbon monoxide on Pt, Ru, and PtRu electrodes. Potential dependent products such as acetaldehyde, acetic acid and carbon monoxide are identified as well as previously

  5. Project LITE Spectroscopy

    NASA Astrophysics Data System (ADS)

    Weeks, E.; Brecher, K.; Carr, P.; Garik, P.

    2003-12-01

    Spectroscopy is one of the most important tools used by astronomers to disentangle information about the universe. However, it is one of the most challenging subjects in undergraduate astronomy courses. Among the most difficult concepts for students to master are Kirchhoff's laws, blackbody radiation, the Stefan-Boltzmann law, Wien's law, the nature and causes of emission and absorption lines, and the relation of spectra to the underlying astronomical and physical processes producing them. Students often seem baffled by the connection between a spectrum seen visually as a color band and the same spectrum plotted graphically as intensity versus wavelength or frequency. Project LITE (Light Inquiry Through Experiments) is a software, curriculum, and materials development project at Boston University. As part of the project, we are currently developing a suite of spectroscopic tools for astronomy education. We are also assessing their effectiveness in improving conceptual understanding of spectroscopic phenomena by astronomy students at the undergraduate level. The spectroscopy component of Project LITE includes take-home laboratory materials and experiments, which are integrated with web-based software. We have also developed a novel quantitative handheld binocular spectrometer (patent pending). Here we present an overview of the Project LITE homelab kits and curriculum, the Spectrum Explorer, and the Project LITE spectrometer. The homelab experiments and the Spectrum Explorer have been tested with students in a non-science majors introductory astronomy course as well as in a School of Education course for prospective elementary school science teachers. We present preliminary results of pre- and post-instruction surveys of student understanding of various spectral properties of light both from students who used the homelab activities and the Spectrum Explorer and those who did not. The Spectrum Explorer (along with many other applets about both the physical and

  6. Neutron Speed Echo Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ioffe, A.

    Neutron speed echo (NSPE) technique is in a way a generalization of the neutron spin echo (NSE) technique. Similar to NSE spectrometers, the resolution of such NSPE spectrometer is extremely high and is not connected with the monochromatization of the incoming beam. However, in contrast to NSE spectrometers, the operation of proposed spectrometer does not necessarily require a polarized neutron beam. Such decoupling the polarization and the resolution is in clear contrast to NSE technique. Because the resolution of a NSPE spectrometer can be a few orders higher than the resolution of NSE spectrometers, one can achieve the energy resolution of about 10-14 eV by the use of ultra cold neutrons; a fact that can be used in some fundamental physics experiments. Though the scattering on the sample impose limitations on the resolution of a NSPE spectrometer, the use of the proposed technique in a low-resolution mode can be useful in the combination with triple-axis spectrometers and allow for the significant improvement of their energy resolution, however, without the use of polarized neutrons. This fact opens new possibilities for the study of magnetic phenomena in solids, where the NSE method is principally not applicable because of the neutron precession in the sample, especially by combining polarization analysis with high-resolution spectroscopy. The proposed technique also allows for an easy implementation of the principle of the NSE focusing, when the resolution ellipse is aligned along a dispersion curve.

  7. Infrared diode laser spectroscopy

    NASA Astrophysics Data System (ADS)

    Civiš, S.; Cihelka, J.; Matulková, I.

    2010-12-01

    Three types of lasers (double-heterostructure 66 K InAsSb/InAsSbP laser diode, room temperature, multi quantum wells with distributed feedback (MQW with DFB) (GaInAsSb/AlGaAsSb based) diode laser and vertical cavity surface emitting lasers (VCSELs) (GaSb based) have been characterized using Fourier transform emission spectroscopy and compared. The photoacoustic technique was employed to determine the detection limit of formaldehyde (less than 1 ppmV) for the strongest absorption line of the v3 + v5 band in the emission region of the GaInAsSb/AlGaAsSb diode laser. The detection limit (less than 10 ppbV) of formaldehyde was achieved in the 2820 cm-1 spectral range in case of InAsSb/InAsSbP laser (fundamental bands of v1, v5). Laser sensitive detection (laser absorption together with high resolution Fourier transform infrared technique including direct laser linewidth measurement, infrared photoacoustic detection of neutral molecules (methane, form-aldehyde) is discussed. Additionally, very sensitive laser absorption techniques of such velocity modulation are discussed for case of laser application in laboratory research of molecular ions. Such sensitive techniques (originally developed for lasers) contributed very much in identifying laboratory microwave spectra of a series of anions (C6H-, C4H-, C2H-, CN-) and their discovery in the interstellar space (C6H-, C4H-).

  8. Relic Neutrino Absorption Spectroscopy

    SciTech Connect

    Eberle, b

    2004-01-28

    Resonant annihilation of extremely high-energy cosmic neutrinos on big-bang relic anti-neutrinos (and vice versa) into Z-bosons leads to sizable absorption dips in the neutrino flux to be observed at Earth. The high-energy edges of these dips are fixed, via the resonance energies, by the neutrino masses alone. Their depths are determined by the cosmic neutrino background density, by the cosmological parameters determining the expansion rate of the universe, and by the large redshift history of the cosmic neutrino sources. We investigate the possibility of determining the existence of the cosmic neutrino background within the next decade from a measurement of these absorption dips in the neutrino flux. As a by-product, we study the prospects to infer the absolute neutrino mass scale. We find that, with the presently planned neutrino detectors (ANITA, Auger, EUSO, OWL, RICE, and SalSA) operating in the relevant energy regime above 10{sup 21} eV, relic neutrino absorption spectroscopy becomes a realistic possibility. It requires, however, the existence of extremely powerful neutrino sources, which should be opaque to nucleons and high-energy photons to evade present constraints. Furthermore, the neutrino mass spectrum must be quasi-degenerate to optimize the dip, which implies m{sub {nu}} 0.1 eV for the lightest neutrino. With a second generation of neutrino detectors, these demanding requirements can be relaxed considerably.

  9. Broadband transmission EPR spectroscopy.

    PubMed

    Hagen, Wilfred R

    2013-01-01

    EPR spectroscopy employs a resonator operating at a single microwave frequency and phase-sensitive detection using modulation of the magnetic field. The X-band spectrometer is the general standard with a frequency in the 9-10 GHz range. Most (bio)molecular EPR spectra are determined by a combination of the frequency-dependent electronic Zeeman interaction and a number of frequency-independent interactions, notably, electron spin - nuclear spin interactions and electron spin - electron spin interactions, and unambiguous analysis requires data collection at different frequencies. Extant and long-standing practice is to use a different spectrometer for each frequency. We explore the alternative of replacing the narrow-band source plus single-mode resonator with a continuously tunable microwave source plus a non-resonant coaxial transmission cell in an unmodulated external field. Our source is an arbitrary wave digital signal generator producing an amplitude-modulated sinusoidal microwave in combination with a broadband amplifier for 0.8-2.7 GHz. Theory is developed for coaxial transmission with EPR detection as a function of cell dimensions and materials. We explore examples of a doublet system, a high-spin system, and an integer-spin system. Long, straigth, helical, and helico-toroidal cells are developed and tested with dilute aqueous solutions of spin label hydroxy-tempo. A detection limit of circa 5 µM HO-tempo in water at 800 MHz is obtained for the present setup, and possibilities for future improvement are discussed.

  10. Meson spectroscopy at COMPASS

    NASA Astrophysics Data System (ADS)

    Grube, Boris

    2016-11-01

    The goal of the COMPASS experiment at CERN is to study the structure and dynamics of hadrons. The two-stage spectrometer used by the experiment has large acceptance and covers a wide kinematic range for charged as well as neutral particles and can therefore measure a wide range of reactions. The spectroscopy of light mesons is performed with negative (mostly π-) and positive (p, π+) hadron beams with a momentum of 190 GeV/c. The light-meson spectrum is measured in different final states produced in diffractive dissociation reactions with squared four-momentum transfer t to the target between 0.1 and 1.0 (GeV=c)2. The flagship channel is the π-π-π+ final state, for which COMPASS has recorded the currently world's largest data sample. These data not only allow to measure the properties of known resonances with high precision, but also to observe new states. Among these is a new axial-vector signal, the a1(1420), with unusual properties. Novel analysis techniques have been developed to extract also the amplitude of the π-π+ subsystem as a function of 3π mass from the data. The findings are confirmed by the analysis of the π-π0π0 final state.

  11. Why Spectroscopy Went South

    NASA Astrophysics Data System (ADS)

    Mills Boyd, Nora

    2015-01-01

    All but forgotten, the first observatory established for astrophysical research in Chile sits atop Cerro San Cristóbal overlooking downtown Santiago. Now called the Manuel Foster Observatory and cared for by the Pontificia Universidad Católica de Chile, the equipment was originally brought to the country by staff of the Lick Observatory in California at the outset of the 20th century under the auspices of the D. O. Mills Expedition. The present paper explores the initial motivation for the expedition. Partial insight can be gained by situating the establishment of the observatory in the context of the so-called 'sidereal problem'—mapping the structure of the stellar system. However, the motivation for this expedition can be further elucidated by understanding the possibilities afforded by the instruments of the 'new astronomy'. Astronomical spectroscopy opened up new observational prospects that turn of the century astronomers simply exploited opportunistically. Understanding the motivation for the observatory will not only be important background for any comprehensive history of the observatory, but also serves to illuminate the exploratory approach characteristic of American astronomers in the early days of astrophysics.

  12. Solar Neutrino Spectroscopy

    NASA Astrophysics Data System (ADS)

    Feilitzsch, F. v.

    1999-01-01

    Since the pioneering experiment of R. Davis et al., which started neutrino astronomy by measuring the solar neutrinos via the inverse beta decay reaction on 37Cl, all solar neutrino experiments find a considerably lower flux than expected by standard solar models. This finding is generally called the solar neutrino problem. Many attempts have been made to explain this result by altering the solar models, or assuming different nuclear cross sections for fusion processes assumed to be the energy sources in the sun. There have been performed numerous experiments recently to investigate the different possibilities to explain the solar neutrino problem. These experiments covered solar physics with helioseismology, nuclear cross section measurements, and solar neutrino experiments. Up to now no convincing explanation based on "standard" physics was suggested. However, assuming nonstandard neutrino properties, i.e. neutrino masses and mixing as expected in most extensions of the standard theory of elementary particle physics, natural solutions for the solar neutrino problem can be found. It appears that with this newly invented neutrino astronomy fundamental information on astrophysics as well as elementary particle physics are tested uniquely. In this contribution an attempt is made to review the situation of the neutrino astronomy for solar neutrino spectroscopy and discuss the future prospects in this field.

  13. BATSE spectroscopy results

    NASA Technical Reports Server (NTRS)

    Schaefer, Bradley E.; Teegarden, Bonnard J.; Cline, Thomas L.; Fishman, G. J.; Meegan, C. A.; Wilson, R. B.; Paciesas, W. S.; Pendleton, G. N.; Matteson, James L.

    1992-01-01

    We present preliminary analyses of gamma-ray burst spectra from the BATSE Spectroscopy Detectors. Our conclusions are: (1) No spectral lines have yet been detected in BATSE data from any cosmic gamma-ray burst. This is not surprising as the data for few bright bursts is available, and previous experiments saw lines in only a small fraction of the bursts. (2) Burst spectra show emission up to 20 MeV, with four of eight examined bursts having significant spectral breaks from 1 to 2 MeV. These breaks are consistent with opacity effects due to the interaction of photons with a high magnetic field. (3) Various distance independent parameters from burst spectra and time histories have no correlation with parameters related to distance. In other words, bright bursts look the same as faint bursts. This places a strong constraint on two population models of bursts. (4) The detection time of individual photons is not correlated from detector to detector, as predicted by Mitrofanov's pulsed emission model.

  14. Slitless Solar Spectroscopy

    NASA Astrophysics Data System (ADS)

    Kamalabadi, F.; Oktem, F. S.; Davila, J. M.

    2014-12-01

    Spectrometers provide our most detailed diagnostics of the solar coronal plasma, and spectral data is routinely used to measure the temperature, density, and flow velocity of coronal features. However, spectrographs suffer from a limited instantaneous field-of-view (FOV). Imaging instruments can provide a large FOV but offer only very limited spectral resolution. In this work, we present an instrument concept that combines the strengths of these two instrument classes, i.e., a large FOV and high spectral resolution. Our approach is based on computational imaging, which involves distributing the spectral imaging task between a physical and a computational system, and then digitally forming images of interest from multiplexed measurements by means of solving an inverse problem. In particular, a nonscanning spectral imaging technique is developed to enable performing spectroscopy over a two-dimensional instantaneous field-of-view. This technique combines a parametric estimation approach with a slitless spectrometer configuration. The associated inverse problem, which can be viewed as a multiframe image deblurring problem, is formulated in a Bayesian estimation framework and computationally efficient algorithms are designed to solve the resulting nonlinear optimization problems. Furthermore, statistical bounds are obtained to characterize the estimation uncertainties and performance limits, and to explore the optimized system design for specific observing requirements. We illustrate that such an instrument concept will facilitate the investigation of highly dynamic solar phenomena such as flares, CMEs, and transient brightening, with a significant reduction in hardware cost and complexity, but at an accuracy comparable with conventional designs.

  15. Spectroscopy Made Easy: Evolution

    NASA Astrophysics Data System (ADS)

    Piskunov, Nikolai; Valenti, Jeff A.

    2017-01-01

    Context. The Spectroscopy Made Easy (SME) package has become a popular tool for analyzing stellar spectra, often in connection with large surveys or exoplanet research. SME has evolved significantly since it was first described in 1996, but many of the original caveats and potholes still haunt users. The main drivers for this paper are complexity of the modeling task, the large user community, and the massive effort that has gone into SME. Aims: We do not intend to give a comprehensive introduction to stellar atmospheres, but will describe changes to key components of SME: the equation of state, opacities, and radiative transfer. We will describe the analysis and fitting procedure and investigate various error sources that affect inferred parameters. Methods: We review the current status of SME, emphasizing new algorithms and methods. We describe some best practices for using the package, based on lessons learned over two decades of SME usage. We present a new way to assess uncertainties in derived stellar parameters. Results: Improvements made to SME, better line data, and new model atmospheres yield more realistic stellar spectra, but in many cases systematic errors still dominate over measurement uncertainty. Future enhancements are outlined.

  16. Variable angle correlation spectroscopy

    SciTech Connect

    Lee, Young Kyo

    1994-05-01

    In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with 13C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system.

  17. Cars Spectroscopy of Propellant Flames

    DTIC Science & Technology

    1983-11-01

    Bele,:1t )"(vaiaable Copy AD AD-E4OI 102 TECMNICA._ REPORT ;RLCD-TR-83047 CARS SPECTROSCOPY Of PROPELLANT FLAMES L. E. HARRIS DTIC ii IELECTE0 "" NOV...4. TITLE (mid Subtitle) 5. TYPE OF REPORT & PERIOD COVERED CARS SPECTROSCOPY OF PROPELLANT FLAMES Final Ś. PERFORMING ORG. REPORT NUMBER 7. AUTHOR(a...ea•abo. Broadband CARS CARS spectra Spectroscopy Propellant *0AUINIACT (0w o roemtae 401 N uueedswr Mu $000tit? b7 61"k Auhee) Obtaining useful

  18. Precision Spectroscopy of Tellurium

    NASA Astrophysics Data System (ADS)

    Coker, J.; Furneaux, J. E.

    2013-06-01

    Tellurium (Te_2) is widely used as a frequency reference, largely due to the fact that it has an optical transition roughly every 2-3 GHz throughout a large portion of the visible spectrum. Although a standard atlas encompassing over 5200 cm^{-1} already exists [1], Doppler broadening present in that work buries a significant portion of the features [2]. More recent studies of Te_2 exist which do not exhibit Doppler broadening, such as Refs. [3-5], and each covers different parts of the spectrum. This work adds to that knowledge a few hundred transitions in the vicinity of 444 nm, measured with high precision in order to improve measurement of the spectroscopic constants of Te_2's excited states. Using a Fabry Perot cavity in a shock-absorbing, temperature and pressure regulated chamber, locked to a Zeeman stabilized HeNe laser, we measure changes in frequency of our diode laser to ˜1 MHz precision. This diode laser is scanned over 1000 GHz for use in a saturated-absorption spectroscopy cell filled with Te_2 vapor. Details of the cavity and its short and long-term stability are discussed, as well as spectroscopic properties of Te_2. References: J. Cariou, and P. Luc, Atlas du spectre d'absorption de la molecule de tellure, Laboratoire Aime-Cotton (1980). J. Coker et al., J. Opt. Soc. Am. B {28}, 2934 (2011). J. Verges et al., Physica Scripta {25}, 338 (1982). Ph. Courteille et al., Appl. Phys. B {59}, 187 (1994) T.J. Scholl et al., J. Opt. Soc. Am. B {22}, 1128 (2005).

  19. Atomic spectroscopy for primary thermometry

    NASA Astrophysics Data System (ADS)

    Truong, G.-W.; Stuart, D.; Anstie, J. D.; May, E. F.; Stace, T. M.; Luiten, A. N.

    2015-10-01

    Spectroscopy has been a key driver and motivator of new understanding at the heart of physics. Here we describe high-precision measurements of the absorption lineshape of an atomic gas with an aim towards primary thermometry. We describe our progress in pushing this type of spectroscopy to the ultimate limit, in particular in describing experimental work with Rubidium and Cesium, although we also consider the potential for other elements in expanding the precision, accuracy and range of the approach. We describe the important technical and theoretical limits which need to be overcome in order to obtain accurate and precise results—these challenges are not unique to atomic spectroscopy but are likely to afflict all high precision spectroscopy measurements. We obtain a value for {{k}\\text{B}}=1.380 545(98)× {{10}-23} J K-1 where the 71 ppm uncertainty arises with difficulties in defining the Lorentzian component of the lineshape.

  20. Vibronic Spectroscopy of 4-ISOCYANOBENZONITRILE

    NASA Astrophysics Data System (ADS)

    Korn, Joseph A.; Mehta-Hurt, Deepali N.; Zwier, Timothy S.

    2013-06-01

    This talk will discuss the jet-cooled vibronic spectroscopy of 4-isocyanobenzonitrile (4IBN, CN-C_6H_4-CN) via resonant two-photon ionization, laser induced fluorescence, dispersed fluorescence, and UV-UV hole burning methods. Much of the vibronic spectroscopy of the molecule shows strong similarities with the symmetric structural isomers dicyano and di-isocyanobenzene. However, in 4IBN, we have identified a series of weak transitions extending well red of the ππ* origin. UV holeburning spectroscopy has been used to confirm that these transitions arise from the same ground state as the others, pointing to the presence of another electronic state. Based on comparison with other nitrilebenzenes, we postulate that the large dipole moment of 4IBN opens the possibility of a charge transfer (CT) state, much as occurs in para-amino substituted benzonitriles. The rich vibronic spectroscopy of this molecule will be explored using dispersed fluorescence.

  1. Ring resonant cavities for spectroscopy

    DOEpatents

    Zare, R.N.; Martin, J.; Paldus, B.A.; Xie, J.

    1999-06-15

    Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS). 6 figs.

  2. 3D Spectroscopy in Astronomy

    NASA Astrophysics Data System (ADS)

    Mediavilla, Evencio; Arribas, Santiago; Roth, Martin; Cepa-Nogué, Jordi; Sánchez, Francisco

    2011-09-01

    Preface; Acknowledgements; 1. Introductory review and technical approaches Martin M. Roth; 2. Observational procedures and data reduction James E. H. Turner; 3. 3D Spectroscopy instrumentation M. A. Bershady; 4. Analysis of 3D data Pierre Ferruit; 5. Science motivation for IFS and galactic studies F. Eisenhauer; 6. Extragalactic studies and future IFS science Luis Colina; 7. Tutorials: how to handle 3D spectroscopy data Sebastian F. Sánchez, Begona García-Lorenzo and Arlette Pécontal-Rousset.

  3. Ring resonant cavities for spectroscopy

    DOEpatents

    Zare, Richard N.; Martin, Juergen; Paldus, Barbara A.; Xie, Jinchun

    1999-01-01

    Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS).

  4. X-ray astronomical spectroscopy

    NASA Technical Reports Server (NTRS)

    Holt, S. S.

    1980-01-01

    The current status of the X-ray spectroscopy of celestial X-ray sources, ranging from nearby stars to distant quasars, is reviewed. Particular emphasis is placed on the role of such spectroscopy as a useful and unique tool in the elucidation of the physical parameters of the sources. The spectroscopic analysis of degenerate and nondegenerate stellar systems, galactic clusters and active galactic nuclei, and supernova remnants is discussed.

  5. Dual Comb Fourier Transform Spectroscopy

    NASA Astrophysics Data System (ADS)

    Hänsch, T. W.; Picqué, N.

    2010-06-01

    The advent of laser frequency combs a decade ago has already revolutionized optical frequency metrology and precision spectroscopy. Extensions of laser combs from the THz region to the extreme ultraviolet and soft x-ray frequencies are now under exploration. Such laser combs have become enabling tools for a growing tree of applications, from optical atomic clocks to attosecond science. Recently, the millions of precisely controlled laser comb lines that can be produced with a train of ultrashort laser pulses have been harnessed for highly multiplexed molecular spectroscopy. Fourier multi-heterodyne spectroscopy, dual comb spectroscopy, or asynchronous optical sampling spectroscopy with frequency combs are emerging as powerful new spectroscopic tools. Even the first proof-of-principle experiments have demonstrated a very exciting potential for ultra-rapid and ultra-sensitive recording of complex molecular spectra. Compared to conventional Fourier transform spectroscopy, recording times could be shortened from seconds to microseconds, with intriguing prospects for spectroscopy of short lived transient species. Longer recording times allow high resolution spectroscopy of molecules with extreme precision, since the absolute frequency of each laser comb line can be known with the accuracy of an atomic clock. The spectral structure of sharp lines of a laser comb can be very useful even in the recording of broadband spectra without sharp features, as they are e.g. encountered for molecular gases or in the liquid phase. A second frequency comb of different line spacing permits the generation of a comb of radio frequency beat notes, which effectively map the optical spectrum into the radio frequency regime, so that it can be recorded with a single fast photodetector, followed by digital signal analysis. In the time domain, a pulse train of a mode-locked femtosecond laser excites some molecular medium at regular time intervals. A second pulse train of different repetition

  6. Photoacoustic Spectroscopy for Chemical Detection

    DTIC Science & Technology

    2012-09-01

    micropipette onto a single photoresist-coated substrate. The substrate was oriented to allow complete coverage by the glycerol/ water solution. Following...pulse laser-induced photoacoustics," Anal. Chem. 70, 3, 651 ( 1998 ). [10] M. H. Xu and L. H. V. Wang, "Photoacoustic imaging in biomedicine," Rev. Sci...1976). [25] A. C. Tam, "Photoacoustics: Spectroscopy and other applications", in Ultrasensitive Laser Spectroscopy, D. S. Klinger , Ed. (Academic

  7. Infrared spectroscopy of comets

    NASA Technical Reports Server (NTRS)

    Disanti, Michael A.; Mumma, M. J.; Hoban, S. M.; Reuter, D.; Espenak, F.; Storrs, A. D.; Lacy, J.; Parmar, R.; Joyce, R.

    1990-01-01

    An observational search for cometary parent molecules using infrared spectroscopy was conducted in the 1 to 5 micron region. The investigation involved two different observing programs, one at moderate spectral resolution and one at fairly high resolution. The lower resolution was used to study cometary spectra in the vicinity of 3.5 micron at wavelength/change in wavelength is approximately or equal to 10(exp 3). Comets P/Brorsen-Metcalf (1989o), Okazaki-Levy-Rudenko (1989r), and Austin (1990c1) were observed with the Cryogenic Spectrometer (CRSP) at Kitt Peak. The detector incorporated an InSb array with 58 spatial elements, each 2.7 min on the sky, and 62 spectral channels per spatial element. An, as yet, unidentified feature was detected at approximately 3.52 micron in Comet Austin (on 1990 May 4, 5, and 6). The feature is possibly present in P/Brorsen-Metcalf (observed on 1989 August 23 and 25), as well. Comet Okazaki-Levy-Rudenko exhibited continuum emission only in this spectral region at the time of the observations (1989 November 14 and 16). The data are presented, and the relationship between the 3.52 micron feature and cometary activity (e.g., water production rate, visibility of the 3.4 micron emission feature) are discussed. The high resolution program probed comet Austin in the 4.8 micron region. These observations were used to search for emission lines comprising the (1-0) vibration-rotation band of the ground electronic state of CO. Retrieval of the lines allows a probe of the population distribution of levels J' = 1 through 4 of the excited (v' = 1) vibrational state within the ground electronic state of CO. Knowledge of this distribution can be used to constrain the rotational temperature. Preliminary analysis suggests the P3 line was present UT May 16 at roughly the 5 sigma level. Results concerning the existence of other lines, and physical conditions inferred therefrom are discussed.

  8. Airborne Submillimeter Spectroscopy

    NASA Technical Reports Server (NTRS)

    Zmuidzinas, J.

    1998-01-01

    This is the final technical report for NASA-Ames grant NAG2-1068 to Caltech, entitled "Airborne Submillimeter Spectroscopy", which extended over the period May 1, 1996 through January 31, 1998. The grant was funded by the NASA airborne astronomy program, during a period of time after the Kuiper Airborne Observatory was no longer operational. Instead. this funding program was intended to help develop instrument concepts and technology for the upcoming SOFIA (Stratospheric Observatory for Infrared Astronomy) project. SOFIA, which is funded by NASA and is now being carried out by a consortium lead by USRA (Universities Space Research Association), will be a 747 aircraft carrying a 2.5 meter diameter telescope. The purpose of our grant was to fund the ongoing development of sensitive heterodyne receivers for the submillimeter band (500-1200 GHz), using sensitive superconducting (SIS) detectors. In 1997 July we submitted a proposal to USRA to construct a heterodyne instrument for SOFIA. Our proposal was successful [1], and we are now continuing our airborne astronomy effort with funding from USRA. A secondary purpose of the NAG2-1068 grant was to continue the anaIN'sis of astronomical data collected with an earlier instrument which was flown on the NASA Kuiper Airborne Observatory (KAO). The KAO instrument and the astronomical studies which were carried out with it were supported primarily under another grant, NAG2-744, which extended over October 1, 1991 through Januarv 31, 1997. For a complete description of the astronomical data and its anailysis, we refer the reader to the final technical report for NAG2-744, which was submitted to NASA on December 1. 1997. Here we report on the SIS detector development effort for SOFIA carried out under NAG2-1068. The main result of this effort has been the demonstration of SIS mixers using a new superconducting material niobium titanium nitride (NbTiN), which promises to deliver dramatic improvements in sensitivity in the 700

  9. Time-resolved vibrational spectroscopy

    SciTech Connect

    Tokmakoff, Andrei; Champion, Paul; Heilweil, Edwin J.; Nelson, Keith A.; Ziegler, Larry

    2009-05-14

    This document contains the Proceedings from the 14th International Conference on Time-Resolved Vibrational Spectroscopy, which was held in Meredith, NH from May 9-14, 2009. The study of molecular dynamics in chemical reaction and biological processes using time-resolved spectroscopy plays an important role in our understanding of energy conversion, storage, and utilization problems. Fundamental studies of chemical reactivity, molecular rearrangements, and charge transport are broadly supported by the DOE's Office of Science because of their role in the development of alternative energy sources, the understanding of biological energy conversion processes, the efficient utilization of existing energy resources, and the mitigation of reactive intermediates in radiation chemistry. In addition, time-resolved spectroscopy is central to all fiveof DOE's grand challenges for fundamental energy science. The Time-Resolved Vibrational Spectroscopy conference is organized biennially to bring the leaders in this field from around the globe together with young scientists to discuss the most recent scientific and technological advances. The latest technology in ultrafast infrared, Raman, and terahertz spectroscopy and the scientific advances that these methods enable were covered. Particular emphasis was placed on new experimental methods used to probe molecular dynamics in liquids, solids, interfaces, nanostructured materials, and biomolecules.

  10. Photoelectron spectroscopy of molecular clusters

    NASA Astrophysics Data System (ADS)

    Zhang, Xu; Pitts, Jonathan; Zheng, Chaowen; Knee, Joseph L.

    1995-09-01

    High resolution photoelectron spectroscopy is applied to the study of molecular clusters. The primary species studied are fluorene-Arn complexes. Spectroscopy of the neutral S1 state has been performed on clusters as large as n equals 30. In order to study the photoelectron spectra of the clusters size selectively mass analyzed threshold ionization (MATI) is used which is a mass resolved version of the ZEKE technique. MATI spectroscopy has been applied to clusters up to n equals 5. The spectral shifts in the S1 origin and ion threshold are used as a measure of the relative stability of the different clusters. Using previous experimental and theoretical work on related clusters the structures of the clusters are inferred from the observed spectral shifts. In some cases multiple conformations of a particular cluster size are identified.

  11. Force Spectroscopy in Studying Infection.

    PubMed

    Zhou, Zhaokun; Leake, Mark C

    2016-01-01

    Biophysical force spectroscopy tools-for example, optical tweezers, magnetic tweezers, atomic force microscopy-have been used to study elastic, mechanical, conformational and dynamic properties of single biological specimens from single proteins to whole cells to reveal information not accessible by ensemble average methods such as X-ray crystallography, mass spectroscopy, gel electrophoresis and so on. Here, we review the application of these tools on a range of infection-related questions from antibody-inhibited protein processivity to virus-cell adhesion. In each case, we focus on how the instrumental design tailored to the biological system in question translates into the functionality suitable for that particular study. The unique insights that force spectroscopy has gained to complement knowledge learned through population averaging techniques in interrogating biomolecular details prove to be instrumental in therapeutic innovations such as those in structure-based drug design.

  12. THz stark spectroscopy (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Feurer, Thomas; Rohwer, Egmont; Akbarimoosavi, Maryam

    2016-09-01

    Stark spectroscopy has been pioneered many decades ago and is a unique tool to extract information on molecular constants such as changes of dipole moments or polarizabilities upon excitation. Here we introduce a new twist, i.e. THz Stark spectroscopy. In THz fields the electric field vector oscillates on time scales of picoseconds and thus much faster than in conventional Stark spectroscopy. It therefore may allow to distinguish between different electric field contributions by analyzing the dynamics of the THz response. We first demonstrate that conventional THz sources can be boosted by combination with field enhancement structures, reaching field strength of GV/m driving several different materials into the nonlinear response regime. Then we discuss THz fields influencing charge transfer in different molecules.

  13. Laser optogalvanic spectroscopy of molecules

    NASA Technical Reports Server (NTRS)

    Webster, C. R.; Rettner, C. T.

    1983-01-01

    In laser optogalvanic (LOG) spectroscopy, a tunable laser is used to probe the spectral characteristics of atomic or molecular species within an electrical discharge in a low pressure gas. Optogalvanic signals arise when the impedance of the discharge changes in response to the absorption of laser radiation. The technique may, therefore, be referred to as impedance spectroscopy. This change in impedance may be monitored as a change in the voltage across the discharge tube. LOG spectra are recorded by scanning the wavelength of a chopped CW dye laser while monitoring the discharge voltage with a lock-in amplifier. LOG signals are obtained if the laser wavelength matches a transition in a species present in the discharge (or flame), and if the absorption of energy in the laser beam alters the impedance of the discharge. Infrared LOG spectroscopy of molecules has been demonstrated and may prove to be the most productive application in the field of optogalvanic techniques.

  14. Raman Spectroscopy of Microbial Pigments

    PubMed Central

    Edwards, Howell G. M.; Oren, Aharon

    2014-01-01

    Raman spectroscopy is a rapid nondestructive technique providing spectroscopic and structural information on both organic and inorganic molecular compounds. Extensive applications for the method in the characterization of pigments have been found. Due to the high sensitivity of Raman spectroscopy for the detection of chlorophylls, carotenoids, scytonemin, and a range of other pigments found in the microbial world, it is an excellent technique to monitor the presence of such pigments, both in pure cultures and in environmental samples. Miniaturized portable handheld instruments are available; these instruments can be used to detect pigments in microbiological samples of different types and origins under field conditions. PMID:24682303

  15. Photoacoustic spectroscopy of condensed matter

    NASA Technical Reports Server (NTRS)

    Somoano, R. B.

    1978-01-01

    Photoacoustic spectroscopy is a new analytical tool that provides a simple nondestructive technique for obtaining information about the electronic absorption spectrum of samples such as powders, semisolids, gels, and liquids. It can also be applied to samples which cannot be examined by conventional optical methods. Numerous applications of this technique in the field of inorganic and organic semiconductors, biology, and catalysis have been described. Among the advantages of photoacoustic spectroscopy, the signal is almost insensitive to light scattering by the sample and information can be obtained about nonradiative deactivation processes. Signal saturation, which can modify the intensity of individual absorption bands in special cases, is a drawback of the method.

  16. X-ray emission spectroscopy.

    PubMed

    Bergmann, Uwe; Glatzel, Pieter

    2009-01-01

    We describe the chemical information that can be obtained by means of hard X-ray emission spectroscopy (XES). XES is presented as a technique that is complementary to X-ray absorption spectroscopy (XAS) and that provides valuable information with respect to the electronic structure (local charge- and spin-density) as well as the ligand environment of a 3d transition metal. We address non-resonant and resonant XES and present results that were recorded on Mn model systems and the Mn(4)Ca-cluster in the oxygen evolving complex of photosystem II. A brief description of the instrumentation is given with an outlook toward future developments.

  17. X-ray Absorption Spectroscopy

    SciTech Connect

    Yano, Junko; Yachandra, Vittal K.

    2009-07-09

    This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

  18. Spectroscopy of transient neutral species via negative ion photoelectron spectroscopy

    SciTech Connect

    Weaver, A.

    1991-12-01

    Negative ion photoelectron spectroscopy has been used to study two types of transient neutral species: bound free radicals (NO{sub 2} and NO{sub 3}) and unstable neutral species ([IHI] and [FH{sub 2}]). The negative ion time-of-flight photoelectron spectrometer used for these experiments is described in detail.

  19. Spectroscopy of transient neutral species via negative ion photoelectron spectroscopy

    SciTech Connect

    Weaver, A.

    1991-12-01

    Negative ion photoelectron spectroscopy has been used to study two types of transient neutral species: bound free radicals (NO{sub 2} and NO{sub 3}) and unstable neutral species ((IHI) and (FH{sub 2})). The negative ion time-of-flight photoelectron spectrometer used for these experiments is described in detail.

  20. Raman spectroscopy of advanced materials.

    PubMed

    Huong, P V

    1996-06-01

    Many micro-structural aspects of advanced materials and the incidence on the physical properties have been elucidated by Raman micro-spectroscopy. The potential of this technique is demonstrated with new materials interesting in both academic and industrial developments: new carbons and diamonds, superconductors, semiconductors, superhards.

  1. A Quantitative Infrared Spectroscopy Experiment.

    ERIC Educational Resources Information Center

    Krahling, Mark D.; Eliason, Robert

    1985-01-01

    Although infrared spectroscopy is used primarily for qualitative identifications, it is possible to use it as a quantitative tool as well. The use of a standard curve to determine percent methanol in a 2,2,2-trifluoroethanol sample is described. Background information, experimental procedures, and results obtained are provided. (JN)

  2. Surface-Enhanced Raman Spectroscopy.

    ERIC Educational Resources Information Center

    Garrell, Robin L.

    1989-01-01

    Reviews the basis for the technique and its experimental requirements. Describes a few examples of the analytical problems to which surface-enhanced Raman spectroscopy (SERS) has been and can be applied. Provides a perspective on the current limitations and frontiers in developing SERS as an analytical technique. (MVL)

  3. Raman spectroscopy of oral bacteria

    NASA Astrophysics Data System (ADS)

    Berger, Andrew J.; Zhu, Qingyuan; Quivey, Robert G.

    2003-10-01

    Raman spectroscopy has been employed to measure the varying concentrations of two oral bacteria in simple mixtures. Evaporated droplets of centrifuged mixtures of Streptococcus sanguis and Streptococcus mutans were analyzed via Raman microspectroscopy. The concentration of s. sanguis was determined based upon the measured Raman spectrum, using partial least squares cross-validation, with an r2 value of 0.98.

  4. Infrared Spectroscopy of Deuterated Compounds.

    ERIC Educational Resources Information Center

    MacCarthy, Patrick

    1985-01-01

    Background information, procedures used, and typical results obtained are provided for an experiment (based on the potassium bromide pressed-pellet method) involving the infrared spectroscopy of deuterated compounds. Deuteration refers to deuterium-hydrogen exchange at active hydrogen sites in the molecule. (JN)

  5. Hollow waveguide cavity ringdown spectroscopy

    NASA Technical Reports Server (NTRS)

    Dreyer, Chris (Inventor); Mungas, Greg S. (Inventor)

    2012-01-01

    Laser light is confined in a hollow waveguide between two highly reflective mirrors. This waveguide cavity is used to conduct Cavity Ringdown Absorption Spectroscopy of loss mechanisms in the cavity including absorption or scattering by gases, liquid, solids, and/or optical elements.

  6. Spectroscopy on the Overhead Projector.

    ERIC Educational Resources Information Center

    Solomon, Sally; And Others

    1994-01-01

    Any overhead projector easily can be converted into a simple spectrometer by placing a piece of diffraction grating over the projecting lens. A detailed description of the apparatus and suggested spectroscopy experiments are included. Demonstrations can utilize solutions of cobalt chloride, potassium permanganate, potassium dichromate, or…

  7. Superconducting microphone for photoacoustic spectroscopy

    SciTech Connect

    Costa Ribeiro, P.; Labrunie, M.; Von der Weid, J.P.; Symko, O.G.

    1982-11-01

    A superconducting microphone has been developed for photoacoustic spectroscopy at low temperatures. The microphone consists of a thin mylar membrane coated with a film of lead whose motion is detected by SQUID magnetometer. For the simple set-up presented here, the limiting pressure sensitivity is 7.5 x 10/sup -14/ atmospheres/Hz/sup 1/2/.

  8. Vibrational Spectroscopy of Ionic Liquids.

    PubMed

    Paschoal, Vitor H; Faria, Luiz F O; Ribeiro, Mauro C C

    2017-01-04

    Vibrational spectroscopy has continued use as a powerful tool to characterize ionic liquids since the literature on room temperature molten salts experienced the rapid increase in number of publications in the 1990's. In the past years, infrared (IR) and Raman spectroscopies have provided insights on ionic interactions and the resulting liquid structure in ionic liquids. A large body of information is now available concerning vibrational spectra of ionic liquids made of many different combinations of anions and cations, but reviews on this literature are scarce. This review is an attempt at filling this gap. Some basic care needed while recording IR or Raman spectra of ionic liquids is explained. We have reviewed the conceptual basis of theoretical frameworks which have been used to interpret vibrational spectra of ionic liquids, helping the reader to distinguish the scope of application of different methods of calculation. Vibrational frequencies observed in IR and Raman spectra of ionic liquids based on different anions and cations are discussed and eventual disagreements between different sources are critically reviewed. The aim is that the reader can use this information while assigning vibrational spectra of an ionic liquid containing another particular combination of anions and cations. Different applications of IR and Raman spectroscopies are given for both pure ionic liquids and solutions. Further issues addressed in this review are the intermolecular vibrations that are more directly probed by the low-frequency range of IR and Raman spectra and the applications of vibrational spectroscopy in studying phase transitions of ionic liquids.

  9. Reflectance spectroscopy for soil analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the last three decades or more, researchers have estimated soil properties using visible and near infrared (VNIR) diffuse reflectance spectroscopy (DRS), with varying results. This presentation reviews the history and state-of –the art of VNIR-DRS, including relative estimation accuracy for var...

  10. Fourier spectroscopy and planetary research

    NASA Technical Reports Server (NTRS)

    Hanel, R. A.; Kunde, V. G.

    1974-01-01

    The application of Fourier Transform Spectroscopy (FTS) to planetary research is reviewed. The survey includes FTS observations of the sun, all the planets except Uranus and Pluto, the Galilean satellites and Saturn's rings. Instrumentation and scientific results are considered and the prospects and limitations of FTS for planetary research in the forthcoming years are discussed.

  11. Current Trends in Atomic Spectroscopy.

    ERIC Educational Resources Information Center

    Wynne, James J.

    1983-01-01

    Atomic spectroscopy is the study of atoms/ions through their interaction with electromagnetic radiation, in particular, interactions in which radiation is absorbed or emitted with an internal rearrangement of the atom's electrons. Discusses nature of this field, its status and future, and how it is applied to other areas of physics. (JN)

  12. Picosecond spectroscopy of dihydro biliverdin

    NASA Astrophysics Data System (ADS)

    Ditto, Manfred; Brunner, Harald; Lippitsch, Max E.

    1991-10-01

    Picosecond time-resolved fluorescence and absorption spectroscopy was performed on dihydro biliverdin, a model for the chromophore in the plant pigment phytochrome, a chromoprotein governing plant growth. Close agreement between the model compound and the native chromophore proves the importance of the saturated pyrrol ring for the decay kinetics and renders chromophore protonation in phytochrome unlikely.

  13. Exciting Developments in Hadron Spectroscopy

    SciTech Connect

    Seth, Kamal K.

    2006-02-11

    There has been a renaissance in hadron spectroscopy during the last couple of years. Long lost states have been tracked down. Unexpected states are showing up all over, and numerous measurements with unprecedented precision are being reported. A review is presented.

  14. Lamin A/C Is Required for ChAT-Dependent Neuroblastoma Differentiation.

    PubMed

    Guglielmi, Loredana; Nardella, Marta; Musa, Carla; Iannetti, Ilaria; Arisi, Ivan; D'Onofrio, Mara; Storti, Andrea; Valentini, Alessandra; Cacci, Emanuele; Biagioni, Stefano; Augusti-Tocco, Gabriella; D'Agnano, Igea; Felsani, Armando

    2016-05-25

    The mouse neuroblastoma N18TG2 clone is unable to differentiate and is defective for the enzymes of the biosynthesis of neurotransmitters. The forced expression of choline acetyltransferase (ChAT) in these cells results in the synthesis and release of acetylcholine (Ach) and hence in the expression of neurospecific features and markers. To understand how the expression of ChAT triggered neuronal differentiation, we studied the differences in genome-wide transcription profiles between the N18TG2 parental cells and its ChAT-expressing 2/4 derived clone. The engagement of the 2/4 cells in the neuronal developmental program was confirmed by the increase of the expression level of several differentiation-related genes and by the reduction of the amount of transcripts of cell cycle genes. At the same time, we observed a massive reorganization of cytoskeletal proteins in terms of gene expression, with the accumulation of the nucleoskeletal lamina component Lamin A/C in differentiating cells. The increase of the Lmna transcripts induced by ChAT expression in 2/4 cells was mimicked treating the parental N18TG2 cells with the acetylcholine receptor agonist carbachol, thus demonstrating the direct role played by this receptor in neuron nuclei maturation. Conversely, a treatment of 2/4 cells with the muscarinic receptor antagonist atropine resulted in the reduction of the amount of Lmna RNA. Finally, the hypothesis that Lmna gene product might play a crucial role in the ChAT-dependent molecular differentiation cascade was strongly supported by Lmna knockdown in 2/4 cells leading to the downregulation of genes involved in differentiation and cytoskeleton formation and to the upregulation of genes known to regulate self-renewal and stemness.

  15. A Gastric Glycoform of MUC5AC Is a Biomarker of Mucinous Cysts of the Pancreas

    PubMed Central

    Sinha, Jessica; Cao, Zheng; Dai, Jianliang; Tang, Huiyuan; Partyka, Katie; Hostetter, Galen; Simeone, Diane M.; Feng, Ziding; Allen, Peter J.; Brand, Randall E.; Haab, Brian B.

    2016-01-01

    Molecular indicators to specify the risk posed by a pancreatic cyst would benefit patients. Previously we showed that most cancer-precursor cysts, termed mucinous cysts, produce abnormal glycoforms of the proteins MUC5AC and endorepellin. Here we sought to validate the glycoforms as a biomarker of mucinous cysts and to specify the oligosaccharide linkages that characterize MUC5AC. We hypothesized that mucinous cysts secrete MUC5AC displaying terminal N-acetylglucosamine (GlcNAc) in either alpha or beta linkage. We used antibody-lectin sandwich assays to detect glycoforms of MUC5AC and endorepellin in cyst fluid samples from three independent cohorts of 49, 32, and 66 patients, and we used monoclonal antibodies to test for terminal, alpha-linked GlcNAc and the enzyme that produces it. A biomarker panel comprising the previously-identified glycoforms of MUC5AC and endorepellin gave 96%, 96%, and 87% accuracy for identifying mucinous cysts in the three cohorts with an average sensitivity of 92% and an average specificity of 94%. Glycan analysis showed that MUC5AC produced by a subset of mucinous cysts displays terminal alpha-GlcNAc, a motif expressed in stomach glands. The alpha-linked glycoform of MUC5AC was unique to intraductal papillary mucinous neoplasms (IPMN), whereas terminal beta-linked GlcNAc was increased in both IPMNs and mucinous cystic neoplasms (MCN). The enzyme that synthesizes alpha-GlcNAc, A4GNT, was expressed in the epithelia of mucinous cysts that expressed alpha-GlcNAc, especially in regions with high-grade dysplasia. Thus IPMNs secrete a gastric glycoform of MUC5AC that displays terminal alpha-GlcNAc, and the combined alpha-GlcNAc and beta-GlcNAc glycoforms form an accurate biomarker of mucinous cysts. PMID:27992432

  16. Optical Spectroscopy at the Nanoscale

    NASA Astrophysics Data System (ADS)

    Hong, Xiaoping

    Recent advances in material science and fabrication techniques enabled development of nanoscale applications and devices with superior performances and high degree of integration. Exotic physics also emerges at nanoscale where confinement of electrons and phonons leads to drastically different behavior from those in the bulk materials. It is therefore rewarding and interesting to investigate and understand material properties at the nanoscale. Optical spectroscopy, one of the most versatile techniques for studying material properties and light-matter interactions, can provide new insights into the nanomaterials. In this thesis, I explore advanced laser spectroscopic techniques to probe a variety of different nanoscale phenomena. A powerful tool in nanoscience and engineering is scanning tunneling microscopy (STM). Its capability in atomic resolution imaging and spectroscopy unveiled the mystical quantum world of atoms and molecules. However identification of molecular species under investigation is one of the limiting functionalities of the STM. To address this need, we take advantage of the molecular `fingerprints' - vibrational spectroscopy, by combining an infrared light sources with scanning tunneling microscopy. In order to map out sharp molecular resonances, an infrared continuous wave broadly tunable optical parametric oscillator was developed with mode-hop free fine tuning capabilities. We then combine this laser with STM by shooting the beam onto the STM substrate with sub-monolayer diamondoids deposition. Thermal expansion of the substrate is detected by the ultrasensitive tunneling current when infrared frequency is tuned across the molecular vibrational range. Molecular vibrational spectroscopy could be obtained by recording the thermal expansion as a function of the excitation wavelength. Another interesting field of the nanoscience is carbon nanotube, an ideal model of one dimensional physics and applications. Due to the small light absorption with

  17. "Solvent Effects" in 1H NMR Spectroscopy.

    ERIC Educational Resources Information Center

    Cavaleiro, Jose A. S.

    1987-01-01

    Describes a simple undergraduate experiment in chemistry dealing with the "solvent effects" in nuclear magnetic resonance (NMR) spectroscopy. Stresses the importance of having students learn NMR spectroscopy as a tool in analytical chemistry. (TW)

  18. Optoacoustic Spectroscopy to Detect Hydrazine Fuels.

    DTIC Science & Technology

    1981-07-01

    the use of optoacoustic spectroscopy to obtain spectra for inorganic samiples and biological materials (304-312). Parker (258) and Parker and Hitke...Appi Spectroscopy 34:/6 (19801). 196. Lutt , K. F. A new recording method for gas analysis by mneans of infrared ibsorption without spectral splitting...Photoacoustic spectroscopy of biological materials. Science 181:657 (1973). 306. Rosencwaig, A. Photoacoustic spectroscopy of solids. Optics Commun 7:305

  19. Quantitative tunneling spectroscopy of nanocrystals

    SciTech Connect

    First, Phillip N; Whetten, Robert L; Schaaff, T Gregory

    2007-05-25

    The proposed goals of this collaborative work were to systematically characterize the electronic structure and dynamics of 3-dimensional metal and semiconducting nanocrystals using scanning tunneling microscopy/spectroscopy (STM/STS) and ballistic electron emission spectroscopy (BEES). This report describes progress in the spectroscopic work and in the development of methods for creating and characterizing gold nanocrystals. During the grant period, substantial effort also was devoted to the development of epitaxial graphene (EG), a very promising materials system with outstanding potential for nanometer-scale ballistic and coherent devices ("graphene" refers to one atomic layer of graphitic, sp2 -bonded carbon atoms [or more loosely, few layers]). Funding from this DOE grant was critical for the initial development of epitaxial graphene for nanoelectronics

  20. Spectroscopy of the Heaviest Elements

    NASA Astrophysics Data System (ADS)

    Clark, Roderick

    2009-10-01

    The specific ``magic'' proton and neutron numbers, representing major spherical shell gaps, beyond 208Pb are a matter of considerable debate. It is well established that nuclei near Z=100, N=152 (252Fm) have well-deformed prolate shapes. By performing prompt and delayed gamma-ray spectroscopy on deformed transfermium nuclei we can learn about the single-particle structure, shell gaps, pairing correlations, and excitation modes in the heaviest nuclei. After a brief overview of state-of-the-art measurements, I will describe recent results from experiments at the 88-Inch Cyclotron of the Lawrence Berkeley National Laboratory which use the Berkeley Gas-filled Separator (BGS). I will then discuss the prospects of a new generation of spectroscopy measurements on the heaviest elements when the BGS is used in conjunction with the GRETINA gamma--ray tracking array.

  1. Molecular Spectroscopy of Living Systems

    NASA Astrophysics Data System (ADS)

    Cheng, Ji-Xin

    2016-06-01

    Molecular spectroscopy has been a powerful tool in the study of molecules in gas phase, condensed phase, and at interfaces. The transition from in vitro spectroscopy to spectroscopic imaging of living systems is opening new opportunities to reveal cellular machinery and to enable molecule-based diagnosis (Science 2015, 350: 1054). Such a transition involves more than a simple combination of spectrometry and microscopy. In this presentation, I will discuss the most recent efforts that have pushed the physical limits of spectroscopic imaging in terms of spectral acquisition speed, detection sensitivity, spatial resolution and imaging depth. I will further highlight significant applications in functional analysis of single cells and in label-free detection of diseases.

  2. Heavy quark spectroscopy and decay

    SciTech Connect

    Schindler, R.H.

    1987-01-01

    The understanding of q anti q systems containing heavy, charmed, and bottom quarks has progressed rapidly in recent years, through steady improvements in experimental techniques for production and detection of their decays. These lectures are meant to be an experimentalist's review of the subject. In the first of two lectures, the existing data on the spectroscopy of the bound c anti c and b anti b systems will be discussed. Emphasis is placed on comparisons with the theoretical models. The second lecture covers the rapidly changing subject of the decays of heavy mesons (c anti q and b anti q), and their excited states. In combination, the spectroscopy and decays of heavy quarks are shown to provide interesting insights into both the strong and electroweak interactions of the heavy quarks. 103 refs., 39 figs.

  3. Raman spectroscopy in halophile research

    PubMed Central

    Jehlička, Jan; Oren, Aharon

    2013-01-01

    Raman spectroscopy plays a major role in robust detection of biomolecules and mineral signatures in halophile research. An overview of Raman spectroscopic investigations in halophile research of the last decade is given here to show advantages of the approach, progress made as well as limits of the technique. Raman spectroscopy is an excellent tool to monitor and identify microbial pigments and other biomolecules in extant and extinct halophile biomass. Studies of bottom gypsum crusts from salterns, native evaporitic sediments, halite inclusions, and endoliths as well as cultures of halophilic microorganisms permitted to understand the content, distribution, and behavior of important molecular species. The first papers describing Raman spectroscopic detection of microbiological and geochemical key markers using portable instruments are highlighted as well. PMID:24339823

  4. Analytical Spectroscopy Using Modular Systems

    NASA Astrophysics Data System (ADS)

    Patterson, Brian M.; Danielson, Neil D.; Lorigan, Gary A.; Sommer, André J.

    2003-12-01

    This article describes the development of three analytical spectroscopy experiments that compare the determination of salicylic acid (SA) content in aspirin tablets. The experiments are based on UV vis, fluorescence, and Raman spectroscopies and utilize modular spectroscopic components. Students assemble their own instruments, optimize them with respect to signal-to-noise, generate calibration curves, determine the SA content in retail aspirin tablets, and assign features in the respective spectra to functional groups within the active material. Using this approach in the discovery-based setting, the students gain invaluable insight into method-specific parameters, such as instrumental components, sample preparation, and analytical capability. In addition, the students learn the fundamentals of fiber optics and signal processing using the low-cost CCD based spectroscopic components.

  5. Spectroscopy, scattering, and KK molecules

    SciTech Connect

    Weinstein, J.

    1994-04-01

    The author presents a pedagogical description of a new theoretical technique, based on the multichannel Schroedinger equation, for simultaneously applying the quark model to both meson spectroscopy and meson-meson scattering. This is an extension of an earlier analysis which led to the prediction that the f{sub o}(975) and a{sub o}(980) scalar mesons are K{bar K} molecular states.

  6. Optical spectroscopy and tooth decay

    NASA Astrophysics Data System (ADS)

    Misra, P.; De, T.; Singh, R.

    2005-11-01

    Optical spectroscopy in the ultraviolet, visible and mid-infrared spectral regions has been used to discriminate between healthy and diseased teeth of patients in the age range 15-75 years. Spectral scans of absorbance versus wavenumber and fluorescence intensity versus wavelength have been recorded and investigated for caries and periodontal disease. Such optical diagnostics can prove very useful in the early detection and treatment of tooth decay.

  7. Flatfielding in Spatial Heterodyne Spectroscopy

    DTIC Science & Technology

    2006-07-01

    similar to that of a Michelson interferometer used for Fourier- transform spectroscopy (FTS) with the return mir- rors replaced by fixed diffraction...Cheben, I. Powell, S. Janz, and D. Xu, “Wavelength- dispersive device based on a Fourier-transform Michelson -type arrayed waveguide grating,” Opt. Lett...C. R. Englert, J. G. Cardon, R. R. Conway, C. M. Brown, and J. Wimperis. “Robust monolithic ultraviolet interferometer for the SHIMMER instrument on

  8. Vibrational Spectroscopy and Quantum Localization

    NASA Astrophysics Data System (ADS)

    Fillaux, François

    These lecture-notes are meant to provide newcomers with an overview of the impact of vibrational spectroscopy in the field of nonlinear dynamics of atoms and molecules, in the perspective of energy localization. In the introduction, the terminology of nonlinear excitations and tentative experimental evidences are briefly recalled in a brief historical perspective. The basic principles of vibrational spectroscopy are presented in section 11 for infrared, Raman and inelastic neutron scattering. The potentialities for each technique to probing energy localization are discussed. In section 12, nonlinear dynamics in isolated molecules are treated within the framework of normal versus local mode representations. It is shown that these complementary representations are not necessarily distinctive of weak versus strong anharmonicity, in the context of chemical complexity. It is emphasized that local modes and energy localization are totally independent concepts. In section 4, examples of nonlinear dynamics in crystals are reviewed: multiphonon bound states, strong coupling between phonons and electrons probed with resonance Raman, local modes and quantum rotation in one-dimension probed with inelastic neutron scattering, strong coupling in hydrogen-bonded crystals and self-trapping probed with time-resolved vibrational-spectroscopy. The extended character of eigenstates in crystals free of impurities and disorder, the nature of the interaction of periodic lattices with plane waves, the Franck-Condon principle and the particle-wave duality in the quantum regime are key factors preventing observation of energy localization. It is shown that free spatially-localized nondissipative classical waves give rise to free pseudoparticles that behave as planar waves in the quantum regime. In conclusion, a clear demonstration that energy localization corresponds to eigenstates is eagerly expected for further evidencing these states with vibrational spectroscopy.

  9. Exoplanet transmission spectroscopy using KMOS

    NASA Astrophysics Data System (ADS)

    Parviainen, Hannu; Aigrain, Suzanne; Thatte, Niranjan; Barstow, Joanna K.; Evans, Thomas M.; Gibson, Neale

    2015-11-01

    KMOS (K-Band Multi Object Spectrograph) is a novel integral field spectrograph installed in the Very Large Telescope's (VLT's) ANTU unit. The instrument offers an ability to observe 24 2.8 arcsec × 2.8 arcsec subfields positionable within a 7.2 arcmin patrol field, each subfield producing a spectrum with a 14 × 14-pixel spatial resolution. The main science drivers for KMOS are the study of galaxies, star formation, and molecular clouds, but its ability to simultaneously measure spectra of multiple stars makes KMOS an interesting instrument for exoplanet atmosphere characterization via transmission spectroscopy. We set to test whether transmission spectroscopy is practical with KMOS, and what are the conditions required to achieve the photometric precision needed, based on observations of a partial transit of WASP-19b, and full transits of GJ 1214b and HD 209458b. Our analysis uses the simultaneously observed comparison stars to reduce the effects from instrumental and atmospheric sources, and Gaussian processes to model the residual systematics. We show that KMOS can, in theory, deliver the photometric precision required for transmission spectroscopy. However, this is shown to require (a) pre-imaging to ensure accurate centring and (b) a very stable night with optimal observing conditions (seeing ˜0.8 arcsec). Combining these two factors with the need to observe several transits, each with a sufficient out-of-transit baseline (and with the fact that similar or better precision can be reached with telescopes and instruments with smaller pressure), we conclude that transmission spectroscopy is not the optimal science case to take advantage of the abilities offered by KMOS and VLT.

  10. Heavy quark production and spectroscopy

    SciTech Connect

    Appel, J.A.

    1993-11-01

    This review covers many new experimental results on heavy flavor production and spectroscopy. It also shows some of the increasingly improved theoretical understanding of results in light of basic perturbative QCD and heavy quark symmetry. At the same time, there are some remaining discrepancies among experiments as well as significant missing information on some of the anticipated lowest lying heavy quark states. Most interesting, perhaps, are some clearly measured production effects awaiting full explanation.

  11. Electronic spectroscopy of diatomic molecules

    NASA Technical Reports Server (NTRS)

    Partridge, Harry; Langhoff, Stephen R.; Bauschlicher, Charles W., Jr.

    1994-01-01

    This article provides an overview of the principal computational approaches and their accuracy for the study of electronic spectroscopy of diatomic molecules. We include a number of examples from our work that illustrate the range of application. We show how full configuration interaction benchmark calculations were instrumental in improving the understanding of the computational requirements for obtaining accurate results for diatomic spectroscopy. With this understanding it is now possible to compute radiative lifetimes accurate to within 10% for systems involving first- and second-row atoms. We consider the determination of the infrared vibrational transition probabilities for the ground states of SiO and NO, based on a globally accurate dipole moment function. We show how we were able to assign the a(sup "5)II state of CO as the upper state in the recently observed emission bands of CO in an Ar matrix. We next discuss the assignment of the photoelectron detachment spectra of NO and the alkali oxide negative ions. We then present several examples illustrating the state-of-the-art in determining radiative lifetimes for valence-valence and valence-Rydberg transitions. We next compare the molecular spectroscopy of the valence isoelectronic B2, Al2, and AlB molecules. The final examples consider systems involving transition metal atoms, which illustrate the difficulty in describing states with different numbers of d electrons.

  12. Vibrational spectroscopy of HNS degradation

    NASA Astrophysics Data System (ADS)

    Alam, M. Kathleen; Martin, Laura; Schmitt, Randal L.; Ten Eyck, Gregory A.; Welle, Eric

    2008-08-01

    Hexanitrostilbene (HNS) is a widely used explosive, due in part to its high thermal stability. Degradation of HNS is known to occur through UV, chemical exposure, and heat exposure, which can lead to reduced performance of the material. Common methods of testing for HNS degradation include wet chemical and surface area testing of the material itself, and performance testing of devices that use HNS. The commonly used chemical tests, such as volatility, conductivity and contaminant trapping provide information on contaminants rather than the chemical stability of the HNS itself. Additionally, these tests are destructive in nature. As an alternative to these methods, we have been exploring the use of vibrational spectroscopy as a means of monitoring HNS degradation non-destructively. In particular, infrared (IR) spectroscopy lends itself well to non-destructive analysis. Molecular variations in the material can be identified and compared to pure samples. The utility of IR spectroscopy was evaluated using pressed pellets of HNS exposed to DETA (diethylaminetriamine). Amines are known to degrade HNS, with the proposed product being a σ-adduct. We have followed these changes as a function of time using various IR sampling techniques including photoacoustic and attenuated total reflectance (ATR).

  13. Isotope effects in ESR spectroscopy.

    PubMed

    Stößer, Reinhard; Herrmann, Werner

    2013-06-07

    In order to present the relationship between ESR spectroscopy and isotope effects three levels are considered: (i) ESR spectroscopy is described on a general level up to the models for interpretation of the experimental spectra, which go beyond the usually used time and mass independent spin-Hamilton operator, (ii) the main characteristics of the generalized isotope effects are worked out, and finally (iii) the basic, mainly quantum mechanical effects are used to describe the coupling of electron spins with the degrees of freedom, which are accessible under the selected conditions, of the respective paramagnetic object under investigation. The ESR parameters and the respective models are formalized so far, that they include the time and mass depending influences and reflect the specific isotope effects. Relations will be established between the effects in ESR spectra to spin relaxation, to spin exchange, to the magnetic isotope effect, to the Jahn-Teller effects, as well as to the influence of zero-point vibrations. Examples will be presented which demonstrate the influence of isotopes as well as the kind of accessible information. It will be differentiated with respect to isotope effects in paramagnetic centres itself and in the respective matrices up to the technique of ESR imaging. It is shown that the use of isotope effects is indispensable in ESR spectroscopy.

  14. Instrument independent diffuse reflectance spectroscopy.

    PubMed

    Yu, Bing; Fu, Henry L; Ramanujam, Nirmala

    2011-01-01

    Diffuse reflectance spectroscopy with a fiber optic probe is a powerful tool for quantitative tissue characterization and disease diagnosis. Significant systematic errors can arise in the measured reflectance spectra and thus in the derived tissue physiological and morphological parameters due to real-time instrument fluctuations. We demonstrate a novel fiber optic probe with real-time, self-calibration capability that can be used for UV-visible diffuse reflectance spectroscopy in biological tissue in clinical settings. The probe is tested in a number of synthetic liquid phantoms over a wide range of tissue optical properties for significant variations in source intensity fluctuations caused by instrument warm up and day-to-day drift. While the accuracy for extraction of absorber concentrations is comparable to that achieved with the traditional calibration (with a reflectance standard), the accuracy for extraction of reduced scattering coefficients is significantly improved with the self-calibration probe compared to traditional calibration. This technology could be used to achieve instrument-independent diffuse reflectance spectroscopy in vivo and obviate the need for instrument warm up and post∕premeasurement calibration, thus saving up to an hour of precious clinical time.

  15. Photoacoustic spectroscopy for process analysis.

    PubMed

    Schmid, Thomas

    2006-03-01

    Photoacoustic spectroscopy (PAS) is based on the absorption of electromagnetic radiation by analyte molecules. The absorbed energy is measured by detecting pressure fluctuations in the form of sound waves or shock pulses. In contrast to conventional absorption spectroscopy (such as UV/Vis spectroscopy), PAS allows the determination of absorption coefficients over several orders of magnitude, even in opaque and strongly scattering samples. Small absorption coefficients, such as those encountered during trace gas monitoring, can be detected with cells with relatively short pathlengths. Furthermore, PA techniques allow absorption spectra of solid samples (including powders, chips or large objects) to be determined, and they permit depth profiling of layered systems. These features mean that PAS can be used for on-line monitoring in technical processes without the need for sample preparation and to perform depth-resolved characterization of industrial products. This article gives an overview on PA excitation and detection schemes employed in analytical chemistry, and reviews applications of PAS in process analytical technology and characterization of industrial products.

  16. Molecular Spectroscopy with Frequency Combs

    NASA Astrophysics Data System (ADS)

    Coddington, Ian

    2010-03-01

    Pulsed femtosecond frequency combs are rapidly developing as a powerful spectroscopic tool. As a spectroscopic source stabilized frequency combs potentially offer broad spectral coverage, near perfect frequency accuracy, low timing jitter and broadband compatibility with resonant cavities. This talk will focus on the first three advantages in a dual comb spectroscopic technique that is highly analogous to traditional Fourier transform spectroscopy. In the dual comb approach, (pioneered in the THz by Keilmann, Van der Weide and coworkers under the name multi-heterodyne spectroscopy), one comb is used to sample a gas and a second frequency comb serves as a local oscillator (LO) that samples the first comb. The LO is held at a slightly different repetition rate than the first comb. When viewed in the time domain, the comb sources each emit a train of pulses. With the difference in repetition rates, for each successive pair of pulses, the timing between the sample and LO laser pulses shifts slightly. Through successive measurements, the LO pulses read out the entire time domain structure of the transmitted sample pulse. Through a Fourier transform, we recover the broadband, complex, absorption profile of the sample gas. In analogy to a Fourier transform spectrometer the LO serves as a scanning interferometer arm. The removal of moving parts from the system along with the addition of high brightness collimated sources brings new flexibility to FTIR spectroscopy. This talk will focus on strengths and limitations of the dual comb technique. Specifically we focus on comb stabilization techniques that allow for long averaging periods, firmware based averaging techniques that keep data sizes manageable and allow for realtime data processing, time domain multiplexing of signal and reference data for continuous removal of system drift, and difference frequency generation techniques to extend this system into the mid IR. We will also discuss methods to improve the sensitivity

  17. Transcutaneous Raman Spectroscopy of Bone

    NASA Astrophysics Data System (ADS)

    Maher, Jason R.

    Clinical diagnoses of bone health and fracture risk typically rely upon measurements of bone density or structure, but the strength of a bone is also dependent upon its chemical composition. One technology that has been used extensively in ex vivo, exposed-bone studies to measure the chemical composition of bone is Raman spectroscopy. This spectroscopic technique provides chemical information about a sample by probing its molecular vibrations. In the case of bone tissue, Raman spectra provide chemical information about both the inorganic mineral and organic matrix components, which each contribute to bone strength. To explore the relationship between bone strength and chemical composition, our laboratory has contributed to ex vivo, exposed-bone animal studies of rheumatoid arthritis, glucocorticoid-induced osteoporosis, and prolonged lead exposure. All of these studies suggest that Raman-based predictions of biomechanical strength may be more accurate than those produced by the clinically-used parameter of bone mineral density. The utility of Raman spectroscopy in ex vivo, exposed-bone studies has inspired attempts to perform bone spectroscopy transcutaneously. Although the results are promising, further advancements are necessary to make non-invasive, in vivo measurements of bone that are of sufficient quality to generate accurate predictions of fracture risk. In order to separate the signals from bone and soft tissue that contribute to a transcutaneous measurement, we developed an overconstrained extraction algorithm that is based upon fitting with spectral libraries derived from separately-acquired measurements of the underlying tissue components. This approach allows for accurate spectral unmixing despite the fact that similar chemical components (e.g., type I collagen) are present in both soft tissue and bone and was applied to experimental data in order to transcutaneously detect, to our knowledge for the first time, age- and disease-related spectral

  18. Raman spectroscopy of bone metastasis

    NASA Astrophysics Data System (ADS)

    Esmonde-White, Karen A.; Sottnik, Joseph; Morris, Michael; Keller, Evan

    2012-02-01

    Raman spectroscopy of bone has been used to characterize chemical changes occurring in diseases such as osteoporosis, osteoarthritis and osteomyelitis. Metastasis of cancer into bone causes changes to bone quality that are similar to those observed in osteoporosis, such as decreased bone strength, but with an accelerated timeframe. In particular, osteolytic (bone degrading) lesions in bone metastasis have a marked effect on patient quality of life because of increased risk of fractures, pain, and hypercalcemia. We use Raman spectroscopy to examine bone from two different mouse models of osteolytic bone metastasis. Raman spectroscopy measures physicochemical information which cannot be obtained through standard biochemical and histological measurements. This study was reviewed and approved by the University of Michigan University Committee on the Care and Use of Animals. Two mouse models of prostate cancer bone metastasis, RM1 (n=3) and PC3-luc (n=4) were examined. Tibiae were injected with RM1 or PC3-luc cancer cells, while the contralateral tibiae received a placebo injection for use as controls. After 2 weeks of incubation, the mice were sacrificed and the tibiae were examined by Raman microspectroscopy (λ=785 nm). Spectroscopic markers corresponding to mineral stoichiometry, bone mineralization, and mineral crystallinity were compared in spectra from the cancerous and control tibiae. X-ray imaging of the tibia confirmed extensive osteolysis in the RM1 mice, with tumor invasion into adjoining soft tissue and moderate osteolysis in the PC3-luc mice. Raman spectroscopic markers indicate that osteolytic lesions are less mineralized than normal bone tissue, with an altered mineral stoichiometry and crystallinity.

  19. Laser sources for Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Kilmer, J.; Iadevaia, A.; Yin, Y.

    2011-06-01

    While conventional Raman Spectroscopy (RS) has predominately used fixed wavelength cw lasers, advanced Raman spectroscopic techniques such as Stimulated Raman and some types of Raman Imaging typically need pulsed lasers with sufficient energy to induce the Raman process. In addition, pulsed lasers are beneficial for the following Raman techniques: Time Resolved Raman (TRR), Resonance Raman (RR), or non linear Raman techniques, such as Coherent anti-Stokes Raman spectroscopy (CARS). Here the naturally narrower linewidth of a ns pulse width laser is advantageous to a broader linewidth ultrafast pulsed laser. In this paper, we report on the development of a compact, highly efficient, high power solid-state Ti: Sapphire laser ideally suited for many Raman spectroscopic techniques. This laser produces nanosecond pulses at kHz repetition rates with a tunable output wavelength from ~1 micron to ~200 nm and pulse energies up to 1 mJ. The narrow bandwidth of this laser (<0.1cm-1) is ideally suited for applications such as Laser-induced fluorescence (LIF) measurement of OH free-radicals concentrations, atmospheric LIDAR and Raman spectroscopy. New KBBF and RBBF deep ultraviolet (DUV) and vacuum ultraviolet (VUV) crystals are now available that enable direct doubling of the SHG output of these tunable Ti: Sapphire lasers to directly achieve wavelengths as short as 175 nm without the need to generate the 3rd harmonic and utilize frequency mixing. This results in a highly efficient output in the DUV/VUV, enabling improved signal to noise ratios (S/N) in these previously difficult wavelength regions. Photonics Industries has recently achieved a few mW of power at 193nm with such direct doubling crystals.

  20. MR spectroscopy of metabolic disorders.

    PubMed

    Cecil, Kim M

    2006-02-01

    The application of MR spectroscopy (MRS) in pediatric brain disorders yields valued information on pathologic processes, such as ischemia, demyelination, gliosis, and neurodegeneration. Because these processes manifest in inborn errors of metabolism, the purposes of this article are to (1) describe the spectral changes that are associated with the relatively common metabolic disorders, with summaries of known spectroscopic features of these disorders; (2) offer suggestions for recognition and distinction of disorders; and (3) provide general guidelines for MRS implementation. Although many conditions have a similar presentation, MRS offers valuable information for the individual patient in diagnosis and therapy when integrated fully into the clinical setting.

  1. Capillary wave spectroscopy on ferrofluids

    NASA Astrophysics Data System (ADS)

    Patzke, J.; Rathke, B.; Will, S.

    2007-12-01

    We investigate the magnetoviscous effect in ferrofluids by Capillary Wave Spectroscopy (CWS, Surface Light Scattering). This technique probes a specific mode of thermally excited surface waves giving information on surface tension and viscosity. In ferrofluids we detect a transition from propagating surface modes to overdamped ones depending on the particle concentration and strength and the orientation of an externally applied magnetic field. We interprete this effect as caused by an increase of the liquid viscosity with an increasing particle concentration and field-strength. Changing the relative orientation of the scattering vector and magnetic field shows that the viscous properties of ferrofluids in a magnetic field are anisotropic. Figs 8, Refs 12.

  2. Simultaneous beta and gamma spectroscopy

    DOEpatents

    Farsoni, Abdollah T.; Hamby, David M.

    2010-03-23

    A phoswich radiation detector for simultaneous spectroscopy of beta rays and gamma rays includes three scintillators with different decay time characteristics. Two of the three scintillators are used for beta detection and the third scintillator is used for gamma detection. A pulse induced by an interaction of radiation with the detector is digitally analyzed to classify the type of event as beta, gamma, or unknown. A pulse is classified as a beta event if the pulse originated from just the first scintillator alone or from just the first and the second scintillator. A pulse from just the third scintillator is recorded as gamma event. Other pulses are rejected as unknown events.

  3. Development of MEMS photoacoustic spectroscopy

    SciTech Connect

    Robinson, Alex Lockwood; Eichenfield, Matthew S.; Griffin, Benjamin; Harvey, Heidi Alyssa; Nielson, Gregory N.; Okandan, Murat; Langlois, Eric; Resnick, Paul James; Shaw, Michael J.; Young, Ian; Givler, Richard C.; Reinke, Charles M.

    2014-01-01

    After years in the field, many materials suffer degradation, off-gassing, and chemical changes causing build-up of measurable chemical atmospheres. Stand-alone embedded chemical sensors are typically limited in specificity, require electrical lines, and/or calibration drift makes data reliability questionable. Along with size, these "Achilles' heels" have prevented incorporation of gas sensing into sealed, hazardous locations which would highly benefit from in-situ analysis. We report on development of an all-optical, mid-IR, fiber-optic based MEMS Photoacoustic Spectroscopy solution to address these limitations. Concurrent modeling and computational simulation are used to guide hardware design and implementation.

  4. Route to Attosecond Nonlinear Spectroscopy

    SciTech Connect

    Reiter, F.; Kienberger, R.; Graf, U.; Schweinberger, W.; Fiess, M.; Goulielmakis, E.; Serebryannikov, E. E.; Zheltikov, A. M.; Schultze, M.; Krausz, F.; Azzeer, A. M.

    2010-12-10

    We demonstrate generation of coherent microjoule-scale, low-order harmonic supercontinua in the deep and vacuum ultraviolet (4-9 eV), resulting from the nonlinear transformations of near-single-cycle laser pulses in a gas cell. We show theoretically that their formation is connected to a novel nonlinear regime, holding promise for the generation of powerful deep-UV and vacuum ultraviolet subfemtosecond pulses. Our work opens the route to pump-probe spectroscopy of subfemtosecond-scale valence-shell phenomena in atoms, molecules, and condensed matter.

  5. Examining pharmaceuticals using terahertz spectroscopy

    NASA Astrophysics Data System (ADS)

    Sulovská, Kateřina; Křesálek, Vojtěch

    2015-10-01

    Pharmaceutical trafficking is common issue in countries where they are under stricter dispensing regime with monitoring of users. Most commonly smuggled pharmaceuticals include trade names Paralen Plus, Modafen, Clarinase repetabs, Aspirin complex, etc. These are transported mainly from Eastern Europe (e.g. Poland, Ukraine, Russia) to countries like Czech Republic, which is said to have one of the highest number of methamphetamine producers in Europe. The aim of this paper is to describe the possibility of terahertz spectroscopy utilization as an examining tool to distinguish between pharmaceuticals containing pseudoephedrine compounds and those without it. Selected medicaments for experimental part contain as an active ingredient pseudoephedrine hydrochloride or pseudoephedrine sulphate. Results show a possibility to find a pseudoephedrine compound spectra in samples according to previously computed and experimentally found ones, and point out that spectra of same brand names pills may vary according to their expiration date, batch, and amount of absorbed water vapours from ambience. Mislead spectrum also occurs during experimental work in a sample without chosen active ingredient, which shows persistent minor inconveniences of terahertz spectroscopy. All measurement were done on the TPS Spectra 3000 instrument.

  6. Planetary Fabry-Perot spectroscopy

    NASA Technical Reports Server (NTRS)

    Trauger, J. T.

    1988-01-01

    Application of high spectral resolution, Earth-based Fabry-Perot spectroscopy to the study of planetary atmospheres, for which current topics are outer planet HD and H2 spectra (atmospheric structure, D/H ratio), Mars CO2, CO, O2, and H2O spectra (atomspheric photochemistry), Venus H2O and HDO, associated laboratory spectroscopy (especially H2 overtone bands, HDO) was accomplished. Monochromatic charge coupled device (CCD) imaging photometry of the Jovian nebula, with images taken in rapid sequence among the diagnostic spectral lines of ionized sulfur species, provided self-supporting snapshots of the Jupiter/Io plasma conditions (spatially resolved electron and ion densities and temperatures), covering the post-Voyager period from 1981 and leading up to the Galileo tour in the early 1990s. High spectral resolution Fabry-Perot/charge coupled device (CCD) imaging of comets (OI, CI, and H2O(+) velocity maps and spatial distriubtions), and Io's charge exchanged neutral jet was studied.

  7. Cavity Enhanced Velocity Modulation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Siller, Brian; Mills, Andrew; McCall, Benjamin J.

    2010-06-01

    Velocity modulation spectroscopy has traditionally been used with a unidirectional multipass White cell to obtain several passes through a plasma in order to obtain strong signals from the absorption of ions, but the total number of passes allowed by this type of setup is limited to ˜8. By placing an optical cavity around an N_2^+ plasma and locking the cavity to a Ti:Sapphire laser, the effective number of passes has been increased to several hundred. Demodulating the signal from the transmitted light at twice the plasma frequency (due to the symmetric nature of the cavity) gives a 2nd derivative lineshape for ions and a Gaussian lineshape for excited neutrals. N_2^+ and N_2^* have been observed to be 78° out of phase with one another. The different lineshapes and phases allow for discrimination and separation of the ion and neutral signals. The high intensity laser light within the cavity causes the transitions to saturate, which allows for the observation of lamb dips; this opens the door to sub-Doppler spectroscopy, as well as to studies of ion-neutral collisional rate coefficients.

  8. Spectroscopy of multicomponent thermal plasma

    NASA Astrophysics Data System (ADS)

    Lebid, Anton; Veklich, Anatoliy; Boretskij, Viacheslav; Fesenko, Sergiy; Semenyshyn, Rostislav

    2012-10-01

    Applications of composite materials in switching devices for the electrical engineering industry stimulate the interest in studying of the arc discharge plasma between composite electrodes. As an industrial application of silver -- cadmium oxide leads to the environmental pollution, the more attention must be paid to the development of composites, which contain alternate materials, in particular, Ag-SnO2-ZnO. Composite materials on copper base with addition of high-melting metals, like tungsten and molybdenum, are widely used as well. The plasma parameters of free burning electric arc discharge between composite electrodes Ag-SnO2-ZnO, Cu-Mo and Cu-W were obtained by optical emission spectroscopy. The radial profiles of temperature and electron density at different arc currents were obtained by spectroscopy techniques. These experimental results were used in calculation of plasma composition in assumption of local thermodynamic equilibrium. So, electric erosion properties of such kind materials were testified. The selection of CuI, AgI, ZnI, MoI and WI spectral lines and their spectroscopic data were carried out.

  9. X-ray Echo Spectroscopy

    NASA Astrophysics Data System (ADS)

    Shvyd'ko, Yuri

    2016-02-01

    X-ray echo spectroscopy, a counterpart of neutron spin echo, is being introduced here to overcome limitations in spectral resolution and weak signals of the traditional inelastic x-ray scattering (IXS) probes. An image of a pointlike x-ray source is defocused by a dispersing system comprised of asymmetrically cut specially arranged Bragg diffracting crystals. The defocused image is refocused into a point (echo) in a time-reversal dispersing system. If the defocused beam is inelastically scattered from a sample, the echo signal acquires a spatial distribution, which is a map of the inelastic scattering spectrum. The spectral resolution of the echo spectroscopy does not rely on the monochromaticity of the x rays, ensuring strong signals along with a very high spectral resolution. Particular schemes of x-ray echo spectrometers for 0.1-0.02 meV ultrahigh-resolution IXS applications (resolving power >108 ) with broadband ≃5 - 13 meV dispersing systems are introduced featuring more than 103 signal enhancement. The technique is general, applicable in different photon frequency domains.

  10. ION PAIR DISSOCIATION: Spectroscopy and Dynamics

    NASA Astrophysics Data System (ADS)

    Suits, Arthur G.; Hepburn, John W.

    2006-05-01

    Ion pair dissociation processes may be studied using coherent vacuum ultraviolet laser sources in a manner entirely analogous to photoelectron spectroscopy, albeit with the anion playing the role of a heavy electron. If the excitation energy is above the dissociation energy and the kinetic energy of the fragment is measured using ion imaging, this approach is termed ion pair imaging spectroscopy (IPIS) and is related to conventional photoelectron spectroscopy. If the excitation energy is just below the dissociation energy and pulsed-field dissociation is employed, this approach is analogous to mass analyzed threshold ionization (MATI) spectroscopy and is termed threshold ion pair production spectroscopy (TIPPS). These approaches provide a novel means of investigating ion thermochemistry and spectroscopy and superexcited state decay dynamics at high resolution.

  11. Modern NMR spectroscopy: a guide for chemists

    SciTech Connect

    Sanders, J.K.M.; Hunter, B.K.

    1988-01-01

    The aim of the authors of Modern NMR Spectroscopy is to bridge the communication gap between the chemist and the spectroscopist. The approach is nonmathematical, descriptive, and pictorial. To illustrate the ideas introduced in the text, the authors provide original spectra obtained specially for this purpose. Examples include spectroscopy of protons, carbon, and less receptive nuclei of interest to inorganic chemists. The authors succeed in making high-resolution NMR spectroscopy comprehensible for the average student or chemist.

  12. Atomic absorption spectroscopy in ion channel screening.

    PubMed

    Stankovich, Larisa; Wicks, David; Despotovski, Sasko; Liang, Dong

    2004-10-01

    This article examines the utility of atomic absorption spectroscopy, in conjunction with cold flux assays, to ion channel screening. The multiplicity of ion channels that can be interrogated using cold flux assays and atomic absorption spectroscopy is summarized. The importance of atomic absorption spectroscopy as a screening tool is further elaborated upon by providing examples of the relevance of ion channels to various physiological processes and targeted diseases.

  13. Surface-Enhanced Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Stiles, Paul L.; Dieringer, Jon A.; Shah, Nilam C.; van Duyne, Richard P.

    2008-07-01

    The ability to control the size, shape, and material of a surface has reinvigorated the field of surface-enhanced Raman spectroscopy (SERS). Because excitation of the localized surface plasmon resonance of a nanostructured surface or nanoparticle lies at the heart of SERS, the ability to reliably control the surface characteristics has taken SERS from an interesting surface phenomenon to a rapidly developing analytical tool. This article first explains many fundamental features of SERS and then describes the use of nanosphere lithography for the fabrication of highly reproducible and robust SERS substrates. In particular, we review metal film over nanosphere surfaces as excellent candidates for several experiments that were once impossible with more primitive SERS substrates (e.g., metal island films). The article also describes progress in applying SERS to the detection of chemical warfare agents and several biological molecules.

  14. Terahertz spectroscopy of plasmonic fractals.

    PubMed

    Agrawal, A; Matsui, T; Zhu, W; Nahata, A; Vardeny, Z V

    2009-03-20

    We use terahertz time-domain spectroscopy to study the transmission properties of metallic films perforated with aperture arrays having deterministic or stochastic fractal morphologies ("plasmonic fractals"), and compare them with random aperture arrays. All of the measured plasmonic fractals show transmission resonances and antiresonances at frequencies that correspond to prominent features in their structure factors in k space. However, in sharp contrast to periodic aperture arrays, the resonant transmission enhancement decreases with increasing array size. This property is explained using a density-density correlation function, and is utilized for determining the underlying fractal dimensionality, D(<2). Furthermore, a sum rule for the transmission resonances and antiresonances in plasmonic fractals relative to the transmission of the corresponding random aperture arrays is obtained, and is shown to be universal.

  15. Photoacoustic spectroscopy for chemical detection

    NASA Astrophysics Data System (ADS)

    Holthoff, Ellen L.; Pellegrino, Paul M.

    2012-06-01

    The Global War on Terror has made rapid detection and identification of chemical and biological agents a priority for Military and Homeland Defense applications. Reliable real-time detection of these threats is complicated by our enemy's use of a diverse range of materials. Therefore, an adaptable platform is necessary. Photoacoustic spectroscopy (PAS) is a useful monitoring technique that is well suited for trace detection of gaseous media. This method routinely exhibits detection limits at the parts-per-billion (ppb) or sub-ppb range. The versatility of PAS also allows for the investigation of solid and liquid analytes. Current research utilizes quantum cascade lasers (QCLs) in combination with an air-coupled solid-phase photoacoustic cell design for the detection of condensed phase material films deposited on a surface. Furthermore, variation of the QCL pulse repetition rate allows for identification and molecular discrimination of analytes based solely on photoacoustic spectra collected at different film depths.

  16. On Impedance Spectroscopy of Supercapacitors

    NASA Astrophysics Data System (ADS)

    Uchaikin, V. V.; Sibatov, R. T.; Ambrozevich, A. S.

    2016-10-01

    Supercapacitors are often characterized by responses measured by methods of impedance spectroscopy. In the frequency domain these responses have the form of power-law functions or their linear combinations. The inverse Fourier transform leads to relaxation equations with integro-differential operators of fractional order under assumption that the frequency response is independent of the working voltage. To compare long-term relaxation kinetics predicted by these equations with the observed one, charging-discharging of supercapacitors (with nominal capacitances of 0.22, 0.47, and 1.0 F) have been studied by means of registration of the current response to a step voltage signal. It is established that the reaction of devices under study to variations of the charging regime disagrees with the model of a homogeneous linear response. It is demonstrated that relaxation is well described by a fractional stretched exponent.

  17. Computer simulation in mechanical spectroscopy

    NASA Astrophysics Data System (ADS)

    Blanter, M. S.

    2012-09-01

    Several examples are given for use of computer simulation in mechanical spectroscopy. On one hand simulation makes it possible to study relaxation mechanisms, and on the other hand to use the colossal accumulation of experimental material to study metals and alloys. The following examples are considered: the effect of Al atom ordering on the Snoek carbon peak in alloys of the system Fe - Al - C; the effect of plastic strain on Finkel'shtein - Rozin relaxation in Fe - Ni - C austenitic steel; checking the adequacy of energy interactions of interstitial atoms, calculated on the basis of a first-principle model by simulation of the concentration dependence of Snoek relaxation parameters in Nb - O.

  18. Detailed spectroscopy of Fm249

    NASA Astrophysics Data System (ADS)

    Lopez-Martens, A.; Hauschild, K.; Yeremin, A. V.; Belozerov, A. V.; Briançon, Ch.; Chelnokov, M. L.; Chepigin, V. I.; Curien, D.; Dorvaux, O.; Gall, B.; Gorshkov, V. A.; Guttormsen, M.; Hanappe, F.; Kabachenko, A. P.; Khalfallah, F.; Korichi, A.; Larsen, A. C.; Malyshev, O. N.; Minkova, A.; Oganessian, Yu. Ts.; Popeko, A. G.; Rousseau, M.; Rowley, N.; Sagaidak, R. N.; Sharo, S.; Shutov, A. V.; Siem, S.; Svirikhin, A. I.; Syed, N. U. H.; Theisen, Ch.

    2006-10-01

    Excited states in Fm249 were populated via the α decay of No253 and the subsequent decay was observed with the GABRIELA detection system installed at the focal plane of the VASSILISSA recoil separator. The energies, spins, and parities of these states could be established through combined α,γ, and conversion-electron spectroscopy. The first members of the ground-state rotational band were identified. Their excitation energies as well as the observation of a cross-over E2 transition confirm the assignment of 7/2+[624] for the ground state of Fm249. Two excited states were also observed and their decay properties suggest that they correspond to the particle excitation 9/2-[734] and hole excitation 5/2+[622]. The analysis suggests that the 279-keV transition de-exciting the 9/2- state has anomalous E1 conversion coefficients.

  19. Ultraviolet, Visible, and Fluorescence Spectroscopy

    NASA Astrophysics Data System (ADS)

    Penner, Michael H.

    Spectroscopy in the ultraviolet-visible (UV-Vis) range is one of the most commonly encountered laboratory techniques in food analysis. Diverse examples, such as the quantification of macrocomponents (total carbohydrate by the phenol-sulfuric acid method), quantification of microcomponents, (thiamin by the thiochrome fluorometric procedure), estimates of rancidity (lipid oxidation status by the thiobarbituric acid test), and surveillance testing (enzyme-linked immunoassays), are presented in this text. In each of these cases, the analytical signal for which the assay is based is either the emission or absorption of radiation in the UV-Vis range. This signal may be inherent in the analyte, such as the absorbance of radiation in the visible range by pigments, or a result of a chemical reaction involving the analyte, such as the colorimetric copper-based Lowry method for the analysis of soluble protein.

  20. Microcoil nuclear magnetic resonance spectroscopy.

    PubMed

    Webb, A G

    2005-08-10

    In comparison with most analytical chemistry techniques, nuclear magnetic resonance has an intrinsically low sensitivity, and many potential applications are therefore precluded by the limited available quantity of certain types of sample. In recent years, there has been a trend, both commercial and academic, towards miniaturization of the receiver coil in order to increase the mass sensitivity of NMR measurements. These small coils have also proved very useful in coupling NMR detection with commonly used microseparation techniques. A further development enabled by small detectors is parallel data acquisition from many samples simultaneously, made possible by incorporating multiple receiver coils into a single NMR probehead. This review article summarizes recent developments and applications of "microcoil" NMR spectroscopy.

  1. Infrared spectroscopy of NGC 1068

    NASA Astrophysics Data System (ADS)

    Depoy, D. L.

    Spectroscopy of the nucleus of the nearby Seyfert 2 galaxy NGC 1068 has been obtained using the IRTF and the facility Cooled-Grating Array Spectrometer (CGAS). The wavelengths observed covered the expected wavelengths of the Bry (n = 7 4), Br (n = 5 4), and the Pf (n = 7 5) hydrogen recombination lines between 2.2 m and 4.6 m. The CGAS has a 32-element InSb array multiplexed by a Reticon and was used at a resolution of 250 km s-1, allowing accurate determination of the line profiles and surrounding continua simultaneously. For example, the S/N at each spectral position in the Br line spectrum was 100. The data show that the infrared lines are not more broadened than the optical hydrogen recombination lines, suggesting that the presence of an obscured Seyfert 1-like active nucleus is unlikely unless the visual extinction through any obscuring material present is larger than 100 mag.

  2. Surface inspection using FTIR spectroscopy

    NASA Technical Reports Server (NTRS)

    Powell, G. L.; Smyrl, N. R.; Williams, D. M.; Meyers, H. M., III; Barber, T. E.; Marrero-Rivera, M.

    1995-01-01

    The use of reflectance Fourier transform infrared (FTIR) spectroscopy as a tool for surface inspection is described. Laboratory instruments and portable instruments can support remote sensing probes that can map chemical contaminants on surfaces with detection limits under the best of conditions in the sub-nanometer range, i.e.. near absolute cleanliness, excellent performance in the sub-micrometer range, and useful performance for films tens of microns thick. Examples of discovering and quantifying contamination such as mineral oils and greases, vegetable oils, and silicone oils on aluminum foil, galvanized sheet steel, smooth aluminum tubing, and sandblasted 7075 aluminum alloy and D6AC steel. The ability to map in time and space the distribution of oil stains on metals is demonstrated. Techniques associated with quantitatively applying oils to metals, subsequently verifying the application, and non-linear relationships between reflectance and the quantity oil are described.

  3. Cartilage analysis by reflection spectroscopy

    NASA Astrophysics Data System (ADS)

    Laun, T.; Muenzer, M.; Wenzel, U.; Princz, S.; Hessling, M.

    2015-07-01

    A cartilage bioreactor with analytical functions for cartilage quality monitoring is being developed. For determining cartilage composition, reflection spectroscopy in the visible (VIS) and near infrared (NIR) spectral region is evaluated. Main goal is the determination of the most abundant cartilage compounds water, collagen I and collagen II. Therefore VIS and NIR reflection spectra of different cartilage samples of cow, pig and lamb are recorded. Due to missing analytical instrumentation for identifying the cartilage composition of these samples, typical literature concentration values are used for the development of chemometric models. In spite of these limitations the chemometric models provide good cross correlation results for the prediction of collagen I and II and water concentration based on the visible and the NIR reflection spectra.

  4. Spectroscopy of Isolated Prebiotic Nucleobases

    NASA Technical Reports Server (NTRS)

    Svadlenak, Nathan; Callahan, Michael P.; Ligare, Marshall; Gulian, Lisa; Gengeliczki, Zsolt; Nachtigallova, Dana; Hobza, Pavel; deVries, Mattanjah

    2011-01-01

    We use multiphoton ionization and double resonance spectroscopy to study the excited state dynamics of biologically relevant molecules as well as prebiotic nucleobases, isolated in the gas phase. Molecules that are biologically relevant to life today tend to exhibit short excited state lifetimes compared to similar but non-biologically relevant analogs. The mechanism is internal conversion, which may help protect the biologically active molecules from UV damage. This process is governed by conical intersections that depend very strongly on molecular structure. Therefore we have studied purines and pyrimidines with systematic variations of structure, including substitutions, tautomeric forms, and cluster structures that represent different base pair binding motifs. These structural variations also include possible alternate base pairs that may shed light on prebiotic chemistry. With this in mind we have begun to probe the ultrafast dynamics of molecules that exhibit very short excited states and search for evidence of internal conversions.

  5. Spectroscopy of 215Rn86

    SciTech Connect

    Debray, M. E.; Davidson, M.; Davidson, J.; Hojman, D.; Kreiner, A. J.; Cardona, M. A.; Lenzi, S.; Napoli, D.

    2007-02-12

    The yrast level structure of 215,216Rn has been studied using in beam spectroscopy {alpha} - {gamma} - {gamma} coincidence techniques mainly through the 207Pb(18O, 2{alpha}2n) and 208Pb(18O, 2{alpha}2n) reactions in the 91-93 MeV energy range, using the 8{pi} GASP-ISIS spectrometer at Legnaro. The obtained low lying level scheme of 215Rn does not exhibit the alternating parity structure observed in their heavier known isotones 216Fr, 217Ra and 218Ac. The level scheme of 216Rn resulting from this study shows >From this result, the lightest nucleus showing evidence for reflection asymmetry is 216Fr defining one lowest-mass corner for this kind of phenomenon as N{>=}129 and Z{>=}87.

  6. Mossbauer spectroscopy of moon samples.

    PubMed

    Muir, A H; Housley, R M; Grant, R W; Abdel-Gawad, M; Blander, M

    1970-01-30

    Lunar bulk sample 10084,85 (< 1 mm size dust), and samples from rocks 10017,17 (fine grained, vesicular), 10046,17 (breccia), 10057,59 (fine grained, vesicular, top surface), 10057,60 (fine grained, vesicular, interior), and 10058,24 (medium grained, not vesicular) have been investigated by (57)Fe Mössbauer spectroscopy. Iron metal and the Fe(2+) minerals ilmenite, pyroxene, troilite, and iron containing glass have been identified. An iron line of sample 10084,85 (originally sealed in nitrogen) showed no significant intensity change when the sample was exposed to air. The antiferromagnetic transition in several lunar ilmenites at 57(0) +/- 2 degrees K corresponds to stoichiometric FeTiO,. Magneticallv separated 10057 showed troilite and somne metallic iron.

  7. Screening spectroscopy of prostate cancer

    NASA Astrophysics Data System (ADS)

    Yermolenko, S. B.; Voloshynskyy, D. I.; Fedoruk, O. S.

    2015-11-01

    The aim of the study was to establish objective parameters of the field of laser and incoherent radiation of different spectral ranges (UV, visible, IR) as a non-invasive optical method of interaction with different samples of biological tissues and fluids of patients to determine the state of prostate cancer and choosing the best personal treatment. The objects of study were selected venous blood plasma of patient with prostate cancer, histological sections of rat prostate gland in the postoperative period. As diagnostic methods have been used ultraviolet spectrometry samples of blood plasma in the liquid state, infrared spectroscopy middle range (2,5-25 microns) dry residue of plasma by spectral diagnostic technique of thin histological sections of biological tissues.

  8. Mossbauer spectroscopy of extraterrestrial materials

    NASA Technical Reports Server (NTRS)

    Agresti, D. G.

    1986-01-01

    Mossbauer Spectroscopy (MS) has recently been added to the tools used by Dr. Richard Morris of the Experimental Planetology Branch of the Solar System Exploration Division at Johnson Space Flight Center in his research on synthetic and natural analogs of lunar and Martian soils. A least-squares fitting program for MS data written originally for an IBM 360 Mainframe computer was adapted for use on an IBM-PC microcomputer. The adapted program has been applied to the analysis of MS spectra obtained from several samples of Antarctic soil under investigation at JSC as analogs to soil of the Martian regolith. Preliminary conclusions have been drawn from the MS data about the composition of the Antarctic samples. Inferences from optical spectra obtained for these same samples have been compared with the MS results.

  9. Molecular force spectroscopy on cells.

    PubMed

    Liu, Baoyu; Chen, Wei; Zhu, Cheng

    2015-04-01

    Molecular force spectroscopy has become a powerful tool to study how mechanics regulates biology, especially the mechanical regulation of molecular interactions and its impact on cellular functions. This force-driven methodology has uncovered a wealth of new information of the physical chemistry of molecular bonds for various biological systems. The new concepts, qualitative and quantitative measures describing bond behavior under force, and structural bases underlying these phenomena have substantially advanced our fundamental understanding of the inner workings of biological systems from the nanoscale (molecule) to the microscale (cell), elucidated basic molecular mechanisms of a wide range of important biological processes, and provided opportunities for engineering applications. Here, we review major force spectroscopic assays, conceptual developments of mechanically regulated kinetics of molecular interactions, and their biological relevance. We also present current challenges and highlight future directions.

  10. Optical Spectroscopy of New Materials

    NASA Technical Reports Server (NTRS)

    White, Susan M.; Arnold, James O. (Technical Monitor)

    1993-01-01

    Composites are currently used for a rapidly expanding number of applications including aircraft structures, rocket nozzles, thermal protection of spacecraft, high performance ablative surfaces, sports equipment including skis, tennis rackets and bicycles, lightweight automobile components, cutting tools, and optical-grade mirrors. Composites are formed from two or more insoluble materials to produce a material with superior properties to either component. Composites range from dispersion-hardened alloys to advanced fiber-reinforced composites. UV/VIS and FTIR spectroscopy currently is used to evaluate the bonding between the matrix and the fibers, monitor the curing process of a polymer, measure surface contamination, characterize the interphase material, monitor anion transport in polymer phases, characterize the void formation (voids must be minimized because, like cracks in a bulk material, they lead to failure), characterize the surface of the fiber component, and measure the overall optical properties for energy balances.

  11. Raman spectroscopy peer review report

    SciTech Connect

    Winkelman, W.D.; Eberlein, S.J.

    1994-09-01

    The Hanford Site in eastern Washington includes 177 underground storage tanks (UST), which contain waste materials produced during the production of nuclear fuels. The materials in the tanks must be characterized to support the retrieval, processing, and final disposition of the waste. Characterization is currently performed by removing waste samples for analyses in a hot cell or laboratory. A review of the Hanford Raman Spectroscopy Program was held in Richland on March 23 and 24, 1994. A team of principal investigators and researchers made presentations that covered both technical and programmatic aspects of the Hanford Site Raman work. After these presentations and discussions, the review panel met in a closed session to formalize a list of findings. The reviewers agreed that Raman spectroscopy is an excellent method to attack the tank waste characterization and screening problems that were presented. They agreed that there was a good chance that the method would be successful as presently envisioned. The reviewers provided the following primary recommendations: evaluation a laser with wavelength in the near infrared; provide optical filters at or near the sampling end of the fiber-optic probe; develop and implement a strategy for frequent calibration of the system; do not try to further increase Raman resolution at the expense of wavelength range; clearly identify and differentiate between requirements for providing a short-term operational system and requirements for optimizing a system for long-term field use; and determine the best optical configuration, which may include reduced fiber-optic diameter and/or short focal length and low F-number spectrographs.

  12. Photoacoustic spectroscopy sample array vessel and photoacoustic spectroscopy method for using the same

    DOEpatents

    Amonette, James E.; Autrey, S. Thomas; Foster-Mills, Nancy S.; Green, David

    2005-03-29

    Methods and apparatus for analysis of multiple samples by photoacoustic spectroscopy are disclosed. Particularly, a photoacoustic spectroscopy sample array vessel including a vessel body having multiple sample cells connected thereto is disclosed. At least one acoustic detector is acoustically coupled with the vessel body. Methods for analyzing the multiple samples in the sample array vessels using photoacoustic spectroscopy are provided.

  13. Photoacoustic spectroscopy sample array vessels and photoacoustic spectroscopy methods for using the same

    DOEpatents

    Amonette, James E.; Autrey, S. Thomas; Foster-Mills, Nancy S.

    2006-02-14

    Methods and apparatus for simultaneous or sequential, rapid analysis of multiple samples by photoacoustic spectroscopy are disclosed. Particularly, a photoacoustic spectroscopy sample array vessel including a vessel body having multiple sample cells connected thereto is disclosed. At least one acoustic detector is acoustically positioned near the sample cells. Methods for analyzing the multiple samples in the sample array vessels using photoacoustic spectroscopy are provided.

  14. Nuclear-transfer spectroscopy using radioactive targets

    SciTech Connect

    Naumann, R.A.; Dewberry, R.; Kouzes, R.T.; Hoff, R.; Boerner, H.; Lanier, R.G.; Mann, L.; Struble, G.L.

    1981-06-01

    The feasibiity and techniques for carrying out transfer spectroscopic experiments with radioactive targets having half lives down to a fraction of a year are reviewed. The use of such radioactive targets is illustrated by recent studies of the spectroscopy of /sup 149/Sm, /sup 174/Lu and /sup 247/Bk using (p,t) transfer spectroscopy.

  15. NMR Spectroscopy and Its Value: A Primer

    ERIC Educational Resources Information Center

    Veeraraghavan, Sudha

    2008-01-01

    Nuclear magnetic resonance (NMR) spectroscopy is widely used by chemists. Furthermore, the use of NMR spectroscopy to solve structures of macromolecules or to examine protein-ligand interactions is popular. Yet, few students entering graduate education in biological sciences have been introduced to this method or its utility. Over the last six…

  16. Molecular ions, Rydberg spectroscopy and dynamics

    SciTech Connect

    Jungen, Ch.

    2015-01-22

    Ion spectroscopy, Rydberg spectroscopy and molecular dynamics are closely related subjects. Multichannel quantum defect theory is a theoretical approach which draws on this close relationship and thereby becomes a powerful tool for the study of systems consisting of a positively charged molecular ion core interacting with an electron which may be loosely bound or freely scattering.

  17. Nonlinear Spectroscopy of Rubidium: An Undergraduate Experiment

    ERIC Educational Resources Information Center

    Jacques, V.; Hingant, B.; Allafort, A.; Pigeard, M.; Roch, J. F.

    2009-01-01

    In this paper, we describe two complementary nonlinear spectroscopy methods which both allow one to achieve Doppler-free spectra of atomic gases. First, saturated absorption spectroscopy is used to investigate the structure of the 5S[subscript 1/2] [right arrow] 5P[subscript 3/2] transition in rubidium. Using a slightly modified experimental…

  18. The origin of grain boundary capacitance in highly doped ceria.

    PubMed

    Souza, Eduardo Caetano C; Goodenough, John B

    2016-02-17

    The origin of a grain-boundary capacitance in mixed oxide-ion/electronic conductors has been investigated for the case of Ce0.8Sm0.2O1.9-δ using a.c. impedance spectroscopy under low pO2 from 250 to 400 °C. The observed capacitance is interpreted in terms of Ce(III):4f(1) electrons first introduced into the grains and not into the grain boundaries.

  19. Cavity Enhanced Ultrafast Transient Absorption Spectroscopy

    NASA Astrophysics Data System (ADS)

    Allison, Thomas K.; Reber, Melanie Roberts; Chen, Yuning

    2015-06-01

    Ultrafast spectroscopy on gas phase systems is typically restricted to techniques involving photoionization, whereas solution phase experiments utilize the detection of light. At Stony Brook, we are developing new techniques for performing femtosecond time-resolved spectroscopy using frequency combs and high-finesse optical resonators. A large detection sensitivity enhancement over traditional methods enables the extension of all-optical ultrafast spectroscopies, such as broad-band transient absorption spectroscopy (TAS) and 2D spectroscopy, to dilute gas phase samples produced in molecular beams. Here, gas phase data can be directly compared to solution phase data. Initial demonstration experiments are focusing on the photodissociation of iodine in small neutral argon clusters, where cluster size strongly influences the effects solvent-caging and geminate recombination. I will discuss these initial results, our high power home-built Yb:fiber laser systems, and also extensions of the methods to the mid-IR to study the vibrational dynamics of hydrogen bonded clusters.

  20. Fourier Transform Infrared Spectroscopy and Photoacoustic Spectroscopy for Saliva Analysis.

    PubMed

    Mikkonen, Jopi J W; Raittila, Jussi; Rieppo, Lassi; Lappalainen, Reijo; Kullaa, Arja M; Myllymaa, Sami

    2016-09-01

    Saliva provides a valuable tool for assessing oral and systemic diseases, but concentrations of salivary components are very small, calling the need for precise analysis methods. In this work, Fourier transform infrared (FT-IR) spectroscopy using transmission and photoacoustic (PA) modes were compared for quantitative analysis of saliva. The performance of these techniques was compared with a calibration series. The linearity of spectrum output was verified by using albumin-thiocyanate (SCN(-)) solution at different SCN(-) concentrations. Saliva samples used as a comparison were obtained from healthy subjects. Saliva droplets of 15 µL were applied on the silicon sample substrate, 6 drops for each specimen, and dried at 37 ℃ overnight. The measurements were carried out using an FT-IR spectrometer in conjunction with an accessory unit for PA measurements. The findings with both transmission and PA modes mirror each other. The major bands presented were 1500-1750 cm(-1) for proteins and 1050-1200 cm(-1) for carbohydrates. In addition, the distinct spectral band at 2050 cm(-1) derives from SCN(-) anions, which is converted by salivary peroxidases to hypothiocyanate (OSCN(-)). The correlation between the spectroscopic data with SCN(-) concentration (r > 0.990 for transmission and r = 0.967 for PA mode) was found to be significant (P < 0.01), thus promising to be utilized in future applications.

  1. Raman Spectroscopy of Ocular Tissue

    NASA Astrophysics Data System (ADS)

    Ermakov, Igor V.; Sharifzadeh, Mohsen; Gellermann, Warner

    The optically transparent nature of the human eye has motivated numerous Raman studies aimed at the non-invasive optical probing of ocular tissue components critical to healthy vision. Investigations include the qualitative and quantitative detection of tissue-specific molecular constituents, compositional changes occurring with development of ocular pathology, and the detection and tracking of ocular drugs and nutritional supplements. Motivated by a better understanding of the molecular mechanisms leading to cataract formation in the aging human lens, a great deal of work has centered on the Raman detection of proteins and water content in the lens. Several protein groups and the hydroxyl response are readily detectable. Changes of protein compositions can be studied in excised noncataractous tissue versus aged tissue preparations as well as in tissue samples with artificially induced cataracts. Most of these studies are carried out in vitro using suitable animal models and conventional Raman techniques. Tissue water content plays an important role in optimum light transmission of the outermost transparent ocular structure, the cornea. Using confocal Raman spectroscopy techniques, it has been possible to non-invasively measure the water to protein ratio as a measure of hydration status and to track drug-induced changes of the hydration levels in the rabbit cornea at various depths. The aqueous humor, normally supplying nutrients to cornea and lens, has an advantageous anterior location for Raman studies. Increasing efforts are pursued to non-invasively detect the presence of glucose and therapeutic concentrations of antibiotic drugs in this medium. In retinal tissue, Raman spectroscopy proves to be an important tool for research into the causes of macular degeneration, the leading cause of irreversible vision disorders and blindness in the elderly. It has been possible to detect the spectral features of advanced glycation and advanced lipooxydation end products in

  2. Biomedical applications of laser spectroscopy

    NASA Astrophysics Data System (ADS)

    Svanberg, Sune

    1999-07-01

    Very soon after the invention of the laser, the use of the thermal effects of the radiation was introduced. Such techniques have been refined and the laser is now routinely used for treatment in many specialities. Photodynamic therapy (PDT) is a non-thermal modality employing the combination of a tumor-seeking agent and activating laser light. During the last 15 years laser spectroscopic techniques have also been developed providing powerful means for non-intrusive medical diagnostics of tissue in real time. At the beginning only few groups were involved in exploratory work, but successively the field has developed now to occupy a large number of research teams, which meet at large specialized conferences. We will here consider three aspects of laser diagnostics: fluorescence, Raman and near-IR, and elastic scattering spectroscopy, and we will also briefly discuss PDT. The activity in the field is very extensive, and rather than trying to give a full overview, illustrations from work performed at the Lund University Medical Laser Center will be given.

  3. Laser crater enhanced Raman spectroscopy.

    PubMed

    Lednev, Vasily N; Sdvizhenskii, Pavel A; Grishin, Mikhail Ya; Filippov, Mikhail N; Shchegolikhin, Alexander N; Pershin, Sergey M

    2017-02-01

    Raman signal enhancement by multiple scattering inside laser crater cones was observed for the first time, to the best of our knowledge. Laser crater enhanced Raman spectroscopy (LCERS) yielded a 14-fold increase in the Raman spectra bands due to efficient multiple scattering of laser irradiation within the laser crater walls. The same pulsed Nd:YAG laser (532 nm, 10 ns) was used for both laser crater formation and Raman scattering experiments by varying the output pulse energy. First, powerful pulses are used to produce the laser crater; then low-energy pulses are used to perform Raman scattering measurements. The laser crater profile and its alignment with the laser beam waist were found to be the key parameters for the optimization of the Raman spectrum intensity enhancement. Raman intensity enhancement resulted from increased surface scattering area at the crater walls, rather than spatially offset Raman scattering. The increased signal-to-noise ratio resulted in limits of detection improvement for quantitative analysis using LCERS.

  4. Spectroscopy of {sup 257}Rf

    SciTech Connect

    Qian, J.; Heinz, A.; Winkler, R.; Khoo, T. L.; Janssens, R. V. F.; Peterson, D.; Seweryniak, D.; Ahmad, I.; Back, B. B.; Carpenter, M. P.; Greene, J. P.; Jiang, C. L.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; Robinson, A.; Savard, G.; Scott, R.; Vondrasek, R.; Wang, X.

    2009-06-15

    The isotope {sup 257}Rf was produced in the fusion-evaporation reaction {sup 208}Pb({sup 50}Ti,n){sup 257}Rf. Reaction products were separated and identified by mass. Delayed spectroscopy of {sup 257}Rf and its decay products was performed. A partial decay scheme with configuration assignments is proposed based on {alpha} hindrance factors. The excitation energy of the 1/2{sup +}[620] configuration in {sup 253}No is proposed. The energy of this 1/2{sup +} state in a series of N=151 isotones increases with nuclear charge, reflecting an increase in the N=152 gap. This gap is deduced to grow substantially from 850 to 1400 keV between Z=94 and 102. An isomeric state in {sup 257}Rf, with a half-life of 160{sub -31}{sup +42} {mu}s, was discovered by detecting internal conversion electrons followed by {alpha} decay. It is interpreted as a three-quasiparticle high-K isomer. A second group of internal conversion electrons, with a half-life of 4.1{sub -1.3}{sup +2.4} s, followed by {alpha} decay, was also observed. These events might originate from the decay of excited states in {sup 257}Lr, populated by electron-capture decay of {sup 257}Rf. Fission of {sup 257}Rf was unambiguously detected, with a branching ratio of b{sub Rf}{sup SF}=0.02{+-}0.01.

  5. Future Directions in Ultraviolet Spectroscopy

    NASA Technical Reports Server (NTRS)

    Sonneborn, George (Editor); Moos, Warren; VanSteenberg, Michael

    2009-01-01

    The 'Future Directions in Ultraviolet Spectroscopy' conference was inspired by the accomplishments of the Far Ultraviolet Spectroscopic Explorer (FUSE) Mission. The FUSE mission was launched in June 1999 and spent over eight years exploring the far-ultraviolet universe, gathering over 64 million seconds of high-resolution spectral data on nearly 3000 astronomical targets. The goal of this conference was not only to celebrate the accomplishments of FUSE, but to look toward the future and understand the major scientific drivers for the ultraviolet capabilities of the next generation fo space observatories. Invited speakers presented discussions based on measurements made by FUSE and other ultraviolet instruments, assessed their connection with measurements made with other techniques and, where appropriate, discussed the implications of low-z measurements for high-z phenomena. In addition to the oral presentations, many participants presented poster papers. The breadth of these presentation made it clear that much good science is still in progress with FUSE data and that these result will continue to have relevance in many scientific areas.

  6. Measuring Gravitation Using Polarization Spectroscopy

    NASA Technical Reports Server (NTRS)

    Matsko, Andrey; Yu, Nan; Maleki, Lute

    2004-01-01

    A proposed method of measuring gravitational acceleration would involve the application of polarization spectroscopy to an ultracold, vertically moving cloud of atoms (an atomic fountain). A related proposed method involving measurements of absorption of light pulses like those used in conventional atomic interferometry would yield an estimate of the number of atoms participating in the interferometric interaction. The basis of the first-mentioned proposed method is that the rotation of polarization of light is affected by the acceleration of atoms along the path of propagation of the light. The rotation of polarization is associated with a phase shift: When an atom moving in a laboratory reference interacts with an electromagnetic wave, the energy levels of the atom are Doppler-shifted, relative to where they would be if the atom were stationary. The Doppler shift gives rise to changes in the detuning of the light from the corresponding atomic transitions. This detuning, in turn, causes the electromagnetic wave to undergo a phase shift that can be measured by conventional means. One would infer the gravitational acceleration and/or the gradient of the gravitational acceleration from the phase measurements.

  7. THz Spectroscopy of the Atmosphere

    NASA Technical Reports Server (NTRS)

    Pickett, Herbert M.

    2000-01-01

    THz spectroscopy of the atmosphere has been driven by the need to make remote sensing measurements of OH. While the THz region can be used for sensitive detection on many atmospheric molecules, the THz region is the best region for measuring the diurnal behavior of stratospheric OH by remote sensing. The infrared region near 3 microns suffers from chemiluminescence and from spectral contamination due to water. The ultraviolet region near 300 nm requires solar illumination. The three techniques for OH emission measurements in the THz region include Fourier Transform interferometry, Fabry-Perot interferometry, and heterodyne radiometry. The first two use cryogenic direct detectors while the last technique uses a local oscillator and a mixer to down convert the THz signal to GHz frequencies. All techniques have been used to measure stratospheric OH from balloon platforms. OH results from the Fabry-Perot based FILOS instrument will be given. Heterodyne measurement of OH at 2.5 THz has been selected to be a component of the Microwave Limb Sounder on the Earth Observing System CHEM-1 polar satellite. The design of this instrument will be described. A balloon-based prototype heterodyne 2.5 THz radiometer had its first flight on, 24 May 1998. Results form this flight will be presented.

  8. FCS and Single Molecule Spectroscopy

    NASA Astrophysics Data System (ADS)

    Rigler, Rudolf

    The idea to develop Fluorescence Fluctuation spectroscopy started when working in Manfred Eigens' Laboratory in G¨ottingen in the Max Planck Institute for Physical Chemistry as a postdoctoral fellow. I had just finished the construction and testing of a fluorescence T-jump machine [1] when Jean Pierre Changeux from Institut Pasteur arrived in G¨ottingen with a bag of freshly isolated nicotinic acetyl choline receptor to use the new fluorescence T-jump apparatus for relaxation kinetic studies of the receptor. Due to the high concentration of detergents present in the preparation and limited conductivity of the solvent leading to strong cavitation in the T-jump cell we could not perform the temperature relaxation experiments. However, this experience raised the question whether the analysis of equilibrium fluctuations by observing changes in the quantum yield of fluorescence would not be an alternative way to follow kinetic processes. In this way all problems related to the instantaneous temperature change could be avoided.

  9. Hyperpolarized 131Xe NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Stupic, Karl F.; Cleveland, Zackary I.; Pavlovskaya, Galina E.; Meersmann, Thomas

    2011-01-01

    Hyperpolarized (hp) 131Xe with up to 2.2% spin polarization (i.e., 5000-fold signal enhancement at 9.4 T) was obtained after separation from the rubidium vapor of the spin-exchange optical pumping (SEOP) process. The SEOP was applied for several minutes in a stopped-flow mode, and the fast, quadrupolar-driven T1 relaxation of this spin I = 3/2 noble gas isotope required a rapid subsequent rubidium removal and swift transfer into the high magnetic field region for NMR detection. Because of the xenon density dependent 131Xe quadrupolar relaxation in the gas phase, the SEOP polarization build-up exhibits an even more pronounced dependence on xenon partial pressure than that observed in 129Xe SEOP. 131Xe is the only stable noble gas isotope with a positive gyromagnetic ratio and shows therefore a different relative phase between hp signal and thermal signal compared to all other noble gases. The gas phase 131Xe NMR spectrum displays a surface and magnetic field dependent quadrupolar splitting that was found to have additional gas pressure and gas composition dependence. The splitting was reduced by the presence of water vapor that presumably influences xenon-surface interactions. The hp 131Xe spectrum shows differential line broadening, suggesting the presence of strong adsorption sites. Beyond hp 131Xe NMR spectroscopy studies, a general equation for the high temperature, thermal spin polarization, P, for spin I⩾1/2 nuclei is presented.

  10. Hyperpolarized 131Xe NMR spectroscopy

    PubMed Central

    Stupic, Karl F.; Cleveland, Zackary I.; Pavlovskaya, Galina E.; Meersmann, Thomas

    2011-01-01

    Hyperpolarized (hp) 131Xe with up to 2.2% spin polarization (i.e., 5000-fold signal enhancement at 9.4 T) was obtained after separation from the rubidium vapor of the spin-exchange optical pumping (SEOP) process. The SEOP was applied for several minutes in a stopped-flow mode, and the fast, quadrupolar-driven T1 relaxation of this spin I = 3/2 noble gas isotope required a rapid subsequent rubidium removal and swift transfer into the high magnetic field region for NMR detection. Because of the xenon density dependent 131Xe quadrupolar relaxation in the gas phase, the SEOP polarization build-up exhibits an even more pronounced dependence on xenon partial pressure than that observed in 129Xe SEOP. 131Xe is the only stable noble gas isotope with a positive gyromagnetic ratio and shows therefore a different relative phase between hp signal and thermal signal compared to all other noble gases. The gas phase 131Xe NMR spectrum displays a surface and magnetic field dependent quadrupolar splitting that was found to have additional gas pressure and gas composition dependence. The splitting was reduced by the presence of water vapor that presumably influences xenon-surface interactions. The hp 131Xe spectrum shows differential line broadening, suggesting the presence of strong adsorption sites. Beyond hp 131Xe NMR spectroscopy studies, a general equation for the high temperature, thermal spin polarization, P, for spin I⩾1/2 nuclei is presented. PMID:21051249

  11. THz spectroscopy of the atmosphere

    NASA Astrophysics Data System (ADS)

    Pickett, Herbert M.

    1999-04-01

    THz spectroscopy of the atmosphere has been driven by the need to make remote sensing measurements of OH. While the THz region can be used for sensitive detection on many atmospheric molecules, the THz region is the best region for measuring the diurnal behavior of stratospheric OH by remote sensing.THe IR region near 3 micrometers requires solar illumination. The three techniques for OH emission measurements in the THz region include Fourier Transform interferometry, Fabry-Perot interferometry, and heterodyne radiometry. The first two use cryogenic direct detectors while the last technique uses a local oscillator and a mixer to down convert the THz signal to GHz frequencies. All techniques have been used to measure stratospheric OH from balloon platforms. OH result from the Fabry-Perot based FILOS instrument will be given. Heterodyne measurement of OH at 2.5 THz has been selected to be a component of the microwave limb sounder on the Earth Observing System CHEM-1 polar satellite. The design of this instrument will be described. A balloon-based prototype heterodyne 2.5 THz radiometer had its first flight on 24 May 1998. Results from this flight will be presented.

  12. Differentiating tissue by fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Woessner, Stefan; Huen, Julien; Malthan, Dirk

    2004-03-01

    A common problem in several surgical applications is the lack of navigational information. Most often, the only source of information about the location of crucial structures, in relation to the surgical instrument, is the visible and tactile sensory input of the surgeon. In some cases, this leads to time-consuming procedures and a high risk for the patient. Therefore, we developed a spectroscopic sensor system for automatic differentiation between several tissue types. For example in milling processes, a sensor that is able to detect bone in contrast to nerve or vein tissue can be used to control the milling process. We showed exemplarily for the cochlea implant, a typical ENT-surgery, that with the help of our sensor system, the milling of bone can be accelerated without increasing the risk for the patient. It is also possible to use this type of sensor system in the area of medical robotics in soft-tissue applications. With real-time information, a continuous registration can take place, in contrast to a registration that is done using static preoperatively acquired images. We showed that our sensor system can be used to dynamically update the location of the patient in relation to CT or MR-images. In conclusion, we have been able to show that well-known spectroscopy sensors can be used to open new possibilities in medical treatment with and without the use of robotics.

  13. Mass resolved resonance ionization spectroscopy of combustion radicals

    SciTech Connect

    Not Available

    1992-06-23

    This report discusses the following topics: REMPI spectroscopy of HCO and DCO; Rempi spectroscopy of the ethynyl radical; REMPI spectroscopy of new electronic states of C{sub 2}; and a flame sampling laser ionization mass spectrometer.

  14. Method and apparatus for optoacoustic spectroscopy

    DOEpatents

    Amer, Nabil M.

    1979-01-01

    A method and apparatus that significantly increases the sensitivity and flexibility of laser optoacoustic spectroscopy, with reduced size. With the method, it no longer is necessary to limit the use of laser optoacoustic spectroscopy to species whose absorption must match available laser radiation. Instead, "doping" with a relatively small amount of an optically absorbing gas yields optoacoustic signatures of nonabsorbing materials (gases, liquids, solids, and aerosols), thus significantly increasing the sensitivity and flexibility of optoacoustic spectroscopy. Several applications of this method are demonstated and/or suggested.

  15. Hypernuclear spectroscopy program at JLab Hall C

    SciTech Connect

    Hashimoto, Osamu; Hashimoto, Osamu; Nakamura, Satoshi; Acha Quimper, Armando; Ahmidouch, Abdellah; Androic, Darko; Asaturyan, Arshak; Asaturyan, Razmik; Baker, O.; Baturin, Pavlo; Benmokhtar, Fatiha; Bosted, Peter; Carlini, Roger; Chen, X.; Christy, Michael; Cole, Leon; Danagoulian, Samuel; Daniel, AJI; Dharmawardane, Kahanawita; Egiyan, Kim; Elaasar, Mostafa; Ent, Rolf; Fenker, Howard; Fujii, Yu; Furic, Miroslav; Gan, Liping; Gaskell, David; Gasparian, Ashot; Gibson, Edward; Gueye, Paul; Halkyard, Rebekah; Honda, D.; Horn, Tanja; Hu, Bitao; Hu, S.; Hungerford, Ed; Ispiryan, Mikayel; Johnston, Kathleen; Jones, Mark; Kalantarians, Narbe; Kaneta, M.; Kato, F.; Kato, Seigo; Kawama, Daisuke; Keppel, Cynthia; Li, Ya; Luo, Wei; Mack, David; Margaryan, Amur; Marikyan, Gagik; Maruyama, Nayuta; Matsumura, Akihiko; Miyoshi, Toshinobu; Mkrtchyan, Arthur; Mkrtchyan, Hamlet; Navasardyan, Tigran; Niculescu, Gabriel; Niculescu, Maria-Ioana; Nomura, Hiroshi; Nonaka, Kenichi; Ohtani, Atsushi; Okayasu, Yuichi; Pamela, Priscilla; Perez, Naipy; Petkovic, Tomislav; Randeniya, Kapugodage; Reinhold, Joerg; Rivera Castillo, Roberto; Roche, Julie; Rodriguez, Victor; Sato, Yoshinori; Seva, Tomislav; Tang, Liguang; Simicevic, Neven; Smith, Gregory; Sumihama, Mizuki; Song, Y.; Tadevosyan, Vardan; Takahashi, Toshiyuki; Tamura, Hirokazu; Tvaskis, Vladas; Vulcan, William; Wang, B.; Wells, Steven; Yan, Chen; Yuan, Lulin; Zamkochian, S.

    2008-05-01

    DOI: http://dx.doi.org/10.1016/j.nuclphysa.2008.01.029
    Hypernuclear production by the (e,e?K+) reaction has unique advantages in hypernuclear spectroscopy of the S=?1 regime. The second-generation spectroscopy experiment on 12C, 7Li and 28Si targets has been recently carried out at JLab Hall C with a new experimental configuration (Tilt method) and also using a new high-resolution kaon spectrometer (HKS). The experiment is described and preliminary results are presented together with the empasis of significance of the (e,e?K+) reaction for ? hypernuclear spectroscopy and its future prospects.

  16. Attenuated total reflection far-ultraviolet spectroscopy

    NASA Astrophysics Data System (ADS)

    Ozaki, Yukihiro; Morisawa, Yusuke; Goto, Takeyoshi; Tanabe, Ichiro

    2016-09-01

    Recently, far-ultraviolet (FUV) spectroscopy of solid and liquid states has been a matter of keen interest because it provides new possibilities for studying electronic structures and transitions of almost all kinds of molecules. It has also great potential for a variety of applications from quantitative and qualitative analysis of aqueous solutions to environmental and geographical analyses. This review describes the state-of- the-art of FUV spectroscopy; an introduction to FUV spectroscopy, the development of FUV spectrometers, investigations on electronic transitions and structure, its various applications, and future prospects.

  17. Raman spectroscopy of biomedical polyethylenes.

    PubMed

    Pezzotti, Giuseppe

    2017-03-27

    With the development of three-dimensional Raman algorithms for local mapping of oxidation and plastic strain, and the ability to resolve molecular orientation patterns with microscopic spatial resolution, there is an opportunity to re-examine many of the foundations on which our understanding of biomedical grade ultra-high molecular weight polyethylenes (UHMWPEs) are based. By implementing polarized Raman spectroscopy into an automatized tool with an improved precision in non-destructively resolving Euler angles, oxidation levels, and microscopic strain, we become capable to make accurate and traceable measurements of the in vitro and in vivo tribological responses of a variety of commercially available UHMWPE bearings for artificial hip and knee joints. In this paper, we first review the foundations and the main algorithms for Raman analyses of oxidation and strain of biomedical polyethylene. Then, we critically re-examine a large body of Raman data previously collected on different polyethylene joint components after in vitro testing or in vivo service, in order to shed new light on an area of particular importance to joint orthopedics: the microscopic nature of UHMWPE surface degradation in the human body. A complex scenario of physical chemistry appears from the Raman analyses, which highlights the importance of molecular-scale phenomena besides mere microstructural changes. The availability of the Raman microscopic probe for visualizing oxidation patterns unveiled striking findings related to the chemical contribution to wear degradation: chain-breaking and subsequent formation of carboxylic acid sites preferentially occur in correspondence of third-phase regions, and they are triggered by emission of dehydroxylated oxygen from ceramic oxide counterparts. These findings profoundly differ from more popular (and simplistic) notions of mechanistic tribology adopted in analyzing joint simulator data.

  18. Neural networks for nuclear spectroscopy

    SciTech Connect

    Keller, P.E.; Kangas, L.J.; Hashem, S.; Kouzes, R.T.

    1995-12-31

    In this paper two applications of artificial neural networks (ANNs) in nuclear spectroscopy analysis are discussed. In the first application, an ANN assigns quality coefficients to alpha particle energy spectra. These spectra are used to detect plutonium contamination in the work environment. The quality coefficients represent the levels of spectral degradation caused by miscalibration and foreign matter affecting the instruments. A set of spectra was labeled with quality coefficients by an expert and used to train the ANN expert system. Our investigation shows that the expert knowledge of spectral quality can be transferred to an ANN system. The second application combines a portable gamma-ray spectrometer with an ANN. In this system the ANN is used to automatically identify, radioactive isotopes in real-time from their gamma-ray spectra. Two neural network paradigms are examined: the linear perception and the optimal linear associative memory (OLAM). A comparison of the two paradigms shows that OLAM is superior to linear perception for this application. Both networks have a linear response and are useful in determining the composition of an unknown sample when the spectrum of the unknown is a linear superposition of known spectra. One feature of this technique is that it uses the whole spectrum in the identification process instead of only the individual photo-peaks. For this reason, it is potentially more useful for processing data from lower resolution gamma-ray spectrometers. This approach has been tested with data generated by Monte Carlo simulations and with field data from sodium iodide and Germanium detectors. With the ANN approach, the intense computation takes place during the training process. Once the network is trained, normal operation consists of propagating the data through the network, which results in rapid identification of samples. This approach is useful in situations that require fast response where precise quantification is less important.

  19. Vibrational spectroscopy of water interfaces

    SciTech Connect

    Du, Quan

    1994-12-01

    The second order nonlinear optical processes of second harmonic generation and sum frequency generation are powerful and versatile tools for studying all kinds of surfaces. They possess unusual surface sensitivity due to the symmetry properties of the second order nonlinear susceptibility. The technique of infrared-visible sum frequency generation (SFG) is particularly attractive because it offers a viable way to do vibrational spectroscopy on any surfaces accessible to light with submonolayer sensitivity. In this thesis, the author applies SFG to study a number of important water interfaces. At the air/water interface, hydrophobic solid/water and liquid/water interfaces, it was found that approximately 25% of surface water molecules have one of their hydrogen pointing away from the liquid water. The large number of unsatisfied hydrogen bonds contributes significantly to the large interfacial energy of the hydrophobic surfaces. At the hydrophilic fused quartz/water interface and a fatty acid monolayer covered water surface, the structure and orientation of surface water molecules are controlled by the hydrogen bonding of water molecules with the surface OH groups and the electrostatic interaction with the surface field from the ionization of surface groups. A change of pH value in the bulk water can significantly change the relative importance of the two interactions and cause a drastic change in orientation of the surface water molecules. SFG has also been applied to study the tribological response of some model lubricant films. Monolayers of Langmuir-Blodgett films were found to disorder orientationaly under mildly high pressure and recover promptly upon removal of the applied pressure.

  20. News from Online: More Spectroscopy

    NASA Astrophysics Data System (ADS)

    Sweeney Judd, Carolyn

    1999-09-01

    on to Evaporative Cooling at http://www.colorado.edu/physics/2000/bec/evap_cool.html. The cartoon professors begin the explanation with a picture of steam rising from a cup of hot coffee. Next is an applet with atoms in a parabolic magnetic trap at http://www.colorado.edu/physics/2000/applets/bec.html. The height of the magnetic trap can be changed in order to allow for escape of the most energetic atoms, resulting in cooling so that the Bose-Einstein Condensate is formed. Physics 2000 demands robust computing power. Check the system requirements on the introductory screen before venturing too far into this site. Martin V. Goldman, from the University of Colorado at Boulder, is the Director of Physics 2000, which received support from the Colorado Commission on Higher Education and the National Science Foundation. David Rea is the Technical Director, and many others help make this excellent site possible. Mark your calendars: October 31 through December 3, 1999! Bookmark this site-- http://www.ched-ccce.org/confchem/1999/d/index.html --and sign up. The Winter 1999 CONFCHEM Online Conference will focus on Developments in Spectroscopy and Innovative Strategies for Teaching Spectroscopy in the Undergraduate Curriculum. Scott Van Bramer of Widener University is the conference chair. Experts will present six papers, each to be followed by online discussions. CONFCHEM Online Conferences are sponsored by the American Chemical Society Division of Chemical Education's Committee on Computers in Chemical Education (CCCE). Several Online Conferences are held each year--all are well worth your time. World Wide Web Addresses EMSpectrum Explorer http://mc2.cchem.berkeley.edu/chemcnx/light_energy/EMSpectrum/emspectrum.html Light and Energy http://mc2.cchem.berkeley.edu/chemcnx/light_energy/index.html Emission Spectrum Java Applet http://mc2.cchem.berkeley.edu/chemcnx/light_energy/applets/emission/index.html Absorption Java Applet http://mc2.cchem

  1. Soil chemical insights provided through vibrational spectroscopy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vibrational spectroscopy techniques provide a powerful approach to study environmental materials and processes. These multifunctional analysis tools can be used to probe molecular vibrations of solid, liquid, and gaseous samples for characterizing materials, elucidating reaction mechanisms, and exam...

  2. Diffraction-limited ultrabroadband terahertz spectroscopy

    NASA Astrophysics Data System (ADS)

    Baillergeau, M.; Maussang, K.; Nirrengarten, T.; Palomo, J.; Li, L. H.; Linfield, E. H.; Davies, A. G.; Dhillon, S.; Tignon, J.; Mangeney, J.

    2016-05-01

    Diffraction is the ultimate limit at which details of objects can be resolved in conventional optical spectroscopy and imaging systems. In the THz spectral range, spectroscopy systems increasingly rely on ultra-broadband radiation (extending over more 5 octaves) making a great challenge to reach resolution limited by diffraction. Here, we propose an original easy-to-implement wavefront manipulation concept to achieve ultrabroadband THz spectroscopy system with diffraction-limited resolution. Applying this concept to a large-area photoconductive emitter, we demonstrate diffraction-limited ultra-broadband spectroscopy system up to 14.5 THz with a dynamic range of 103. The strong focusing of ultrabroadband THz radiation provided by our approach is essential for investigating single micrometer-scale objects such as graphene flakes or living cells, and besides for achieving intense ultra-broadband THz electric fields.

  3. Raman and Photoluminescence Spectroscopy in Mineral Identification

    NASA Astrophysics Data System (ADS)

    Kuehn, J. W.

    2014-06-01

    Raman spectroscopy is particularly useful for rapid identification of minerals and gemstones. Raman spectrometers also allow PL studies for authentication of samples and geological provenance, diamond type screening and detection of HPHT treatments.

  4. How Much Inorganic Spectroscopy and Photochemistry?

    ERIC Educational Resources Information Center

    Gray, Harry B.

    1980-01-01

    Describes three levels of courses to treat adequately the ground state electronic structures, the spectroscopy, and the photochemistry of inorganic molecules. Suggests sequences for the courses without repeating material taught in previous courses. (Author/JN)

  5. Sensors Based on Spectroscopy of Guided Waves

    NASA Astrophysics Data System (ADS)

    Homola, Jiří

    The last two decades have witnessed remarkable progress in the develpment of affinity biosensors and their applications in areas such as environmental protection, biotechnology, medical diagnostics, drug screening, food safety, and security. An affinity biosensor consists of a transducer and a biological recognition element which is able to interact with a selected analyte. Various optical methods have been exploited in biosensors including fluorescence spectroscopy, interferometry (reflectometric white light interferometry, modal interferometry in optical waveguide structures), and spectroscopy of guided modes of optical waveguides. Optical biosensors based on spectroscopy of guided modes of optical waveguides - grating coupler, resonant mirror, and surface plasmon resonance (SPR) - rely on the measurement of binding-induced refractive index changes and thus are label-free technologies. This paper reviews fundamentals of optical sensors based on spectroscopy of guided modes of optical waveguides and their applications.

  6. Teaching the Rovibronic Spectroscopy of Molecular Iodine

    ERIC Educational Resources Information Center

    Williamson, J. Charles

    2007-01-01

    The rovibronic spectroscopy of molecular iodine provides a clearer understanding of the electronic potential parameters of various systems to the undergraduate students. The technique also helps them to test the various other quantum mechanical concepts.

  7. Multiphoton, optical fiber-based fluorescence spectroscopy

    NASA Astrophysics Data System (ADS)

    Bereś-Pawlik, ElŻbieta; Stawska, Hanna; Popenda, Maciej; Pajewski, Łukasz; Malinowska, Natalia; Hossa, Robert

    2016-12-01

    This paper presents investigation of normal and cancerous tissue by the means of one and two photon fluorescence spectroscopy. A comparison those methods has been conducted, allowing for eventual determination of granting the best possible diagnostic results.

  8. Diffraction-limited ultrabroadband terahertz spectroscopy

    PubMed Central

    Baillergeau, M.; Maussang, K.; Nirrengarten, T.; Palomo, J.; Li, L. H.; Linfield, E. H.; Davies, A. G.; Dhillon, S.; Tignon, J.; Mangeney, J.

    2016-01-01

    Diffraction is the ultimate limit at which details of objects can be resolved in conventional optical spectroscopy and imaging systems. In the THz spectral range, spectroscopy systems increasingly rely on ultra-broadband radiation (extending over more 5 octaves) making a great challenge to reach resolution limited by diffraction. Here, we propose an original easy-to-implement wavefront manipulation concept to achieve ultrabroadband THz spectroscopy system with diffraction-limited resolution. Applying this concept to a large-area photoconductive emitter, we demonstrate diffraction-limited ultra-broadband spectroscopy system up to 14.5 THz with a dynamic range of 103. The strong focusing of ultrabroadband THz radiation provided by our approach is essential for investigating single micrometer-scale objects such as graphene flakes or living cells, and besides for achieving intense ultra-broadband THz electric fields. PMID:27142959

  9. Absorption Spectroscopy in Homogeneous and Micellar Solutions.

    ERIC Educational Resources Information Center

    Shah, S. Sadiq; Henscheid, Leonard G.

    1983-01-01

    Describes an experiment which has helped physical chemistry students learn principles of absorption spectroscopy, the effect of solvent polarity on absorption spectra, and some micellar chemistry. Background information and experimental procedures are provided. (JN)

  10. Investigations on polarimetric terahertz frequency domain spectroscopy

    NASA Astrophysics Data System (ADS)

    Gong, Yandong; Zhang, Banghong; Notake, Takashi; Minamide, Hiroaki; Olivo, Malini; Sugii, Shigeki

    2014-04-01

    A polarimetric Terahertz frequency-domain spectroscopy system is presented which has an additional polarization measurement function at the Terahertz band. The achromatic Terahertz waveplate, which acts as the key device in the system, is also presented.

  11. Photoacoustic spectroscopy of man infecting protozoans

    SciTech Connect

    Acosta-Avalos, D.; Alvarado-Gil, J. J.; Vargas, H.

    1998-08-28

    In this paper the fundamentals of photothermal spectroscopy are presented, special emphasis is done in the obtention of the optical absorption spectra. It is shown that this spectroscopy can be used successfully for the monitoring of protozoans that could infect the human. The usefulness of the technique is illustrated in the special case of Leishmania, where it is possible to find that the stage when the protozoan infect vertebrate cells show important differences in relation to the protozoans infecting insects.

  12. Torque-mixing Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Losby, Joseph; Fani Sani, Fatemeh; Grandmont, Dylan; Diao, Zhu; Belov, Miro; Burgess, Jacob; Compton, Shawn; Hiebert, Wayne; Vick, Doug; Mohammad, Kaveh; Salimi, Elham; Bridges, Gregory; Thomson, Douglas; Freeman, Mark

    A universal, mechanical torque method for magnetic resonance spectroscopy is presented. In analogy to resonance detection by induction, a signal proportional to the transverse component of a precessing dipole moment can be measured as a pure mechanical torque in broadband, frequency-swept spectroscopy. Comprehensive electron spin resonance of a single-crystal, mesoscopic yttrium iron garnet disk at room temperature are presented to demonstrate the method. The rich detail allows analysis of even complex 3D spin textures.

  13. Meson Spectroscopy at CLAS and CLAS12

    SciTech Connect

    Carlos Salgado

    2011-10-01

    We report on meson spectroscopy using the CLAS at Jefferson Lab. We study photo-production of exotic mesons and strangeonia on the largest data sample ever to be produced at photon energies of about 5 GeV. We also describe an experiment to continue meson spectroscopy at CLAS12 (CLAS energy upgrade) using electroproduction at very low Q2 ('quasireal photons') up to photon energies of 10 GeV.

  14. Photoacoustic spectroscopy of Entamoeba histolytica strains

    NASA Astrophysics Data System (ADS)

    Acosta-Avalos, D.; Alvarado-Gil, J. J.; Silva, E. F.; Orozco, E.; de Menezes, L. F.; Vargas, H.

    2005-06-01

    Pathogenic and non-pathogenic strains of E. histolytica are studied using photoacoustic spectroscopy. It is shown that the pathogenic strain presents a spectrum similar to that of iron sulfur proteins. The non-pathogenic strain does not show any relevant absorption at the studied wavelength range. The differences observed between the optical absorption spectra of both strains opens the possibility of using photoacoustic spectroscopy as a reliable and simple technique to identify different types of E. histolytica strains.

  15. Medical diagnostics using terahertz pulsed spectroscopy

    NASA Astrophysics Data System (ADS)

    Zaytsev, Kirill I.; Kudrin, Konstantin G.; Koroleva, Svetlana A.; Fokina, Irina N.; Volodarskaya, Svetlana I.; Novitskaya, Ekaterina V.; Perov, Artem N.; Karasik, Valeriy E.; Yurchenko, Stanislav O.

    2014-03-01

    The paper contains recent results of studying the ability of human body disease diagnosis with terahertz time-domain spectroscopy. In vitro skin cancer samples (squamous cell carcinoma, epithelioid cell melanoma, infiltrating carcinoma) were studied experimentally with terahertz pulsed spectrometer. The parametrical in vitro images of skin cancers are presented. The ability to make early tooth cariosity diagnosis with terahertz time-domain spectroscopy was also shown experimentally. The results of studying the in vitro tooth samples are presented and discussed.

  16. Applications of Raman spectroscopy in life science

    NASA Astrophysics Data System (ADS)

    Martin, Airton A.; T. Soto, Cláudio A.; Ali, Syed M.; Neto, Lázaro P. M.; Canevari, Renata A.; Pereira, Liliane; Fávero, Priscila P.

    2015-06-01

    Raman spectroscopy has been applied to the analysis of biological samples for the last 12 years providing detection of changes occurring at the molecular level during the pathological transformation of the tissue. The potential use of this technology in cancer diagnosis has shown encouraging results for the in vivo, real-time and minimally invasive diagnosis. Confocal Raman technics has also been successfully applied in the analysis of skin aging process providing new insights in this field. In this paper it is presented the latest biomedical applications of Raman spectroscopy in our laboratory. It is shown that Raman spectroscopy (RS) has been used for biochemical and molecular characterization of thyroid tissue by micro-Raman spectroscopy and gene expression analysis. This study aimed to improve the discrimination between different thyroid pathologies by Raman analysis. A total of 35 thyroid tissues samples including normal tissue (n=10), goiter (n=10), papillary (n=10) and follicular carcinomas (n=5) were analyzed. The confocal Raman spectroscopy allowed a maximum discrimination of 91.1% between normal and tumor tissues, 84.8% between benign and malignant pathologies and 84.6% among carcinomas analyzed. It will be also report the application of in vivo confocal Raman spectroscopy as an important sensor for detecting advanced glycation products (AGEs) on human skin.

  17. Surface film formation on nickel electrodes in a propylene carbonate solution at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Mogi, Ryo; Inaba, Minoru; Iriyama, Yasutoshi; Abe, Takeshi; Ogumi, Zempachi

    The effect of temperature on surface film formation on nickel electrode was studied in 1 mol dm -3 bis(perfluoroethylsulfonyl)imide dissolved in propylene carbonate by atomic force microscopy (AFM) and ac impedance spectroscopy. Cyclic voltammetry measurements revealed that electrolyte decomposition reactions are accelerated at elevated temperatures, especially at 60 and 80 °C. In situ AFM measurements showed that the film formation is fast and the resulting surface film is thicker at 80 °C than at room temperature. Furthermore, it was confirmed by ac impedance measurements that the resistance of surface film was very low at elevated temperatures. These results were discussed in relation to superior cycling characteristics of lithium deposition and dissolution at the elevated temperatures.

  18. Bidimensional spectroscopy of interacting galaxies

    NASA Astrophysics Data System (ADS)

    Chatzichristou, E. T.

    We have undertaken a program of studying the central few kpc regions of interacting/merger candidates, that were specifically chosen to have a range of nuclear activity, IR properties and strength of interaction. Here we present data obtained using the integral field spectrograph ARGUS, on the CFHT for few of these objects. Unlike slit spectroscopy, these data provide a direct two-dimensional picture of the wavelength-dependant emission and absorption line properties of these galaxies. The main conclusions are: (1) Mkn 789 is a recent merger product, undergoing a strong burst of star formation, while the older stellar component did not have yet the time to relax. It has no compact nuclear structure and its strong star formation powers a large scale outflow ("superwind"), which gives characteristic multiple profiles. Mkn 463 on the other hand, appears at an intermediate merging stage where at least one of its two visible nuclei had time to become activated, showing a Seyfert-like spectrum. The distinct kinematic feature here is a strongly blueshifted component that is interpreted in terms of bowshocks driven by a radio jet into the ambient gas. (2) UGC 3995 is the brightest member of a pair of interacting spirals, has a low-ionization, Seyfert-like spectrum. The velocity field is smooth, characteristic of a retrogradely rotating disk, but we find rotation of the kinematic axis with wavelength, that correspond to isophotal distortions and an obvious line profile substructure. It seems that this is a distinct kinematic feature in Seyfert-like nuclei independently of their interaction stage, indicating radial gas motions that might be related to the activation of the central engine. (3) Both mergers (Mkn 463, Mkn 789) have higher IR activity, as expressed by the LFIR excess and "warm" far-IR colours, among the objects in our sample. This seems to be independent of the nature of the central engine. On the other hand, the 25 microns characteristic excess emission of

  19. Optical Spectroscopy of Stardust Samples

    NASA Technical Reports Server (NTRS)

    Keller, Lindsay P.

    2006-01-01

    The Stardust spacecraft collected dust samples of the Kuiper belt comet 81P Wild-2 in aerogel and returned them to Earth January 15, 2006. Preliminary examination (PE) of the collected dust includes teams focused on mineralogy, chemical composition, isotopic measurements, organic analysis, cratering and spectroscopic properties. The main PE science goals are to provide an initial characterization of the returned samples with an emphasis on the capture process and its effects on the samples, a comparison of Stardust samples to other meteoritic materials, and the abundance of presolar materials in the Stardust samples. The science objectives of the Spectroscopy team are to obtain spectroscopic data on Stardust particles through infrared (IR), UV/Vis and Raman measurements of particles in aerogel, extracted particles, keystones, and microtome thin sections. These data will be used to answer fundamental science questions about the nature of the samples, but will also serve as preliminary mineralogical data to guide follow-on measurements that will be performed in the other preliminary examination teams. The IR characteristics of Stardust particles are measured to determine: 1) the nature of the indigenous 3.4 micron organic feature, is it detected and can it be differentiated/deconvolved from the contaminated aerogel? How does it compare to features observed in interplanetary dust particles (IDPs) and to astronomical measurements of comets and interstellar dust? 2) the shape and fine structure within the 10 micron silicate feature. Overlap with the strong Si-O stretching vibration from the aerogel complicates this analysis, but we hope to determine if the feature is dominated by amorphous silicates such as those observed in IDPs and comets and whether or not crystalline silicates (e.g. olivine, pyroxene, clays) are present, 3) the presence of secondary (alteration) phases. Deep Impact results suggest that IR observations of Stardust particles should be evaluated for

  20. HD209458b Transit Spectroscopy

    NASA Astrophysics Data System (ADS)

    Harrington, J.; Deming, L. D.; Matthews, K.; Richardson, L. J.; Rojo, P.; Steyert, D.; Wiedemann, G.; Zeehandelaar, D.

    2002-09-01

    We search for the spectral signature of H2O, CH4, and CO on the extrasolar planet HD 209458b using transit spectroscopy. The planet will modulate the stellar spectrum during transit. The extinction altitude of tangent rays of a given wavelength depends on the abundance and distribution of molecular species that absorb at that wavelength. The depth of the occultation at a given wavelength depends on the cross-sectional area of the planet, which is determined by the extinction altitude. For deep lines of H2O, CH4, and CO, the effect is about 0.07%, due to the ~750 km scale height. Our S/N calculations show that well-calibrated, ground-based spectra, integrated over time and wavelength, can measure or place useful limits on the atmospheric abundances of H2O, CH4, and CO. Carbon forms predominantly CH4 below 1400 K and CO if hotter. Since the effective temperature is around 1400 K, detecting CH4 and/or CO would provide a tight constraint on atmospheric temperatures. Observations began in August 2001 at Palomar and we have 12 additional nights granted in 2002 at Keck, VLT, and IRTF. The expected modulation of the stellar spectrum is model-dependent: high-altitude hazes, photochemical effects, and different thermal profiles would substantially modify the effect for the same planetary elemental abundances. Since the effect is subtle compared to the noise in the data, we correlate model spectra against thousands of observed spectra and average the correlations to test whether the data support a given model. We are developing a radiative-transfer model to predict the spectrum of a given planetary model, and we are measuring H2O, CH4, and CO in the laboratory at 1300 K, with pressure-broadening by H2, to make our model spectra realistic at these elevated temperatures (crucial for detecting H2O). Analysis of the 2001 data and acquisition of 2002 data are in progress. We solicit participation by those who wish to test their planetary models.

  1. Soft X-Ray and Vacuum Ultraviolet Based Spectroscopy of the Actinides

    SciTech Connect

    Tobin, J G

    2011-03-17

    The subjects of discussion included: VUV photoelectron spectroscopy, X-ray photoelectron spectroscopy, Synchrotron-radiation-based photoelectron spectroscopy, Soft x-ray absorption spectroscopy, Soft x-ray emission spectroscopy, Inverse photoelectron spectroscopy, Bremstrahlung Isochromat Spectroscopy, Low energy IPES, Resonant inverse photoelectron spectroscopy.

  2. REVIEW OF METHODS OF OPTICAL GAS Detection by Direct Optical Spectroscopy, with Emphasis on Correlation Spectroscopy

    NASA Astrophysics Data System (ADS)

    Dakin, John P.; Chambers, Paul

    This chapter reviews the development of optical gas sensors, starting with an initial emphasis on optical-fibre remoted techniques and finishing with a particular focus on our own group's work on highly selective methods using correlation spectroscopy. This latter section includes extensive theoretical modelling of a correlation spectroscopy method, and compares theory with practice for a CO2 sensor.

  3. Raman spectroscopy: the gateway into tomorrow's virology

    PubMed Central

    Lambert, Phelps J; Whitman, Audy G; Dyson, Ossie F; Akula, Shaw M

    2006-01-01

    In the molecular world, researchers act as detectives working hard to unravel the mysteries surrounding cells. One of the researchers' greatest tools in this endeavor has been Raman spectroscopy. Raman spectroscopy is a spectroscopic technique that measures the unique Raman spectra for every type of biological molecule. As such, Raman spectroscopy has the potential to provide scientists with a library of spectra that can be used to unravel the makeup of an unknown molecule. However, this technique is limited in that it is not able to manipulate particular structures without disturbing their unique environment. Recently, a novel technology that combines Raman spectroscopy with optical tweezers, termed Raman tweezers, evades this problem due to its ability to manipulate a sample without physical contact. As such, Raman tweezers has the potential to become an incredibly effective diagnostic tool for differentially distinguishing tissue, and therefore holds great promise in the field of virology for distinguishing between various virally infected cells. This review provides an introduction for a virologist into the world of spectroscopy and explores many of the potential applications of Raman tweezers in virology. PMID:16805914

  4. Raman spectroscopy: the gateway into tomorrow's virology.

    PubMed

    Lambert, Phelps J; Whitman, Audy G; Dyson, Ossie F; Akula, Shaw M

    2006-06-28

    In the molecular world, researchers act as detectives working hard to unravel the mysteries surrounding cells. One of the researchers' greatest tools in this endeavor has been Raman spectroscopy. Raman spectroscopy is a spectroscopic technique that measures the unique Raman spectra for every type of biological molecule. As such, Raman spectroscopy has the potential to provide scientists with a library of spectra that can be used to unravel the makeup of an unknown molecule. However, this technique is limited in that it is not able to manipulate particular structures without disturbing their unique environment. Recently, a novel technology that combines Raman spectroscopy with optical tweezers, termed Raman tweezers, evades this problem due to its ability to manipulate a sample without physical contact. As such, Raman tweezers has the potential to become an incredibly effective diagnostic tool for differentially distinguishing tissue, and therefore holds great promise in the field of virology for distinguishing between various virally infected cells. This review provides an introduction for a virologist into the world of spectroscopy and explores many of the potential applications of Raman tweezers in virology.

  5. Review of optical breast imaging and spectroscopy

    NASA Astrophysics Data System (ADS)

    Grosenick, Dirk; Rinneberg, Herbert; Cubeddu, Rinaldo; Taroni, Paola

    2016-09-01

    Diffuse optical imaging and spectroscopy of the female breast is an area of active research. We review the present status of this field and discuss the broad range of methodologies and applications. Starting with a brief overview on breast physiology, the remodeling of vasculature and extracellular matrix caused by solid tumors is highlighted that is relevant for contrast in optical imaging. Then, the various instrumental techniques and the related methods of data analysis and image generation are described and compared including multimodality instrumentation, fluorescence mammography, broadband spectroscopy, and diffuse correlation spectroscopy. We review the clinical results on functional properties of malignant and benign breast lesions compared to host tissue and discuss the various methods to improve contrast between healthy and diseased tissue, such as enhanced spectroscopic information, dynamic variations of functional properties, pharmacokinetics of extrinsic contrast agents, including the enhanced permeability and retention effect. We discuss research on monitoring neoadjuvant chemotherapy and on breast cancer risk assessment as potential clinical applications of optical breast imaging and spectroscopy. Moreover, we consider new experimental approaches, such as photoacoustic imaging and long-wavelength tissue spectroscopy.

  6. Microcoil NMR spectroscopy: a novel tool for biological high throughput NMR spectroscopy.

    PubMed

    Hopson, Russell E; Peti, Wolfgang

    2008-01-01

    Microcoil NMR spectroscopy is based on the increase of coil sensitivity for smaller coil diameters (approximately 1/d). Microcoil NMR probes deliver a remarkable mass-based sensitivity increase (8- to 12-fold) when compared with commonly used 5-mm NMR probes. Although microcoil NMR probes are a well established analytical tool for small molecule liquid-state NMR spectroscopy, after spectroscopy only recently have microcoil NMR probes become available for biomolecular NMR spectroscopy. This chapter highlights differences between commercially available microcoil NMR probes suitable for biomolecular NMR spectroscopy. Furthermore, it provides practical guidance for the use of microcoil probes and shows direct applications for structural biology and structural genomics, such as optimal target screening and structure determination, among others.

  7. Ultrafast Laser-Based Spectroscopy and Sensing: Applications in LIBS, CARS, and THz Spectroscopy

    PubMed Central

    Leahy-Hoppa, Megan R.; Miragliotta, Joseph; Osiander, Robert; Burnett, Jennifer; Dikmelik, Yamac; McEnnis, Caroline; Spicer, James B.

    2010-01-01

    Ultrafast pulsed lasers find application in a range of spectroscopy and sensing techniques including laser induced breakdown spectroscopy (LIBS), coherent Raman spectroscopy, and terahertz (THz) spectroscopy. Whether based on absorption or emission processes, the characteristics of these techniques are heavily influenced by the use of ultrafast pulses in the signal generation process. Depending on the energy of the pulses used, the essential laser interaction process can primarily involve lattice vibrations, molecular rotations, or a combination of excited states produced by laser heating. While some of these techniques are currently confined to sensing at close ranges, others can be implemented for remote spectroscopic sensing owing principally to the laser pulse duration. We present a review of ultrafast laser-based spectroscopy techniques and discuss the use of these techniques to current and potential chemical and environmental sensing applications. PMID:22399883

  8. Evaluating minerals of environmental concern using spectroscopy

    USGS Publications Warehouse

    Swayze, G.A.; Clark, R.N.; Higgins, C.T.; Kokaly, R.F.; Eric, Livo K.; Hoefen, T.M.; Ong, C.; Kruse, F.A.

    2006-01-01

    Imaging spectroscopy has been successfully used to aid researchers in characterizing potential environmental impacts posed by acid-rock drainage, ore-processing dust on mangroves, and asbestos in serpentine mineral deposits and urban dust. Many of these applications synergistically combine field spectroscopy with remote sensing data, thus allowing more-precise data calibration, spectral analysis of the data, and verification of mapping. The increased accuracy makes these environmental evaluation tools efficient because they can be used to focus field work on those areas most critical to the research effort. The use of spectroscopy to evaluate minerals of environmental concern pushes current imaging spectrometer technology to its limits; we present laboratory results that indicate the direction for future designs of imaging spectrometers.

  9. Photoacoustic Spectroscopy Analysis of Traditional Chinese Medicine

    NASA Astrophysics Data System (ADS)

    Chen, Lu; Zhao, Bin-xing; Xiao, Hong-tao; Tong, Rong-sheng; Gao, Chun-ming

    2013-09-01

    Chinese medicine is a historic cultural legacy of China. It has made a significant contribution to medicine and healthcare for generations. The development of Chinese herbal medicine analysis is emphasized by the Chinese pharmaceutical industry. This study has carried out the experimental analysis of ten kinds of Chinese herbal powder including Fritillaria powder, etc., based on the photoacoustic spectroscopy (PAS) method. First, a photoacoustic spectroscopy system was designed and constructed, especially a highly sensitive solid photoacoustic cell was established. Second, the experimental setup was verified through the characteristic emission spectrum of the light source, obtained by using carbon as a sample in the photoacoustic cell. Finally, as the photoacoustic spectroscopy analysis of Fritillaria, etc., was completed, the specificity of the Chinese herb medicine analysis was verified. This study shows that the PAS can provide a valid, highly sensitive analytical method for the specificity of Chinese herb medicine without preparing and damaging samples.

  10. Subpiconewton dynamic force spectroscopy using magnetic tweezers.

    PubMed

    Kruithof, M; Chien, F; de Jager, M; van Noort, J

    2008-03-15

    We introduce a simple method for dynamic force spectroscopy with magnetic tweezers. This method allows application of subpiconewton force and twist control by calibration of the applied force from the height of the magnets. Initial dynamic force spectroscopy experiments on DNA molecules revealed a large hysteresis that is caused by viscous drag on the magnetic bead and will conceal weak interactions. When smaller beads are used, this hysteresis is sufficiently reduced to reveal intramolecular interactions at subpiconewton forces. Compared with typical quasistatic force spectroscopy, a significant reduction of measurement time is achieved, allowing the real-time study of transient structures and reaction intermediates. As a proof of principle, nucleosome-nucleosome interactions on a subsaturated chromatin fiber were analyzed.

  11. Accuracy Estimation in Force Spectroscopy Experiments

    NASA Astrophysics Data System (ADS)

    Rankl, Christian; Kienberger, Ferry; Gruber, Hermann; Blaas, Dieter; Hinterdorfer, Peter

    2007-08-01

    Force spectroscopy is a useful tool for the investigation of molecular interactions. We here present a detailed analysis of parameter estimation in force spectroscopy experiments. It provides the values of the statistical errors of the kinetic off-rate constant koff and the energy length scale xβ to be considered using the single barrier model. As a biologically relevant experimental system we used the interaction between human rhinovirus serotype 2 and a recombinant derivative of the very-low density lipoprotein receptor. The interaction forces of single virus-receptor pairs were measured at different loading rates and analysed according to the single barrier model. Accuracy estimates of koff and xβ were obtained by Monte Carlo simulation and bootstrapping. For this model of virus-receptor attachment, force spectroscopy experiments yielded xβ=(0.38± 0.07) nm and \\ln koff=(-2.3± 1.0)\\ln s-1.

  12. Nuclear-spectroscopy problems studied with neutrons

    SciTech Connect

    Raman, S.

    1982-01-01

    Nuclear spectroscopy with neutrons continues to have a major impact on the progress of nuclear science. Neutrons, being uncharged, are particularly useful for the study of low energy reactions. Recent advances in time-of-flight spectroscopy, as well as in the gamma ray spectroscopy following neutron capture, have permitted precision studies of unbound and bound nuclear levels and related phenomena. By going to new energy domains, by using polarized beams and targets, through the invention of new kinds of detectors, and through the general improvement in beam quantity and quality, new features of nuclear structure and reactions have been obtained that are not ony interesting per se but are also grist for old and new theory mills. The above technical advances have opened up new opportunities for further discoveries.

  13. Small-Volume Nuclear Magnetic Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Fratila, Raluca M.; Velders, Aldrik H.

    2011-07-01

    Nuclear magnetic resonance (NMR) spectroscopy is one of the most information-rich analytical techniques available. However, it is also inherently insensitive, and this drawback precludes the application of NMR spectroscopy to mass- and volume-limited samples. We review a particular approach to increase the sensitivity of NMR experiments, namely the use of miniaturized coils. When the size of the coil is reduced, the sample volume can be brought down to the nanoliter range. We compare the main coil geometries (solenoidal, planar, and microslot/stripline) and discuss their applications to the analysis of mass-limited samples. We also provide an overview of the hyphenation of microcoil NMR spectroscopy to separation techniques and of the integration with lab-on-a-chip devices and microreactors.

  14. High-harmonic spectroscopy of aligned molecules

    NASA Astrophysics Data System (ADS)

    Yun, Hyeok; Yun, Sang Jae; Lee, Gae Hwang; Nam, Chang Hee

    2017-01-01

    High harmonics emitted from aligned molecules driven by intense femtosecond laser pulses provide the opportunity to explore the structural information of molecules. The field-free molecular alignment technique is an expedient tool for investigating the structural characteristics of linear molecules. The underlying physics of field-free alignment, showing the characteristic revival structure specific to molecular species, is clearly explained from the quantum-phase analysis of molecular rotational states. The anisotropic nature of molecules is shown from the harmonic polarization measurement performed with spatial interferometry. The multi-orbital characteristics of molecules are investigated using high-harmonic spectroscopy, applied to molecules of N2 and CO2. In the latter case the two-dimensional high-harmonic spectroscopy, implemented using a two-color laser field, is applied to distinguish harmonics from different orbitals. Molecular high-harmonic spectroscopy will open a new route to investigate ultrafast dynamics of molecules.

  15. Nuclear-spectroscopy problems studied with neutrons

    NASA Astrophysics Data System (ADS)

    Raman, S.

    Nuclear spectroscopy with neutrons continues to have a major impact on the progress of nuclear science. Neutrons, being uncharged, are particularly useful for the study of low energy reactions. Recent advances in time-of-flight spectroscopy, as well as in the gamma ray spectroscopy following neutron capture, have permitted precision studies of unbound and bound nuclear levels and related phenomena. By going to new energy domains, by using polarized beams and targets, through the invention of new kinds of detectors, and through the general improvement in beam quantity and quality, new features of nuclear structure and reactions were obtained that are not only interesting per se but are also grist for old and new theory mills. The above technical advances have opened up opportunities for further discoveries.

  16. Broadband single-molecule excitation spectroscopy

    PubMed Central

    Piatkowski, Lukasz; Gellings, Esther; van Hulst, Niek F.

    2016-01-01

    Over the past 25 years, single-molecule spectroscopy has developed into a widely used tool in multiple disciplines of science. The diversity of routinely recorded emission spectra does underpin the strength of the single-molecule approach in resolving the heterogeneity and dynamics, otherwise hidden in the ensemble. In early cryogenic studies single molecules were identified by their distinct excitation spectra, yet measuring excitation spectra at room temperature remains challenging. Here we present a broadband Fourier approach that allows rapid recording of excitation spectra of individual molecules under ambient conditions and that is robust against blinking and bleaching. Applying the method we show that the excitation spectra of individual molecules exhibit an extreme distribution of solvatochromic shifts and distinct spectral shapes. Importantly, we demonstrate that the sensitivity and speed of the broadband technique is comparable to that of emission spectroscopy putting both techniques side-by-side in single-molecule spectroscopy. PMID:26794035

  17. Raman spectroscopy at the tritium laboratory Karlsruhe

    SciTech Connect

    Schloesser, M.; Bornschein, B.; Fischer, S.; Kassel, F.; Rupp, S.; Sturm, M.; James, T.M.; Telle, H.H.

    2015-03-15

    Raman spectroscopy is employed successfully for analysis of hydrogen isotopologues at the Tritium Laboratory Karlsruhe (TLK). Raman spectroscopy is based on the inelastic scattering of photons off molecules. Energy is transferred to the molecules as rotational/vibrational excitation being characteristic for each type of molecule. Thus, qualitative analysis is possible from the Raman shifted light, while quantitative information can be obtained from the signal intensities. After years of research and development, the technique is now well-advanced providing fast (< 10 s), precise (< 0.1%) and true (< 3%) compositional analysis of gas mixtures of hydrogen isotopologues. In this paper, we summarize the recent achievements in the further development on this technique, and the various applications for which it is used at TLK. Raman spectroscopy has evolved as a versatile, highly accurate key method for quantitative analysis complementing the port-folio of analytic techniques at the TLK.

  18. An Introduction to Coherent Multidimensional Spectroscopy.

    PubMed

    Chen, Peter C

    2016-12-01

    Coherent multidimensional spectroscopy is a field that has drawn much attention as an optical analogue to multidimensional nuclear magnetic resonance imaging. Coherent multidimensional spectroscopic techniques produce spectra that show the magnitude of an optical signal as a function of two or more pulsed laser frequencies. Spectra can be collected in either the frequency or the time domain. In addition to improving resolution and overcoming spectral congestion, coherent multidimensional spectroscopy provides the ability to investigate and conduct studies based upon the relationship between different peaks. The purpose of this paper is to provide a general introduction to the area of coherent multidimensional spectroscopy, to provide a brief overview of current experimental approaches, and to discuss some emerging developments in this relatively young field.

  19. Torque-mixing magnetic resonance spectroscopy.

    PubMed

    Losby, J E; Fani Sani, F; Grandmont, D T; Diao, Z; Belov, M; Burgess, J A J; Compton, S R; Hiebert, W K; Vick, D; Mohammad, K; Salimi, E; Bridges, G E; Thomson, D J; Freeman, M R

    2015-11-13

    A universal, torque-mixing method for magnetic resonance spectroscopy is presented. In analogy to resonance detection by magnetic induction, the transverse component of a precessing dipole moment can be measured in sensitive broadband spectroscopy, here using a resonant mechanical torque sensor. Unlike induction, the torque amplitude allows equilibrium magnetic properties to be monitored simultaneously with the spin dynamics. Comprehensive electron spin resonance spectra of a single-crystal, mesoscopic yttrium iron garnet disk at room temperature reveal assisted switching between magnetization states and mode-dependent spin resonance interactions with nanoscale surface imperfections. The rich detail allows analysis of even complex three-dimensional spin textures. The flexibility of microelectromechanical and optomechanical devices combined with broad generality and capabilities of torque-mixing magnetic resonance spectroscopy offers great opportunities for development of integrated devices.

  20. Study of virus by Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Moor, K.; Kitamura, H.; Hashimoto, K.; Sawa, M.; Andriana, B. B.; Ohtani, K.; Yagura, T.; Sato, H.

    2013-02-01

    Problem of viruses is very actual for nowadays. Some viruses, which are responsible for human of all tumors, are about 15 %. Main purposes this study, early detection virus in live cell without labeling and in the real time by Raman spectroscopy. Micro Raman spectroscopy (mRs) is a technique that uses a Raman spectrometer to measure the spectra of microscopic samples. According to the Raman spectroscopy, it becomes possible to study the metabolites of a live cultured cell without labeling. We used mRs to detect the virus via HEK 293 cell line-infected adenovirus. We obtained raman specters of lives cells with viruses in 24 hours and 7 days after the infection. As the result, there is some biochemical changing after the treatment of cell with virus. One of biochemical alteration is at 1081 cm-1. For the clarification result, we use confocal fluorescent microscopy and transmission electron microscopy (TEM).

  1. Alpha Coincidence Spectroscopy studied with GEANT4

    SciTech Connect

    Dion, Michael P.; Miller, Brian W.; Tatishvili, Gocha; Warren, Glen A.

    2013-11-02

    Abstract The high-energy side of peaks in alpha spectra, e.g. 241Am, as measured with a silicon detector has structure caused mainly by alpha-conversion electron and to some extent alphagamma coincidences. We compare GEANT4 simulation results to 241Am alpha spectroscopy measurements with a passivated implanted planar silicon detector. A large discrepancy between the measurements and simulations suggest that the GEANT4 photon evaporation database for 237Np (daughter of 241Am decay) does not accurately describe the conversion electron spectrum and therefore was found to have large discrepancies with experimental measurements. We describe how to improve the agreement between GEANT4 and alpha spectroscopy for actinides of interest by including experimental measurements of conversion electron spectroscopy into the photon evaporation database.

  2. Laser-induced breakdown spectroscopy in Asia

    NASA Astrophysics Data System (ADS)

    Wang, Zhen-Zhen; Deguchi, Yoshihiro; Zhang, Zhen-Zhen; Wang, Zhe; Zeng, Xiao-Yan; Yan, Jun-Jie

    2016-12-01

    Laser-induced breakdown spectroscopy (LIBS) is an analytical detection technique based on atomic emission spectroscopy to measure the elemental composition. LIBS has been extensively studied and developed due to the non-contact, fast response, high sensitivity, real-time and multi-elemental detection features. The development and applications of LIBS technique in Asia are summarized and discussed in this review paper. The researchers in Asia work on different aspects of the LIBS study in fundamentals, data processing and modeling, applications and instrumentations. According to the current research status, the challenges, opportunities and further development of LIBS technique in Asia are also evaluated to promote LIBS research and its applications.

  3. The ROSPHERE γ-ray spectroscopy array

    NASA Astrophysics Data System (ADS)

    Bucurescu, D.; Căta-Danil, I.; Ciocan, G.; Costache, C.; Deleanu, D.; Dima, R.; Filipescu, D.; Florea, N.; Ghiţă, D. G.; Glodariu, T.; Ivaşcu, M.; Lică, R.; Mărginean, N.; Mărginean, R.; Mihai, C.; Negret, A.; Niţă, C. R.; Olăcel, A.; Pascu, S.; Sava, T.; Stroe, L.; Şerban, A.; Şuvăilă, R.; Toma, S.; Zamfir, N. V.; Căta-Danil, G.; Gheorghe, I.; Mitu, I. O.; Suliman, G.; Ur, C. A.; Braunroth, T.; Dewald, A.; Fransen, C.; Bruce, A. M.; Podolyák, Zs.; Regan, P. H.; Roberts, O. J.

    2016-11-01

    The ROmanian array for SPectroscopy in HEavy ion REactions (ROSPHERE) has been designed as a multi-detector setup dedicated to γ-ray spectroscopy studies at the Bucharest 9 MV Tandem accelerator. Consisting of up to 25 detectors (either Compton suppressed HPGe detectors or fast LaBr3(Ce) scintillator detectors) together with a state of the art plunger device, ROSPHERE is a powerful tool for lifetime measurements using the Recoil Distance Doppler Shift (RDDS) and the in-beam Fast Electronic Scintillation Timing (FEST) methods. The array's geometry, detectors, electronics and data acquisition system are described. Selected results from the first experimental campaigns are also presented.

  4. On black hole spectroscopy via adiabatic invariance

    NASA Astrophysics Data System (ADS)

    Jiang, Qing-Quan; Han, Yan

    2012-12-01

    In this Letter, we obtain the black hole spectroscopy by combining the black hole property of adiabaticity and the oscillating velocity of the black hole horizon. This velocity is obtained in the tunneling framework. In particular, we declare, if requiring canonical invariance, the adiabatic invariant quantity should be of the covariant form Iadia = ∮pi dqi. Using it, the horizon area of a Schwarzschild black hole is quantized independently of the choice of coordinates, with an equally spaced spectroscopy always given by ΔA = 8 π lp2 in the Schwarzschild and Painlevé coordinates.

  5. Coherent Raman spectroscopy for supersonic flow measurments

    NASA Technical Reports Server (NTRS)

    She, C. Y.

    1986-01-01

    In collaboration with NASA/Langley Research Center, a truly nonintrusive and nonseeding method for measuring supersonic molecular flow parameters was proposed and developed at Colorado State University. The feasibility of this Raman Doppler Velocimetry (RDV), currently operated in a scanning mode, was demonstrated not only in a laboratory environment at Colorado State University, but also in a major wind tunnel at NASA/Langley Research Center. The research progress of the RDV development is summarized. In addition, methods of coherent Rayleigh-Brillouin spectroscopy and single-pulse coherent Raman spectroscopy are investigated, respectively, for measurements of high-pressure and turbulent flows.

  6. Process analytical applications of Raman spectroscopy.

    PubMed

    Rantanen, Jukka

    2007-02-01

    There is an increasing demand for new approaches to understand the chemical and physical phenomena that occur during pharmaceutical unit operations. Obtaining real-time information from processes opens new perspectives for safer and more efficient manufacture of pharmaceuticals. Raman spectroscopy provides a molecular level insight into processing, and therefore it is a future process analytical tool. In this review, different applications of Raman spectroscopy in the field of process analysis of pharmaceutical solid dosage forms are summarized. In addition, pitfalls associated with interfacing to the process environment and challenges within data management are discussed.

  7. Spectroscopy of element 115 decay chains.

    PubMed

    Rudolph, D; Forsberg, U; Golubev, P; Sarmiento, L G; Yakushev, A; Andersson, L-L; Di Nitto, A; Düllmann, Ch E; Gates, J M; Gregorich, K E; Gross, C J; Heßberger, F P; Herzberg, R-D; Khuyagbaatar, J; Kratz, J V; Rykaczewski, K; Schädel, M; Åberg, S; Ackermann, D; Block, M; Brand, H; Carlsson, B G; Cox, D; Derkx, X; Eberhardt, K; Even, J; Fahlander, C; Gerl, J; Jäger, E; Kindler, B; Krier, J; Kojouharov, I; Kurz, N; Lommel, B; Mistry, A; Mokry, C; Nitsche, H; Omtvedt, J P; Papadakis, P; Ragnarsson, I; Runke, J; Schaffner, H; Schausten, B; Thörle-Pospiech, P; Torres, T; Traut, T; Trautmann, N; Türler, A; Ward, A; Ward, D E; Wiehl, N

    2013-09-13

    A high-resolution α, x-ray, and γ-ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum für Schwerionenforschung. Thirty correlated α-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z=115. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z>112. Comprehensive Monte Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.

  8. Spectroscopy of element 115 decay chains

    SciTech Connect

    Rudolph, Dirk; Forsberg, U.; Golubev, P.; Sarmiento, L. G.; Yakushev, A.; Andersson, L.-L.; Di Nitto, A.; Duehllmann, Ch. E.; Gates, J. M.; Gregorich, K. E.; Gross, Carl J; Hessberger, F. P.; Herzberg, R.-D; Khuyagbaatar, J.; Kratz, J. V.; Rykaczewski, Krzysztof Piotr; Schaedel, M.; Aberg, S.; Ackermann, D.; Block, M.; Brand, H.; Carlsson, B. G.; Cox, D.; Derkx, X.; Eberhardt, K.; Even, J.; Fahlander, C.; Gerl, J.; Jaeger, E.; Kindler, B.; Krier, J.; Kojouharov, I.; Kurz, N.; Lommel, B.; Mistry, A.; Mokry, C.; Nitsche, H.; Omtvedt, J. P.; Papadakis, P.; Ragnarsson, I.; Runke, J.; Schaffner, H.; Schausten, B.; Thoerle-Pospiech, P.; Torres, T.; Traut, T.; Trautmann, N.; Tuerler, A.; Ward, A.; Ward, D. E.; Wiehl, N.

    2013-01-01

    A high-resolution a, X-ray and -ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum fu r Schwerionenforschung. Thirty correlated a-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z = 115. The data includes first candidates of fingerprinting the decay step Mt --> Bh with characteristic X rays. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z > 112. Comprehensive Monte-Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.

  9. Electrochemical Impedance Spectroscopy Of Metal Alloys

    NASA Technical Reports Server (NTRS)

    Macdowell, L. G.; Calle, L. M.

    1993-01-01

    Report describes use of electrochemical impedance spectroscopy (EIS) to investigate resistances of 19 alloys to corrosion under conditions similar to those of corrosive, chloride-laden seaside environment of Space Transportation System launch site. Alloys investigated: Hastelloy C-4, C-22, C-276, and B-2; Inconel(R) 600, 625, and 825; Inco(R) G-3; Monel 400; Zirconium 702; Stainless Steel 304L, 304LN, 316L, 317L, and 904L; 20Cb-3; 7Mo+N; ES2205; and Ferralium 255. Results suggest electrochemical impedance spectroscopy used to predict corrosion performances of metal alloys.

  10. Fluorescence Spectroscopy with Surface Plasmon Excitation

    NASA Astrophysics Data System (ADS)

    Neumann, T.; Kreiter, M.; Knoll, W.

    In recent years, much effort has been directed towards the development of optical biosensors. While direct sensors are capable of monitoring the presence of an analyte without the use of labelling groups, the class of indirect sensors exploits the signal enhancement caused by bound marker molecules. Surface plasmon spectroscopy (SPS) as a direct detection method [1] is known to lack sensitivity for monitoring of low molecular mass analytes. In order to enhance the sensitivity and to improve the detection limit the technique was combined with fluorescence detection schemes in surface plasmon fluorescence spectroscopy (SPFS), as described recently [2]. Here, we briefly review the theory of plasmon excitation and the experimental realization of SPFS.

  11. Large Area X-Ray Spectroscopy Mission

    NASA Technical Reports Server (NTRS)

    Tananbaum, H.

    1997-01-01

    The Large Area X-ray Spectroscopy (LAXS) mission concept study continues to evolve strongly following the merging of the LAXS mission with the Next Generation X-ray Observatory (NGXO, PI: Nick White) into the re-named High Throughput X-ray Spectroscopy (HTXS) Mission. HTXS retains key elements of the LAXS proposal, including the use of multiple satellites for risk-reduction and cost savings. A key achievement of the program has been the recommendation by the Structure and Evolution of the Universe (SEUS) (April 1997) for a new start for the HTXS mission in the 2000-2004 timeframe.

  12. A Brief History of Spectroscopy on EBIT

    SciTech Connect

    Beiersdorfer, P

    2007-02-28

    In the autumn of 1986, the first electron beam ion trap, EBIT, was put into service as a light source for the spectroscopy of highly charged ions. On the occasion of the twentieth anniversary of EBIT, we review its early uses for spectroscopy, from the first measurements of x rays from L-shell xenon ions in 1986 to its conversion to SuperEBIT in 1992 and rebirth as EBIT-I in 2001. Together with their sibling, EBIT-II, these machines have been used at Livermore to perform a multitude of seminal studies of the physics of highly charged ions.

  13. BOOK REVIEW: Principles of Plasma Spectroscopy

    NASA Astrophysics Data System (ADS)

    Osterheld, A. L.

    1998-08-01

    This book gives a comprehensive treatment of plasma spectroscopy, the quantitative study of line and continuous radiation from high temperature plasmas. This highly interdisciplinary field combines elements of atomic, plasma and statistical physics, and has wide application to simulations and diagnostics of laboratory and astrophysical plasmas. Plasma spectroscopy is naturally intertwined with magnetic and inertial fusion energy science. Radiative processes in plasmas are important in the design of fusion facilities, and can be used to diagnose and control conditions in fusion plasmas. In turn, fusion scientists and facilities have played a central role in developing plasma spectroscopy theory and applications. The book covers radiation from plasmas, spectral line broadening, atomic processes in plasmas and level kinetic models, radiative transfer and applications to spectroscopic plasma diagnostics. It is successful both as an introductory text and as a source book of theoretical and experimental research. The book presents a broad development of the theoretical foundations of these topics, and discusses the seminal papers and critical experiments. There is a strong emphasis on applications of plasma spectroscopy, primarily to plasma diagnostics and calculations of radiative cooling rates. Extensive references (current through the end of 1995) point readers to original material and detailed discussions of advanced topics. Of course, a single text cannot treat all aspects of plasma spectroscopy in depth. The strongest and most detailed section of the book is a long chapter on spectral line broadening. For me, the most significant omission is lack of a discussion of laser assisted transitions which can occur in plasmas produced by high intensity lasers. The book was intentionally written to be accessible to young researchers and graduate students. The level is roughly that of a graduate text. It assumes some familiarity with quantum mechanics and statistical

  14. Physics of ultracold Fermi gases revealed by spectroscopies

    NASA Astrophysics Data System (ADS)

    Törmä, Päivi

    2016-04-01

    This article provides a brief review of how various spectroscopies have been used to investitage many-body quantum phenomena in the context of ultracold Fermi gases. In particular, work done with RF spectroscopy, Bragg spectroscopy and lattice modulation spectroscopy is considered. The theoretical basis of these spectroscopies, namely linear response theory in the many-body quantum physics context is briefly presented. Experiments related to the BCS-BEC crossover, imbalanced Fermi gases, polarons, possible pseudogap and Fermi liquid behaviour and measuring the contact are discussed. Remaining open problems and goals in the field are sketched from the perspective how spectroscopies could contribute.

  15. Imaging Intelligence with Proton Magnetic Resonance Spectroscopy

    ERIC Educational Resources Information Center

    Jung, Rex E.; Gasparovic, Charles; Chavez, Robert S.; Caprihan, Arvind; Barrow, Ranee; Yeo, Ronald A.

    2009-01-01

    Proton magnetic resonance spectroscopy ([to the first power]H-MRS) is a technique for the assay of brain neurochemistry "in vivo." N-acetylaspartate (NAA), the most prominent metabolite visible within the [to the first power]H-MRS spectrum, is found primarily within neurons. The current study was designed to further elucidate NAA-cognition…

  16. Laser spectroscopy and dynamics of transient species

    SciTech Connect

    Clouthier, D.J.

    1993-12-01

    The goal of this program is to study the vibrational and electronic spectra and excited state dynamics of a number of transient sulfur and oxygen species. A variety of supersonic jet techniques, as well as high resolution FT-IR and intracavity dye laser spectroscopy, have been applied to these studies.

  17. Monitoring enzymatic ATP hydrolysis by EPR spectroscopy.

    PubMed

    Hacker, Stephan M; Hintze, Christian; Marx, Andreas; Drescher, Malte

    2014-07-14

    An adenosine triphosphate (ATP) analogue modified with two nitroxide radicals is developed and employed to study its enzymatic hydrolysis by electron paramagnetic resonance spectroscopy. For this application, we demonstrate that EPR holds the potential to complement fluorogenic substrate analogues in monitoring enzymatic activity.

  18. Nanoparticles and nanowires: synchrotron spectroscopy studies

    SciTech Connect

    Sham, T.K.

    2008-08-11

    This paper reviews the research in nanomaterials conducted in our laboratory in the last decade using conventional and synchrotron radiation techniques. While preparative and conventional characterisation techniques are described, emphasis is placed on the analysis of nanomaterials using synchrotron radiation. Materials of primary interests are metal nanoparticles and semiconductor nanowires and nanoribbons. Synchrotron techniques based on absorption spectroscopy such as X-ray absorption fine structures (XAFS), which includes X-ray absorption near edge structures (XANES) and extended X-ray absorption fine structures (EXFAS), and de-excitation spectroscopy, including X-ray excited optical luminescence (XEOL), time-resolved X-ray excited optical luminescence (TRXEOL) and X-ray emission spectroscopy (XES) are described. We show that the tunability, brightness, polarisation and time structure of synchrotron radiation are providing unprecedented capabilities for nanomaterials analysis. Synchrotron studies of prototype systems such as gold nanoparticles, 1-D nanowires of group IV materials, C, Si and Ge as well as nanodiamond, and compound semiconductors, ZnS, CdS, ZnO and related materials are used to illustrate the power and unique capabilities of synchrotron spectroscopy in the characterisation of local structure, electronic structure and optical properties of nanomaterials.

  19. Results and Frontiers in Lattice Baryon Spectroscopy

    SciTech Connect

    Bulava, John; Morningstar, Colin; Edwards, Robert; Richards, David; Fleming, George; Juge, K. Jimmy; Lichtl, Adam C.; Mathur, Nilmani; Wallace, Stephen J.

    2007-10-26

    The Lattice Hadron Physics Collaboration (LHPC) baryon spectroscopy effort is reviewed. To date the LHPC has performed exploratory Lattice QCD calculations of the low-lying spectrum of Nucleon and Delta baryons. These calculations demonstrate the effectiveness of our method by obtaining the masses of an unprecedented number of excited states with definite quantum numbers. Future work of the project is outlined.

  20. Optical Spectroscopy of Dynamically Compressed Liquids.

    DTIC Science & Technology

    1986-06-30

    VA 22217-5000 ELEMENTNO. NO 11 TITLE (Include Security Cia.iicoo OPTICAL SPECTROSCOPY OIF DYNAMICA I Y COMPRFSSFnI I TQIIITD), (1N1.A A--,FT% 12...Enhanced Solid-State Reactivity and the Chemistry of Shock-Compressed Fluids , 7th Rocky Mountain Regional Meeting of the American Chemical Society, June 6-8

  1. Spectroscopy and decays of charm and bottom

    SciTech Connect

    Butler, J.N.

    1997-10-01

    After a brief review of the quark model, we discuss our present knowledge of the spectroscopy of charm and bottom mesons and baryons. We go on to review the lifetimes, semileptonic, and purely leptonic decays of these particles. We conclude with a brief discussion B and D mixing and rare decays.

  2. Ir Spectroscopy and Nickel (II) Hexammines

    ERIC Educational Resources Information Center

    Reedijk, J.; And Others

    1975-01-01

    Describes an experiment, for the general chemistry laboratory, intended to introduce the student to infrared spectroscopy. After being introduced to the theory of molecular vibrations on an elementary level, each student receives a list of 5-7 nickel (II) ammines to be prepared, analyzed and characterized by infrared spectoscopy. (MLH)

  3. Dielectric Spectroscopy of Fresh Chicken Breast Meat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Technical abstract The dielectric properties of fresh chicken breast meat were measured at temperatures from 5 to 85 degrees °C over the frequency range from 10 MHz to 1.8 GHz by dielectric spectroscopy techniques with an open-ended coaxial-line probe and impedance analyzer. Samples were cut from ...

  4. Dielectric Spectroscopy of Fresh Chicken Breast Meat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The dielectric properties of fresh chicken breast meat were measured at temperatures from 5 to 85 'C over the frequency range from 10 MHz to 1.8 GHz by dielectric spectroscopy techniques with an open-ended coaxial-line probe and impedance analyzer. Samples were cut from both the Pectoralis major an...

  5. Spectroscopy with trapped highly charged ions

    SciTech Connect

    Beiersdorfer, P

    2008-01-23

    We give an overview of atomic spectroscopy performed on electron beam ion traps at various locations throughout the world. Spectroscopy at these facilities contributes to various areas of science and engineering, including but not limited to basic atomic physics, astrophysics, extreme ultraviolet lithography, and the development of density and temperature diagnostics of fusion plasmas. These contributions are accomplished by generating, for example, spectral surveys, making precise radiative lifetime measurements, accounting for radiative power emitted in a given wavelength band, illucidating isotopic effects, and testing collisional-radiative models. While spectroscopy with electron beam ion traps had originally focused on the x-ray emission from highly charged ions interacting with the electron beam, the operating modes of such devices have expanded to study radiation in almost all wavelength bands from the visible to the hard x-ray region; and at several facilities the ions can be studied even in the absence of an electron beam. Photon emission after charge exchange or laser excitation has been observed, and the work is no longer restricted to highly charged ions. Much of the experimental capabilities are unique to electron beam ion traps, and the work performed with these devices cannot be undertaken elsewhere. However, in other areas the work on electron beam ion traps rivals the spectroscopy performed with conventional ion traps or heavy-ion storage rings. The examples we present highlight many of the capabilities of the existing electron beam ion traps and their contributions to physics.

  6. Mechanical spectroscopy of Snoek type relaxation

    NASA Astrophysics Data System (ADS)

    Golovin, S. A.; Golovin, I. S.

    2012-09-01

    A review is presented for work in the area of elasticity for metals and alloys with a body-centered cubic lattice caused by diffusion under stress of interstitial atoms, i.e., Snoek relaxation in metals and Snoek type relaxation in alloys. Practical possibilities in analyzing materials of this class by mechanical spectroscopy are demonstrated.

  7. Synthetic frequency protocol in the Ramsey spectroscopy

    NASA Astrophysics Data System (ADS)

    Yudin, V. I.; Basalaev, M. Yu; Taichenachev, A. V.

    2017-01-01

    We develop an universal method to significantly suppress probe-induced shifts in any types of atomic clocks using the Ramsey spectroscopy. The frequency shifts can be suppressed considerably below a fractional level of 10‑18 practically for any optical atomic clocks.

  8. Using GPU Programming for Inverse Spectroscopy

    SciTech Connect

    David Gerts; N. Fredette; H. Wimberly

    2010-07-01

    The Idaho National Laboratory (INL) has developed a detector that relies heavily on computationally expensive inverse spectroscopy algorithms to determine probabilistic three dimensional mappings of the source and its intensity. This inverse spectroscopy algorithm applies to material accountability due to the potential to determine where nuclear sources are present as a function of time and space. And yet because the novel algorithm can become prohibitively expensive on a standard desktop PC, the INL has incorporated new hardware from the commercial graphics community. General programming for graphics processing units (GPUs) is not a new concept. However, the application of GPUs to evidence theory-based inverse spectroscopy is both novel and particularly apropos. Improvements while using a (slightly upgraded) standard PC are approximately three orders of magnitude, making a ten hour computation in less than four seconds. This significantly changes the concept of prohibitively expensive calculations and makes application to materials accountability possible in near real time. Indeed, the sensor collection time is now expected to dominate the time required to determine the source and its intensity, instead of the inverse spectroscopy method.

  9. A New Spin on Photoemission Spectroscopy

    SciTech Connect

    Jozwiak, Chris

    2008-12-01

    The electronic spin degree of freedom is of general fundamental importance to all matter. Understanding its complex roles and behavior in the solid state, particularly in highly correlated and magnetic materials, has grown increasingly desirable as technology demands advanced devices and materials based on ever stricter comprehension and control of the electron spin. However, direct and efficient spin dependent probes of electronic structure are currently lacking. Angle Resolved Photoemission Spectroscopy (ARPES) has become one of the most successful experimental tools for elucidating solid state electronic structures, bolstered by-continual breakthroughs in efficient instrumentation. In contrast, spin-resolved photoemission spectroscopy has lagged behind due to a lack of similar instrumental advances. The power of photoemission spectroscopy and the pertinence of electronic spin in the current research climate combine to make breakthroughs in Spin and Angle Resolved Photoemission Spectroscopy (SARPES) a high priority . This thesis details the development of a unique instrument for efficient SARPES and represents a radical departure from conventional methods. A custom designed spin polarimeter based on low energy exchange scattering is developed, with projected efficiency gains of two orders of magnitude over current state-of-the-art polarimeters. For energy analysis, the popular hemispherical analyzer is eschewed for a custom Time-of-Flight (TOF) analyzer offering an additional order of magnitude gain in efficiency. The combined instrument signifies the breakthrough needed to perform the high resolution SARPES experiments necessary for untangling the complex spin-dependent electronic structures central to today's condensed matter physics.

  10. Planar diode multiplier chains for THz spectroscopy

    NASA Technical Reports Server (NTRS)

    Maiwald, Frank W.; Drouin, Brian J.; Pearson, John C.; Mehdi, Imran; Lewena, Frank; Endres, Christian; Winnewisser, Gisbert

    2005-01-01

    High-resolution laboratory spectroscopy is utilized as a diagnostic tool to determine noise and harmonic content of balanced [9]-[11] and unbalanced [12]-[14] multiplier designs. Balanced multiplier designs suppress unintended harmonics more than -20dB. Much smaller values were measured on unbalanced multipliers.

  11. Raman Spectroscopy Cell-based Biosensors

    PubMed Central

    Notingher, Ioan

    2007-01-01

    One of the main challenges faced by biodetection systems is the ability to detect and identify a large range of toxins at low concentrations and in short times. Cell-based biosensors rely on detecting changes in cell behaviour, metabolism, or induction of cell death following exposure of live cells to toxic agents. Raman spectroscopy is a powerful technique for studying cellular biochemistry. Different toxic chemicals have different effects on living cells and induce different time-dependent biochemical changes related to cell death mechanisms. Cellular changes start with membrane receptor signalling leading to cytoplasmic shrinkage and nuclear fragmentation. The potential advantage of Raman spectroscopy cell-based systems is that they are not engineered to respond specifically to a single toxic agent but are free to react to many biologically active compounds. Raman spectroscopy biosensors can also provide additional information from the time-dependent changes of cellular biochemistry. Since no cell labelling or staining is required, the specific time dependent biochemical changes in the living cells can be used for the identification and quantification of the toxic agents. Thus, detection of biochemical changes of cells by Raman spectroscopy could overcome the limitations of other biosensor techniques, with respect to detection and discrimination of a large range of toxic agents. Further developments of this technique may also include integration of cellular microarrays for high throughput in vitro toxicological testing of pharmaceuticals and in situ monitoring of the growth of engineered tissues.

  12. Demonstration of Berry Phase in Optical Spectroscopy

    NASA Technical Reports Server (NTRS)

    Xia, Hui-Rong; Zhang, Yong; Jiang, Hong-Ji; Ding, Liang-En

    1996-01-01

    In this paper we demonstrate that the observed phase shift of the RF signal and its intensity dependence under extreme low pump and probe laser field conditions are dominated by Berry phase effect in optical spectroscopy with good adiabatic approximation, which provides all features' agreements between the theoretical and the experimental results.

  13. Near-field single molecule spectroscopy

    SciTech Connect

    Xie, X.S.; Dunn, R.C.

    1995-02-01

    The high spatial resolution and sensitivity of near-field fluorescence microscopy allows one to study spectroscopic and dynamical properties of individual molecules at room temperature. Time-resolved experiments which probe the dynamical behavior of single molecules are discussed. Ground rules for applying near-field spectroscopy and the effect of the aluminum coated near-field probe on spectroscopic measurements are presented.

  14. Terahertz homodyne self-mixing transmission spectroscopy

    SciTech Connect

    Mohr, Till Breuer, Stefan; Blömer, Dominik; Patel, Sanketkumar; Schlosser, Malte; Birkl, Gerhard; Elsäßer, Wolfgang; Simonetta, Marcello; Deninger, Anselm; Giuliani, Guido

    2015-02-09

    A compact homodyne self-mixing terahertz spectroscopy concept is experimentally investigated and confirmed by calculations. This method provides amplitude and phase information of the terahertz radiation emitted by a photoconductive antenna in a transmission experiment where a rotating chopper wheel serves as a feedback mirror. As a proof-of-principle experiment the frequency-dependent refractive index of Teflon is measured.

  15. Fourier Transform Infrared Spectroscopy Part III. Applications.

    ERIC Educational Resources Information Center

    Perkins, W. D.

    1987-01-01

    Discusses the use of the FT-IR spectrometer in analyses that were previously avoided. Examines some of the applications of this spectroscopy with aqueous solutions, circular internal reflection, samples with low transmission, diffuse reflectance, infrared emission, and the infrared microscope. (TW)

  16. Gamma ray spectroscopy in astrophysics. [conferences

    NASA Technical Reports Server (NTRS)

    Cline, T. L. (Editor); Ramaty, R. (Editor)

    1978-01-01

    Experimental and theoretical aspects of gamma ray spectroscopy in high energy astrophysics are discussed. Line spectra from solar, stellar, planetary, and cosmic gamma rays are examined as well as HEAO investigations, the prospects of a gamma ray observatory, and follow-on X-ray experiments in space.

  17. Handbook of Infrared Spectroscopy of Ultrathin Films

    NASA Astrophysics Data System (ADS)

    Tolstoy, Valeri P.; Chernyshova, Irina; Skryshevsky, Valeri A.

    2003-05-01

    Because of the rapid increase in commercially available Fourier transform infrared spectrometers and computers over the past ten years, it has now become feasible to use IR spectrometry to characterize very thin films at extended interfaces. At the same time, interest in thin films has grown tremendously because of applications in microelectronics, sensors, catalysis, and nanotechnology. The Handbook of Infrared Spectroscopy of Ultrathin Films provides a practical guide to experimental methods, up-to-date theory, and considerable reference data, critical for scientists who want to measure and interpret IR spectra of ultrathin films. This authoritative volume also: Offers information needed to effectively apply IR spectroscopy to the analysis and evaluation of thin and ultrathin films on flat and rough surfaces and on powders at solid-gaseous, solid-liquid, liquid-gaseous, liquid-liquid, and solid-solid interfaces. Provides full discussion of theory underlying techniques Describes experimental methods in detail, including optimum conditions for recording spectra and the interpretation of spectra Gives detailed information on equipment, accessories, and techniques Provides IR spectroscopic data tables as appendixes, including the first compilation of published data on longitudinal frequencies of different substances Covers new approaches, such as Surface Enhanced IR spectroscopy (SEIR), time-resolved FTIR spectroscopy, high-resolution microspectroscopy and using synchotron radiation

  18. DETECTION OF PATHOGENS BY FLOURESCENCE SPECTROSCOPY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract This study was performed as a preliminary study for rapid detection of food bone pathogens by fluorescence spectroscopy. E coli, Salmonella and Campylobactor which are the most commonly found in food were used in this study. Bacteria were grown in agar plate and diluted in saline and prepa...

  19. Photoelectron Spectroscopy of U Oxide at LLNL

    SciTech Connect

    Tobin, J G; Yu, S; Chung, B W; Waddill, G D

    2010-03-02

    In our laboratory at LLNL, an effort is underway to investigate the underlying complexity of 5f electronic structure with spin-resolved photoelectron spectroscopy using chiral photonic excitation, i.e. Fano Spectroscopy. Our previous Fano measurements with Ce indicate the efficacy of this approach and theoretical calculations and spectral simulations suggest that Fano Spectroscopy may resolve the controversy concerning Pu electronic structure and electron correlation. To this end, we have constructed and commissioned a new Fano Spectrometer, testing it with the relativistic 5d system Pt. Here, our preliminary photoelectron spectra of the UO{sub 2} system are presented. X-ray photoelectron spectroscopy has been used to characterize a sample of UO{sub 2} grown on an underlying substrate of Uranium. Both AlK{alpha} (1487 eV) and MgK{alpha} (1254 eV) emission were utilized as the excitation. Using XPS and comparing to reference spectra, it has been shown that our sample is clearly UO{sub 2}.

  20. Electron spectrometer for gas-phase spectroscopy

    SciTech Connect

    Bozek, J.D.; Schlachter, A.S.

    1997-04-01

    An electron spectrometer for high-resolution spectroscopy of gaseous samples using synchrotron radiation has been designed and constructed. The spectrometer consists of a gas cell, cylindrical electrostatic lens, spherical-sector electron energy analyzer, position-sensitive detector and associated power supplies, electronics and vacuum pumps. Details of the spectrometer design are presented together with some representative spectra.

  1. BRIEF COMMUNICATIONS: Picosecond spectroscopy of pyrrol pigments

    NASA Astrophysics Data System (ADS)

    Lippitsch, M. E.; Leitner, A.; Riegler, M.; Aussenegg, F. R.

    1982-05-01

    Picosecond fluorescence and absorption spectroscopy methods were used to study pyrromethenone, pyrromethene, and biliverdin. These methods made it possible to determine some details of the kinetics of various relaxation mechanisms. The results obtained provided a better understanding of the biological action of pyrrol pigments.

  2. Spectroscopy of Sound Transmission in Solid Samples

    ERIC Educational Resources Information Center

    Campbell, Dean J.; Peterson, Joshua P.; Fitzjarrald, Tamara J.

    2013-01-01

    These laboratory experiments are designed to familiarize students with concepts of spectroscopy by using sound waves. Topics covered in these experiments include the structure of nitinol alloys and polymer chain stiffness as a function of structure and temperature. Generally, substances that are stiffer or have higher symmetry at the molecular…

  3. Surface-Enhanced Femtosecond Stimulated Raman Spectroscopy.

    PubMed

    Frontiera, Renee R; Henry, Anne-Isabelle; Gruenke, Natalie L; Van Duyne, Richard P

    2011-05-19

    Surface-enhanced Raman spectroscopy (SERS) and femtosecond stimulated Raman spectroscopy (FSRS) have revolutionized the Raman spectroscopy field. SERS provides spectroscopic detection of single molecules, and FSRS enables the acquisition of Raman spectra on the ultrafast time scale of molecular motion. Here, we present the first successful combination of these two techniques, demonstrating surface-enhanced femtosecond stimulated Raman spectroscopy (SE-FSRS) using gold nanoantennas with embedded reporter molecules. Using a picosecond Raman and femtosecond probe pulse, the time- and ensemble-averaged enhancement factor is estimated to be in the range of 10(4)-10(6). We report the line shapes, power dependence, and magnitude of the SE-FSRS signal and discuss contributions to sample degradation on the minute time scale. With these first successful proof-of-principle experiments, time-resolved SE-FSRS techniques can now be rationally attempted with the goals of investigating the dynamics of plasmonic materials as well as examining the contributions of environmental heterogeneities by probing more homogeneous molecular subsets.

  4. X-ray spectroscopy of magnetic CVs

    NASA Astrophysics Data System (ADS)

    Matt, Giorgio

    I discuss two topics in X-ray spectroscopy of magnetic CVs: reflection from the white dwarf surface, and opacity effects in the post shock plasma. I also briefly mention future observational perspectives, with particular emphasis on the Constellation X-ray mission.

  5. Ballistic-hole spectroscopy of interfaces

    NASA Technical Reports Server (NTRS)

    Hecht, M. H.; Bell, L. D.; Kaiser, W. J.; Davis, L. C.

    1990-01-01

    A new technique allows direct control and measurement of ballistic-hole transport through interfaces. This spectroscopy has been applied to determine the detailed properties of hole transmission through metal-semiconductor interfaces and probe the valence-band structure of subsurface semiconductor heterostructures. The ballistic-hole probe is created by electron-tunneling-microscopy methods and provides high-spatial-resolution capabilities.

  6. Variational method for lattice spectroscopy with ghosts

    SciTech Connect

    Burch, Tommy; Hagen, Christian; Gattringer, Christof; Glozman, Leonid Ya.; Lang, C.B.

    2006-01-01

    We discuss the variational method used in lattice spectroscopy calculations. In particular we address the role of ghost contributions which appear in quenched or partially quenched simulations and have a nonstandard euclidean time dependence. We show that the ghosts can be separated from the physical states. Our result is illustrated with numerical data for the scalar meson.

  7. Beam-Foil Spectroscopy - Quo Vadis?

    SciTech Connect

    Trabert, E

    2008-05-26

    Beam-foil spectroscopy after 45 years: what has been realized of the promises, what is the state of the art, what is the status of the field, what present atomic physics problems should the technique be applied to, where can it be done? Will it be done? Beam-foil spectroscopy and its sibling techniques have been outstandingly productive tools of atomic physics, providing both important data and insight. For some forty years, the developments have led to improvements in working range and reliability, and catalogues of desirable further measurements can be formulated. However, most of the key persons who have carried out and directed much of the development effort are nearing retirement, and with them the leading facilities. it is thus not likely that many of the desirable BFS projects discussed will presently be pursued. High-Z element, high-charge state spectroscopy and some specific long-lived level lifetime measurements will, however, be taken over by electron beam ion traps, and heavy-ion storage rings will contribute some important benchmark measurements on electric-dipole forbidden or hyperfine-induced transitions. Beam-foil spectroscopy can still be expected to solve a number of interesting atomic physics questions, but as a technique, at present, it has dropped from fashion and support.

  8. EUV spectroscopy of 3 RSCVn binaries

    NASA Technical Reports Server (NTRS)

    Dupree, A. K.; Brickhouse, Nancy S.; Hanson, G. J.

    1995-01-01

    The extreme ultraviolet (EUV) spectroscopy of several binary stars containing cool components is used to define the high temperature plasma structure of these stars and their stellar atmospheres. Different line emission spectra are reported, along with a spectrum analysis of Capella, a nearby bright multiple star system, using data from the EUVE satellite.

  9. Fourier Transform Spectroscopy, Eleventh International Conference. Proceedings

    SciTech Connect

    de Haseth, J.A.

    1998-05-01

    These proceedings represent the papers presented at the Eleventh International Conference on Fourier Transform Spectroscopy held in August, 1997 in Athens, Georgia, USA. The Conference provided an atmosphere for people of diverse backgrounds to congregate and exchange information. The topics discussed included applications of Fourier transform spectroscopy to surface science, biological systems, atmospheric science, forensics and textiles, etc. Biochemical and biomedical studies utilizing Fourier Transform infrared spectroscopy formed a large section of the Conference Applications to semiconductor industry, namely monitoring of CVD processes and photoresists were also discussed. Most of the applications were in the near and mid infrared, with a few extending to the far infrared and visible regions of the electromagnetic spectrum. In the Keynote Address, Fourier Transform Ion Cyloctron Resonance Spectroscopy was reviewed by Professor Alan G. Marshall of the National High Magnetic Field Laboratory in Florida. Altogether 152 papers were presented at the Conference and out of these, 15 have been abstracted for the Energy, Science and Technology database. (AIP)

  10. Photoelectron Spectroscopy in Advanced Placement Chemistry

    ERIC Educational Resources Information Center

    Benigna, James

    2014-01-01

    Photoelectron spectroscopy (PES) is a new addition to the Advanced Placement (AP) Chemistry curriculum. This article explains the rationale for its inclusion, an overview of how the PES instrument records data, how the data can be analyzed, and how to include PES data in the course. Sample assessment items and analysis are included, as well as…

  11. Studies of atmospheric molecules by multiphoton spectroscopy

    SciTech Connect

    Johnson, P.M.

    1991-10-01

    Carbon dioxide presents a great challenge to spectroscopy because of its propensity toward dissociation in all of its excited states. Multiphoton ionization spectroscopy is usually not applicable to the study of dissociating molecules because the dissociation competes effectively with ionization, resulting in no signal. We reasoned, however, that with high enough laser fluence, ionization could compete with dissociation in the longer lived states, exposing them for study from the continuous spectral background resulting from rapidly dissociating states. We describe the various spectroscopic and photophysical effects found through the multiphoton ionization and multiphoton photoelectron spectra. A recently developed variant of threshold ionization spectroscopy, usually called ZEKE, has shown a great deal of usefulness in providing the same information as traditional photoelectron spectroscopy but with higher resolution and much better signal-to-noise when using standard laboratory lasers. Threshold ionization techniques locate the states of an ion by scanning a light source across the ionization continuum of a neutral and somehow detecting when electrons are produced with no kinetic energy. We chose to develop our capabilities in threshold ionization spectroscopy using aromatic molecules because of their importance and because their electronic structure allows a pump-probe type of excitation scheme which avoids the use of vacuum ultraviolet laser beams. Among aromatics, the azines are noted for their small S{sub 1}-T{sub 1} energy gap which give them unique and interesting photophysical properties. We have continued our work on the multiphoton spectrum of metastable nitrogen produced by an electric discharge in supersonic beam. We have been able to assign more of the lines and simulated their rotational structure but many peaks remain unassigned.

  12. An instrument for the investigation of actinides with spin resolved photoelectron spectroscopy and bremsstrahlung isochromat spectroscopy

    SciTech Connect

    Yu, S.-W.; Tobin, J. G.; Chung, B. W.

    2011-01-01

    A new system for spin resolved photoelectron spectroscopy and bremsstrahlung isochromat spectroscopy has been built and commissioned at Lawrence Livermore National Laboratory for the investigation of the electronic structure of the actinides.Actinide materials are very toxic and radioactive and therefore cannot be brought to most general user facilities for spectroscopic studies. The technical details of the new system and preliminary data obtained therein will be presented and discussed.

  13. Raman spectroscopy of saliva as a perspective method for periodontitis diagnostics Raman spectroscopy of saliva

    NASA Astrophysics Data System (ADS)

    Gonchukov, S.; Sukhinina, A.; Bakhmutov, D.; Minaeva, S.

    2012-01-01

    In view of its potential for biological tissues analyses at a molecular level, Raman spectroscopy in optical range has been the object of biomedical research for the last years. The main aim of this work is the development of Raman spectroscopy for organic content identifying and determination of biomarkers of saliva at a molecular level for periodontitis diagnostics. Four spectral regions were determined: 1155 and 1525 cm-1, 1033 and 1611 cm-1, which can be used as biomarkers of this widespread disease.

  14. Modeling the Effect of Polychromatic Light in Quantitative Absorbance Spectroscopy

    ERIC Educational Resources Information Center

    Smith, Rachel; Cantrell, Kevin

    2007-01-01

    Laboratory experiment is conducted to give the students practical experience with the principles of electronic absorbance spectroscopy. This straightforward approach creates a powerful tool for exploring many of the aspects of quantitative absorbance spectroscopy.

  15. Emerging technology: applications of Raman spectroscopy for prostate cancer.

    PubMed

    Kast, Rachel E; Tucker, Stephanie C; Killian, Kevin; Trexler, Micaela; Honn, Kenneth V; Auner, Gregory W

    2014-09-01

    There is a need in prostate cancer diagnostics and research for a label-free imaging methodology that is nondestructive, rapid, objective, and uninfluenced by water. Raman spectroscopy provides a molecular signature, which can be scaled from micron-level regions of interest in cells to macroscopic areas of tissue. It can be used for applications ranging from in vivo or in vitro diagnostics to basic science laboratory testing. This work describes the fundamentals of Raman spectroscopy and complementary techniques including surface enhanced Raman scattering, resonance Raman spectroscopy, coherent anti-Stokes Raman spectroscopy, confocal Raman spectroscopy, stimulated Raman scattering, and spatially offset Raman spectroscopy. Clinical applications of Raman spectroscopy to prostate cancer will be discussed, including screening, biopsy, margin assessment, and monitoring of treatment efficacy. Laboratory applications including cell identification, culture monitoring, therapeutics development, and live imaging of cellular processes are discussed. Potential future avenues of research are described, with emphasis on multiplexing Raman spectroscopy with other modalities.

  16. Two-dimensional vibrational-electronic spectroscopy

    SciTech Connect

    Courtney, Trevor L.; Fox, Zachary W.; Slenkamp, Karla M.; Khalil, Munira

    2015-10-21

    Two-dimensional vibrational-electronic (2D VE) spectroscopy is a femtosecond Fourier transform (FT) third-order nonlinear technique that creates a link between existing 2D FT spectroscopies in the vibrational and electronic regions of the spectrum. 2D VE spectroscopy enables a direct measurement of infrared (IR) and electronic dipole moment cross terms by utilizing mid-IR pump and optical probe fields that are resonant with vibrational and electronic transitions, respectively, in a sample of interest. We detail this newly developed 2D VE spectroscopy experiment and outline the information contained in a 2D VE spectrum. We then use this technique and its single-pump counterpart (1D VE) to probe the vibrational-electronic couplings between high frequency cyanide stretching vibrations (ν{sub CN}) and either a ligand-to-metal charge transfer transition ([Fe{sup III}(CN){sub 6}]{sup 3−} dissolved in formamide) or a metal-to-metal charge transfer (MMCT) transition ([(CN){sub 5}Fe{sup II}CNRu{sup III}(NH{sub 3}){sub 5}]{sup −} dissolved in formamide). The 2D VE spectra of both molecules reveal peaks resulting from coupled high- and low-frequency vibrational modes to the charge transfer transition. The time-evolving amplitudes and positions of the peaks in the 2D VE spectra report on coherent and incoherent vibrational energy transfer dynamics among the coupled vibrational modes and the charge transfer transition. The selectivity of 2D VE spectroscopy to vibronic processes is evidenced from the selective coupling of specific ν{sub CN} modes to the MMCT transition in the mixed valence complex. The lineshapes in 2D VE spectra report on the correlation of the frequency fluctuations between the coupled vibrational and electronic frequencies in the mixed valence complex which has a time scale of 1 ps. The details and results of this study confirm the versatility of 2D VE spectroscopy and its applicability to probe how vibrations modulate charge and energy transfer in a

  17. Spectroscopy: An Introduction for Talented High School Students.

    ERIC Educational Resources Information Center

    Magyar, Elaine; Magyar, James G.

    1989-01-01

    Investigates the four week chemistry program in a summer program in science and mathematics. Identifies weekly topics for the program: (1) color and visible spectroscopy; (2) UV spectroscopy, fluorescence, and chemiluminescence; (3) IR and NMR spectroscopy; and (4) lists 12 individual projects. (MVL)

  18. Ultrafast time-resolved vibrational spectroscopies of carotenoids in photosynthesis.

    PubMed

    Hashimoto, Hideki; Sugisaki, Mitsuru; Yoshizawa, Masayuki

    2015-01-01

    This review discusses the application of time-resolved vibrational spectroscopies to the studies of carotenoids in photosynthesis. The focus is on the ultrafast time regime and the study of photophysics and photochemistry of carotenoids by femtosecond time-resolved stimulated Raman and four-wave mixing spectroscopies. This article is part of a Special Issue entitled: Vibrational spectroscopies and bioenergetic systems.

  19. UV-VIS absorption spectroscopy: Lambert-Beer reloaded.

    PubMed

    Mäntele, Werner; Deniz, Erhan

    2017-02-15

    UV-VIS absorption spectroscopy is used in almost every spectroscopy laboratory for routine analysis or research. All spectroscopists rely on the Lambert-Beer Law but many of them are less aware of its limitations. This tutorial discusses typical problems in routine spectroscopy that come along with technical limitations or careless selection of experimental parameters. Simple rules are provided to avoid these problems.

  20. UV-VIS absorption spectroscopy: Lambert-Beer reloaded

    NASA Astrophysics Data System (ADS)

    Mäntele, Werner; Deniz, Erhan

    2017-02-01

    UV-VIS absorption spectroscopy is used in almost every spectroscopy laboratory for routine analysis or research. All spectroscopists rely on the Lambert-Beer Law but many of them are less aware of its limitations. This tutorial discusses typical problems in routine spectroscopy that come along with technical limitations or careless selection of experimental parameters. Simple rules are provided to avoid these problems.

  1. Collinear laser spectroscopy of radioisotopes of zirconium

    NASA Astrophysics Data System (ADS)

    Thayer, H. L.; Billowes, J.; Campbell, P.; Dendooven, P.; Flanagan, K. T.; Forest, D. H.; Griffith, J. A. R.; Huikari, J.; Jokinen, A.; Moore, R.; Nieminen, A.; Tungate, G.; Zemlyanoi, S.; Äystö, J.

    2003-09-01

    Isotope shifts and hyperfine structures have been measured for radioisotopes of ionic zirconium using on-line laser spectroscopy at the IGISOL facility in Jyväskylä, where the installation of an ion beam cooler/buncher has significantly improved the experimental sensitivity. Measurements have been made on all the neutron-deficient isotopes from 87Zr to 90Zr, including the isomers 87m,89mZr, and the neutron-rich isotopes from 96Zr to 102Zr. The change in mean square charge radii between the isotopes and the nuclear moments of the odd isotopes have been extracted. The data show a sudden increase in the mean square charge radius at mass A = 100, consistent with an onset of nuclear deformation which has been observed in the gamma ray spectroscopy of isotope chains in this region of the nuclear chart.

  2. Raman spectroscopy of transition metal dichalcogenides

    NASA Astrophysics Data System (ADS)

    Saito, R.; Tatsumi, Y.; Huang, S.; Ling, X.; Dresselhaus, M. S.

    2016-09-01

    Raman spectroscopy of transition metal dichalcogenides (TMDs) is reviewed based on our recent theoretical and experimental works. First, we discuss the semi-classical and quantum mechanical description for the polarization dependence of Raman spectra of TMDs in which the optical dipole transition matrix elements as a function of laser excitation energy are important for understanding the polarization dependence of the Raman intensity and Raman tensor. Overviewing the symmetry of TMDs, we discuss the dependence of the Raman spectra of TMDs on layer thickness, polarization, laser energy and the structural phase. Furthermore, we discuss the Raman spectra of twisted bilayer and heterostructures of TMDs. Finally, we give our perspectives on the Raman spectroscopy of TMDs.

  3. Raman spectroscopy of transition metal dichalcogenides.

    PubMed

    Saito, R; Tatsumi, Y; Huang, S; Ling, X; Dresselhaus, M S

    2016-09-07

    Raman spectroscopy of transition metal dichalcogenides (TMDs) is reviewed based on our recent theoretical and experimental works. First, we discuss the semi-classical and quantum mechanical description for the polarization dependence of Raman spectra of TMDs in which the optical dipole transition matrix elements as a function of laser excitation energy are important for understanding the polarization dependence of the Raman intensity and Raman tensor. Overviewing the symmetry of TMDs, we discuss the dependence of the Raman spectra of TMDs on layer thickness, polarization, laser energy and the structural phase. Furthermore, we discuss the Raman spectra of twisted bilayer and heterostructures of TMDs. Finally, we give our perspectives on the Raman spectroscopy of TMDs.

  4. Spectroscopy and optical imaging of coalescing droplets

    NASA Astrophysics Data System (ADS)

    Ivanov, Maksym; Viderström, Michel; Chang, Kelken; Ramírez Contreras, Claudia; Mehlig, Bernhard; Hanstorp, Dag

    2016-09-01

    We report on experimental investigations of the dynamics of colliding liquid droplets by combining optical trapping, spectroscopy and high-speed color imaging. Two droplets with diameters between 5 and 50 microns are suspended in quiescent air by optical traps. The traps allows us to control the initial positions, and hence the impact parameter and the relative velocity of the colliding droplets. Movies of the droplet dynamics are recorded using high-speed digital movie cameras at a frame rate of up to 63000 frames per second. A fluorescent dye is added to one of the colliding droplets. We investigate the temporal evolution of the scattered and fluorescence light from the colliding droplets with concurrent spectroscopy and color imaging. This technique can be used to detect the exchange of molecules between a pair of neutral or charged droplets.

  5. Applications of Raman spectroscopy to gemology.

    PubMed

    Bersani, Danilo; Lottici, Pier Paolo

    2010-08-01

    Being nondestructive and requiring short measurement times, a low amount of material, and no sample preparation, Raman spectroscopy is used for routine investigation in the study of gemstone inclusions and treatments and for the characterization of mounted gems. In this work, a review of the use of laboratory Raman and micro-Raman spectrometers and of portable Raman systems in the gemology field is given, focusing on gem identification and on the evaluation of the composition, provenance, and genesis of gems. Many examples are shown of the use of Raman spectroscopy as a tool for the identification of imitations, synthetic gems, and enhancement treatments in natural gemstones. Some recent developments are described, with particular attention being given to the semiprecious stone jade and to two important organic materials used in jewelry, i.e., pearls and corals.

  6. Proton magnetic resonance spectroscopy in multiple sclerosis

    SciTech Connect

    Wolinsky, J.S.; Narayana, P.A.; Fenstermacher, M.J. )

    1990-11-01

    Regional in vivo proton magnetic resonance spectroscopy provides quantitative data on selected chemical constituents of brain. We imaged 16 volunteers with clinically definite multiple sclerosis on a 1.5 tesla magnetic resonance scanner to define plaque-containing volumes of interest, and obtained localized water-suppressed proton spectra using a stimulated echo sequence. Twenty-five of 40 plaque-containing regions provided spectra of adequate quality. Of these, 8 spectra from 6 subjects were consistent with the presence of cholesterol or fatty acids; the remainder were similar to those obtained from white matter of normal volunteers. This early experience with regional proton spectroscopy suggests that individual plaques are distinct. These differences likely reflect dynamic stages of the evolution of the demyelinative process not previously accessible to in vivo investigation.

  7. Squeezed-light spin noise spectroscopy

    NASA Astrophysics Data System (ADS)

    Lucivero, Vito Giovanni; Jiménez-Martínez, Ricardo; Kong, Jia; Mitchell, Morgan W.

    2016-05-01

    We report quantum enhancement of Faraday rotation spin noise spectroscopy by polarization squeezing of the probe beam. Using natural abundance Rb in 100 Torr of N2 buffer gas and squeezed light from a subthreshold optical parametric oscillator stabilized 20 GHz to the blue of the D1 resonance, we observe that an input squeezing of 3.0 dB improves the signal-to-noise ratio by 1.5 to 2.6 dB over the combined (power)⊗(number density) ranges (0.5-4.0 mW)⊗(1.5 ×1012cm-3 to 1.3 ×1013 cm-3), covering the ranges used in optimized spin noise spectroscopy experiments. We also show that squeezing improves the tradeoff between statistical sensitivity and broadening effects, a previously unobserved quantum advantage.

  8. Astatine and Yttrium Resonant Ionization Laser Spectroscopy

    NASA Astrophysics Data System (ADS)

    Teigelhoefer, Andrea

    Providing intense, contamination-free beams of rare isotopes to experiments is a challenging task. At isotope separator on-line facilities such as ISAC at TRIUMF, the choice of production target and ion source are key to the successful beam delivery. Due to their element-selectivity, high efficiency and versatility, resonant ionization laser ion sources (RILIS) gain increasingly in importance. The spectroscopic data available are typically incomplete in the region of excited- and autoionizing atomic states. In order to find the most efficient ionization scheme for a particular element, further spectroscopy is often required. The development of efficient laser resonant ionization schemes for yttrium and astatine is presented in this thesis. For yttrium, two ionization schemes with comparable relative intensities were found. Since for astatine, only two transitions were known, the focus was to provide data on atomic energy levels using resonance ionization spectroscopy. Altogether 41 previously unknown astatine energy levels were found.

  9. Dual ETALON Frequency Comb (defcom) Spectroscopy

    NASA Astrophysics Data System (ADS)

    Chandler, David W.; Strecker, Kevin E.

    2012-06-01

    A new spectrometer based on an interferogram produced by the output of two separate confocal etalons is described and first experiments will be described. This spectrometer has the resolution of the Free Spectral Range (FSR) of the etalons on a single laser shot over the bandwidth of the light source that that is used to excite the etalons. With signal averaging and scanning of the etalon mirror the resolution can be that of the "ring-down" time of the etalons. By placing the sample of interest within one of the etalons one obtains the sensitivity of cavity ring down spectroscopy while performing Cavity Ring Down (CRD) spectroscopy over the entire bandwidth of the laser source used to excite the etalon. First data on measurements of overtone absorptions of water and weak electronic gamma-band absorption of oxygen will be presented. Work supported by DOE Basic Energy Sciences.

  10. Broadband Phase Spectroscopy over Turbulent Air Paths.

    PubMed

    Giorgetta, Fabrizio R; Rieker, Gregory B; Baumann, Esther; Swann, William C; Sinclair, Laura C; Kofler, Jon; Coddington, Ian; Newbury, Nathan R

    2015-09-04

    Broadband atmospheric phase spectra are acquired with a phase-sensitive dual-frequency-comb spectrometer by implementing adaptive compensation for the strong decoherence from atmospheric turbulence. The compensation is possible due to the pistonlike behavior of turbulence across a single spatial-mode path combined with the intrinsic frequency stability and high sampling speed associated with dual-comb spectroscopy. The atmospheric phase spectrum is measured across 2 km of air at each of the 70,000 comb teeth spanning 233  cm(-1) across hundreds of near-infrared rovibrational resonances of CO(2), CH(4), and H(2)O with submilliradian uncertainty, corresponding to a 10(-13) refractive index sensitivity. Trace gas concentrations extracted directly from the phase spectrum reach 0.7 ppm uncertainty, demonstrated here for CO(2). While conventional broadband spectroscopy only measures intensity absorption, this approach enables measurement of the full complex susceptibility even in practical open path sensing.

  11. Fluorescence spectroscopy applied to orange trees

    NASA Astrophysics Data System (ADS)

    Marcassa, L. G.; Gasparoto, M. C. G.; Belasque, J., Jr.; Lins, E. C.; Dias Nunes, F.; Bagnato, V. S.

    2006-05-01

    In this work, we have applied laser-induced fluorescence spectroscopy to investigate biological processes in orange trees (Citrus aurantium L.). We have chosen to investigate water stress and Citrus Canker, which is a disease caused by the Xanthomonas axonopodis pv. citri bacteria. The fluorescence spectroscopy was investigated by using as an excitation source a 442-nm 15-mW HeCd gas multimode discharge laser and a 532-nm 10-mW Nd3+:YAG laser. The stress manifestation was detected by the variation of fluorescence ratios of the leaves at different wavelengths. The fluorescence ratios present a significant variation, showing the possibility to observe water stress by fluorescence spectrum. The Citrus Canker’s contaminated leaves were discriminated from the healthy leaves using a more complex analysis of the fluorescence spectra. However, we were unable to discriminate it from another disease, and new fluorescence experiments are planned for the future.

  12. Application of visible spectroscopy in waste sorting

    NASA Astrophysics Data System (ADS)

    Spiga, Philippe; Bourely, Antoine

    2011-10-01

    Today, waste recycling, (bottles, papers...), is a mechanical operation: the waste are crushed, fused and agglomerated in order to obtain new manufactured products (e.g. new bottles, clothes ...). The plastics recycling is the main application in the color sorting process. The colorless plastics recovered are more valuable than the colored plastics. Other emergent applications are in the paper sorting, where the main goal is to sort dyed paper from white papers. Up to now, Pellenc Selective Technologies has manufactured color sorting machines based on RGB cameras. Three dimensions (red, green and blue) are no longer sufficient to detect low quantities of dye in the considered waste. In order to increase the efficiency of the color detection, a new sorting machine, based on visible spectroscopy, has been developed. This paper presents the principles of the two approaches and their difference in terms of sorting performance, making visible spectroscopy a clear winner.

  13. Positron annihilation induced Auger electron spectroscopy

    NASA Technical Reports Server (NTRS)

    Weiss, Alex; Koymen, A. R.; Mehl, David; Jensen, K. O.; Lei, Chun; Lee, K. H.

    1990-01-01

    Recently, Weiss et al. have demonstrated that it is possible to excite Auger transitions by annihilating core electrons using a low energy (less than 30eV) beam of positrons. This mechanism makes possible a new electron spectroscopy, Positron annihilation induced Auger Electron Spectroscopy (PAES). The probability of exciting an Auger transition is proportional to the overlap of the positron wavefunction with atomic core levels. Since the Auger electron energy provides a signature of the atomic species making the transition, PAES makes it possible to determine the overlap of the positron wavefunction with a particular element. PAES may therefore provide a means of detecting positron-atom complexes. Measurements of PAES intensities from clean and adsorbate covered Cu surfaces are presented which indicate that approx. 5 percent of positrons injected into CU at 25eV produce core annihilations that result in Auger transitions.

  14. Diffuse reflectance spectroscopy of liver tissue

    NASA Astrophysics Data System (ADS)

    Reistad, Nina; Nilsson, Jan; Vilhelmsson Timmermand, Oskar; Sturesson, Christian; Andersson-Engels, Stefan

    2015-06-01

    Diffuse reflectance spectroscopy (DRS) with a fiber-optic contact probe is a cost-effective, rapid, and non-invasive optical method used to extract diagnosis information of tissue. By combining commercially available VIS- and NIR-spectrometers with various fiber-optic contact-probes, we have access to the full wavelength range from around 400 to 1600 nm. Using this flexible and portable spectroscopy system, we have acquired ex-vivo DRS-spectra from murine, porcine, and human liver tissue. For extracting the tissue optical properties from the measured spectra, we have employed and compared predictions from two models for light propagation in tissue, diffusion theory model (DT) and Monte Carlo simulations (MC). The focus in this work is on the capacity of this DRS-technique in discriminating metastatic tumor tissue from normal liver tissue as well as in assessing and characterizing damage to non-malignant liver tissue induced by preoperative chemotherapy for colorectal liver metastases.

  15. In vivo absorption spectroscopy for absolute measurement.

    PubMed

    Furukawa, Hiromitsu; Fukuda, Takashi

    2012-10-01

    In in vivo spectroscopy, there are differences between individual subjects in parameters such as tissue scattering and sample concentration. We propose a method that can provide the absolute value of a particular substance concentration, independent of these individual differences. Thus, it is not necessary to use the typical statistical calibration curve, which assumes an average level of scattering and an averaged concentration over individual subjects. This method is expected to greatly reduce the difficulties encountered during in vivo measurements. As an example, for in vivo absorption spectroscopy, the method was applied to the reflectance measurement in retinal vessels to monitor their oxygen saturation levels. This method was then validated by applying it to the tissue phantom under a variety of absorbance values and scattering efficiencies.

  16. Atomic vapor spectroscopy in integrated photonic structures

    SciTech Connect

    Ritter, Ralf; Kübler, Harald; Pfau, Tilman; Löw, Robert; Gruhler, Nico; Pernice, Wolfram

    2015-07-27

    We investigate an integrated optical chip immersed in atomic vapor providing several waveguide geometries for spectroscopy applications. The narrow-band transmission through a silicon nitride waveguide and interferometer is altered when the guided light is coupled to a vapor of rubidium atoms via the evanescent tail of the waveguide mode. We use grating couplers to couple between the waveguide mode and the radiating wave, which allow for addressing arbitrary coupling positions on the chip surface. The evanescent atom-light interaction can be numerically simulated and shows excellent agreement with our experimental data. This work demonstrates a next step towards miniaturization and integration of alkali atom spectroscopy and provides a platform for further fundamental studies of complex waveguide structures.

  17. Stress measurement in MEMS using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Animoto, Sherwin T.; Chang, Dick J.; Birkitt, Andra D.

    1998-09-01

    Raman spectroscopy is used as a non-contact method in measuring stresses at the surface of a crystalline structure or the crystalline-coated surface of an amorphous structure. The stress measurement capability is based on the relative frequency shift of Raman spectra when the crystal lattice is strained. The Raman spectroscopy has a resolution on the order of a few micrometer (micrometers ) which may be used to probe the local non-uniform stress distribution and thus address the material nonhomogeneity. This paper presents the Raman secular equation for general and cubic crystal systems and discusses the stress field effects to Raman frequency shifts and polarization. Experimental testing will include the calibration of the Raman signal versus mechanically applied stresses using single crystal strips, poly-silicon coatings deposited on different specimen configurations, and the stress measurements on a frequently used MEMS structure, cantilever beam, subject to electrostatic forces. Correlation of the experimental results with the analytical prediction will be addressed.

  18. Meson Spectroscopy At Jlab At 12 Gev

    SciTech Connect

    Fegan, Stuart

    2014-12-01

    The 12 GeV upgrade to the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab will enable a new generation of experiments in hadronic nuclear physics, seeking to address fundamental questions in our understanding of QCD. The existence of exotic states, suggested by both quark models and lattice calculations, would allow gluonic degrees of freedom to be explored, and may help explain the role played by gluons in the QCD interaction. This article will review the meson spectroscopy program being planned at the lab following the 12 GeV upgrade, utilising real and quasi-real photon beams in two of the lab's four experimental halls, whose distinct capabilities will enable an extensive set of spectroscopy experiments to be performed at the same facility.

  19. One-dimensional frequency-based spectroscopy.

    PubMed

    Cygan, Agata; Wcisło, Piotr; Wójtewicz, Szymon; Masłowski, Piotr; Hodges, Joseph T; Ciuryło, Roman; Lisak, Daniel

    2015-06-01

    Recent developments in optical metrology have tremendously improved the precision and accuracy of the horizontal (frequency) axis in measured spectra. However, the vertical (typically absorbance) axis is usually based on intensity measurements that are subject to instrumental errors which limit the spectrum accuracy. Here we report a one-dimensional spectroscopy that uses only the measured frequencies of high-finesse cavity modes to provide complete information about the dispersive properties of the spectrum. Because this technique depends solely on the measurement of frequencies or their differences, it is insensitive to systematic errors in the detection of light intensity and has the potential to become the most accurate of all absorptive and dispersive spectroscopic methods. The experimental results are compared to measurements by two other high-precision cavity-enhanced spectroscopy methods. We expect that the proposed technique will have significant impact in fields such as fundamental physics, gas metrology and environmental remote sensing.

  20. Raman spectroscopy of newberyite, hannayite and struvite

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; Weier, Matt L.; Martens, Wayde N.; Henry, Dermot A.; Mills, Stuart J.

    2005-11-01

    The phosphate minerals hannayite, newberyite and struvite have been studied by Raman spectroscopy using a thermal stage. Hannayite and newberyite are characterised by an intense band at around 980 cm -1 assigned to the v symmetric stretching vibration of the HPO 4 units. In contrast the symmetric stretching mode is observed at 942 cm -1 for struvite. The Raman spectra are characterised by multiple v anti-symmetric stretching bands and v and v bending modes indicating strong distortion of the HPO 4 and PO 4 units. Hannayite and newberyite are defined by bands at 3382 and 3350 cm -1 attributed to HOPO 3 vibrations and hannayite and struvite by bands at 2990, 2973 and 2874 assigned to NH 4+ bands. Raman spectroscopy has proven most useful for the analysis of these 'cave' minerals where complex paragenetic relationships exist between the minerals.

  1. FINESSE: A Dedicated Transiting Exoplanet Spectroscopy Mission

    NASA Astrophysics Data System (ADS)

    Bean, Jacob; FINESSE Science Team

    2017-01-01

    FINESSE (Fast INfrared Exoplanet Spectroscopy Survey Explorer) is a proposed space mission dedicated to performing a statistical census of transiting exoplanet atmospheres. The objectives of FINESSE are to test theories of planetary origins and climate, enable comparative planetology, and open up discovery space on atmospheric chemistry, planetary evolution, and other topics. The baseline design for FINESSE is a 75 cm telescope observing from L2. The FINESSE instrument is a high throughput spectrometer with continuous coverage from 0.5 to 5.0 microns in a single shot. FINESSE will survey on order of 1000 exoplanets with a combination of transmission, dayside emission, and phase-resolved emission spectroscopy during a two year mission. As of this writing FINESSE will be proposed for the NASA Medium-Class Explorers (MIDEX) announcement of opportunity in December 2016. I will present an overview of FINESSE, including the mission concept, science drivers, and expected results from extensive simulations.

  2. (Resonance ionization spectroscopy and its applications)

    SciTech Connect

    Ramsey, J.M.

    1990-10-11

    The Fifth International Symposium in Resonance Ionization Spectroscopy and Its Applications was attended. The Joint Research Centre of the European Communities at Ispra, Italy was also visited. The traveler presented an invited talk, chaired a meeting session and gave an impromptu presentation on how current laser technology limits the development of commercial instrumentation based upon Resonance Ionization Spectroscopy. The conference was truely international with scientists from 19 countries and less than 1/4 from the US. The meeting also provided a health mixture of experimentalists and theoreticians. Technical developments reported included the use of electric field ionization from laser prepared Rydberg states as a way to reduce background signals and commercial development of an optical parametric oscillator for replacing pulsed dye laser. A speaker from the Soviet Union suggested their willingness to market hardware they have developed based upon the resonance ionization technique.

  3. Broadband Phase Spectroscopy over Turbulent Air Paths

    NASA Astrophysics Data System (ADS)

    Giorgetta, Fabrizio R.; Rieker, Gregory B.; Baumann, Esther; Swann, William C.; Sinclair, Laura C.; Kofler, Jon; Coddington, Ian; Newbury, Nathan R.

    2015-09-01

    Broadband atmospheric phase spectra are acquired with a phase-sensitive dual-frequency-comb spectrometer by implementing adaptive compensation for the strong decoherence from atmospheric turbulence. The compensation is possible due to the pistonlike behavior of turbulence across a single spatial-mode path combined with the intrinsic frequency stability and high sampling speed associated with dual-comb spectroscopy. The atmospheric phase spectrum is measured across 2 km of air at each of the 70 000 comb teeth spanning 233 cm-1 across hundreds of near-infrared rovibrational resonances of CO2 , CH4 , and H2O with submilliradian uncertainty, corresponding to a 10-13 refractive index sensitivity. Trace gas concentrations extracted directly from the phase spectrum reach 0.7 ppm uncertainty, demonstrated here for CO2 . While conventional broadband spectroscopy only measures intensity absorption, this approach enables measurement of the full complex susceptibility even in practical open path sensing.

  4. Fluorescence spectroscopy of rhodopsins: Insights and approaches

    PubMed Central

    Alexiev, Ulrike; Farrens, David L.

    2014-01-01

    Fluorescence spectroscopy has become an established tool at the interface of biology, chemistry and physics because of its exquisite sensitivity and recent technical advancements. However, rhodopsin proteins present the fluorescence spectroscopist with a unique set of challenges and opportunities due to the presence of the light-sensitive retinal chromophore. This review briefly summarizes some approaches that have successfully met these challenges and the novel insights they have yielded about rhodopsin structure and function. We start with a brief overview of fluorescence fundamentals and experimental methodologies, followed by more specific discussions of technical challenges rhodopsin proteins present to fluorescence studies. Finally, we end by discussing some of the unique insights that have been gained specifically about visual rhodopsin and its interactions with affiliate proteins through the use of fluorescence spectroscopy. PMID:24183695

  5. FTIR Spectroscopy for Carbon Family Study.

    PubMed

    Ţucureanu, Vasilica; Matei, Alina; Avram, Andrei Marius

    2016-11-01

    Fourier transform Infrared (FTIR) spectroscopy is a versatile technique for the characterization of materials belonging to the carbon family. Based on the interaction of the IR radiation with matter this technique may be used for the identification and characterization of chemical structures. Most important features of this method are: non-destructive, real-time measurement and relatively easy to use. Carbon basis for all living systems has found numerous industrial applications from carbon coatings (i.e. amorphous and nanocrystalline carbon films: diamond-like carbon (DLC) films) to nanostructured materials (fullerenes, nanotubes, graphene) and carbon materials at nanoscale or carbon dots (CDots). In this paper, we present the FTIR vibrational spectroscopy for the characterization of diamond, amorphous carbon, graphite, graphene, carbon nanotubes (CNTs), fullerene and carbon quantum dots (CQDs), without claiming to cover entire field.

  6. Anharmonic Vibrational Spectroscopy on Metal Transition Complexes

    NASA Astrophysics Data System (ADS)

    Latouche, Camille; Bloino, Julien; Barone, Vincenzo

    2014-06-01

    Advances in hardware performance and the availability of efficient and reliable computational models have made possible the application of computational spectroscopy to ever larger molecular systems. The systematic interpretation of experimental data and the full characterization of complex molecules can then be facilitated. Focusing on vibrational spectroscopy, several approaches have been proposed to simulate spectra beyond the double harmonic approximation, so that more details become available. However, a routine use of such tools requires the preliminary definition of a valid protocol with the most appropriate combination of electronic structure and nuclear calculation models. Several benchmark of anharmonic calculations frequency have been realized on organic molecules. Nevertheless, benchmarks of organometallics or inorganic metal complexes at this level are strongly lacking despite the interest of these systems due to their strong emission and vibrational properties. Herein we report the benchmark study realized with anharmonic calculations on simple metal complexes, along with some pilot applications on systems of direct technological or biological interest.

  7. White light spectroscopy for free flap monitoring.

    PubMed

    Fox, Paige M; Zeidler, Kamakshi; Carey, Joseph; Lee, Gordon K

    2013-03-01

    White light spectroscopy non-invasively measures hemoglobin saturation at the capillary level rendering an end-organ measurement of perfusion. We hypothesized this technology could be used after microvascular surgery to allow for early detection of ischemia and thrombosis. The Spectros T-Stat monitoring device, which utilizes white light spectroscopy, was compared with traditional flap monitoring techniques including pencil Doppler and clinical exam. Data were prospectively collected and analyzed. Results from 31 flaps revealed a normal capillary hemoglobin saturation of 40-75% with increase in saturation during the early postoperative period. One flap required return to the operating room 12 hours after microvascular anastomosis. The T-stat system recorded an acute decrease in saturation from ~50% to less than 30% 50 min prior to identification by clinical exam. Prompt treatment resulted in flap salvage. The Spectros T-Stat monitor may be a useful adjunct for free flap monitoring providing continuous, accurate perfusion assessment postoperatively.

  8. Spontaneous transient ultrafast coherent raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Meiselman, Seth

    I explore the application of Transient Coherent Ultrafast Phonon Spectroscopy (TCUPS) to the measurement of vibrational coherence dynamics of liquid alcohols. The demonstrated technique is complementary to and, in some cases, simpler than traditional stimulated spectroscopy techniques in that it does not require more than one laser and is free of non-resonant background. I demonstrate coherence measurements of single-photon-level collective excitations: a single vibrational state at 1033 (1/cm) in; a pair of simultaneous excited vibrational states at 2834 and 2944 (1/cm) in methanol; and three simultaneous excited states at 2885, ˜2930, and 2976 (1/cm) in isopropanol. I develop a Fourier-transform-based analysis of the TCUPS data that overcomes poor signal-to-noise ratio and signal degradation due to etaloning and fluorescence. The coherence lifetimes and oscillation frequencies agree with frequency-domain line-shape measurements and femtosecond Coherent anti-Stokes Raman Scattering (CARS) measurements.

  9. [Infrared spectroscopy application in soil organic matter].

    PubMed

    Wu, J; Xi, S; Jiang, Y

    1998-02-01

    As an important method to study the constitution and properties of macromolecular organic compounds, the infrared spectroscopy has been more and more widely taken in the researches of soil organic matters (SOM). Especially,the application of FTIR and the combined uses of FTIR with chromatogram etc. have made the researches of SOM get a great progress in many aspects. In this paper, the infrared spectroscopy applications were reviewed in SOM. It includes the following contents: the methods to study SOM by IR, studies on the constitution of soil humic substances (SHS), extraction of SOM and classification of SHS, decomposition, transformation and humification of organic matters, the differences of SOM in different situations, the interactions of SHS with metais, clay minerals and other organics in soil.

  10. Polymorph Discrimination using Low Wavenumber Raman Spectroscopy

    PubMed Central

    Roy, Saikat; Chamberlin, Brianna; Matzger, Adam J.

    2016-01-01

    Characterization of crystalline polymorphs and their quantitation has become an integral part of the pre-clinical drug development process. Raman spectroscopy is a powerful technique for the rapid identification of phases of pharmaceuticals. In the present work we demonstrate the use of low wavenumber Raman vibrational spectroscopy (including phonon measurement) for discrimination among polymorphs. A total of 10 polymorphic pharmaceuticals were employed to conduct a critical assessment. Raman scattering in the low frequency region (10–400 cm−1), which includes crystal lattice vibrations, has been analyzed and the results indicate lattice phonon Raman scattering can be used for rapid discrimination of polymorphic phases with additional discriminating power compared to conventional collection strategies. Moreover structural insight and conformational changes can be detected with this approach. PMID:27642248

  11. Microfluidic devices for terahertz spectroscopy of biomolecules.

    PubMed

    George, Paul A; Hui, Wallace; Rana, Farhan; Hawkins, Benjamin G; Smith, A Ezekiel; Kirby, Brian J

    2008-02-04

    We demonstrate microfluidic devices for terahertz spectroscopy of biomolecules in aqueous solutions. The devices are fabricated out of a plastic material that is both mechanically rigid and optically transparent with near-zero dispersion in the terahertz frequency range. Using a lowpower terahertz time-domain spectrometer, we experimentally measure the absorption spectra of the vibrational modes of bovine serum albumin from 0.5 - 2.5 THz and find good agreement with previously reported data obtained using large-volume solutions and a high-power free-electron laser. Our results demonstrate the feasibility of performing high sensitivity terahertz spectroscopy of biomolecules in aqueous solutions with detectable molecular quantities as small as 10 picomoles using microfluidic devices.

  12. Raman spectroscopy in pharmaceutical product design.

    PubMed

    Paudel, Amrit; Raijada, Dhara; Rantanen, Jukka

    2015-07-15

    Almost 100 years after the discovery of the Raman scattering phenomenon, related analytical techniques have emerged as important tools in biomedical sciences. Raman spectroscopy and microscopy are frontier, non-invasive analytical techniques amenable for diverse biomedical areas, ranging from molecular-based drug discovery, design of innovative drug delivery systems and quality control of finished products. This review presents concise accounts of various conventional and emerging Raman instrumentations including associated hyphenated tools of pharmaceutical interest. Moreover, relevant application cases of Raman spectroscopy in early and late phase pharmaceutical development, process analysis and micro-structural analysis of drug delivery systems are introduced. Finally, potential areas of future advancement and application of Raman spectroscopic techniques are discussed.

  13. Method and apparatus for time dispersive spectroscopy

    DOEpatents

    Tarver, III, Edward E.; Siems, William F.

    2003-06-17

    Methods and apparatus are described for time dispersive spectroscopy. In particular, a modulated flow of ionized molecules of a sample are introduced into a drift region of an ion spectrometer. The ions are subsequently detected by an ion detector to produce an ion detection signal. The ion detection signal can be modulated to obtain a signal useful in assaying the chemical constituents of the sample.

  14. Standoff spectroscopy using a conditioned target

    DOEpatents

    Van Neste, Charles W.; Morales-Rodriguez, Marissa E.; Senesac, Lawrence R.; Thundat, Thomas G.

    2011-12-20

    A system and method are disclosed for standoff spectroscopy of molecules (e.g. from a residue) on a surface from a distance. A source emits radiation that modifies or conditions the residue, such as through photodecomposition. A spectral generating source measures a spectrum of the residue before and after the residue is exposed to the radiation from that source. The two spectra are compared to produce a distinct identification of the residues on the surface or identify certain properties of the residue.

  15. Photoacoustic spectroscopy of β-hematin

    NASA Astrophysics Data System (ADS)

    Samson, Edward B.; Goldschmidt, Benjamin S.; Whiteside, Paul J. D.; Sudduth, Amanda S. M.; Custer, John R.; Beerntsen, Brenda; Viator, John A.

    2012-06-01

    Malaria affects over 200 million individuals annually, resulting in 800 000 fatalities. Current tests use blood smears and can only detect the disease when 0.1-1% of blood cells are infected. We are investigating the use of photoacoustic flowmetry to sense as few as one infected cell among 10 million or more normal blood cells, thus diagnosing infection before patients become symptomatic. Photoacoustic flowmetry is similar to conventional flow cytometry, except that rare cells are targeted by nanosecond laser pulses to induce ultrasonic responses. This system has been used to detect single melanoma cells in 10 ml of blood. Our objective is to apply photoacoustic flowmetry to detection of the malaria pigment hemozoin, which is a byproduct of parasite-digested hemoglobin in the blood. However, hemozoin is difficult to purify in quantities greater than a milligram, so a synthetic analog, known as β-hematin was derived from porcine hemin. The specific purpose of this study is to establish the efficacy of using β-hematin, rather than hemozoin, for photoacoustic measurements. We characterized β-hematin using UV-vis spectroscopy, TEM, and FTIR, then tested the effects of laser irradiation on the synthetic product. We finally determined its absorption spectrum using photoacoustic excitation. UV-vis spectroscopy verified that β-hematin was distinctly different from its precursor. TEM analysis confirmed its previously established nanorod shape, and comparison of the FTIR results with published spectroscopy data showed that our product had the distinctive absorbance peaks at 1661 and 1206 cm-1. Also, our research indicated that prolonged irradiation dramatically alters the physical and optical properties of the β-hematin, resulting in increased absorption at shorter wavelengths. Nevertheless, the photoacoustic absorption spectrum mimicked that generated by UV-vis spectroscopy, which confirms the accuracy of the photoacoustic method and strongly suggests that

  16. Characterization of Degradation Using Reflectance Spectroscopy (Postprint)

    DTIC Science & Technology

    2013-08-01

    could be performed in field. Fourier transform infrared (FTIR) devices have been developed with in field inspection capabilities [4]. Spectroscopy is a...the data to be transformed to a linear model. In these cases, all the techniques for linear models may be applied such as PCA and PLS [6, 7]. These...number of molecules of that oscillator type. This is known as the Lorentz model in dispersion analysis 1597 This article is copyrighted as indicated in

  17. Integral field spectroscopy of HH161

    NASA Astrophysics Data System (ADS)

    Gevorgyan, M.; Movsessian, T. A.; Magakian, T. Yu.; Andreasyan, H. R.

    2016-09-01

    This work presents the Observations of HH 161 carried out in Byurakan Astrophysical Observatory using multipupil spectrograph VAGR, attached on prime focus of the 2.6 m telescope. The integral field spectroscopy is very effective method to investigate the kinematics and physical parameters of Herbig-Haro objects. The results of the study of the Herbig-Haro jet HH 161 are presented below.

  18. Atomic Force Microscope for Imaging and Spectroscopy

    NASA Technical Reports Server (NTRS)

    Pike, W. T.; Hecht, M. H.; Anderson, M. S.; Akiyama, T.; Gautsch, S.; deRooij, N. F.; Staufer, U.; Niedermann, Ph.; Howald, L.; Mueller, D.

    2000-01-01

    We have developed, built, and tested an atomic force microscope (AFM) for extraterrestrial applications incorporating a micromachined tip array to allow for probe replacement. It is part of a microscopy station originally intended for NASA's 2001 Mars lander to identify the size, distribution, and shape of Martian dust and soil particles. As well as imaging topographically down to nanometer resolution, this instrument can be used to reveal chemical information and perform infrared and Raman spectroscopy at unprecedented resolution.

  19. Online fluorescence suppression in modulated Raman spectroscopy.

    PubMed

    De Luca, Anna Chiara; Mazilu, Michael; Riches, Andrew; Herrington, C Simon; Dholakia, Kishan

    2010-01-15

    Label-free chemical characterization of single cells is an important aim for biomedical research. Standard Raman spectroscopy provides intrinsic biochemical markers for noninvasive analysis of biological samples but is often hindered by the presence of fluorescence background. In this paper, we present an innovative modulated Raman spectroscopy technique to filter out the Raman spectra from the fluorescence background. The method is based on the principle that the fluorescence background does not change whereas the Raman scattering is shifted by the periodical modulation of the laser wavelength. Exploiting this physical property and importantly the multichannel lock-in detection of the Raman signal, the modulation technique fulfills the requirements of an effective fluorescence subtraction method. Indeed, once the synchronization and calibration procedure is performed, minimal user intervention is required, making the method online and less time-consuming than the other fluorescent suppression methods. We analyze the modulated Raman signal and shifted excitation Raman difference spectroscopy (SERDS) signal of 2 mum-sized polystyrene beads suspended in a solution of fluorescent dye as a function of modulation rate. We show that the signal-to-noise ratio of the modulated Raman spectra at the highest modulation rate is 3 times higher than the SERDS one. To finally evaluate the real benefits of the modulated Raman spectroscopy, we apply our technique to Chinese hamster ovary cells (CHO). Specifically, by analyzing separate spectra from the membrane, cytoplasm, and nucleus of CHO cells, we demonstrate the ability of this method to obtain localized sensitive chemical information from cells, away from the interfering fluorescence background. In particular, statistical analysis of the Raman data and classification using PCA (principal component analysis) indicate that our method allows us to distinguish between different cell locations with higher sensitivity and

  20. Visible light optical coherence correlation spectroscopy.

    PubMed

    Broillet, Stephane; Szlag, Daniel; Bouwens, Arno; Maurizi, Lionel; Hofmann, Heinrich; Lasser, Theo; Leutenegger, Marcel

    2014-09-08

    Optical coherence correlation spectroscopy (OCCS) allows studying kinetic processes at the single particle level using the backscattered light of nanoparticles. We extend the possibilities of this technique by increasing its signal-to-noise ratio by a factor of more than 25 and by generalizing the method to solutions containing multiple nanoparticle species. We applied these improvements by measuring protein adsorption and formation of a protein monolayer on superparamagnetic iron oxide nanoparticles under physiological conditions.

  1. Biological Sensing with Terahertz Circular Dichroism Spectroscopy

    DTIC Science & Technology

    2005-05-31

    S.J. and Plaxco, K.W. (2003) “Terahertz circular dichroism spectroscopy: a potential approach to unbiased, in situ life detection.” Astrobiology , 3...detection.” Astrobiology , 3, 489-504 Xu, J., Ramian, G.J., Galan, J.F., Savvidis, P.G., Scopatz, A.M., Birge, R.R., Allen, S.J. and Plaxco, K.W. (2004

  2. Raman spectroscopy of triolein under high pressures

    NASA Astrophysics Data System (ADS)

    Tefelski, D. B.; Jastrzębski, C.; Wierzbicki, M.; Siegoczyński, R. M.; Rostocki, A. J.; Wieja, K.; Kościesza, R.

    2010-03-01

    This article presents results of the high pressure Raman spectroscopy of triolein. Triolein, a triacylglyceride (TAG) of oleic acid, is an unsaturated fat, present in natural oils such as olive oil. As a basic food component and an energy storage molecule, it has considerable importance for food and fuel industries. To generate pressure in the experiment, we used a high-pressure cylindrical chamber with sapphire windows, presented in (R.M. Siegoczyński, R. Kościesza, D.B. Tefelski, and A. Kos, Molecular collapse - modification of the liquid structure induced by pressure in oleic acid, High Press. Res. 29 (2009), pp. 61-66). Pressure up to 750 MPa was applied. A Raman spectrometer in "macro"-configuration was employed. Raman spectroscopy provides information on changes of vibrational modes related to structural changes of triolein under pressure. Interesting changes in the triglyceride C‒H stretching region at 2650-3100 cm-1 were observed under high-pressures. Changes were also observed in the ester carbonyl (C˭ O) stretching region 1700-1780 cm-1 and the C‒C stretching region at 1050-1150 cm-1. The overall luminescence of the sample decreased under pressure, making it possible to set longer spectrum acquisition time and obtain more details of the spectrum. The registered changes suggest that the high-pressure solid phase of triolein is organized as β-polymorphic, as was reported in (C. Akita, T. Kawaguchi, and F. Kaneko, Structural study on polymorphism of cis-unsaturated triacylglycerol: Triolein, J. Phys. Chem. B 110 (2006), pp. 4346-4353; E. Da Silva and D. Rousseau, Molecular order and thermodynamics of the solid-liquid transition in triglycerides via Raman spectroscopy, Phys. Chem. Chem. Phys. 10 (2008), pp. 4606-4613) (with temperature-induced phase transitions). The research has shown that Raman spectroscopy in TAGs under pressure reveals useful information about its structural changes.

  3. Photoelectron Spectroscopy for Identification of Chemical States

    NASA Technical Reports Server (NTRS)

    Novakov, T.

    1971-01-01

    The technique of X-ray photoelectron spectroscopy and the fundamental electronic interactions constituting the basis of the method will be discussed. The method provides information about chemical states ("oxidation states") of atoms in molecules. In addition, quantitative elemental analysis can be performed using the same method. On the basis of this information identification of chemical species is possible. Examples of applications are discussed with particular references to the study of smog particulate matter.

  4. Laser Spectroscopy for Atmospheric and Environmental Sensing

    PubMed Central

    Fiddler, Marc N.; Begashaw, Israel; Mickens, Matthew A.; Collingwood, Michael S.; Assefa, Zerihun; Bililign, Solomon

    2009-01-01

    Lasers and laser spectroscopic techniques have been extensively used in several applications since their advent, and the subject has been reviewed extensively in the last several decades. This review is focused on three areas of laser spectroscopic applications in atmospheric and environmental sensing; namely laser-induced fluorescence (LIF), cavity ring-down spectroscopy (CRDS), and photoluminescence (PL) techniques used in the detection of solids, liquids, aerosols, trace gases, and volatile organic compounds (VOCs). PMID:22303184

  5. Towards precision spectroscopy of baryonic resonances

    DOE PAGES

    Doring, Michael; Mai, Maxim; Ronchen, Deborah

    2017-01-26

    Recent progress in baryon spectroscopy is reviewed. In a common effort, various groups have analyzed a set of new high-precision polarization observables from ELSA. The Julich-Bonn group has finalized the analysis of pion-induced meson-baryon production, the potoproduction of pions and eta mesons, and (almost) the KΛ final state. Lastly, as data become preciser, statistical aspects in the analysis of excited baryons become increasingly relevant and several advances in this direction are proposed.

  6. Frequency shifts in gravitational resonance spectroscopy

    DOE PAGES

    Baeßler, S.; Nesvizhevsky, V. V.; Pignol, G.; ...

    2015-02-25

    Quantum states of ultracold neutrons in a gravitational field are characterized through gravitational resonance spectroscopy. This paper discusses systematic effects that appear in the spectroscopic measurements. The discussed frequency shifts-which we call the Stern-Gerlach shift, interference shift, and spectator-state shift-appear in conceivable measurement schemes and have general importance. Lastly, these shifts have to be taken into account in precision experiments.

  7. b and c spectroscopy at LHCb

    NASA Astrophysics Data System (ADS)

    de Simone, Patrizia

    2014-06-01

    The LHCb experiment is designed to study the decays and properties of heavy flavoured hadrons produced in the forward region from pp collisions at the CERN Large Hadron Collider. It has recorded the world's largest data sample of beauty and charm hadrons, enabling precise studies into the spectroscopy of such particles, including discoveries of new states and measurements of their properties such as masses, width and quantum numbers. The latest results in this area are reviewed.

  8. Sensitivity Limits of Nanomechanical Resonance Spectroscopy

    NASA Astrophysics Data System (ADS)

    Greaney, P. Alex

    2009-03-01

    The sensitivity limit of the recently proposed chemical sensing method, nanomechanical resonance spectroscopy (NRS) ootnotetextP.A. Greaney and J.C. Grossman, Nano Letters, 8, 2648-2652, (2008)., is investigated using classical molecular dynamics simulations. The NRS method exploits the preferential transfer of energy between resonant modes, using an array of nanomechanical resonators to interrogate the vibrational spectrum of an analyte directly. We report on the effects of solvent and complex analytes.

  9. Data Treatment in Electron and Ion Spectroscopy.

    DTIC Science & Technology

    1979-12-01

    IA) Sprinter. It. W. and Pocker. D. J., Rcriew of Scientific Instruments, % ol. 48, 1977, p. 74. 171 Smith, 1). P., Journal of Applied Phyisics , Vol...Bonding" monitored by T. W. Haas. This report covers work conducted inhouse during the period July 1977 through July 1979. It was published in Applied ...Baun, W. L., "Data Treatment in Electron and Ion Spectroscopy," Applied SurjaceAnalysis. ASTMSTP699. T. L. Bart ,nd L. . Davis. Ids., American

  10. Microwave spectroscopy of biomolecular building blocks.

    PubMed

    Alonso, José L; López, Juan C

    2015-01-01

    Microwave spectroscopy, considered as the most definitive gas phase structural probe, is able to distinguish between different conformational structures of a molecule, because they have unique spectroscopic constants and give rise to distinct individual rotational spectra.Previously, application of this technique was limited to molecular specimens possessing appreciable vapor pressures, thus discarding the possibility of studying many other molecules of biological importance, in particular those with high melting points, which had a tendency to undergo thermal reactions, and ultimately degradation, upon heating.Nowadays, the combination of laser ablation with Fourier transform microwave spectroscopy techniques, in supersonic jets, has enabled the gas-phase study of such systems. In this chapter, these techniques, including broadband spectroscopy, as well as results of their application into the study of the conformational panorama and structure of biomolecular building blocks, such as amino acids, nucleic bases, and monosaccharides, are briefly discussed, and with them, the tools for conformational assignation - rotational constants, nuclear quadrupole coupling interaction, and dipole moment.

  11. A Guided Inquiry Approach to NMR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Parmentier, Laura E.; Lisensky, George C.; Spencer, Brock

    1998-04-01

    We present a novel way to introduce NMR spectroscopy into the general chemistry curriculum as part of a week-long aspirin project in our one-semester introductory course. Aspirin is synthesized by reacting salicylic acid and acetic anhydride. Purity is determined by titration and IR and NMR spectroscopy. Students compare IR and NMR spectra of their aspirin product to a series of reference spectra obtained by the class. Students are able to interpret the IR spectra of their aspirin using IR data from previous experiments. NMR is introduced by having students collect 1H NMR spectra of a series of reference compounds chosen to include some of the structural features of aspirin and compare spectra and structures of the reference compounds to develop a correlation chart for chemical shifts. This process is done in small groups using shared class data and is guided by a series of questions designed to relate the different kinds of hydrogen atoms to number and position of peaks in the NMR spectrum. Students then identify the peaks in the NMR spectrum of their aspirin product and relate percent purity by titration with spectral results and percent yield. This is an enjoyable project that combines the synthesis of a familiar material with a guided inquiry-based introduction to NMR spectroscopy.

  12. Biosensing with T-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Fischer, Bernd M.; Helm, Hanspeter; Abbott, Derek

    2007-07-01

    In the recent years, it has been shown that terahertz (or T-ray) spectroscopy is a versatile tool for biosensing and safety applications. This is due to the fact that the THz-spectra of many biomolecules show very characteristic, distinct spectroscopic features. Furthermore, most non-metallic packaging materials are nearly transparent in this frequency range (0.1 - 6 THz, 3 cm -1 - 200 cm -1), so that it is possible to non-invasively identify even sealed substances like pharmaceuticals, illicit drugs or explosives by their spectroscopic signatures. This opens a significant potential for a wide range of applications from quality control of pharmaceutical substances via safety applications through to biomedical applications. The individual spectroscopic features below approximately 5 THz that spurred the increased world wide interest in T-ray spectroscopy are mainly due to intermolecular rather than intramolecular vibrations in the polycrystalline samples. The spectra of more complex biomolecules, like proteins and nucleotides, typically show less or even no sharp features, due to the lack of long- range intermolecular order. Furthermore, due to the typically significantly smaller sample amount, the signal to noise ratio is strongly increased. Water shows a strong absorption in this frequency range, which all together makes real biomedical applications of T-ray spectroscopy rather difficult. Yet, by combining a careful sample preparation, novel experimental techniques and an advanced signal processing of the experimental data we can still clearly distinguish between even complex biomolecules and therefore demonstrate the potential the technique holds for biomedical applications.

  13. Optics and Spectroscopy at Surfaces and Interfaces

    NASA Astrophysics Data System (ADS)

    Bordo, Vladimir G.; Rubahn, Horst-Günter

    2005-10-01

    This book covers linear and nonlinear optics as well as optical spectroscopy at solid surfaces and at interfaces between a solid and a liquid or gas. The authors give a concise introduction to the physics of surfaces and interfaces. They discuss in detail physical properties of solid surfaces and of their interfaces to liquids and gases and provide the theoretical background for understanding various optical techniques. The major part of the book is dedicated to a broad review on optical techniques and topical applications such as infrared and optical spectroscopy or optical microscopy. Discussions of nonlinear optics, but also nano-optics and local spectroscopy complement this self-contained work. Helpful features include about 50 problems with solutions, a glossary and a thoroughly elaborated list of topical references. The book is suited as a text for graduate students but also for scientists working in physics, chemistry, materials or life sciences who look for an expert introduction to surface optical aspects of their studies.

  14. NATO Advanced Study Institute on Spectroscopy

    NASA Technical Reports Server (NTRS)

    DiBartolo, Baldassare; Barnes, James (Technical Monitor)

    2001-01-01

    This booklet presents an account of the course 'Spectroscopy of Systems with Spatially Confined Structures' held in Erice-Sicily, Italy, from June 15 to June 30, 2001. This meeting was organized by the International School of Atomic and Molecular Spectroscopy of the 'Ettore Majorana' Centre for Scientific Culture. The purpose of this course was to present and discuss nanometer-scale physics, a rapidly progressing field. The top-down approach of semiconductor technology will soon meet the scales of the bottom-up approaches of supramolecular chemistry and of spatially localized excitations in ionic crystals. This course dealt with the fabrication, measurement and understanding of the relevant structures and brought together the scientific communities responsible for these development. The advances in this area of physics have already let to applications in optoelectronics and will likely lead to many more. The subjects of the course included spatially resolved structures such as quantum wells, quantum wires and quantum dots, single atoms and molecules, clusters, fractal systems, and the development of related techniques like near-field spectroscopy and confocal microscopy to study such systems.

  15. Surface-Enhanced Impulsive Coherent Vibrational Spectroscopy

    NASA Astrophysics Data System (ADS)

    Du, Juan; Harra, Juha; Virkki, Matti; Mäkelä, Jyrki M.; Leng, Yuxin; Kauranen, Martti; Kobayashi, Takayoshi

    2016-11-01

    Surface-enhanced Raman spectroscopy (SERS) has attracted a lot of attention in molecular sensing because of the remarkable ability of plasmonic metal nanostructures to enhance the weak Raman scattering process. On the other hand, coherent vibrational spectroscopy triggered by impulsive excitation using ultrafast laser pulses provides complete information about the temporal evolution of molecular vibrations, allowing dynamical processes in molecular systems to be followed in “real time”. Here, we combine these two concepts and demonstrate surface-enhanced impulsive vibrational spectroscopy. The vibrational modes of the ground and excited states of poly[2-methoxy-5-(2-ethylhexyloxy)‑1,4-phenylenevinylene] (MEH-PPV), spin-coated on a substrate covered with monodisperse silver nanoparticles, are impulsively excited with a sub-10 fs pump pulse and characterized with a delayed broad-band probe pulse. The maximum enhancement in the spectrally and temporally resolved vibrational signatures averaged over the whole sample is about 4.6, while the real-time information about the instantaneous vibrational amplitude together with the initial vibrational phase is preserved. The phase is essential to determine the vibrational contributions from the ground and excited states.

  16. Perspective: Two-dimensional resonance Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Molesky, Brian P.; Guo, Zhenkun; Cheshire, Thomas P.; Moran, Andrew M.

    2016-11-01

    Two-dimensional resonance Raman (2DRR) spectroscopy has been developed for studies of photochemical reaction mechanisms and structural heterogeneity in complex systems. The 2DRR method can leverage electronic resonance enhancement to selectively probe chromophores embedded in complex environments (e.g., a cofactor in a protein). In addition, correlations between the two dimensions of the 2DRR spectrum reveal information that is not available in traditional Raman techniques. For example, distributions of reactant and product geometries can be correlated in systems that undergo chemical reactions on the femtosecond time scale. Structural heterogeneity in an ensemble may also be reflected in the 2D spectroscopic line shapes of both reactive and non-reactive systems. In this perspective article, these capabilities of 2DRR spectroscopy are discussed in the context of recent applications to the photodissociation reactions of triiodide and myoglobin. We also address key differences between the signal generation mechanisms for 2DRR and off-resonant 2D Raman spectroscopies. Most notably, it has been shown that these two techniques are subject to a tradeoff between sensitivity to anharmonicity and susceptibility to artifacts. Overall, recent experimental developments and applications of the 2DRR method suggest great potential for the future of the technique.

  17. Fluorescence fluctuation spectroscopy in reduced detection volumes.

    PubMed

    Blom, H; Kastrup, L; Eggeling, C

    2006-02-01

    Fluorescence fluctuation spectroscopy is a versatile technique applied to in vitro and in vivo investigations of biochemical processes such as interactions, mobilities or densities with high specifity and sensitivity. The prerequisite of this dynamical fluorescence technique is to have, at a time, only few fluorescent molecules in the detection volume in order to generate significant fluorescence fluctuations. For usual confocal fluorescence microscopy this amounts to a useful concentration in the nanomolar range. The concentration of many biomolecules in living cell or on cell membranes is, however, often quite high, usually in the micro- to the millimolar range. To allow fluctuation spectroscopy and track intracellular interaction or localization of single fluorescently labeled biomolecules in such crowded environments, development of detection volumes with nanoscale resolution is necessary. As diffraction prevents this in the case of light microscopy, new (non-invasive) optical concepts have been developed. In this mini-review article we present recent advancements, implemented to decrease the detection volume below that of normal fluorescence microscopy. Especially, their combination with fluorescence fluctuation spectroscopy is emphasized.

  18. Using Raman spectroscopy to characterize biological materials.

    PubMed

    Butler, Holly J; Ashton, Lorna; Bird, Benjamin; Cinque, Gianfelice; Curtis, Kelly; Dorney, Jennifer; Esmonde-White, Karen; Fullwood, Nigel J; Gardner, Benjamin; Martin-Hirsch, Pierre L; Walsh, Michael J; McAinsh, Martin R; Stone, Nicholas; Martin, Francis L

    2016-04-01

    Raman spectroscopy can be used to measure the chemical composition of a sample, which can in turn be used to extract biological information. Many materials have characteristic Raman spectra, which means that Raman spectroscopy has proven to be an effective analytical approach in geology, semiconductor, materials and polymer science fields. The application of Raman spectroscopy and microscopy within biology is rapidly increasing because it can provide chemical and compositional information, but it does not typically suffer from interference from water molecules. Analysis does not conventionally require extensive sample preparation; biochemical and structural information can usually be obtained without labeling. In this protocol, we aim to standardize and bring together multiple experimental approaches from key leaders in the field for obtaining Raman spectra using a microspectrometer. As examples of the range of biological samples that can be analyzed, we provide instructions for acquiring Raman spectra, maps and images for fresh plant tissue, formalin-fixed and fresh frozen mammalian tissue, fixed cells and biofluids. We explore a robust approach for sample preparation, instrumentation, acquisition parameters and data processing. By using this approach, we expect that a typical Raman experiment can be performed by a nonspecialist user to generate high-quality data for biological materials analysis.

  19. Planar Tunneling Spectroscopy of Graphene Nanodevices

    NASA Astrophysics Data System (ADS)

    Wang, Joel I.-Jan; Bretheau, Landry; Pisoni, Riccardo; Watanabe, Kenji; Taniguchi, Takashi; Jarillo-Herrero, Pablo

    2-D Van-der-Waals mesoscopic physics have seen a rapid development in the last 10 years, with new materials each year added to the toolbox. Stacking them like Lego enables the combination of their individual electronic properties. In particular, hexagonal boron nitride, which is an insulator, gives the possibility to perform planar (2-D to 2-D) tunneling spectroscopy within this type of heterostructures. Unlike standard transport measurements, tunneling spectroscopy enables to probe the electronic properties in the energy domain. Moreover, since planar tunneling probes a large area of the system, global quantum features such as quantum Hall effect, superconducting proximity effect or quantum confinement can be investigated. In this talk, we will present implementation of heterostructures consisting of graphene, hexagonal boron nitride, and graphite, fabricated for planar tunneling spectroscopy. In order to reveal the intrinsic properties of materials, the fabrication scheme aims at preserving the pristine nature of the 2-DEGS as well as minimizing the doping introduced by external probes. As a demonstration, measurements of these devices in normal states, high magnetic field environment, and induced superconducting state will be presented.

  20. Threshold photodetachment spectroscopy of negative ions

    SciTech Connect

    Kitsopoulos, T.N.

    1991-12-01

    This thesis is concerned with the development and application of high resolution threshold photodetachment spectroscopy of negative ions. Chapter I deals with the principles of our photodetachment technique, and in chapter II a detailed description of the apparatus is presented. The threshold photodetachment spectra of I{sup {minus}}, and SH{sup {minus}}, presented in the last sections of chapter II, indicated that a resolution of 3 cm{sup {minus}1} can be achieved using our technique. In chapter III the threshold photodetachment spectroscopy study of the transition state region of I + HI and I + Di reactions is discussed. Our technique probes the transition state region directly, and the results of our study are the first unambiguous observations of reactive resonances in a chemical reaction. Chapters IV, V and VI are concerned with the spectroscopy of small silicon and carbon clusters. From our spectra we were able to assign electronic state energies and vibrational frequencies for the low lying electronics states of Si{sub n} (n=2,3,4), C{sub 5} and their corresponding anions.

  1. Magnetic resonance spectroscopy of the human brain

    NASA Astrophysics Data System (ADS)

    Strózik-Kotlorz, D.

    2014-01-01

    I give a brief description of the magnetic resonance spectroscopy (MRS) in the human brain examinations. MRS allows a noninvasive chemical analysis of the brain using a standard high field MR system. Nowadays, the dominant form of MR brain spectroscopy is proton spectroscopy. Two main techniques of MRS, which utilize the chemical shift of metabolites in the external magnetic field, are SVS (single voxel) and CSI (single slice). The major peaks in the spectrum of a normal brain include NAA, Cr, Cho and m-Ins, which are neuronal, energetic, membrane turnover and glial markers, respectively. In disease, two pathological metabolites can be found in the brain spectra: Lac, which is end product of anaerobic glycolysis and Lip, which is a marker of membrane breakdown, occurring in necrosis. The common way to analyze clinical spectra is to determine metabolite ratios, e.g. NAA/Cr, Cho/Cr, Cho/NAA. This analysis permits a safe and noninvasive examination of the brain tissue as each disease state has its own characteristic spectroscopic image. MRS is a valuable diagnostic tool in such clinical applications as detecting brain tumors and differentiating tumors from inflammatory and infectious processes. Proton MRS is also very helpful in diagnostic of ischemic lesions, Alzheimer's disease and hepatic encephalopathy. The MRS brain spectra should always be correlated with the Magnetic Resonance Imaging (MRI) results and alone cannot make neurological diagnosis.

  2. Visualizing Infrared (IR) Spectroscopy with Computer Animation

    NASA Technical Reports Server (NTRS)

    Abrams, Charles B.; Fine, Leonard W.

    1996-01-01

    IR Tutor, an interactive, animated infrared (IR) spectroscopy tutorial has been developed for Macintosh and IBM-compatible computers. Using unique color animation, complicated vibrational modes can be introduced to beginning students. Rules governing the appearance of IR absorption bands become obvious because the vibrational modes can be visualized. Each peak in the IR spectrum is highlighted, and the animation of the corresponding normal mode can be shown. Students can study each spectrum stepwise, or click on any individual peak to see its assignment. Important regions of each spectrum can be expanded and spectra can be overlaid for comparison. An introduction to the theory of IR spectroscopy is included, making the program a complete instructional package. Our own success in using this software for teaching and research in both academic and industrial environments will be described. IR Tutor consists of three sections: (1) The 'Introduction' is a review of basic principles of spectroscopy. (2) 'Theory' begins with the classical model of a simple diatomic molecule and is expanded to include larger molecules by introducing normal modes and group frequencies. (3) 'Interpretation' is the heart of the tutorial. Thirteen IR spectra are analyzed in detail, covering the most important functional groups. This section features color animation of each normal mode, full interactivity, overlay of related spectra, and expansion of important regions. This section can also be used as a reference.

  3. Ultrasensitive laser spectroscopy for breath analysis

    NASA Astrophysics Data System (ADS)

    Wojtas, J.; Bielecki, Z.; Stacewicz, T.; Mikołajczyk, J.; Nowakowski, M.

    2012-03-01

    At present there are many reasons for seeking new methods and technologies that aim to develop new and more perfect sensors for different chemical compounds. However, the main reasons are safety ensuring and health care. In the paper, recent advances in the human breath analysis by the use of different techniques are presented. We have selected non-invasive ones ensuring detection of pathogenic changes at a molecular level. The presence of certain molecules in the human breath is used as an indicator of a specific disease. Thus, the analysis of the human breath is very useful for health monitoring. We have shown some examples of diseases' biomarkers and various methods capable of detecting them. Described methods have been divided into non-optical and optical methods. The former ones are the following: gas chromatography, flame ionization detection, mass spectrometry, ion mobility spectrometry, proton transfer reaction mass spectrometry, selected ion flow tube mass spectrometry. In recent twenty years, the optical methods have become more popular, especially the laser techniques. They have a great potential for detection and monitoring of the components in the gas phase. These methods are characterized by high sensitivity and good selectivity. The spectroscopic sensors provide the opportunity to detect specific gases and to measure their concentration either in a sampling place or a remote one. Multipass spectroscopy, cavity ring-down spectroscopy, and photo-acoustic spectroscopy were characterised in the paper as well.

  4. Mineral mapping and applications of imaging spectroscopy

    USGS Publications Warehouse

    Clark, R.N.; Boardman, J.; Mustard, J.; Kruse, F.; Ong, C.; Pieters, C.; Swayze, G.A.

    2006-01-01

    Spectroscopy is a tool that has been used for decades to identify, understand, and quantify solid, liquid, or gaseous materials, especially in the laboratory. In disciplines ranging from astronomy to chemistry, spectroscopic measurements are used to detect absorption and emission features due to specific chemical bonds, and detailed analyses are used to determine the abundance and physical state of the detected absorbing/emitting species. Spectroscopic measurements have a long history in the study of the Earth and planets. Up to the 1990s remote spectroscopic measurements of Earth and planets were dominated by multispectral imaging experiments that collect high-quality images in a few, usually broad, spectral bands or with point spectrometers that obtained good spectral resolution but at only a few spatial positions. However, a new generation of sensors is now available that combines imaging with spectroscopy to create the new discipline of imaging spectroscopy. Imaging spectrometers acquire data with enough spectral range, resolution, and sampling at every pixel in a raster image so that individual absorption features can be identified and spatially mapped (Goetz et al., 1985).

  5. Surface-Enhanced Impulsive Coherent Vibrational Spectroscopy

    PubMed Central

    Du, Juan; Harra, Juha; Virkki, Matti; Mäkelä, Jyrki M.; Leng, Yuxin; Kauranen, Martti; Kobayashi, Takayoshi

    2016-01-01

    Surface-enhanced Raman spectroscopy (SERS) has attracted a lot of attention in molecular sensing because of the remarkable ability of plasmonic metal nanostructures to enhance the weak Raman scattering process. On the other hand, coherent vibrational spectroscopy triggered by impulsive excitation using ultrafast laser pulses provides complete information about the temporal evolution of molecular vibrations, allowing dynamical processes in molecular systems to be followed in “real time”. Here, we combine these two concepts and demonstrate surface-enhanced impulsive vibrational spectroscopy. The vibrational modes of the ground and excited states of poly[2-methoxy-5-(2-ethylhexyloxy)−1,4-phenylenevinylene] (MEH-PPV), spin-coated on a substrate covered with monodisperse silver nanoparticles, are impulsively excited with a sub-10 fs pump pulse and characterized with a delayed broad-band probe pulse. The maximum enhancement in the spectrally and temporally resolved vibrational signatures averaged over the whole sample is about 4.6, while the real-time information about the instantaneous vibrational amplitude together with the initial vibrational phase is preserved. The phase is essential to determine the vibrational contributions from the ground and excited states. PMID:27812020

  6. Scalable NMR spectroscopy with semiconductor chips

    PubMed Central

    Ha, Dongwan; Paulsen, Jeffrey; Sun, Nan; Song, Yi-Qiao; Ham, Donhee

    2014-01-01

    State-of-the-art NMR spectrometers using superconducting magnets have enabled, with their ultrafine spectral resolution, the determination of the structure of large molecules such as proteins, which is one of the most profound applications of modern NMR spectroscopy. Many chemical and biotechnological applications, however, involve only small-to-medium size molecules, for which the ultrafine resolution of the bulky, expensive, and high-maintenance NMR spectrometers is not required. For these applications, there is a critical need for portable, affordable, and low-maintenance NMR spectrometers to enable in-field, on-demand, or online applications (e.g., quality control, chemical reaction monitoring) and co-use of NMR with other analytical methods (e.g., chromatography, electrophoresis). As a critical step toward NMR spectrometer miniaturization, small permanent magnets with high field homogeneity have been developed. In contrast, NMR spectrometer electronics capable of modern multidimensional spectroscopy have thus far remained bulky. Complementing the magnet miniaturization, here we integrate the NMR spectrometer electronics into 4-mm2 silicon chips. Furthermore, we perform various multidimensional NMR spectroscopies by operating these spectrometer electronics chips together with a compact permanent magnet. This combination of the spectrometer-electronics-on-a-chip with a permanent magnet represents a useful step toward miniaturization of the overall NMR spectrometer into a portable platform. PMID:25092330

  7. New Spectroscopy at BaBar

    SciTech Connect

    Mazzoni, M.A.; /INFN, Rome

    2007-04-18

    The Babar experiment at the SLAC B factory has accumulated a high luminosity that offers the possibility of systematic studies of quarkonium spectroscopy and of investigating rare new phenomena. Recent results in this field are presented. In recent times spectroscopy has become exciting again, after the discovery of new states that are not easily explained by conventional models. States such as the X(3872) and the Y(4260) could be new excited charmonium states, but require precise measurements for positive identification. The BaBar experiment [1] is installed at the asymmetric storage ring PEP-II. 90% of the data accumulated by BaBar are taken at the Y(4S) (10.58 GeV) and 10% just below (10.54 GeV). The BaBar detector includes a 5-layer, double-sided silicon vertex tracker and a 40-layer drift chamber in a 1.5 T solenoidal magnetic field, which detect charged particles and measures their momenta and ionization energy losses. Photons, electrons, and neutral hadrons are detected with a CsI(Tl)-crystal electromagnetic calorimeter. An internally reflecting ring-imaging Cherenkov is also used for particle id. Penetrating muon and neutral hadrons are identified by an array of resistive-plate chambers embedded in the steel of the flux return. The detector allows good track and vertex resolution, good particle id and good photon detection so it is especially suited for spectroscopy studies.

  8. Hypernuclear Spectroscopy at JLab Hall C

    SciTech Connect

    Hashimoto, Osamu; Doi, Daisuke; Fujii, Yu; Toshiyuki, Gogami; Kanda, Hiroki; Kaneta, M; Kawama, Daisuke; Maeda, Kazushige; Maruta, Tomofumi; Matsumura, Akihiko; Nagao, Sho; Nakamura, Satoshi; Shichijo, Ayako; Tamura, Hirokazu; Taniya, Naotaka; Yamamoto, Taku; Yokota, Kosuke; Kato, S; Sato, Yoshinori; Takahashi, Toshiyuki; Noumi, Hiroyuki; Motoba, T; Hiyama, E; Albayrak, Ibrahim; Ates, Ozgur; Chen, Chunhua; Christy, Michael; Keppel, Cynthia; Kohl, Karl; Li, Ya; Liyanage, Anusha Habarakada; Tang, Liguang; Walton, T; Ye, Zhihong; Yuan, Lulin; Zhu, Lingyan; Baturin, Pavlo; Boeglin, Werner; Dhamija, Seema; Markowitz, Pete; Raue, Brian; Reinhold, Joerg; Hungerford, Ed; Ent, Rolf; Fenker, Howard; Gaskell, David; Horn, Tanja; Jones, Mark; Smith, Gregory; Vulcan, William; Wood, Stephen; Johnston, C; Simicevic, Neven; Wells, Stephen; Samantha, Chhanda; Hu, Bitao; Shen, Ji; Wang, W; Zhang, Xiaozhuo; Zhang, Yi; Feng, Jing; Fu, Y; Zhou, Jian; Zhou, S; Jiang, Yi; Lu, H; Yan, Xinhu; Ye, Yunxiu; Gan, Liping; Ahmidouch, Abdellah; Danagoulian, Samuel; Gasparian, Ashot; Elaasar, Mostafa; Wesselmann, Frank; Asaturyan, Arshak; Margaryan, Amur; Mkrtchyan, Arthur; Mkrtchyan, Hamlet; Tadevosyan, Vardan; Androic, Darko; Furic, Miroslav; Petkovic, Tomislav; Seva, Tomislav; Niculescu, Gabriel; Niculescu, Maria-Ioana; Rodriguez, Victor; Cisbani, Evaristo; Cusanno, Francesco; Garibaldi, Franco; Urciuoli, Guido; De Leo, Raffaele; Maronne, S; Achenbach, Carsten; Pochodzalla, J

    2010-03-01

    Since the 1st generation experiment, E89-009, which was successfully carried out as a pilot experiment of (e,e'K+) hypernuclear spectroscopy at JLab Hall C in 2000, precision hypernuclear spectroscopy by the (e,e'K+) reactions made considerable progress. It has evolved to the 2nd generation experiment, E01-011, in which a newly constructed high resolution kaon spectrometer (HKS) was installed and the “Tilt method” was adopted in order to suppress large electromagnetic background and to run with high luminosity. Preliminary high-resolution spectra of 7ΛHe and 28ΛAl together with that of 12ΛB that achieved resolution better than 500 keV(FWHM) were obtained. The third generation experiment, E05-115, has completed data taking with an experimental setup combining a new splitter magnet, high resolution electron spectrometer (HES) and the HKS used in the 2nd generation experiment. The data were accumulated with targets of 7Li, 9Be, 10B, 12C and 52Cr as well as with those of CH2 and H2O for calibration. The analysis is under way with particular emphasis of determining precision absolute hypernuclear masses. In this article, hypernuclear spectroscopy program in the wide mass range at JLab Hall C that has undergone three generation is described.

  9. Noise autocorrelation spectroscopy with coherent Raman scattering

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoji G.; Konorov, Stanislav O.; Hepburn, John W.; Milner, Valery

    2008-02-01

    Coherent anti-Stokes Raman scattering (CARS) with femtosecond laser pulses has become a widespread method in nonlinear optical spectroscopy and microscopy. As a third-order nonlinear process, femtosecond CARS exhibits high efficiency at low average laser power. High sensitivity to molecular structure enables detection of small quantities of complex molecules and non-invasive biological imaging. Temporal and spectral resolution of CARS is typically limited by the duration of the excitation pulses and their frequency bandwidth, respectively. Broadband femtosecond pulses are advantageous for time-resolved CARS spectroscopy, but offer poor spectral resolution. The latter can be improved by invoking optical or quantum interference at the expense of increasing complexity of instrumentation and susceptibility to noise. Here, we present a new approach to coherent Raman spectroscopy in which high resolution is achieved by means of deliberately introduced noise. The proposed method combines the efficiency of a coherent process with the robustness of incoherent light. It does require averaging over different noise realizations, but no temporal scanning or spectral pulse shaping as commonly used by frequency-resolved spectroscopic methods with ultrashort pulses.

  10. Determining the Authenticity of Gemstones Using Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Aponick, Aaron; Marchozzi, Emedio; Johnston, Cynthia R.; Wigal, Carl T.

    1998-04-01

    The benefits of laser spectroscopy in the undergraduate curriculum have been the focus of several recent articles in this journal. Raman spectroscopy has been of particular interest since the similarities of Raman to conventional infrared spectroscopy make the interpretation of spectral data well within undergraduate comprehension. In addition, the accessibility to this technology is now within the reach of most undergraduate institutions. This paper reports the development of an experiment using Raman spectroscopy which determines the authenticity of both diamonds and pearls. The resulting spectra provide an introduction to vibrational spectroscopy and can be used in a variety of laboratory courses ranging from introductory chemistry to instrumental analysis.

  11. A simple decay-spectroscopy station at CRIS-ISOLDE

    NASA Astrophysics Data System (ADS)

    Lynch, K. M.; Cocolios, T. E.; Althubiti, N.; Farooq-Smith, G. J.; Gins, W.; Smith, A. J.

    2017-02-01

    A new decay-spectroscopy station (DSS2.0) has been designed by the CRIS collaboration for use at the radioactive ion beam facility, ISOLDE. With the design optimised for both charged-particle and γ-ray detection, the DDS2.0 allows high-efficiency decay spectroscopy to be performed. The DSS2.0 complements the existing decay-spectroscopy system at the CRIS experiment, and together provide the ability to perform laser-assisted nuclear decay spectroscopy on both ground state and long-lived isomeric species. This paper describes the new decay-spectroscopy station and presents the characterisation studies that have recently been performed.

  12. Spectroscopy techniques for human disease diagnosis

    NASA Astrophysics Data System (ADS)

    Navas-Moreno, Maria

    2011-12-01

    Modern medicine would benefit from the pursuit of new, more specific and easier to implement diagnosis tools. In recent years, Raman scattering, surface-enhanced Raman scattering and fluorescence spectroscopy have proven to be successful diagnostic techniques for a wide range of diseases including atherosclerosis, kidney stones, bone diseases, diabetes, and a wide collection of neoplasms. Optical spectroscopy has several advantages over more traditional diagnostic methods (i.e., histopathology, quantitative PCR, etc.) such as faster data analysis, nonspecific sample preparation, nonspecific labels/reagents/antibodies usage requirements, and immediate on-site implementation. In the present work, label-free in vitro fluorescence and surface enhanced Raman scattering (SERS) spectroscopy have been used to differentiate between blood cells of patients affected with myeloproliferative neoplasms (MPN) and those of healthy subjects. The SERS technique has also been applied to hemoglobin variants as well as to serum obtained from patients affected with chronic heart failure who positively or negatively responded to the seasonal influenza vaccine. We found that spectral ratios of the background fluorescence intensity that accompanies the SERS spectra of granulocytes serve as excellent markers for the presence of MPNs. In addition, we also found expression dysregulation of two hypoxia induced factor regulated genes, which correlates with our results obtained by SERS spectroscopy assay in MPN patients and supports the presence of the Warburg effect in MPNs. We hypothesize that SERS measures metabolic change in granulocytes through two possible mechanisms: (i) Changes in dielectric properties of the environment surrounding the silver-cell interface; and (ii) changes in flavin adenine dinucleotide concentrations, which in turn changes the relative contribution of the autofluorescence to the emission spectrum. These hypotheses are supported by SERS measurement of 2-deoxy

  13. Ultraviolet spectroscopy of the extended solar corona

    NASA Astrophysics Data System (ADS)

    Kohl, John L.; Noci, Giancarlo; Cranmer, Steven R.; Raymond, John C.

    2006-04-01

    The first observations of ultraviolet spectral line profiles and intensities from the extended solar corona (i.e., more than 1.5 solar radii from Sun-center) were obtained on 13 April 1979 when a rocket-borne ultraviolet coronagraph spectrometer of the Harvard-Smithsonian Center for Astrophysics made direct measurements of proton kinetic temperatures, and obtained upper limits on outflow velocities in a quiet coronal region and a polar coronal hole. Following those observations, ultraviolet coronagraphic spectroscopy has expanded to include observations of over 60 spectral lines in coronal holes, streamers, coronal jets, and solar flare/coronal mass ejection (CME) events. Spectroscopic diagnostic techniques have been developed to determine proton, electron and ion kinetic temperatures and velocity distributions, proton and ion bulk flow speeds and chemical abundances. The observations have been made during three sounding rocket flights, four Shuttle deployed and retrieved Spartan 201 flights, and the Solar and Heliospheric Observatory (SOHO) mission. Ultraviolet spectroscopy of the extended solar corona has led to fundamentally new views of the acceleration regions of the solar wind and CMEs. Observations with the Ultraviolet Coronagraph Spectrometer (UVCS) on SOHO revealed surprisingly large temperatures, outflow speeds, and velocity distribution anisotropies in coronal holes, especially for minor ions. Those measurements have guided theorists to discard some candidate physical processes of solar wind acceleration and to increase and expand investigations of ion cyclotron resonance and related processes. Analyses of UVCS observations of CME plasma properties and the evolution of CMEs have provided the following: temperatures, inflow velocities and derived values of resistivity and reconnection rates in CME current sheets, compression ratios and extremely high ion temperatures behind CME shocks, and three dimensional flow velocities and magnetic field chirality in

  14. Optical spectroscopy of nanoscale and heterostructured oxides

    NASA Astrophysics Data System (ADS)

    Senty, Tess R.

    Through careful analysis of a material's properties, devices are continually getting smaller, faster and more efficient each day. Without a complete scientific understanding of material properties, devices cannot continue to improve. This dissertation uses optical spectroscopy techniques to understand light-matter interactions in several oxide materials with promising uses mainly in light harvesting applications. Linear absorption, photoluminescence and transient absorption spectroscopy are primarily used on europium doped yttrium vanadate nanoparticles, copper gallium oxide delafossites doped with iron, and cadmium selenide quantum dots attached to titanium dioxide nanoparticles. Europium doped yttrium vanadate nanoparticles have promising applications for linking to biomolecules. Using Fourier-transform infrared spectroscopy, it was shown that organic ligands (benzoic acid, 3-nitro 4-chloro-benzoic acid and 3,4-dihydroxybenzoic acid) can be attached to the surface of these molecules using metal-carboxylate coordination. Photoluminescence spectroscopy display little difference in the position of the dominant photoluminescence peaks between samples with different organic ligands although there is a strong decrease in their intensity when 3,4-dihydroxybenzoic acid is attached. It is shown that this strong quenching is due to the presence of high-frequency hydroxide vibrational modes within the organic linker. Ultraviolet/visible linear absorption measurements on delafossites display that by doping copper gallium oxide with iron allows for the previously forbidden fundamental gap transition to be accessed. Using tauc plots, it is shown that doping with iron lowers the bandgap from 2.8 eV for pure copper gallium oxide, to 1.7 eV for samples with 1 -- 5% iron doping. Using terahertz transient absorption spectroscopy measurements, it was also determined that doping with iron reduces the charge mobility of the pure delafossite samples. A comparison of cadmium selenide

  15. Fourier transform infrared spectroscopy and Raman spectroscopy as tools for identification of steryl ferulates.

    PubMed

    Mandak, Eszter; Zhu, Dan; Godany, Tamas A; Nyström, Laura

    2013-03-13

    Steryl ferulates are a mixture of minor bioactive compounds, possessing well-established health benefits. However, individual steryl ferulate species show structural differences, which seem to substantially influence their health-promoting potential. In this study, we tested Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy, as potential tools in the identification of steryl ferulates. On the basis of our spectral data obtained from various individual steryl ferulates and steryl ferulate mixtures extracted from rice (γ-oryzanol), corn bran, and wheat bran, we provide comprehensive peak assignment tables for both FTIR and Raman. With the help of FTIR spectroscopy, structural differences between individual steryl ferulates were possible to identify, such as the presence of the cyclopropane ring and additional differences in the side chain of the sterane skeleton. Data obtained with Raman spectroscopy provided us with a control for FTIR peak assignment and also with some additional information on the samples. However, detecting structural differences between steryl ferulates was not possible with this method. We consider that FTIR spectroscopy alone or combined with Raman provides detailed data on the structures of steryl ferulates. Moreover, thorough peak assignment tables presented in this study could prove to be helpful tools when identifying steryl ferulates, especially as a group, in future studies.

  16. Issues in light meson spectroscopy: The case for meson spectroscopy at CEBAF

    SciTech Connect

    Godfrey, S.

    1994-04-01

    The author reviews some outstanding issues in meson spectroscopy. The most important qualitative issue is whether hadrons with explicit gluonic degrees of freedom exist. To answer this question requires a much better understanding of conventional q{bar q} mesons. The author therefore begins by examining the status of conventional meson spectroscopy and how the situation can be improved. The expected properties of gluonic excitations are discussed with particular emphasis on hybrids to give guidance to experimental searches. Multiquark systems are commented upon as they are likely to be important in the mass region under study and will have to be understood better. In the final section the author discusses the opportunities that CEBAF can offer for the study of meson spectroscopy.

  17. IR Spectroscopy of PAHs in Dense Clouds

    NASA Astrophysics Data System (ADS)

    Allamandola, Louis; Bernstein, Max; Mattioda, Andrew; Sandford, Scott

    2007-05-01

    Interstellar PAHs are likely to be a component of the ice mantles that form on dust grains in dense molecular clouds. PAHs frozen in grain mantles will produce IR absorption bands, not IR emission features. A couple of very weak absorption features in ground based spectra of a few objects embedded in dense clouds may be due to PAHs. Additionally spaceborne observations in the 5 to 8 ?m region, the region in which PAH spectroscopy is rich, reveal unidentified new bands and significant variation from object to object. It has not been possible to properly evaluate the contribution of PAH bands to these IR observations because the laboratory absorption spectra of PAHs condensed in realistic interstellar mixed-molecular ice analogs is lacking. This experimental data is necessary to interpret observations because, in ice mantles, the interaction of PAHs with the surrounding molecules effects PAH IR band positions, widths, profiles, and intrinsic strengths. Furthermore, PAHs are readily ionized in pure H2O ice, further altering the PAH spectrum. This laboratory proposal aims to remedy the situation by studying the IR spectroscopy of PAHs frozen in laboratory ice analogs that realistically reflect the composition of the interstellar ices observed in dense clouds. The purpose is to provide laboratory spectra which can be used to interpret IR observations. We will measure the spectra of these mixed molecular ices containing PAHs before and after ionization and determine the intrinsic band strengths of neutral and ionized PAHs in these ice analogs. This will enable a quantitative assessment of the role that PAHs can play in determining the 5-8 ?m spectrum of dense clouds and will directly address the following two fundamental questions associated with dense cloud spectroscopy and chemistry: 1- Can PAHs be detected in dense clouds? 2- Are PAH ions components of interstellar ice?

  18. Visible Light Spectroscopy of GEO Debris

    NASA Technical Reports Server (NTRS)

    Seitzer, Patrick; Lederer, Susan M.; Cowardin, Heather; Barker, Edwin S.; Abercromby, Kira J.

    2012-01-01

    Our goal is to understand the physical characteristics of debris at geosynchronous orbit (GEO). Our approach is to compare the observed reflectance as a function of wavelength with laboratory measurements of typical spacecraft surfaces to understand what the materials are likely to be. Because debris could be irregular in shape and tumbling at an unknown rate, rapid simultaneous measurements over a range of wavelengths are required. Acquiring spectra of optically faint objects with short exposure times to minimize these effects requires a large telescope. We describe optical spectroscopy obtained during 12-14 March 2012 with the IMACS imaging spectrograph on the 6.5-m 'Walter Baade' Magellan telescope at Las Campanas Observatory in Chile. When used in f/2 imaging mode for acquisition, this instrument has a field of view of 30 arc-minutes in diameter. After acquisition and centering of a GEO object, a 2.5 arc-second wide slit and a grism are moved into the beam for spectroscopy. We used a 200 l/mm grism blazed at 660 nm for wavelength coverage in the 500-900 nm region. Typical exposure times for spectra were 15-30 seconds. Spectra were obtained for five objects in the GEO regime listed as debris in the US Space Command public catalog, and one high area to mass ratio GEO object. In addition spectra were obtained of three cataloged IDCSP (Initial Defense Communications Satellite Program) satellites with known initial properties just below the GEO regime. All spectra were calibrated using white dwarf flux standards and solar analog stars. We will describe our experiences using Magellan, a telescope never used previously for orbital debris spectroscopy, and our initial results.

  19. Ultraviolet Photodissociation Action Spectroscopy of Protonated Azabenzenes

    NASA Astrophysics Data System (ADS)

    Hansen, Christopher S.; Blanksby, Stephen J.; Bieske, Evan; Reimers, Jeffrey R.; Trevitt, Adam J.

    2014-06-01

    Azabenzenes are derivatives of benzene containing between one and six nitrogen atoms. Protonated azabenzenes are the fundamental building blocks of many biomolecules, charge-transfer dyes, ionic liquids and fluorescent tags. However, despite their ubiquity, there exists limited spectroscopic data that reveals the structure, behaviour and stability of these systems in their excited states. For the case of pyridinium (C_5H_5N-H^+), the simplest azabenzene, the electronic spectroscopy is complicated by short excited state lifetimes, efficient non-radiative deactivation methods and limited fluorescence. Ultraviolet (UV) photodissociation (PD) action spectroscopy provides new insight into the spectroscopic details, excited state behaviour and photodissociation processes of a series of protonated azabenzenes including pyridinium, diazeniums and their substituted derivatives. The room-temperature UV PD action spectra, often exhibiting vibronic detail,^b will be presented alongside PD mass spectra and the kinetic data from structurally-diagnostic ion-molecule reaction kinetics. Analysis of the spectra, with the aid of quantum chemical calculations, reveal that many azabenzenes prefer a non-planar excited state geometry reminiscent of the structures encountered in 'channel 3'-like deactivation of aromatics. The normal modes active in this isomerization contribute largely to the spectroscopy of the N-pyridinium ion as they build upon totally-symmetric vibronic transitions leading to repeating sets of closely-spaced spectral features. Hansen, C.S. et al.; J. Am. Soc. Mass Spectrom. 24:932-940 (2013) Hansen, C.S. et al.; J. Phys. Chem. A 117:10839-10846 (2013)

  20. Multivariate optical computation for predictive spectroscopy.

    PubMed

    Nelson, M P; Aust, J F; Dobrowolski, J A; Verly, P G; Myrick, M L

    1998-01-01

    A novel optical approach to predicting chemical and physical properties based on principal component analysis (PCA) is proposed and evaluated using a data set from earlier work. In our approach, a regression vector produced by PCA is designed into the structure of a set of paired optical filters. Light passing through the paired filters produces an analog detector signal that is directly proportional to the chemical/physical property for which the regression vector was designed. This simple optical computational method for predictive spectroscopy is evaluated in several ways, using the example data for numeric simulation. First, we evaluate the sensitivity of the method to various types of spectroscopic errors commonly encountered and find the method to have the same susceptibilities toward error as standard methods. Second, we use propagation of errors to determine the effects of detector noise on the predictive power of the method, finding the optical computation approach to have a large multiplex advantage over conventional methods. Third, we use two different design approaches to the construction of the paired filter set for the example measurement to evaluate manufacturability, finding that adequate methods exist to design appropriate optical devices. Fourth, we numerically simulate the predictive errors introduced by design errors in the paired filters, finding that predictive errors are not increased over conventional methods. Fifth, we consider how the performance of the method is affected by light intensities that are not linearly related to chemical composition (as in transmission spectroscopy) and find that the method is only marginally affected. In summary, we conclude that many types of predictive measurements based on use of regression (or other) vectors and linear mathematics can be performed more rapidly, more effectly, and at considerably lower cost by the proposed optical computation method than by traditional dispersive or interferometric

  1. Surface studies of praseodymium by electron spectroscopies

    NASA Astrophysics Data System (ADS)

    Krawczyk, Mirosław; Pisarek, Marcin; Lisowski, Wojciech; Jablonski, Aleksander

    2016-12-01

    Electron transport properties in praseodymium (Pr) foil samples were studied by elastic-peak electron spectroscopy (EPES). Prior to EPES measurements, the Pr sample surface was pre-sputtered by Ar ions with ion energy of 2-3 keV. After such treatment, the Pr sample still contained about 10 at.% of residual oxygen in the surface region, as detected by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES) analyses. The inelastic mean free path (IMFP), characterizing electron transport within this region (4 nm-thick), was evaluated from EPES using both Ni and Au standards as a function of energy in the range of 0.5-2 keV. Experimental IMFPs, λ, were approximated by the simple function λ = kEp, where E is energy (in eV), and k = 0.1549 and p = 0.7047 were the fitted parameters. These values were compared with IMFPs for the praseodymium surface in which the presence of oxygen was tentatively neglected, and also with IMFPs resulting from the TPP-2M predictive equation for bulk praseodymium. We found that the measured IMFP values to be only slightly affected by neglect of oxygen in calculations. The fitted function applied here was consistent with the energy dependence of the EPES-measured IMFPs. Additionally, the measured IMFPs were found to be from 2% to 4.2% larger than the predicted IMFPs for praseodymium in the energy range of 500-1000 eV. For electron energies of 1500 eV and 2000 eV, there was an inverse correlation between these values, and then the resulting deviations of -0.4% and -2.7%, respectively, were calculated.

  2. Ultrafast Nonlinear Spectroscopy of Red Fluorescent Proteins

    NASA Astrophysics Data System (ADS)

    Konold, Patrick Eugene

    Red-emitting homologues (RFPs) of the native Green Fluorescent Protein (GFP) with emission wavelengths beyond 650 nm are desirable probes for in vivo imaging experiments. They offer the potential for deeper tissue penetration and lower background scatter given a cleaner spectral window. However, bioimaging applications are hindered by poor photophysics ( e.g. low fluorescence quantum yield, high photobleaching), which limits experimental resolution and represents a significant obstacle towards utilization for low copy-number, long-duration imaging applications. In this thesis, a variety of femtosecond nonlinear electronic spectroscopies were employed jointly with site-directed mutagenesis to investigate the photophysical properties of RFPs. In one study, the molecular mechanism of red emission was pursued in two notable RFPs, mPlum and TagRFP675. Solvation dynamics observed with time-resolved transient grating spectroscopy were interpreted with the aid of molecular dynamics simulations to indicate that their red-emission is correlated with the ability of specific chromophore-sidechain hydrogen-bonding interactions to interconvert between direct and water-mediated states. In a second set of studies, two-dimensional double quantum coherence spectroscopy was used to probe the electronic transitions of mPlum. It was discovered that it displayed a response distinctly different from an organic dye in bulk solvent. Modeling indicate of these spectra indicate the spectral features may be attributed to the existence of multiple high-lying (n>1) excited states. The results provide new insight into the electronic structure of these widely used fluorescent probes.

  3. Photoelectron spectroscopy and the dipole approximation

    SciTech Connect

    Hemmers, O.; Hansen, D.L.; Wang, H.

    1997-04-01

    Photoelectron spectroscopy is a powerful technique because it directly probes, via the measurement of photoelectron kinetic energies, orbital and band structure in valence and core levels in a wide variety of samples. The technique becomes even more powerful when it is performed in an angle-resolved mode, where photoelectrons are distinguished not only by their kinetic energy, but by their direction of emission as well. Determining the probability of electron ejection as a function of angle probes the different quantum-mechanical channels available to a photoemission process, because it is sensitive to phase differences among the channels. As a result, angle-resolved photoemission has been used successfully for many years to provide stringent tests of the understanding of basic physical processes underlying gas-phase and solid-state interactions with radiation. One mainstay in the application of angle-resolved photoelectron spectroscopy is the well-known electric-dipole approximation for photon interactions. In this simplification, all higher-order terms, such as those due to electric-quadrupole and magnetic-dipole interactions, are neglected. As the photon energy increases, however, effects beyond the dipole approximation become important. To best determine the range of validity of the dipole approximation, photoemission measurements on a simple atomic system, neon, where extra-atomic effects cannot play a role, were performed at BL 8.0. The measurements show that deviations from {open_quotes}dipole{close_quotes} expectations in angle-resolved valence photoemission are observable for photon energies down to at least 0.25 keV, and are quite significant at energies around 1 keV. From these results, it is clear that non-dipole angular-distribution effects may need to be considered in any application of angle-resolved photoelectron spectroscopy that uses x-ray photons of energies as low as a few hundred eV.

  4. Chirped Laser Dispersion Spectroscopy: Fundamentals and Applications

    NASA Astrophysics Data System (ADS)

    Plant, Genevieve B.

    The subject of this thesis is the fundamentals, implementation, and applications of Chirped Laser Dispersion Spectroscopy (CLaDS), an alternative dispersion spectroscopy technique that aims to overcome some limitations of absorption-based sensing. CLaDS preserves many of the benefits of dispersion sensing, namely baseline-free operation, immunity to received intensity, and linearity with sample concentration, and is fairly easy to implement without the need for stabilized interferometers, mode-locked lasers, and complex optical configurations required by many other dispersion-based sensors. First an introduction to CLaDS and a derivation of the spectroscopic signals are provided, highlighting fundamental similarities and differences to absorption-based sensing. Next the fundamental limit of CLaDS is investigated through analysis of the shot-noise limited performance under ideal operating conditions. This in turn allows for a theoretical and direct comparison to the shot-noise-limited performance of direct laser absorption spectroscopy (DLAS). This investigation shows that when full spectral scan fitting of realistic unknown parameters for each technique is used, both techniques demonstrate the same efficiency of parameter extraction. Following this theoretical investigation of ideal CLaDS performance, the technical details, methods of implementation, and component-introduced limitations of real-world CLaDS systems are discussed. Also included is a discussion of the first demonstration of an optical heterodyne enhanced CLaDS technique (HE-CLaDS). To overcome some of the technical limitations imposed by system instability, a modulation based technique (CM-CLaDS) was developed; the theory, optimization and noise characteristics of which are detailed. Finally, several applications of CLaDS are provided. These include atmospheric sensing, distributed sensor networks, and fiber dispersion characterization, all of which aim at demonstrating the technical advantages of the

  5. Quadrupole transitions revealed by Borrmann spectroscopy.

    PubMed

    Pettifer, Robert F; Collins, Stephen P; Laundy, David

    2008-07-10

    The Borrmann effect-a dramatic increase in transparency to X-ray beams-is observed when X-rays satisfying Bragg's law diffract through a perfect crystal. The minimization of absorption seen in the Borrmann effect has been explained by noting that the electric field of the X-ray beam approaches zero amplitude at the crystal planes, thus avoiding the atoms. Here we show experimentally that under conditions of absorption suppression, the weaker electric quadrupole absorption transitions are effectively enhanced to such a degree that they can dominate the absorption spectrum. This effect can be exploited as an atomic spectroscopy technique; we show that quadrupole transitions give rise to additional structure at the L(1), L(2) and L(3) absorption edges of gadolinium in gadolinium gallium garnet, which mark the onset of excitations from 2s, 2p(1/2) and 2p(3/2) atomic core levels, respectively. Although the Borrmann effect served to underpin the development of the theory of X-ray diffraction, this is potentially the most important experimental application of the phenomenon since its first observation seven decades ago. Identifying quadrupole features in X-ray absorption spectroscopy is central to the interpretation of 'pre-edge' spectra, which are often taken to be indicators of local symmetry, valence and atomic environment. Quadrupolar absorption isolates states of different symmetries to that of the dominant dipole spectrum, and typically reveals orbitals that dominate the electronic ground-state properties of lanthanides and 3d transition metals, including magnetism. Results from our Borrmann spectroscopy technique feed into contemporary discussions regarding resonant X-ray diffraction and the nature of pre-edge lines identified by inelastic X-ray scattering. Furthermore, because the Borrmann effect has been observed in photonic materials, it seems likely that the quadrupole enhancement reported here will play an important role in modern optics.

  6. Visible Light Spectroscopy of GEO Debris

    NASA Astrophysics Data System (ADS)

    Seitzer, P.; Abercromby, K. J.; Barker, E. S.; Cardona, T.; Lederer, S. M.; Cowardin, H.

    2012-09-01

    Our goal is to understand the physical characteristics of debris at geosynchronous orbit (GEO). Our approach is to compare the observed reflectance as a function of wavelength with laboratory measurements of typical spacecraft surfaces to understand what the materials are likely to be. Because debris could be irregular in shape and tumbling at an unknown rate, rapid simultaneous measurements over a range of wavelengths are required. Acquiring spectra of optically faint objects with short exposure times to minimize these effects requires a large telescope. We describe optical spectroscopy obtained with two imaging spectrographs on the 6.5-m Magellan telescopes at Las Campanas Observatory in Chile. Our first observing run was 12-14 March 2012 with the IMACS imaging spectrograph on the 'Walter Baade' telescope, which was followed by a run on 1-2 May 2012 on the 'Landon Clay' telescope. Both telescopes have spectrographs with an imaging mode for acquisition. After acquisition and centering of a GEO object, a slit and grism are moved into the beam for spectroscopy. We used low resolution grisms blazed near 600 nm for wavelength coverage in the 400-800 nm region. Typical exposure times for spectra were 15-30 seconds. Spectra were obtained for objects in the GEO regime listed as debris in the US Space Command public catalog, and one high area to mass ratio GEO object. In addition spectra were obtained of IDCSP (Initial Defense Communications Satellite Program) satellites with known initial properties just below the GEO regime. All spectra were calibrated using white dwarf flux standards and solar analog stars. We will describe our experiences using Magellan, a telescope never used previously for orbital debris spectroscopy, and our initial results. 1. This work is supported by NASAs Orbital Debris Program Office, Johnson Space Center, Houston, Texas, USA. 2. This paper includes data gathered with the 6.5 meter Magellan Telescopes located at Las Campanas Observatory, Chile.

  7. Estimating radiological background using imaging spectroscopy

    SciTech Connect

    Bernacki, Bruce E.; Schweppe, John E.; Stave, Sean C.; Jordan, David V.; Kulisek, Jonathan A.; Stewart, Trevor N.; Seifert, Carolyn E.

    2014-06-13

    Optical imaging spectroscopy is investigated as a method to estimate radiological background by spectral identification of soils, sediments, rocks, minerals and building materials derived from natural materials and assigning tabulated radiological emission values to these materials. Radiological airborne surveys are undertaken by local, state and federal agencies to identify the presence of radiological materials out of regulatory compliance. Detection performance in such surveys is determined by (among other factors) the uncertainty in the radiation background; increased knowledge of the expected radiation background will improve the ability to detect low-activity radiological materials. Radiological background due to naturally occurring radiological materials (NORM) can be estimated by reference to previous survey results, use of global 40K, 238U, and 232Th (KUT) values, reference to existing USGS radiation background maps, or by a moving average of the data as it is acquired. Each of these methods has its drawbacks: previous survey results may not include recent changes, the global average provides only a zero-order estimate, the USGS background radiation map resolutions are coarse and are accurate only to 1 km – 25 km sampling intervals depending on locale, and a moving average may essentially low pass filter the data to obscure small changes in radiation counts. Imaging spectroscopy from airborne or spaceborne platforms can offer higher resolution identification of materials and background, as well as provide imaging context information. AVIRIS hyperspectral image data is analyzed using commercial exploitation software to determine the usefulness of imaging spectroscopy to identify qualitative radiological background emissions when compared to airborne radiological survey data.

  8. Time-resolved orbital angular momentum spectroscopy

    SciTech Connect

    Noyan, Mehmet A.; Kikkawa, James M.

    2015-07-20

    We introduce pump-probe magneto-orbital spectroscopy, wherein Laguerre-Gauss optical pump pulses impart orbital angular momentum to the electronic states of a material and subsequent dynamics are studied with 100 fs time resolution. The excitation uses vortex modes that distribute angular momentum over a macroscopic area determined by the spot size, and the optical probe studies the chiral imbalance of vortex modes reflected off the sample. First observations in bulk GaAs yield transients that evolve on time scales distinctly different from population and spin relaxation, as expected, but with surprisingly large lifetimes.

  9. Optical Spectroscopy of Marine Bioadhesive Interfaces

    NASA Astrophysics Data System (ADS)

    Barlow, Daniel E.; Wahl, Kathryn J.

    2012-07-01

    Marine organisms have evolved extraordinarily effective adhesives that cure underwater and resist degradation. These underwater adhesives differ dramatically in structure and function and are composed of multiple proteins assembled into functional composites. The processes by which these bioadhesives cure—conformational changes, dehydration, polymerization, and cross-linking—are challenging to quantify because they occur not only underwater but also in a buried interface between the substrate and the organism. In this review, we highlight interfacial optical spectroscopy approaches that can reveal the biochemical processes and structure of marine bioadhesives, with particular emphasis on macrofoulers such as barnacles and mussels.

  10. Surface photovoltage spectroscopy of carbon nitride powder

    SciTech Connect

    Dittrich, Th.; Fiechter, S.; Thomas, A.

    2011-08-22

    Powder of carbon nitride has been investigated by surface photovoltage spectroscopy at temperatures between 30 deg. C and 150 deg. C. Photo-generated holes were preferentially separated towards the external surface. Electronic states below the optical band gap from which charge separation may be possible have not been observed. The band gap of the investigated carbon nitride decreased from 2.93 to 2.80 eV with increasing temperature from 30 deg. C to 150 deg. C. The material exhibits a higher optical transition at E = 3.6 eV. Results are discussed from the point of view of photo-catalytic water splitting with carbon nitride.

  11. Nuclear Forensics using Gamma-ray Spectroscopy

    NASA Astrophysics Data System (ADS)

    Norman, E. B.

    2016-09-01

    Much of George Dracoulis's research career was devoted to utilising gamma-ray spectroscopy in fundamental studies in nuclear physics. This same technology is useful in a wide range of applications in the area of nuclear forensics. Over the last several years, our research group has made use of both high- and low-resolution gamma-ray spectrometers to: identify the first sample of plutonium large enough to be weighed; determine the yield of the Trinity nuclear explosion; measure fission fragment yields as a function of target nucleus and neutron energy; and observe fallout in the U. S. from the Fukushima nuclear reactor accident.

  12. Infrared spectroscopy study of irradiated PVDF

    SciTech Connect

    Chappa, Veronica; Grosso, Mariela del; Garcia Bermudez, Gerardo; Behar, Moni

    2007-10-26

    The effects induced by 1 MeV/amu ion irradiations were compared to those induced by 4-12 MeV/amu irradiations. Structural analysis with infrared spectroscopy (FTIR) was carried out on PVDF irradiated using C and He beams with different fluences. From these spectra it was observed, as a function of fluence, an overall destruction of the polymer, amorphization of the crystalline regions and the creation of in-chain unsaturations. The track dimensions were determined using a previously developed Monte Carlo simulation code and these results were compared to a semiempirical model.

  13. Spectroscopy of Francium, recent developments at TRIUMF

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Orozco, L. A.; Collister, R.; Gwinner, G.; Tandecki, M.; Behr, J. A.; Pearson, M. R.; Gomez, E.; Aubin, S.; Frpnc Collaboration

    2014-05-01

    We present the current results of our program of precision spectroscopy on Francium using the recently commissioned Francium Trapping Facility at TRIUMF during two runs. The measurements include 7P1 / 2 state hyperfine splitting of isotopes 206 - 213 , 221Fr as well as isotope shift measurements on the 7S1 / 2 --> 7 P11 / 2 (D 1) transition. The statistical and systematic errors are small enough that measurements can provide information needed to understand future work on weak interaction physics using microwave and optical excitation of parity non conserving transitions. Work supported by NSERC and NRC from Canada, NSF and DOE from USA, CONACYT from Mexico.

  14. Raman Spectroscopy Of Glass-Crystalline Transformations

    NASA Astrophysics Data System (ADS)

    Haro, E.; Balkanski, M.

    1988-01-01

    Glass-crystalline transition is induced by laser irradiation on a GeSe bulk glass sample. The structural changes are detected by Raman spectroscopy. The speed of the crystallization process depends on the laser irradiation intensity. We have studied this crystallization process for three different powers of irradiation. It is found that the speed of crystallization increases with power. Stokes and anti-Stokes spectra were recorded during the transformation. From this data temperature was inferred at different stages of crystallization. The significance of this temperature is discussed.

  15. Spectroscopy of Moses Rock Kimberlite Diatreme

    NASA Technical Reports Server (NTRS)

    Pieters, C. M.; Mustard, J. F.

    1985-01-01

    Three types of remote sensing data (Airborne Imaging Spectroscopy (AIS), NS001, Zeiss IR-photographs) were obtained for the Moses Rock kimberlite dike in southern Utah. The goal is to identify and characterize the mantle derived mafic component in such volcanic features. The Zeiss and NS001 images provide information on the regional setting and allow units of the dike to be distinguished from surrounding material. A potential unmapped satellite dike was identified. The AIS data provide characterizing information of the surface composition of the dike. Serpentized olivine-bearing soils are (tentatively) identified from the AIS spectra for a few areas within the dike.

  16. Triplet absorption spectroscopy and electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Ghafoor, F.; Nazmitdinov, R. G.

    2016-09-01

    Coherence phenomena in a four-level atomic system, cyclically driven by three coherent fields, are investigated thoroughly at zero and weak magnetic fields. Each strongly interacting atomic state is converted to a triplet due to a dynamical Stark effect. Two dark lines with a Fano-like profile arise in the triplet absorption spectrum with anomalous dispersions. We provide conditions to control the widths of the transparency windows by means of the relative phase of the driving fields and the intensity of the microwave field, which closes the optical system loop. The effect of Doppler broadening on the results of the triplet absorption spectroscopy is analysed in detail.

  17. Analog detection for cavity lifetime spectroscopy

    DOEpatents

    Zare, Richard N.; Harb, Charles C.; Paldus, Barbara A.; Spence, Thomas G.

    2001-05-15

    An analog detection system for determining a ring-down rate or decay rate 1/.tau. of an exponentially decaying ring-down beam issuing from a lifetime or ring-down cavity during a ring-down phase. Alternatively, the analog detection system determines a build-up rate of an exponentially growing beam issuing from the cavity during a ring-up phase. The analog system can be employed in continuous wave cavity ring-down spectroscopy (CW CRDS) and pulsed CRDS (P CRDS) arrangements utilizing any type of ring-down cavity including ring-cavities and linear cavities.

  18. Analog detection for cavity lifetime spectroscopy

    DOEpatents

    Zare, Richard N.; Harb, Charles C.; Paldus, Barbara A.; Spence, Thomas G.

    2003-01-01

    An analog detection system for determining a ring-down rate or decay rate 1/.tau. of an exponentially decaying ring-down beam issuing from a lifetime or ring-down cavity during a ring-down phase. Alternatively, the analog detection system determines a build-up rate of an exponentially growing beam issuing from the cavity during a ring-up phase. The analog system can be employed in continuous wave cavity ring-down spectroscopy (CW CRDS) and pulsed CRDS (P CRDS) arrangements utilizing any type of ring-down cavity including ring-cavities and linear cavities.

  19. Occlusal caries detection using polarized Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Ionita, I.; Bulou, A.

    2008-02-01

    The tooth enamel, because of its hydroxyapatite composition, must present a Raman spectrum with strong polarization anisotropy. Carious lesions of the enamel will produce an alteration of local symmetry and will increase much more scattering of light. This will reduce the anisotropy of the Raman spectra. Because of the difference between high sensitivity to polarization of the 959 cm -1 Raman peak in sound enamel and low sensitivity in carried enamel, Raman polarized spectroscopy could be a useful method to early detect teeth caries.

  20. Candida parapsilosis Biofilm Identification by Raman Spectroscopy

    PubMed Central

    Samek, Ota; Mlynariková, Katarina; Bernatová, Silvie; Ježek, Jan; Krzyžánek, Vladislav; Šiler, Martin; Zemánek, Pavel; Růžička, Filip; Holá, Veronika; Mahelová, Martina

    2014-01-01

    Colonies of Candida parapsilosis on culture plates were probed directly in situ using Raman spectroscopy for rapid identification of specific strains separated by a given time intervals (up to months apart). To classify the Raman spectra, data analysis was performed using the approach of principal component analysis (PCA). The analysis of the data sets generated during the scans of individual colonies reveals that despite the inhomogeneity of the biological samples unambiguous associations to individual strains (two biofilm-positive and two biofilm-negative) could be made. PMID:25535081

  1. Candida parapsilosis biofilm identification by Raman spectroscopy.

    PubMed

    Samek, Ota; Mlynariková, Katarina; Bernatová, Silvie; Ježek, Jan; Krzyžánek, Vladislav; Šiler, Martin; Zemánek, Pavel; Růžička, Filip; Holá, Veronika; Mahelová, Martina

    2014-12-22

    Colonies of Candida parapsilosis on culture plates were probed directly in situ using Raman spectroscopy for rapid identification of specific strains separated by a given time intervals (up to months apart). To classify the Raman spectra, data analysis was performed using the approach of principal component analysis (PCA). The analysis of the data sets generated during the scans of individual colonies reveals that despite the inhomogeneity of the biological samples unambiguous associations to individual strains (two biofilm-positive and two biofilm-negative) could be made.

  2. Infrared Spectroscopy of Blood for Disease Identification

    NASA Astrophysics Data System (ADS)

    Pichardo, J. L.; Huerta-Franco, R.; Álvarez, R. R.; Bernal, J.; Gutiérrez-Juárez, G.; Palomares-Anda, P.

    2003-09-01

    Total reflectance attenuated infrared Fourier transform spectroscopy was used to analyze blood samples. Plasma and red blood cells were separated by centrifugation. The spectra were recorded from 200 to 4000 cm-1 under the same conditions for all samples. Samples of healthy donors were compared with those patients with different diseases (polycythemia and high blood pressure). Patients were under medical control at the time of the study. However, the preliminary results reveal that blood samples from healthy subjects had different infrared spectra compared to the non healthy patients.

  3. Multichannel euv spectroscopy of high temperature plasmas

    SciTech Connect

    Fonck, R.J.

    1983-11-01

    Spectroscopy of magnetically confined high temperature plasmas in the visible through x-ray spectral ranges deals primarily with the study of impurity line radiation or continuum radiation. Detailed knowledge of absolute intensities, temporal behavior, and spatial distributions of the emitted radiation is desired. As tokamak facilities become more complex, larger, and less accessible, there has been an increased emphasis on developing new instrumentation to provide such information in a minimum number of discharges. The availability of spatially-imaging detectors for use in the vacuum ultraviolet region (especially the intensified photodiode array) has generated the development of a variety of multichannel spectrometers for applications on tokamak facilities.

  4. Assessing PDT response with diffuse optical spectroscopies

    NASA Astrophysics Data System (ADS)

    Rohrbach, Daniel J.

    Photodynamic therapy (PDT) is used to treat a variety of conditions including cancer. Effective PDT requires three components: a photosensitizer (PS), light of a specific wavelength to activate the PS and oxygen. When all three are present in a lesion it leads to cell death and vascular destruction. Optical techniques such as diffuse reflectance spectroscopy (DRS), diffuse fluorescence spectroscopy (DFS) and diffuse correlation spectroscopy (DCS) can be used to quantify vascular parameters and photosensitizer content before and after PDT, providing valuable information for assessing response. For the quantification of vascular parameters, a probe-specific empirical light transport model was developed. A look-up-table was constructed using tissue simulating phantoms made of Intralipid to control the scattering, India Ink to control the absorption and water. The empirical model allowed the quantification of optical properties as well as the vascular parameters blood volume fraction (BVf) and blood oxygen saturation (SO2) with DRS. Blood flow was measured using DCS. For the quantification of PS content two techniques were used. DRS was used to fit the absorption of the PS and DFS measured the fluorescence of the PS. For quantification of PS content from measured fluorescence, a correction factor was developed using Monte Carlo simulations to account for the optical properties at the excitation and emission wavelengths. The three techniques were used to assess PDT response in pre-clinical and clinical studies. For the preclinical study, mice were treated with HPPH-PDT and blood flow was measured continuously with DCS. Blood flow variables were compared to STAT3 crosslinking (a molecular marker for PDT photoreaction) and CD31 staining (to visualize intact endothelial cells after PDT). For the clinical study, patients in a clinical trial for HPPH-PDT were measured with DRS, DFS and DCS before and after treatment. Multiple parameters were compared to the clinical response

  5. Extending applicability of terahertz spectroscopy for biosensing

    NASA Astrophysics Data System (ADS)

    Parthasarathy, Ramakrishnan

    Terahertz (THz) vibrational resonance spectroscopy has recently emerged as a promising technique for fingerprinting biological molecules. Absorption spectra in this frequency range (0.1-10 THz) reflect molecular internal vibrations involving the weakest hydrogen bonds and/or non-bonded interactions, which are species specific. Of prime importance is improving detection sensitivity of molecules with low absorption characteristics in the THz gap. Also of importance is the characterization of biological molecules in the THz gap (10-25 cm-1) by physical parameters (refractive index and absorption coefficient) rather than sample dependent parameters (transmission, reflection) and extending spectroscopy to the low THz range where remote sensing is most viable. To address the sensitivity issue, it is shown that periodic arrays of rectangular slots with subwavelength width provide for local electromagnetic field enhancements due to edge effects in the low frequency range of interest, 10-25 cm-1 (300-750 GHz). Periodic structures of Au, doped Si and InSb were studied. InSb is confirmed to offer the highest results with the local power enhancements on the order of 1100 at frequency 14 cm -1. InSb and Si have large skin depths in the frequency range of interest and so the analysis of their structures was done through the Fourier expansion method of field diffracted from gratings. Au however has small skin depths at these frequencies compared to the thickness. Surface impedance boundary conditions were employed to model the Au structure, for which the Fourier expansion method was unsuitable owing to the huge magnitude of Au permittivity. The applications possibly include development of novel bio-sensors, with the strongly enhanced local electromagnetic fields leading to increased detection sensitivity, and monitoring biophysical processes such as DNA denaturation. Transmission and reflection data from parallel, independent experiments are utilized in the Interference

  6. Optical spectroscopy of marine bioadhesive interfaces.

    PubMed

    Barlow, Daniel E; Wahl, Kathryn J

    2012-01-01

    Marine organisms have evolved extraordinarily effective adhesives that cure underwater and resist degradation. These underwater adhesives differ dramatically in structure and function and are composed of multiple proteins assembled into functional composites. The processes by which these bioadhesives cure--conformational changes, dehydration, polymerization, and cross-linking--are challenging to quantify because they occur not only underwater but also in a buried interface between the substrate and the organism. In this review, we highlight interfacial optical spectroscopy approaches that can reveal the biochemical processes and structure of marine bioadhesives, with particular emphasis on macrofoulers such as barnacles and mussels.

  7. Bragg spectroscopy of strongly interacting Fermi gases

    NASA Astrophysics Data System (ADS)

    Lingham, M. G.; Fenech, K.; Peppler, T.; Hoinka, S.; Dyke, P.; Hannaford, P.; Vale, C. J.

    2016-10-01

    This article provides an overview of recent developments and emerging topics in the study of two-component Fermi gases using Bragg spectroscopy. Bragg scattering is achieved by exposing a gas to two intersecting laser beams with a slight frequency difference and measuring the momentum transferred to the atoms. By varying the Bragg laser detuning, it is possible to measure either the density or spin response functions which characterize the basic excitations present in the gas. Specifically, one can measure properties such as the dynamic and static structure factors, Tan's universal contact parameter and observe signatures for the onset of pair condensation locally within a gas.

  8. Blood proteins analysis by Raman spectroscopy method

    NASA Astrophysics Data System (ADS)

    Artemyev, D. N.; Bratchenko, I. A.; Khristoforova, Yu. A.; Lykina, A. A.; Myakinin, O. O.; Kuzmina, T. P.; Davydkin, I. L.; Zakharov, V. P.

    2016-04-01

    This work is devoted to study the possibility of plasma proteins (albumin, globulins) concentration measurement using Raman spectroscopy setup. The blood plasma and whole blood were studied in this research. The obtained Raman spectra showed significant variation of intensities of certain spectral bands 940, 1005, 1330, 1450 and 1650 cm-1 for different protein fractions. Partial least squares regression analysis was used for determination of correlation coefficients. We have shown that the proposed method represents the structure and biochemical composition of major blood proteins.

  9. Photoelectron Emission Spectroscopy of Liquid Water.

    DTIC Science & Technology

    1981-04-01

    correlated to solvation free energies for H2O+(aq) and OH (aq)., DD ,FO*M 1473 EDITIOOF INOV so iS OBSOLETE Unclassified SECURITY CLASSIFICATION OF THIS PAGE...Photoelectron spectroscopy Reorganization free energy Water, liquid 20. ABSTRACT (Chlnw am ef We, aid* it nooe"mr and 1iEru’h hr 190k le 6) The threshold... energy Et a 10.06 eV (0.002 @V standard deviation) is detemined for phot~oelectron emission by litquid water and is correlated with Et a 8.45 eV for

  10. Preface: Special Topic on Multidimensional Spectroscopy

    NASA Astrophysics Data System (ADS)

    Mukamel, Shaul; Bakker, Huib J.

    2015-06-01

    Multidimensional signals are generated by subjecting molecules to sequences of short optical pulses and recording correlation plots related to the various controlled delay periods. These techniques which span all the way from the THz to the x-ray regimes provide qualitatively new structural and dynamical molecular information not available from conventional one-dimensional techniques. This issue surveys the recent experimental and theoretical progresses in this rapidly developing 20 year old field which illustrates the novel insights provided by multidimensional techniques into electronic and nuclear motions. It should serve as a valuable source for experts in the field and help introduce newcomers to this exciting and challenging branch of nonlinear spectroscopy.

  11. Attosecond quantum-beat spectroscopy in helium

    NASA Astrophysics Data System (ADS)

    Shivaram, Niranjan; Tong, Xiao-Min; Timmers, Henry; Sandhu, Arvinder

    2016-03-01

    The evolution of electron wavepackets determines the course of many physical and chemical phenomena, and attosecond spectroscopy aims to measure and control such dynamics in real time. Here, we investigate radial electron wavepacket motion in helium by using an XUV attosecond pulse train to prepare a coherent superposition of excited states and a delayed femtosecond IR pulse to ionize them. Quantum-beat signals observed in the high resolution photoelectron spectrogram allow us to follow the field-free evolution of the bound electron wavepacket and determine the time-dependent ionization dynamics of the low-lying 2{{p}} state.

  12. Low Temperature Trapping: from Reactions to Spectroscopy

    NASA Astrophysics Data System (ADS)

    Schlemmer, S.; Asvany, O.; Brunken, S.

    2013-06-01

    The kinetics of ion - molecule reactions are investigated in higher-order multipole traps by observation of the temporal evolution of mass selected parent ions in the presence of a neutral reaction partner. Rate coeffients for fast reactions (proceeding at collision rate) and very slow reactions (taking millions of collisions) are determined over a wide range of temperatures. Endothermic or hindered reactions can be promoted by excitation of the ion via absorption of a photon. Scanning the photon energy while detecting the number of product ions establishes an action spectroscopy method which we developed over the last 10-15 years and termed LIR: laser or light induced reactions. The main advantages of LIR are mass selection of the parent ion and low temperature conditions in the trap. Long storage times in combination with a near unity detection efficiency make LIR one of the most sensitive spectroscopy methods. The status quo of LIR will be discussed on selected examples. Recent measurements are concerned with ro-vibrational spectra of CH_2D^+ and CH_5^+ at highest resolution using cw OPO radiation. In the particular case of CH_5^+, the lines in the mid IR have been measured at a nominal temperature of 10 K and a frequency comb has been used for absolute calibration. Line positions can be determined to an accuracy which shall enable us in the future to obtain rotational spectra in a THz-IR double resonance approach. We tested the feasibility of this two photon method recently on H_2D^+. S. Schlemmer, T. Kuhn, E. Lescop, and D. Gerlich, Laser excited N_2^+ in a 22-Pole Trap: Experimental Studies of Rotational Relaxation Processes, Int. J. Mass Spectrometry and Ion Processes, 185-187, 589-602, (1999), S.D. Ivanov, O. Asvany, A. Witt, E. Hugo, G. Mathias, B. Redlich, D. Marx and S. Schlemmer, Quantum-induced symmetry breaking explains infrared spectra of CH_5^+ isotopologues, Nature Chemistry, 2, 298-302 (2010) S. Gaertner, J. Krieg, A. Klemann, O. Asvany and S

  13. THz Emission Spectroscopy for THz Spintronics

    NASA Astrophysics Data System (ADS)

    Jarik Huisman, Thomas; Rasing, Theo

    2017-01-01

    Spintronics is used as the standard for the readout of magnetically stored data and also has commercial applications for writing data. The generation, control and detection of spin-polarized currents, spin-dependent electric transport, and pure spin currents on the subpicosecond (10-12 s) timescale are the next challenges in spintronics. Terahertz (THz, 1012 Hz) emission spectroscopy has proven to be an excellent tool for investigating these challenges. In this short review, we outline the functioning of this spectroscopic technique and its recent applications to spintronics.

  14. Thermal degradation of polyketones. Vibrational spectroscopy studies

    NASA Astrophysics Data System (ADS)

    Conti, G.; Sommazzi, A.

    1993-03-01

    Thermal degradation studies of regular alternating polymers of carbon monoxide and olefin have been followed by FT-IR spectroscopy. The I.R spectra of solid samples, performed in inert atmosphere and in high vacuum, were recorded as a function of time at different temperatures. From the I.R. data it is possible to conclude that the reaction process, near the melting point of the polymers, could consist of intra or intermolecular hydrogen transfer yielding an enol and a small quantity of insaturations. The thermal degradation process, at temperatures higher than melting point, involves the scission of the polymer chain and produces fragments with a large number of insaturations.

  15. Detection of Endolithes Using Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Dumas, S.; Dutil, Y.; Joncas, G.

    2009-12-01

    On Earth, the Dry Valleys of Antarctica provide the closest martian-like environment for the study of extremophiles. Colonies of bacterias are protected from the freezing temperatures, the drought and UV light. They represent almost half of the biomass of those regions. Due to their resilience, endolithes are one possible model of martian biota. We propose to use infrared spectroscopy to remotely detect those colonies even if there is no obvious sign of their presence. This remote sensing approach reduces the risk of contamination or damage to the samples.

  16. Mössbauer spectroscopy of Basal Ganglia

    NASA Astrophysics Data System (ADS)

    Miglierini, Marcel; Lančok, Adriana; Kopáni, Martin; Boča, Roman

    2014-10-01

    Chemical states, structural arrangement, and magnetic features of iron deposits in biological tissue of Basal Ganglia are characterized. The methods of SQUID magnetometry and electron microscopy are employed. 57Fe Mössbauer spectroscopy is used as a principal method of investigation. Though electron microscopy has unveiled robust crystals (1-3 μm in size) of iron oxides, they are not manifested in the corresponding 57Fe Mössbauer spectra. The latter were acquired at 300 K and 4.2 K and resemble ferritin-like behavior.

  17. Vibrational spectroscopy standoff detection of threat chemicals

    NASA Astrophysics Data System (ADS)

    Ortiz-Rivera, William; Pacheco-Londoño, Leonardo C.; Castro-Suarez, John R.; Felix-Rivera, Hilsamar; Hernandez-Rivera, Samuel P.

    2011-06-01

    Spectroscopy based standoff detection systems: Raman and FTIR have been tested for detection of threat chemicals, including highly energetic materials, homemade explosives, explosives formulations and high explosives mixtures. Other threat chemicals studied included toxic industrial compounds (TIC) and chemical agent simulants. Microorganisms and biological threat agent simulants have also been detected at standoff distances. Open Path FTIR has been used to detect vapors and chemicals deposited on metal surfaces at μg/cm2 levels at distances as far as 30 m in active mode and 60 m in passive mode. In the case of Raman telescope, standoff distances for acetonitrile and ammonium nitrate were 140 m.

  18. Invariant mass spectroscopy of halo nuclei

    SciTech Connect

    Nakamura, Takashi

    2008-11-11

    We have applied the invariant mass spectroscopy to explore the low-lying exited states of halo nuclei at intermediate energies around 70 MeV/nucleon at RIKEN. As examples, we show here the results of Coulomb breakup study for {sup 11}Li using the Pb target, as well as breakup reactions of {sup 14}Be with p and C targets. The former study revealed a strong Coulomb breakup cross section reflecting the large enhancement of E1 strength at low excitation energies (soft E1 excitation). The latter revealed the observation of the first 2{sup +} state in {sup 14}Be.

  19. Hadron Spectroscopy in Double Pomeron Exchange Experiments

    SciTech Connect

    Albrow, Michael

    2016-11-15

    Central exclusive production in hadron-hadron collisions at high energies, for example p + p -> p + X + p, where the "+" represents a large rapidity gap, is a valuable process for spectroscopy of mesonic states X. At collider energies the gaps can be large enough to be dominated by pomeron exchange, and then the quantum numbers of the state X are restricted. Isoscalar JPC = 0++ and 2++ mesons are selected, and our understanding of these spectra is incomplete. In particular, soft pomeron exchanges favor gluon-dominated states such as glueballs, which are expected in QCD but not yet well established. I will review some published data.

  20. Characterization of amino acids using Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Jenkins, Amanda L.; Larsen, Richard A.; Williams, Timothy B.

    2005-05-01

    A key process in the development of new drugs is elucidation of the interaction between the drug molecule and the target protein. Such knowledge then makes it possible to make systematic structural modifications of the drug molecule to optimize the interaction. Many analytical techniques can be applied to proteins in solution such as circular dichroism, ultraviolet, and fluorescence spectroscopy but these all have limitations. In this paper, we investigate the feasibility of using relatively simple, visible light Raman spectroscopic methods to investigate amino acids and related biopolymers.

  1. Photoelectron spectroscopy of nitromethane anion clusters

    NASA Astrophysics Data System (ADS)

    Pruitt, Carrie Jo M.; Albury, Rachael M.; Goebbert, Daniel J.

    2016-08-01

    Nitromethane anion and nitromethane dimer, trimer, and hydrated cluster anions were studied by photoelectron spectroscopy. Vertical detachment energies, estimated electron affinities, and solvation energies were obtained from the photoelectron spectra. Cluster structures were investigated using theoretical calculations. Predicted detachment energies agreed with experiment. Calculations show water binds to nitromethane anion through two hydrogen bonds. The dimer has a non-linear structure with a single ionic Csbnd H⋯O hydrogen bond. The trimer has two different solvent interactions, but both involve the weak Csbnd H⋯O hydrogen bond.

  2. B and D spectroscopy at LEP

    SciTech Connect

    Muheim, Franz

    1999-02-17

    Results from the four LEP experiments ALEPH, DELPHI, L3, and OPAL on the spectroscopy of B and charmed mesons are presented. The predictions of Heavy Quark Effective Theory (HQET) for the masses and the widths of excited L=1 B mesons are supported by a new measurement from L3. A few B{sub c}{sup +} candidate events have masses consistent with the recent CDF observation and the predictions. New results on D** production and B{yields}D**l{nu} are also presented. The evidence for a D*{sup '} meson reported recently by DELPHI is not supported by OPAL and CLEO.

  3. Cavity-locked ring down spectroscopy

    DOEpatents

    Zare, Richard N.; Paldus, Barbara A.; Harb, Charles C.; Spence, Thomas

    2000-01-01

    Distinct locking and sampling light beams are used in a cavity ring-down spectroscopy (CRDS) system to perform multiple ring-down measurements while the laser and ring-down cavity are continuously locked. The sampling and locking light beams have different frequencies, to ensure that the sampling and locking light are decoupled within the cavity. Preferably, the ring-down cavity is ring-shaped, the sampling light is s-polarized, and the locking light is p-polarized. Transmitted sampling light is used for ring-down measurements, while reflected locking light is used for locking in a Pound-Drever scheme.

  4. γ-ray spectroscopy of 209Tl

    DOE PAGES

    Amro, B. M. S.; Lister, C. J.; McCutchan, E. A.; ...

    2017-01-30

    Here, states in 209TI were populated using a multi-nucleon transfer reaction with a 136Xe beam impinging on a thick 208Pb target at E = 785 MeV. The beam was pulsed at 825 ns intervals in order to perform isomer decay spectroscopy. The known Jπ = 17/2+ isomer in 209TI was located at 1228(4) keV and measured to have a half-life of T1/2 = 146(10) ns. A second isomer with Jπ = 13/2+ were found to have T1/2 = 14(5) ns.

  5. High-resolution flurescence spectroscopy in immunoanalysis

    SciTech Connect

    Grubor, Nenad M.

    2005-01-01

    The work presented in this dissertation combines highly sensitive and selective fluorescence line-narrowing spectroscopy (FLNS) detection with various modes of immunoanalytical techniques. It has been shown that FLNS is capable of directly probing molecules immunocomplexed with antibodies, eliminating analytical ambiguities that may arise from interferences that accompany traditional immunochemical techniques. Moreover, the utilization of highly cross-reactive antibodies for highly specific analyte determination has been demonstrated. Finally, they demonstrate the first example of the spectral resolution of diastereomeric analytes based on their interaction with a cross-reactive antibody.

  6. The spectroscopy of comets: Introductory remarks

    NASA Astrophysics Data System (ADS)

    Delsemme, A. H.

    1981-10-01

    Emphasis in cometary spectroscopy is on production rates, becuase they open the door to more fundamental clues about the origin and the history of the solar system, through the understanding of comet chemistry. In order to establish production rates quantitatively, suggestion are provided, in particular: to study the lifetimes of all hypothetical parents, against all processes of decay, namely photodissociations, photoionizations and ion-molecule reactions; and to study the velocity of all molecular fragments resulting from all the decay processes, through the balance sheet of the energy distribution before and after each decay process.

  7. Phase-Modulation Gas-Correlation Spectroscopy

    NASA Technical Reports Server (NTRS)

    Rider, David M.; Schofield, John T.; Margolis, Jack S.; Mccleese, Daniel J.

    1989-01-01

    Electro-optic phase-modulation gas-correlation spectroscopy demonstrated in laboratory tests promising candidate technique for remote sensing of gases, temperatures, and wind velocities in atmosphere. In technique radiation emitted by sample atmosphere passed through electro-optic phase modulator, and modulated and unmodulated versions of spectrum alternately passed through reference absorption cell containing gas to be detected. Radiation emerging from reference cell band-pass filtered and detected. Correlation signal is difference in intensity between phase-modulated and unmodulated detected signals.

  8. Moessbauer spectroscopy of the SNC meteorite Zagami

    NASA Technical Reports Server (NTRS)

    Agerkvist, D. P.; Vistisen, L.

    1993-01-01

    We have performed Mossbauer spectroscopy on two different pieces of the meteorite Zagami belonging to the group of SNC meteorites. In one of the samples we found a substantial amount of olivine inter grown with one kind of pyroxene, and also another kind of pyroxene very similar to the pyroxene in the other sample we examined. Both samples showed less than 1 percent of Fe(3+) in the silicate phase. The group of SNC meteorites called shergottites, to which Zagami belongs, are achondrites whose texture, mineralogy and composition resembles those of terrestrial diabases. The results from the investigation are presented.

  9. Method for conducting nonlinear electrochemical impedance spectroscopy

    DOEpatents

    Adler, Stuart B.; Wilson, Jamie R.; Huff, Shawn L.; Schwartz, Daniel T.

    2015-06-02

    A method for conducting nonlinear electrochemical impedance spectroscopy. The method includes quantifying the nonlinear response of an electrochemical system by measuring higher-order current or voltage harmonics generated by moderate-amplitude sinusoidal current or voltage perturbations. The method involves acquisition of the response signal followed by time apodization and fast Fourier transformation of the data into the frequency domain, where the magnitude and phase of each harmonic signal can be readily quantified. The method can be implemented on a computer as a software program.

  10. Raman Spectroscopy of Soft Musculoskeletal Tissues

    PubMed Central

    Esmonde-White, Karen

    2015-01-01

    Tendon, ligament, and joint tissues are important in maintaining daily function. They can be affected by disease, age, and injury. Slow tissue turnover, hierarchical structure and function, and nonlinear mechanical properties present challenges to diagnosing and treating soft musculoskeletal tissues. Understanding these tissues in health, disease, and injury is important to improving pharmacologic and surgical repair outcomes. Raman spectroscopy is an important tool in the examination of soft musculoskeletal tissues. This article highlights exciting basic science and clinical/translational Raman studies of cartilage, tendon, and ligament. PMID:25286106

  11. Testing fruit quality by photoacoustic spectroscopy assay

    NASA Astrophysics Data System (ADS)

    Popa, C.; Dumitras, D. C.; Patachia, M.; Banita, S.

    2014-10-01

    This study was conducted with the aim of testing the hypothesis that raspberry and strawberry fruits from nonorganic farming release more ethylene gas compounds compared to organic ones. At the same time, the experiments focused on evaluation of the potential and capabilities of the laser photoacoustic spectroscopy (LPAS) method in the assessment of fruit quality related to the effects of nitrogen. Ethylene gas can be harmful and carcinogenic, because it can accelerate the natural ripening process of physiologically mature fruits and makes the fruits more consistent in size. With the advantages of LPAS, we demonstrate that the concentration of ethylene from nonorganic raspberry and strawberry fruits is greater than from organic ones.

  12. Characterization of Thalidomide using Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Cipriani, Penelope; Smith, Candace Y.

    2008-02-01

    Thalidomide is a potent anticancer therapeutic drug whose mechanism of action has not yet been elucidated. In this report, experimental Raman spectroscopy is used to determine and characterize the vibrational frequencies of the drug. These normal modes are then compared to their quantum mechanical counterparts, which have been computed using density functional theory. Upon analysis of the spectra, we found that there was a high level of agreement between the wavenumbers. As such, this spectroscopic technique may be a viable tool for examining the way in which this drug interacts with its target molecules.

  13. Vacuum Ultraviolet Action Spectroscopy of Polysaccharides

    NASA Astrophysics Data System (ADS)

    Enjalbert, Quentin; Brunet, Claire; Vernier, Arnaud; Allouche, Abdul-Rahman; Antoine, Rodolphe; Dugourd, Philippe; Lemoine, Jérôme; Giuliani, Alexandre; Nahon, Laurent

    2013-08-01

    We studied the optical properties of gas-phase polysaccharides (maltose, maltotetraose, and maltohexaose) ions by action spectroscopy using the coupling between a quadrupole ion trap and a vacuum ultraviolet (VUV) beamline at the SOLEIL synchrotron radiation facility (France) in the 7 to 18 eV range. The spectra provide unique benchmarks for evaluation of theoretical data on electronic transitions of model carbohydrates in the VUV range. The effects of the nature of the charge held by polysaccharide ions on the relaxation processes were also explored. Finally the effect of isomerization of polysaccharides (with melezitose and raffinose) on their photofragmentation with VUV photons is presented.

  14. Mössbauer spectroscopy of Basal Ganglia

    SciTech Connect

    Miglierini, Marcel; Lančok, Adriana; Kopáni, Martin; Boča, Roman

    2014-10-27

    Chemical states, structural arrangement, and magnetic features of iron deposits in biological tissue of Basal Ganglia are characterized. The methods of SQUID magnetometry and electron microscopy are employed. {sup 57}Fe Mössbauer spectroscopy is used as a principal method of investigation. Though electron microscopy has unveiled robust crystals (1-3 μm in size) of iron oxides, they are not manifested in the corresponding {sup 57}Fe Mössbauer spectra. The latter were acquired at 300 K and 4.2 K and resemble ferritin-like behavior.

  15. Role of Raman spectroscopy and surface enhanced Raman spectroscopy in colorectal cancer

    PubMed Central

    Jenkins, Cerys A; Lewis, Paul D; Dunstan, Peter R; Harris, Dean A

    2016-01-01

    Colorectal cancer (CRC) is the fourth most common cancer in the United Kingdom and is the second largest cause of cancer related death in the United Kingdom after lung cancer. Currently in the United Kingdom there is not a diagnostic test that has sufficient differentiation between patients with cancer and those without cancer so the current referral system relies on symptomatic presentation in a primary care setting. Raman spectroscopy and surface enhanced Raman spectroscopy (SERS) are forms of vibrational spectroscopy that offer a non-destructive method to gain molecular information about biological samples. The techniques offer a wide range of applications from in vivo or in vitro diagnostics using endoscopic probes, to the use of micro-spectrometers for analysis of biofluids. The techniques have the potential to detect molecular changes prior to any morphological changes occurring in the tissue and therefore could offer many possibilities to aid the detection of CRC. The purpose of this review is to look at the current state of diagnostic technology in the United Kingdom. The development of Raman spectroscopy and SERS in clinical applications relation for CRC will then be discussed. Finally, future areas of research of Raman/SERS as a clinical tool for the diagnosis of CRC are also discussed. PMID:27190582

  16. Atomic Absorption Spectroscopy, Atomic Emission Spectroscopy, and Inductively Coupled Plasma-Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Miller, Dennis D.; Rutzke, Michael A.

    Atomic spectroscopy has played a major role in the development of our current database for mineral nutrients and toxicants in foods. When atomic absorption spectrometers became widely available in the 1960s, the development of atomic absorption spectroscopy (AAS) methods for accurately measuring trace amounts of mineral elements in biological samples paved the way for unprecedented advances in fields as diverse as food analysis, nutrition, biochemistry, and toxicology (1). The application of plasmas as excitation sources for atomic emission spectroscopy (AES) led to the commercial availability of instruments for inductively coupled plasma - atomic emission spectroscopy (ICP-AES) beginning in the late 1970s. This instrument has further enhanced our ability to measure the mineral composition of foods and other materials rapidly, accurately, and precisely. More recently, plasmas have been joined with mass spectrometers (MS) to form inductively coupled plasma-mass spectrometer ICP-MS instruments that are capable of measuring mineral elements with extremely low detection limits. These three instrumental methods have largely replaced traditional wet chemistry methods for mineral analysis of foods, although traditional methods for calcium, chloride, iron, and phosphorus remain in use today (see Chap. 12).

  17. Raman spectroscopy system with hollow fiber probes

    NASA Astrophysics Data System (ADS)

    Liu, Bing-hong; Shi, Yi-Wei

    2012-11-01

    A Raman remote spectroscopy system was realized using flexible hollow optical fiber as laser emittion and signal collection probes. A silver-coated hollow fiber has low-loss property and flat transmission characteristics in the visible wavelength regions. Compared with conventional silica optical fiber, little background fluorescence noise was observed with optical fiber as the probe, which would be of great advantages to the detection in low frequency Raman shift region. The complex filtering and focusing system was thus unnecessary. The Raman spectra of CaCO3 and PE were obtained by using the system and a reasonable signal to noise ratio was attained without any lens. Experiments with probes made of conventional silica optical fibers were also conducted for comparisons. Furthermore, a silver-coated hollow glass waveguide was used as sample cell to detect liquid phase sample. We used a 6 cm-long hollow fiber as the liquid cell and Butt-couplings with emitting and collecting fibers. Experiment results show that the system obtained high signal to noise ratio because of the longer optical length between sample and laser light. We also give the elementary theoretical analysis for the hollow fiber sample cell. The parameters of the fiber which would affect the system were discussed. Hollow fiber has shown to be a potential fiber probe or sample cell for Raman spectroscopy.

  18. THz Spectroscopy and Spectroscopic Database for Astrophysics

    NASA Technical Reports Server (NTRS)

    Pearson, John C.; Drouin, Brian J.

    2006-01-01

    Molecule specific astronomical observations rely on precisely determined laboratory molecular data for interpretation. The Herschel Heterodyne Instrument for Far Infrared, a suite of SOFIA instruments, and ALMA are each well placed to expose the limitations of available molecular physics data and spectral line catalogs. Herschel and SOFIA will observe in high spectral resolution over the entire far infrared range. Accurate data to previously unimagined frequencies including infrared ro-vibrational and ro-torsional bands will be required for interpretation of the observations. Planned ALMA observations with a very small beam will reveal weaker emission features requiring accurate knowledge of higher quantum numbers and additional vibrational states. Historically, laboratory spectroscopy has been at the front of submillimeter technology development, but now astronomical receivers have an enormous capability advantage. Additionally, rotational spectroscopy is a relatively mature field attracting little interest from students and funding agencies. Molecular data base maintenance is tedious and difficult to justify as research. This severely limits funding opportunities even though data bases require the same level of expertise as research. We report the application of some relatively new receiver technology into a simple solid state THz spectrometer that has the performance required to collect the laboratory data required by astronomical observations. Further detail on the lack of preparation for upcoming missions by the JPL spectral line catalog is given.

  19. High Precision Rovibrational Spectroscopy of OH+

    NASA Astrophysics Data System (ADS)

    Markus, Charles R.; Hodges, James N.; Perry, Adam J.; Kocheril, G. Stephen; Müller, Holger S. P.; McCall, Benjamin J.

    2016-02-01

    The molecular ion OH+ has long been known to be an important component of the interstellar medium. Its relative abundance can be used to indirectly measure cosmic ray ionization rates of hydrogen, and it is the first intermediate in the interstellar formation of water. To date, only a limited number of pure rotational transitions have been observed in the laboratory making it necessary to indirectly calculate rotational levels from high-precision rovibrational spectroscopy. We have remeasured 30 transitions in the fundamental band with MHz-level precision, in order to enable the prediction of a THz spectrum of OH+. The ions were produced in a water cooled discharge of O2, H2, and He, and the rovibrational transitions were measured with the technique Noise Immune Cavity Enhanced Optical Heterodyne Velocity Modulation Spectroscopy. These values have been included in a global fit of field free data to a 3Σ- linear molecule effective Hamiltonian to determine improved spectroscopic parameters which were used to predict the pure rotational transition frequencies.

  20. Nonlinear infrared spectroscopy free from spectral selection

    PubMed Central

    Paterova, Anna; Lung, Shaun; Kalashnikov, Dmitry A.; Krivitsky, Leonid A.

    2017-01-01

    Infrared (IR) spectroscopy is an indispensable tool for many practical applications including material analysis and sensing. Existing IR spectroscopy techniques face challenges related to the inferior performance and the high cost of IR-grade components. Here, we develop a new method, which allows studying properties of materials in the IR range using only visible light optics and detectors. It is based on the nonlinear interference of entangled photons, generated via Spontaneous Parametric Down Conversion (SPDC). In our interferometer, the phase of the signal photon in the visible range depends on the phase of an entangled IR photon. When the IR photon is traveling through the media, its properties can be found from observations of the visible photon. We directly acquire the SPDC signal with a visible range CCD camera and use a numerical algorithm to infer the absorption coefficient and the refraction index of the sample in the IR range. Our method does not require the use of a spectrometer and a slit, thus it allows achieving higher signal-to-noise ratio than the earlier developed method. PMID:28218302