Sample records for spectroscopic analysis study

  1. Comparative study of ATR and transflection IR spectroscopic techniques for the analysis of hallucinogenic mushrooms.

    PubMed

    Koçak, A; De Cotiis, L M; Hoffman, D B

    2010-02-25

    This paper compares the use of ATR and transflection spectroscopic techniques for the qualitative analysis of psilocin extracted from hallucinogenic mushrooms and control spiked mushrooms. Both techniques gave comparable results and agreed with prior GC/MS analysis of the actual case samples. PMID:19969433

  2. Spectroscopic studies of glass structure

    SciTech Connect

    Brow, R.K.

    1994-08-01

    Today`s understanding of the molecular-level structure of inorganic glasses has been transformed by the availability of a wide range of sensitive spectroscopic probes. Today we can relate glass composition to quantitative distributions of glass-forming cations and to changes in oxygen bonding and modifying cation geometries. Future spectroscopic studies will result in improved descriptions of anion and cation geometries and should provide glass scientists with the capability to optimize atomic arrangements for specific optical, electrical, and thermal properties.

  3. Spectroscopic Analysis of H? Dots

    NASA Astrophysics Data System (ADS)

    Feddersen, Jesse; Salzer, J. J.; Gronwall, C.

    2013-06-01

    We present spectroscopic measurements of ~200 faint point sources of emission - called H? dots - found in narrow-band images taken for the ALFALFA H? project. Our image analysis catalogs emission-line sources that are not optically associated with the target ALFALFA galaxy. Analyzing spectra of these sources, we find isolated extragalactic HII regions, ultra-low luminosity dwarf galaxies, background (higher redshift) galaxies, and QSOs. We give a summary of the photometric and spectroscopic properties of the full sample of H? dots discovered to date. We also illustrate why these objects are of astrophysical interest. For example, using coarse oxygen abundance measurements of the low luminosity dwarf galaxies, we detect signs of a possible flattening in the local Luminosity-Metallicity relation. We also find luminous [O III]-detected star-forming galaxies at z ~ 0.32 with unusually low oxygen abundances.

  4. An experimental and density functional study on conformational and spectroscopic analysis of 5-methoxyindole-2-carboxylic acid.

    PubMed

    Cinar, Mehmet; Karabacak, Mehmet; Asiri, Abdullah M

    2015-02-25

    In this article, a brief conformational and spectroscopic characterization of 5-methoxyindole-2-carboxylic acid (5-MeOICA) via experimental techniques and applications of quantum chemical methods is presented. The conformational analysis of the studied molecule was determined theoretically using density functional computations for ground state, and compared with previously reported experimental findings. The vibrational transitions were examined by measured FT-IR and FT-Raman spectroscopic data, and also results obtained from B3LYP and CAM-B3LYP functionals in combination with 6-311++G(d,p) basis set. The recorded proton and carbon NMR spectra in DMSO solution were analyzed to obtain the exact conformation. Due to intermolecular hydrogen bondings, NMR calculations were performed for the dimeric form of 5-MeOICA and so chemical shifts of those protons were predicted more accurately. Finally, electronic properties of steady compound were identified by a comparative study of UV absorption spectra in ethanol and water solution and TD-DFT calculations. PMID:25255480

  5. Nuclear spectroscopic studies

    SciTech Connect

    Bingham, C.R.; Guidry, M.W.; Riedinger, L.L.; Sorensen, S.P.

    1993-02-08

    The Nuclear Physics group at the University of Tennessee, Knoxville is involved in several aspects of heavy-ion physics including both nuclear structure and reaction mechanisms. While our main emphasis is on experimental problems involving heavy-ion accelerators, we have maintained a strong collaboration with several theorists in order to best pursue the physics of our measurements. During the last year we have led several experiments at the Holifield Heavy Ion Research Facility and participated in others at Argonne National Laboratory. Also, we continue to be very active in the collaboration to study ultra-relativistic heavy ion physics utilizing the SPS accelerator at CERN in Geneva, Switzerland and in a RHIC detector R D project. Our experimental work is in four broad areas: (1) the structure of nuclei at high angular momentum, (2) heavy-ion induced transfer reactions, (3) the structure of nuclei far from stability, and (4) ultra-relativistic heavy-ion physics. The results of studies in these particular areas will be described in this document in sections IIA, IIB, IIC, and IID, respectively. Areas (1), (3), and (4) concentrate on the structure of nuclear matter in extreme conditions of rotational motion, imbalance of neutrons and protons, or very high temperature and density. Area (2) pursues the transfer of nucleons to states with high angular momentum, both to learn about their structure and to understand the transfer of particles, energy, and angular momentum in collisions between heavy ions. An important component of our program is the strong emphasis on the theoretical aspects of nuclear structure and reactions.

  6. Studies of the interaction between FNC and human hemoglobin: a spectroscopic analysis and molecular docking.

    PubMed

    Li, Huiyi; Dou, Huanjing; Zhang, Yuhai; Li, Zhigang; Wang, Ruiyong; Chang, Junbiao

    2015-02-01

    FNC (2'-deoxy-2'-bfluoro-4'-azidocytidine) is a novel nucleoside analogue with pharmacologic effects on several human diseases. In this work, the binding of FNC to human hemoglobin (HHb) have been investigated by absorption spectroscopy, fluorescence quenching technique, synchronous fluorescence, three-dimensional fluorescence and molecular modeling methods. Analysis of fluorescence data showed that the binding of FNC to HHb occurred via a static quenching mechanism. Thermodynamic analysis and molecular modeling suggest that hydrogen bond and van der Waals force are the mainly binding force in the binding of FNC to HHb. PMID:25448944

  7. VIRUS-MEMBRANE INTERACTIONS spectroscopic studies

    E-print Network

    Hemminga, Marcus A.

    #12;#12;VIRUS-MEMBRANE INTERACTIONS spectroscopic studies #12;Promotor: dr. T.J. Schaafsma VIRUS-MEMB NE INTERACTIONS spectroscopic studies PROEFSCHRIFT ter verkrijging van de graad van doctor. Dr. T.J. Schaafsma was mijn promotor. Het onderzoek is uitgevoerd binnen de "virusgroep", waarvan

  8. Experimental and theoretical spectroscopic analysis, HOMO-LUMO, and NBO studies of cyanuric chloride

    NASA Astrophysics Data System (ADS)

    Prabhaharan, M.; Prabakaran, A. R.; Srinivasan, S.; Gunasekaran, S.

    2014-06-01

    The vibrational spectral analysis of cyanuric chloride was carried out by using FT-Raman and FT-IR spectra in the range 100-4000 cm-1 and 400-4000 cm-1 respectively. The structure optimization was done and structural characteristics were determined by Density Functional Theory (B3LYP) method with 6-31G(d,p) and 6-311++G(d,p) basis sets. The vibrational wavenumbers have been calculated and scaled values are compared with experimental FT-IR and FT-Raman spectra. A detailed interpretation of the vibrational spectra of the molecule has been made on the basis of the calculated Potential Energy Distribution (PED). The Natural bonding orbital (NBO) analysis performed to confirm the stability of the molecule arising from hyper conjugation and delocalization. The Mulliken atomic charges were also calculated. The computed HOMO-LUMO energy gap shows that charge transfer occurs within the molecule. The thermodynamic properties at different temperatures have been calculated from the vibrational analysis.

  9. Experimental and theoretical spectroscopic analysis, HOMO-LUMO, and NBO studies of cyanuric chloride.

    PubMed

    Prabhaharan, M; Prabakaran, A R; Srinivasan, S; Gunasekaran, S

    2014-06-01

    The vibrational spectral analysis of cyanuric chloride was carried out by using FT-Raman and FT-IR spectra in the range 100-4000cm(-1) and 400-4000cm(-1) respectively. The structure optimization was done and structural characteristics were determined by Density Functional Theory (B3LYP) method with 6-31G(d,p) and 6-311++G(d,p) basis sets. The vibrational wavenumbers have been calculated and scaled values are compared with experimental FT-IR and FT-Raman spectra. A detailed interpretation of the vibrational spectra of the molecule has been made on the basis of the calculated Potential Energy Distribution (PED). The Natural bonding orbital (NBO) analysis performed to confirm the stability of the molecule arising from hyper conjugation and delocalization. The Mulliken atomic charges were also calculated. The computed HOMO-LUMO energy gap shows that charge transfer occurs within the molecule. The thermodynamic properties at different temperatures have been calculated from the vibrational analysis. PMID:24650880

  10. The Spectroscopic study of {sup 33}Ar

    SciTech Connect

    Adimi, N. [Centre d'Etudes Nucleaires de Bordeaux Gradignan, Universite Bordeaux 1, UMR 5797 CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175 Gradignan (France); Faculte de Physique, USTHB, B.P.32, El Alia, 16111 Bab Ezzouar, Alger (Algeria); Dominguez-Reyes, R.; Alcorta, M.; Borge, M. J. G.; Perea, A.; Tengblad, O. [Institutode Estructura de la Materia, CSIC, Serrano 113bis, E-28006-Madrid (Spain); Bey, A.; Blank, B.; Dossat, C.; Giovinazzo, J.; Matea, I. [Centre d'Etudes Nucleaires de Bordeaux Gradignan, Universite Bordeaux 1, UMR 5797 CNRS/IN2P3, Chemin du Solarium, BP 120, F-33175 Gradignan (France); Oliveira Santos, F. de; Madurga, M.; Thomas, J. C. [Grand Accelerateur National d'Ions Lourds, B.P. 55027, F-14076 Caen Cedex 05 (France); Fynbo, H. O. U.; Knudsen, H. H. [Department of Physics and Astronomy, University of Aarhus, Ny Munkegade 1520, DK-8000 Aarhus C (Denmark); Suemmerer, K. [Gesellschaft fuer Schwerionenforschung mbH, Planckstrasse 1, D-64291 Darmstadt (Germany)

    2011-10-28

    The proton-rich nucleus {sup 33}Ar has been produced at the low-energy facility SPIRAL at GANIL. Spectroscopic studies of gamma and p emission of this nucleus were performed with the 'Silicon Cube' detection system. The analysis of proton and gamma singles and coincidence spectra allowed us to establish a complete decay scheme of this nucleus. The comparison of the Gamow-Teller strength distribution deduced from our experiment and the theoretical one obtained with the Shell Model permitted the determination of a quenching factor for the Gamow-Teller strength.

  11. Spectroscopic, electronic structure and natural bond orbital analysis of o-fluoronitrobenzene and p-fluoronitrobenzene: A comparative study

    Microsoft Academic Search

    V. Arjunan; S. Thillai Govindaraja; S. Sakiladevi; M. Kalaivani; S. Mohan

    2011-01-01

    Experimental FTIR, FT-Raman and FT-NMR spectroscopic studies of o-fluoronitrobenzene and p-fluoronitrobenzene have been carried out. A detailed quantum chemical calculations have been performed using DFT\\/B3LYP method with 6-311++G** and 6-31G** basis sets. Complete vibrational analyses of the compounds were performed. The temperature dependence of thermodynamic properties has been analysed. The atomic charges, electronic exchange interaction and charge delocalisation of the

  12. Study on molecular structure, spectroscopic behavior, NBO, and NLO analysis of 3-methylbezothiazole-2-thione

    NASA Astrophysics Data System (ADS)

    Chand, Satish; Al-Omary, Fatmah A. M.; El-Emam, Ali A.; Shukla, Vikas K.; Prasad, Onkar; Sinha, Leena

    2015-07-01

    Experimentally observed spectral data (FT-TR and FT-Raman) of 3-methylbezothiazole-2-thione (3MBT2T) were compared with the spectral data obtained by DFT/B3LYP method using 6-311++G(d,p) basis set. UV-Vis spectrum of the title compound was recorded and the electronic properties, such as frontier molecular orbitals and band gap energies were calculated by TD-DFT approach. The molecular properties like dipole moment, polarizability, first static hyperpolarizability, molecular electrostatic potential surface (MEPs), and contour map were calculated to get a better comprehension of the properties of the title molecule. Natural bond orbital (NBO) analysis was applied to investigate the stability of the molecule arising from charge delocalization. Global and local reactivity descriptors were also computed to predict reactivity and reactive sites on the molecule.

  13. Microwave spectroscopic studies of molecular recognition: Analysis of diastereomeric interactions between ethanol and oxirane derivatives

    NASA Astrophysics Data System (ADS)

    Borho, Nicole; Xu, Yunjie

    2007-06-01

    High resolution microwave spectroscopy complimented by ab initio calculations has been used to elucidate the diastereomeric interactions in a set of small model complexes. Ethanol, a transient chiral alcohol, was combined with oxirane (achiral), methyl-oxiraneootnotetextmark[1] (1 stereocenter) and trans-2,3-dimethyloxirane (2 stereocenters) to form hydrogen-bonded 1:1 complexes. The rotational constants of two conformers of ethanoloxirane, six conformers of ethanolmethyl-oxirane and three conformers of ethanoltrans-2,3-dimethyloxirane have been determined and the relative stability order of the conformers has been established. The dependence of the observed intensity on pressure, nozzle temperature and different carrier gases has been investigated for the case of ethanoltrans-2,3-dimethyloxirane to give a first insight into the kinetical and thermodynamical influence on the formation of different conformers. The step-by-step methyl addition to oxirane helps to unravel the diastereomeric interactions at play via analysis of the subtle energy differences between each set of conformers, allowing for a detailed understanding of molecular recognition in this benchmark system.ootnotetextmark[1]Nicole Borho, Yunjie Xu, Angew. Chem., 2006, (VIP paper, Published Online: 17 Nov 2006, DOI: 10.1002/anie.200603809).

  14. Vibrational spectroscopic investigation and conformational analysis of 1-heptylamine: A comparative density functional study

    NASA Astrophysics Data System (ADS)

    Tursun, Mahir; Ke?an, Gürkan; Parlak, Cemal; ?enyel, Mustafa

    2013-10-01

    FT-IR and Raman spectra of 1-heptylamine (1-ha) have been recorded in the region of 4000-10 cm-1 and 4000-50 cm-1, respectively. The conformational analysis, optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of 1-ha (C7H17N) have been examined by means of the Becke-3-Lee-Yang-Parr (B3LYP) density functional theory (DFT) method together with the 6-31++G(d,p) basis set. Furthermore, reliable vibrational assignments have been made on the basis of potential energy distribution (PED) and the thermodynamics functions, highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of 1-ha have been predicted. Calculations have been carried out with the possible ten conformational isomers (TT, TG, GT, GT1, GG1, GG2, GG3, GG4, GG5, GG6; T and G denote trans and gauge) of 1-ha, both in gas phase and in solution. Solvent effects have theoretically been investigated using benzene and methanol. All results indicate that the B3LYP method provides satisfactory evidence for the prediction of vibrational frequencies and the TT isomer is the most stable form of 1-ha.

  15. Vibrational Spectroscopic Investigation and Conformational Analysis of 1-HEPTYLAMINE: a Comparative Density Functional Study

    NASA Astrophysics Data System (ADS)

    Tursun, Mahir; Kesan, Gurkan; Parlak, Cemal; Senyel, Mustafa

    2013-06-01

    FT-IR and Raman spectra of 1-heptylamine (1-ha) were experimentally reported in the region of 4000-10 cm-1 and 4000-100 cm-1, respectively. The conformational analysis, optimized geometric parameters, normal mode frequencies and corresponding vibrational assignments of 1-ha (C7H17N) were theoretically examined by means of Becke-3-Lee-Yang-Parr (B3-LYP) density functional theory (DFT) method together with 6-31++G(d,p) basis set. Furthermore, reliable vibrational assignments were made on the basis of potential energy distribution (PED) calculated and the thermodynamics functions, highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of 1-ha were predicted. Calculations were carried out with the possible ten conformational isomers (TT, TG, GT, GT1, GG1, GG2, GG3, GG4, GG5, GG6; T and G denote trans and gauge) of 1-ha, both in gas phase and in solution. Solvent effects were investigated using benzene and methanol. All results indicates that B3-LYP method provides satisfactory results for the prediction vibrational wavenumbers, TT isomer is the most stable form of 1-ha and the conformational energy barrier is independent of the solvent whereas the vibrational frequencies and assignments, IR and Raman intensities of 1-ha are solvent dependent.

  16. Application of comparative vibrational spectroscopic and mechanistic studies in analysis of fisetin structure

    NASA Astrophysics Data System (ADS)

    Dimitri? Markovi?, Jasmina M.; Markovi?, Zoran S.; Milenkovi?, Dejan; Jeremi?, Svetlana

    2011-12-01

    This paper addresses experimental and theoretical research in fisetin (2-(3,4-dihydroxyphenyl)-3,7-dihydroxychromen-4-one) structure by means of experimental IR and Raman spectroscopies and mechanistic calculations. Density Functional Theory calculations, with M05-2X functional and the 6-311+G (2df, p) basis set implemented in the Gaussian 09 package, are performed with the aim to support molecular structure, vibrational bands' positions and their intensities. Potential energy distribution (PED) values and the description of the largest vibrational contributions to the normal modes are calculated. The most intense bands appear in the 1650-1500 cm -1 wavenumber region. This region involves a combination of the C dbnd O, C2 dbnd C3 and C-C stretching vibrational modes. Most of the bands in the 1500-1000 cm -1 range involve C-C stretching, O-C stretching and in-plane C-C-H, C-O-H, C-C-O and C-C-C bending vibrations of the rings. The region below 1000 cm -1 is characteristic to the combination of in plane C-C-C-H, H-C-C-H, C-C-C-C, C-C-O-C and out of plane O-C-C-C, C-C-O-C, C-C-C-C torsional modes. The Raman spectra of baicalein and quercetin were used for qualitative comparison with fisetin spectrum and verification of band assignments. The applied detailed vibrational spectral analysis and the assignments of the bands, proposed on the basis of fundamentals, reproduced the experimental results with high degree of accuracy.

  17. FT-IR spectroscopic analysis to study the firing processes of prehistoric ceramics

    NASA Astrophysics Data System (ADS)

    Barone, G.; Crupi, V.; Longo, F.; Majolino, D.; Mazzoleni, P.; Tanasi, D.; Venuti, V.

    2011-05-01

    In this work, we present a FT-IR absorbance investigation on prehistoric ceramics with the aim of characterizing the phase transformations that occur during the cooking processes. The measurements were performed on several potteries belonging to the Middle Bronze Age excavated in the Catania hinterland (Sicily, Southern Italy). Based on the macroscopic observation, the samples may be distinguished on coarse and fine ceramics, and the petrographic study showed a strongly heterogeneous structure and composition. The results were compared with the data obtained by means of X-ray diffraction (XRD) and with the microscopic qualitative observations of the birefringence of the groundmass. The whole set of the data showed a firing temperature in the 800-900 °C range. The simultaneous presence in several samples of calcite and clay minerals and of new-formed Ca-silicates should be indicative of a quite primitive technological firing process with strong temperature variation inside the kiln.

  18. Studies on the binding of fulvic acid with transferrin by spectroscopic analysis

    NASA Astrophysics Data System (ADS)

    Zhang, Xiu-feng; Yang, Guang; Dong, Yu; Zhao, Yan-qin; Sun, Xiao-ran; Chen, Lei; Chen, Hong-bo

    2015-02-01

    Transferrin has shown potential in the delivery of anticancer drugs into primarily proliferating cancer cells that over-express transferrin receptors. Fulvic acid has a wide range of biological and pharmacological activities which caused widespread concerns, the interaction of fulvic acid with human serum transferrin (Tf) has great significance for gaining a deeper insight about anticancer activities of fulvic acid. In this study, the mechanism of interaction between fulvic acid and Tf, has been investigated by using fluorescence quenching, thermodynamics, synchronous fluorescence and circular dichroism (CD) under physiological condition. Our results have shown that fulvic acid binds to Tf and form a new complex, and the calculated apparent association constants are 5.04 × 108 M-1, 5.48 × 107 M-1, 7.38 × 106 M-1 from the fluorescence quenching at 288 K, 298 K, and 310 K. The thermodynamic parameters indicate that hydrogen bonding and weak van der Waals are involved in the interaction between fulvic acid and Tf. The binding of fulvic acid to Tf causes the ?-helix structure content of the protein to reduce, and resulting that peptide chains of Tf become more stretched. Our results have indicated a mechanism of the interaction between fulvic acid and Tf, which may provide information for possible design of methods to deliver drug molecules via transferrin to target tissues and cells effectively.

  19. Multivariate analysis methods for spectroscopic blood analysis

    NASA Astrophysics Data System (ADS)

    Wood, Michael F. G.; Rohani, Arash; Ghazalah, Rashid; Vitkin, I. Alex; Pawluczyk, Romuald

    2012-01-01

    Blood tests are an essential tool in clinical medicine with the ability diagnosis or monitor various diseases and conditions; however, the complexities of these measurements currently restrict them to a laboratory setting. P&P Optica has developed and currently produces patented high performance spectrometers and is developing a spectrometer-based system for rapid reagent-free blood analysis. An important aspect of this analysis is the need to extract the analyte specific information from the measured signal such that the analyte concentrations can be determined. To this end, advanced chemometric methods are currently being investigated and have been tested using simulated spectra. A blood plasma model was used to generate Raman, near infrared, and optical rotatory dispersion spectra with glucose as the target analyte. The potential of combined chemometric techniques, where multiple spectroscopy modalities are used in a single regression model to improve the prediction ability was investigated using unfold partial least squares and multiblock partial least squares. Results show improvement in the predictions of glucose levels using the combined methods and demonstrate potential for multiblock chemometrics in spectroscopic blood analysis.

  20. Interaction of salmon gonadotropin subunits : spectroscopic studies

    E-print Network

    Paris-Sud XI, Université de

    Interaction of salmon gonadotropin subunits : spectroscopic studies R. SALESSE, J. GARNIER, B en Josas, France Summary. Pituitary gonadotropins of female and male pacific salmon Oncorhynchus) and in salmon (Donaldson et al., 1972), although physicochemical, biological or immunological evidence for two

  1. Qualitative spectroscopic study of magnetic nozzle flow

    NASA Technical Reports Server (NTRS)

    Umeki, T.; Turchi, P. J.

    1992-01-01

    The physics of the magnetic nozzle flow for a 100-kW-level quasi-steady MPD thruster was studied by photographic spectroscopy focusing on the plasma model in the flow and the acceleration mechanism. Spectroscopic visualization for the flow-species analysis indicates that the plasma-exhaust flow dominated by NII species were confined by the magnetic nozzle effect to collimate the flow for the better thruster performance. Inside the nozzle, the plasma flow was found to be in nonhomogeneous collisional-radiative condition. There appears to be a substantial flow acceleration from the magnetic nozzle inlet to the outlet with slight expansion. This suggests that the flow resembles that of constant area supersonic duct flow with cooling.

  2. Spectroscopic Studies of Abell Clusters

    NASA Astrophysics Data System (ADS)

    Way, Michael Joseph

    The objectives of this work are to use spectroscopic techniques to accurately categorize galaxies as either HII region star forming galaxies or as Active Galactic Nuclei powered via a black hole, and to use radial velocities and projected positions of galaxies in clusters to obtain the total cluster mass and its distribution. The masses and distributions compare well to X-ray mass measurements. The commonly used Dressler, A., Thompson, I. & Shectman, S. 1985, ApJ, 288, 481 technique for discriminating between Active Galactic Nuclei and HII region galaxies uses the measurement of the equivalent width of the emission lines (OII) 3727 A, H/beta, and (OIII) 5007 A. High quality spectra from 42 galaxies were taken and it is shown that their method is not capable of distinguishing between Active Galactic Nuclei and HII region galaxies. The emission line flux from H/beta, (OIII) 5007 A, (OI) 6300 A, H?, (NII) 6583 A, and (SII) 6716+6731 A in combination with the method of Veilleux, S. & Osterbrock, D. E. 1987, ApJS, 63, 295 must be used to accurately distinguish between Active Galactic Nuclei and HII region galaxies. Galaxy radial velocities from spectroscopic data and their projected 2-D positions in clusters are used to obtain robust estimates of the total mass and mass distribution in two clusters. The total mass is calculated using the Virial theorem after removing substructure. The mass distribution is estimated via several robust statistical tests for 1-D, 2-D and 3-D structure. It is shown that the derived mass estimates agree well with those found independently from hot X-ray gas emission in clusters.

  3. A PHOTOMETRIC AND SPECTROSCOPIC STUDY OF DWARF AND GIANT GALAXIES IN THE COMA CLUSTER. I. WIDE-AREA PHOTOMETRIC SURVEY: OBSERVATION AND DATA ANALYSIS1

    E-print Network

    Iye, Masanori

    A PHOTOMETRIC AND SPECTROSCOPIC STUDY OF DWARF AND GIANT GALAXIES IN THE COMA CLUSTER. I. WIDE photometric and spectroscopic survey of wide areas in the Coma cluster, aiming to investigate the properties. Subject headings: galaxies: clusters: general -- galaxies: clusters: individual (Coma) -- galaxies

  4. Spectroscopic analysis of irradiated erythrocytes

    NASA Astrophysics Data System (ADS)

    Selim, Nabila S.; Desouky, Omar S.; Ismail, Nagla M.; Dakrory, Amira Z.

    2011-12-01

    The aim of the present work is to study the effect of gamma radiation on the lipid part of the erythrocyte membrane, and to test the efficiency of lipoic acid as a radioprotector. This effect was evaluated using electron paramagnetic resonance (EPR), and Fourier transform infrared (FT-IR) spectroscopy. The results showed an increase in the number of spin density by 14%, 22% and 65% after exposure to 25, 50 and 100 Gy respectively; whereas there was a decline in the obtained density after incubation with lipoic acid by a factor of approximately 32%. The FT-IR spectra of the irradiated erythrocytes samples showed a marked decrease in the intensity of all characteristic peaks, which increased as the irradiation dose increased. The second-derivative of these spectra, allow the conformationally sensitive membrane acyl chain methylene stretching modes to be separated from the protein (mostly hemoglobin) vibrations that dominate the spectra of intact cells. The 2850 cm -1 band showed changes in the band shape and position after exposure to 50 and 100 Gy. Therefore it can be concluded that the band at 2850 cm -1 only is useful in monitoring the radiation effect of the lipids cell membrane intact cells.

  5. Spectroscopic study in Z-pinch discharge

    SciTech Connect

    Garamoon, A.A.; Saudy, A.H.; Shark, W. [Al-Azhar Univ., Cairo (Egypt)] [and others

    1995-12-31

    The temporal variation of the emitted line intensity has been investigated, and thus an important information about the dynamic ionization stages in the Z-pinch discharge has been studied. Also the electron temperature Te, has been deduced by using a spectroscopic technique.

  6. Quadrupole resonance spectroscopic study of narcotic materials

    NASA Astrophysics Data System (ADS)

    Rayner, Timothy J.; West, Rebecca; Garroway, Allen N.; Lyndquist, R.; Yesinowski, James P.

    1997-02-01

    Bulk narcotic detection systems based upon Quadrupole Resonance Analysis (QRA) technology have a major advantage over imaging technologies, in that QRA is chemical-specific and consequently has a lower rate of false alarms. QRA is a magnetic resonance technology which occurs as a result of the inherent molecular properties of the atomic nuclei in crystalline and amorphous solids. The QRA response is characterized by 1) the precessional frequency of the nucleus, and 2) the nature of the electric field gradient experienced by the nucleus,due to its molecular environment. Another important detection parameter is linewidth, resonant quality. All of these parameters depend on sample purity and manufacturing process. Quantum Magnetics recently carried out a study on the QRA signatures of various narcotic materials with the support of the US Army, US Customs, and the Office of National Drug Control Policy. The aim of the study was to fully characterize the variation in QRA spectroscopic parameters of different samples of cocaine base and cocaine hydrochloride. The results from this study ar discussed here.

  7. Binding of the iminium and alkanolamine forms of sanguinarine to lysozyme: spectroscopic analysis, thermodynamics, and molecular modeling studies.

    PubMed

    Jash, Chandrima; Payghan, Pavan V; Ghoshal, Nanda; Suresh Kumar, Gopinatha

    2014-11-20

    Sanguinarine (SGR) exists in charged iminium (SGRI) and neutral alkanolamine (SGRA) forms. The binding of these two forms to the protein lysozyme (Lyz) was investigated by fluorescence, UV-vis absorbance and circular dichroism spectroscopy, and in silico molecular docking approaches. Binding thermodynamics were studied by microcalorimetry. Both forms of sanguinarine quenched the intrinsic fluorescence of Lyz, but the quenching efficiencies varied on the basis of binding that was derived after correction for an inner-filter effect. The equilibrium binding constants at 25 ± 1.0 °C for the iminium and alkanolamine forms were 1.17 × 10(5) and 3.32 × 10(5) M(-1), respectively, with approximately one binding site for both forms of the protein. Conformational changes of the protein in the presence of SGR were confirmed by absorbance, circular dichroism, three-dimensional fluorescence, and synchronous fluorescence spectroscopy. Microcalorimetry data revealed that SGRI binding is endothermic and predominantly involves electrostatic and hydrophobic interactions, whereas SGRA binding is exothermic and dominated by hydrogen-bonding interactions. The molecular distances (r) of 3.27 and 3.04 nm between the donor (Lyz) and the SGRI and SGRA acceptors, respectively, were calculated according to Förster's theory. These data suggested that both forms were bound near the Trp-62/63 residues of Lyz. Stronger binding of SGRA than SGRI was apparent from the results of both structural and thermodynamic experiments. Molecular docking studies revealed that the putative binding site for the SGR analogues resides at the catalytic site. The docking results are in accordance with the spectroscopic and thermodynamic data, further validating the stronger binding of SGRA over SGRI to Lyz. The binding site is situated near a deep crevice on the protein surface and is close to several crucial amino acid residues, including Asp-52, Glu-35, Trp-62, and Trp-63. This study advances our knowledge of the structural nature and thermodynamic aspects of binding between the putative anticancer alkaloid sanguinarine and lysozyme. PMID:25354369

  8. Synthesis, spectroscopic studies and thermal analysis of charge-transfer complex of 2,2?-bipyridine with 4-hydroxybenzoic acid in different polar solvents

    NASA Astrophysics Data System (ADS)

    Rzokee, Abdulsatar Abduljabbar; Ahmad, Afaq

    2014-11-01

    The charge-transfer (CT) complex formed between 2,2?-bipyridine with 4-hydroxybenzoic acid has been studied in methanol and acetone at room temperature. The charge-transfer complex was characterized on the basis of FT-IR, 1H NMR, XRD studies of the solid CT complex, UV-Visible spectroscopy, thermogravimetric analysis (TGA-DTA) and conductivity and the results were discussed. The particle size and the energy of the charge-transfer complex were also determined. The data obtained from the spectroscopic studies indicate the formation of 1:1 charge-transfer complex, associated with a proton migration from the acceptor to the donor followed by intermolecular hydrogen bonding. The conductivity was found to increase with increase in the concentration of the donor.

  9. FT-IR, FT-Raman, dispersive Raman, NMR spectroscopic studies and NBO analysis of 2-Bromo-1H-Benzimidazol by density functional method

    NASA Astrophysics Data System (ADS)

    Sas, E. B.; Kurt, M.; Karabacak, M.; Poiyamozhi, A.; Sundaraganesan, N.

    2015-02-01

    In this study, geometrical optimization, FT-IR (4000-400 cm-1), FT-Raman (4000-40 cm-1), dispersive Raman (4000-40 cm-1) spectroscopic analysis, electronic structure and 1H and 13C nuclear magnetic resonance (NMR) studies of 2-Bromo-1H-Benzimidazol (abbreviated as 2Br1HB) were undertaken by utilizing DFT/B3LYP with 6-311+G(d,p) basis set. The results of the calculations were applied to simulate spectra of the title compound, which show good agreement with observed spectra. Complete vibrational assignments, analysis and correlations of the fundamental modes for 2Br1HB compound were carried out. Stability of the molecule arising from hyperconjugative interactions, charge delocalization was analyzed using natural bond orbital (NBO) analysis. The molecule orbital contributions were studied by using the total density of states (TDOS), partial density of states (PDOS), and overlap population density of states (OPDOS). The electronic properties like HOMO-LUMO energies and molecular electrostatic potential (MEP) analysis were reported. The calculated HOMO and LUMO energies shows that charge transfer interactions take place within the molecule. Mulliken population analysis on atomic charges was also calculated. Good correlation between the experimental 1H and 13C NMR chemical shifts in DMSO solution and calculated gauge-including atomic orbital (GIAO) shielding tensors were found.

  10. NGC 6067: A spectroscopic study

    NASA Astrophysics Data System (ADS)

    Alonso-Santiago, J.; Negueruela, I.; Marco, A.; Dorda, R.

    2015-05-01

    NGC 6067 is a young open cluster in the Norma Cloud. Its age is around 100 Ma. It hosts a large population of evolved stars: 14 luminous red stars (most of which K Ib supergiants and late-G/early-K giants), 6--8 B giants, two A/F supergiants and two Cepheids (F/G supergiants). All this would imply that NGC 6067 represent one of the best laboratories in the Galaxy to study the evolution of intermediate-mass stars. Thackeray et al. (1962, MNRAS 124, 445T) performed the first complete study of this cluster but it has been poorly studied since then. We obtained high resolution echelle spectra (R=48000) using FEROS (Fiber Extended Range Optical Spectrograph) mounted on the ESO 2.2 m telescope at La Silla Observatory (Chile) in May 2011. Here we present preliminary results based on this spectroscopy and the UBV photometry listed in Terndrup & Pinsonneault (2007, ApJ 671, 1640).

  11. Spectroscopic studies of the transplutonium elements

    SciTech Connect

    Carnall, W.T.; Conway, J.G.

    1983-01-01

    The challenging opportunity to develop insights into both atomic structure and the effects of bonding in compounds makes the study of actinide spectroscopy a particularly fruitful and exciting area of scientific endeavor. It is also the interpretation of f-element spectra that has stimulated the development of the most sophisticated theoretical modeling attempted for any elements in the periodic table. The unique nature of the spectra and the wealth of fine detail revealed make possible sensitive tests of both physical models and the results of Hartree-Fock type ab initio calculations. This paper focuses on the unique character of heavy actinide spectroscopy. It discusses how it differs from that of the lighter member of the series and what are the special properties that are manifested. Following the introduction, the paper covers the following: (1) the role of systematic studies and the relationships of heavy-actinide spectroscopy to ongoing spectroscopic investigations of the lighter members of the series; (2) atomic (free-ion) spectra which covers the present status of spectroscopic studies with transplutonium elements, and future needs and directions in atomic spectroscopy; (3) the spectra of actinide compounds which covers the present status and future directions of spectroscopic studies with compounds of the transplutonium elements; and other spectroscopies. 1 figure, 2 tables.

  12. Spectroscopic Analysis of Planetary Host Stars

    NASA Astrophysics Data System (ADS)

    Rittipruk, P.; Yushchenko, A.; Kang, Y. W.

    2014-08-01

    We observed the high resolution spectra of extra-solar planet host stars. The spectroscopic data of host stars were observed using the CHIRON echelle spectrometer and R-C Spectrograph for magnetic activity on the SMART-1.5 meter telescope at CTIO, Chile. The analysis of spectroscopic data was performed using URAN and SYNTHE programs. These spectra allow us to determine the effective temperatures, surface gravities, microturbulent velocities and, finally, the chemical composition of the hosts was obtained by spectrum synthesis. One of the targets, namely HD 47536, the host of two planets, appeared to be a halo star with overabundances of neutron capture elements. The effective temperature and the surface gravity of this star are 4400 K and log=1.5 respectively, the iron is underabundant by 0.6 dex. The heavy elements (up to thorium, Z=90) show the overabundances with respect to iron. The signs of accretion of interstellar gas are found in the atmosphere of this star.

  13. Nuclear spectroscopic studies. Progress report

    SciTech Connect

    Bingham, C.R.; Guidry, M.W.; Riedinger, L.L.; Sorensen, S.P.

    1993-02-08

    The Nuclear Physics group at the University of Tennessee, Knoxville is involved in several aspects of heavy-ion physics including both nuclear structure and reaction mechanisms. While our main emphasis is on experimental problems involving heavy-ion accelerators, we have maintained a strong collaboration with several theorists in order to best pursue the physics of our measurements. During the last year we have led several experiments at the Holifield Heavy Ion Research Facility and participated in others at Argonne National Laboratory. Also, we continue to be very active in the collaboration to study ultra-relativistic heavy ion physics utilizing the SPS accelerator at CERN in Geneva, Switzerland and in a RHIC detector R&D project. Our experimental work is in four broad areas: (1) the structure of nuclei at high angular momentum, (2) heavy-ion induced transfer reactions, (3) the structure of nuclei far from stability, and (4) ultra-relativistic heavy-ion physics. The results of studies in these particular areas will be described in this document in sections IIA, IIB, IIC, and IID, respectively. Areas (1), (3), and (4) concentrate on the structure of nuclear matter in extreme conditions of rotational motion, imbalance of neutrons and protons, or very high temperature and density. Area (2) pursues the transfer of nucleons to states with high angular momentum, both to learn about their structure and to understand the transfer of particles, energy, and angular momentum in collisions between heavy ions. An important component of our program is the strong emphasis on the theoretical aspects of nuclear structure and reactions.

  14. Spectroscopic Chemical Analysis Methods and Apparatus

    NASA Technical Reports Server (NTRS)

    Hug, William F.; Reid, Ray D.

    2012-01-01

    This invention relates to non-contact spectroscopic methods and apparatus for performing chemical analysis and the ideal wavelengths and sources needed for this analysis. It employs deep ultraviolet (200- to 300-nm spectral range) electron-beam-pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor lightemitting devices, and hollow cathode metal ion lasers. Three achieved goals for this innovation are to reduce the size (under 20 L), reduce the weight [under 100 lb (.45 kg)], and reduce the power consumption (under 100 W). This method can be used in microscope or macroscope to provide measurement of Raman and/or native fluorescence emission spectra either by point-by-point measurement, or by global imaging of emissions within specific ultraviolet spectral bands. In other embodiments, the method can be used in analytical instruments such as capillary electrophoresis, capillary electro-chromatography, high-performance liquid chromatography, flow cytometry, and related instruments for detection and identification of unknown analytes using a combination of native fluorescence and/or Raman spectroscopic methods. This design provides an electron-beampumped semiconductor radiation-producing method, or source, that can emit at a wavelength (or wavelengths) below 300 nm, e.g. in the deep ultraviolet between about 200 and 300 nm, and more preferably less than 260 nm. In some variations, the method is to produce incoherent radiation, while in other implementations it produces laser radiation. In some variations, this object is achieved by using an AlGaN emission medium, while in other implementations a diamond emission medium may be used. This instrument irradiates a sample with deep UV radiation, and then uses an improved filter for separating wavelengths to be detected. This provides a multi-stage analysis of the sample. To avoid the difficulties related to producing deep UV semiconductor sources, a pumping approach has been developed that uses ballistic electron beam injection directly into the active region of a wide bandgap semiconductor material.

  15. A Spectroscopic Study of Open Cluster Candidates

    NASA Astrophysics Data System (ADS)

    Hamm, Karen; Beaton, R.; Zasowski, G.; Damke, G.; Majewski, S. R.; Frinchaboy, P. M.; Schiavon, R. P.; Carlberg, J. K.

    2013-01-01

    The known catalog of well studied Galactic open clusters has proven to be a powerful tool for exploring the dynamics, abundance patterns, and star formation history of the Galactic disk. This catalog, however, is far from complete and the exploration of newly discovered or poorly studied systems continues to augment our understanding of the Galaxy. We report on new spectroscopic data obtained for six previously unknown or unstudied open star cluster candidates in the outer Milky Way disk. These cluster candidates were visually identified using mid-infrared images taken as part of the GLIMPSE-360 Spitzer-IRAC survey and subsequently found to have little or no analysis in the existing literature. Near- and mid-infrared photometry (2MASS+IRAC) were used to isolate potential cluster member stars, and then fundamental cluster parameters were determined by comparing member candidate color-magnitude distributions to theoretical isochrones. To confirm cluster membership and improve the derived parameters for the clusters, we obtained spectroscopy to determine radial velocities and mean chemical abundances. Three of the clusters (FSR 0494, FSR 0665, and one newly discovered open cluster) were targeted as part of the APOGEE survey, resulting in high-resolution ( 22,500) H-band spectra. Low-resolution ( 1200) optical spectroscopy was obtained for candidate members of three additional clusters (Berkeley 14, Berkeley 14a, and SAI 24) with the APO 3.5m telescope and DIS spectrograph. We present our results on the clusters' membership, mean chemical abundances, and mean kinematics, and we revisit our previous results of the fundamental cluster parameters using revised membership determinations.

  16. Primordial matter in the outer solar system - A study of its chemical composition from remote spectroscopic analysis

    NASA Astrophysics Data System (ADS)

    Encrenaz, T.

    1984-06-01

    Spectroscopic data from ground-based, IUE and Voyager instrumentation are examined for evidence of primordial matter in the giant planets and small bodies of the solar system. Searches are conducted for primitive matter to determine conditions in the early solar system as evidenced by objects that have not changed much since then. The H2/He and D/H ratio on Jupiter has been accepted as the same for the early solar system nebula. A factor of two carbon enrichment on Jupiter and Saturn supports theories of planetary formation that posit core formation first and later accretion of an atmosphere. The Halley comet fly-bys are expected to yield data on the physical and chemical properties of dust in the Primordial Nebula.

  17. Molecular structure investigation and spectroscopic studies on 2,3-difluorophenylboronic acid: a combined experimental and theoretical analysis.

    PubMed

    Karabacak, Mehmet; Kose, Etem; Atac, Ahmet; Ali Cipiloglu, M; Kurt, Mustafa

    2012-11-01

    This work presents the characterization of 2,3-difluorophenylboronic acid (abbreviated as 2,3-DFPBA, C(6)H(3)B(OH)(2)F(2)) by quantum chemical calculations and spectral techniques. The spectroscopic properties were investigated by FT-IR, FT-Raman UV-Vis, (1)H and (13)C nuclear magnetic resonance (NMR) techniques. The FT-IR spectrum (4000-400 cm(-1)) and the FT-Raman spectrum (3500-10 cm(-1)) in the solid phase were recorded for 2,3-DFPBA. The (1)H and (13)C NMR spectra were recorded in DMSO solution. The UV-Vis absorption spectra of the 2,3-DFPBA that dissolved in water and ethanol were recorded in the range of 200-400 nm. There are four possible conformers for this molecule. The computational results diagnose the most stable conformer of the 2,3-DFPBA as the trans-cis form. The structural and spectroscopic data of the molecule were obtained for all four conformers from DFT (B3LYP) with 6-311++G (d,p) basis set calculations. The theoretical wavenumbers were scaled and compared with experimental FT-IR and FT-Raman spectra. The complete assignments were performed on the basis of the experimental results and total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method, interpreted in terms of fundamental modes. We obtained good consistency between experimental and theoretical spectra. (13)C and (1)H NMR chemical shifts of the molecule were calculated by using the gauge-invariant atomic orbital (GIAO) method. The electronic properties, such as excitation energies, absorption wavelengths, HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. Finally the calculation results were analyzed to simulate infrared, Raman, NMR and UV spectra of the 2,3-DFPBA which show good agreement with observed spectra. PMID:22902933

  18. Spectroscope

    NSDL National Science Digital Library

    McDonald Observatory

    2008-01-01

    In this activity, learners construct their own spectroscope as they explore and observe spectra from familiar light sources. Learners can be challenged to make technological improvements to their spectroscopes and/or participate in extension activities that expand their understanding of different kinds of spectra and sharpen their observing skills.

  19. Vibrational spectroscopic studies of mesna and dimesna

    NASA Astrophysics Data System (ADS)

    Li, Ying-Sing; Wang, Yu; Church, Jeffrey S.; Garzena, Fabio; Zhang, Zanxing; An, Danqui

    2003-06-01

    Raman, and infrared spectra of mesna and dimesna have been collected in the present spectroscopic studies. Based on the group frequencies, relative intensities and Raman depolarization measurements, some vibrational assignments have been suggested. For both mesna and dimesna, at least two rotational conformers have been identified. Adsorption behavior was investigated from the recorded surface-enhanced Raman scattering (SERS) spectra. It was found that both mesna and dimesna adsorbed as thiolate on silver sol particles with the cleavage of the S?H bond in mesna and the S?S bond in dimesna. For the adsorbed thiolate, two conformers existed in the adsorption state.

  20. Spectroscopic analysis and charge transfer interaction studies of 4-benzyloxy-2-nitroaniline insecticide: A density functional theoretical approach

    NASA Astrophysics Data System (ADS)

    Arul Dhas, D.; Hubert Joe, I.; Roy, S. D. D.; Balachandran, S.

    2015-01-01

    A widespread exploration on the intra-molecular charge transfer interaction through an efficient ?-conjugated path from a strong electron-donor group (amino) to a strong electron-acceptor group (nitro) has been carried out using FTIR, FT-Raman, UV-Vis, fluorescence and NMR spectra on insecticide compound 4-benzyloxy-2-nitroaniline. Density functional theory method is used to determine optimized molecular geometry, harmonic vibrational wavenumbers and intensities using 6-311G(d,p) basis set by means of Gaussian 09W program suit. A comprehensive investigation on the sp2 to sp3 hybridization and non-planarity property has been performed. Natural bond orbital analysis is used to study the existence of C-H⋯O, N-H⋯O and C-H⋯? proper and improper hydrogen bonds. The HOMO and LUMO analysis reveals the possibility of charge transfer within the molecule. A complete assignment of the experimental absorption peaks in the ultraviolet region has also been performed. Isotropic chemical shifts of 13C, 1H, 15N and 18O NMR and nuclear spin-spin coupling constants have been computed using the gauge-invariant atomic orbital method. The biological activity of substituent amino and nitro groups are evident from the hydrogen bonds through which the target amino acids are linked to the drug as evidenced from molecular docking.

  1. Study on the interactions of trans-resveratrol and curcumin with bovine ?-lactalbumin by spectroscopic analysis and molecular docking.

    PubMed

    Mohammadi, Fakhrossadat; Moeeni, Marzieh

    2015-05-01

    The ability of bovine ?-lactalbumin (BLA) as a whey protein to carry curcumin and trans-resveratrol as two natural polyphenolic compounds was investigated by fluorescence quenching measurements and docking studies. Curcumin is the bioactive component of turmeric and trans-resveratrol is abundant in different types of fruits and vegetables. The binding parameters such as binding constants and the number of substantive binding sites have been estimated from the analysis of fluorescence quenching measurements. The differences in affinities of curcumin and trans-resveratrol for BLA were compared. The short Förster's distance (r) between donor (BLA) and acceptor (curcumin and trans-resveratrol) and also the binding constant values demonstrated the strong interaction between these two polyphenolic compounds and BLA. The thermodynamic parameters were obtained from the fluorescence quenching measurements in different temperatures. It can be concluded from the sign and magnitude of ?H and ?S that the final ligand-protein complexes were stabilized by hydrogen bonds. The considerable change in microregion of the Trp residues in BLA is observed upon the binding of the trans-resveratrol to BLA by synchronous fluorescence while this conformation alteration was not observed upon interaction with curcumin. It was indicated by docking studies that curcumin come closer to the Trp-118 than to other tryptophans and trans-resveratrol binds in the vicinity of Trp-60 and Trp-104. Docking studies indicated that these two compounds bind to BLA by two hydrogen bonds. The calculated distances between bound ligands and tryptophans obtained by docking studies were in agreement with fluorescence resonance energy transfer results. Therefore, the strong interaction of curcumin and trans-resveratrol with BLA was confirmed by theoretical and experimental studies. These achieved results may be applicable in the milk industry and drug formulation. PMID:25746281

  2. Spectroscope

    NSDL National Science Digital Library

    Oakland Discovery Center

    2011-01-01

    In this activity (posted on March 12, 2011), learners follow the steps to construct a spectroscope, a tool used to analyze light and color. First, learners use relatively simple materials to construct the device. Then, learners look through their spectroscopes at a variety of different light sources including incandescents, LEDs, compact fluorescents, sun light, etc. and compare what they observe. This resource includes a few examples of how certain chemicals form different colors of light.

  3. Molecular structure and spectroscopic analysis of 1,4-Bis(1-methyl-2-benzimidazolyl)benzene; XRD, FT-IR, dispersive-Raman, NMR and DFT studies.

    PubMed

    Eren, Bilge; Unal, Arslan

    2013-02-15

    This study reports the structural characterization of a bis-benzimidazole derivative, 1,4-Bis(1-methyl-2-benzimidazolyl)benzene (BMBB), by using spectroscopic and quantum chemical methods. The BMBB molecule was synthesized under microwave conditions and was characterized by using single-crystal X-ray diffraction, FT-IR, dispersive Raman and NMR spectroscopies. The potential energy surface scan study was carried out for the conformation of the theoretical structure. Quantum chemical calculations of relative energies, molecular geometry, vibrational wavenumbers, frontier molecular orbitals, atomic charges and gauge including atomic orbital (GIAO) (1)H and (13)C-NMR chemical shifts of the compound were carried out by using density functional method (DFT) at B3LYP/6-311++G(d,p) theory level. The complete assignments of the vibrational modes were performed with DFT calculations combined with scaled quantum mechanics force field (SQMFF) methodology. A satisfactory consistency between the experimental and theoretical findings was obtained. On account of the relative energies, population analysis and XRD results, the most stable conformational form of the molecule was also determined. PMID:23261617

  4. DFT computations and spectroscopic analysis of p-bromoacetanilide

    NASA Astrophysics Data System (ADS)

    Gnanasambandan, T.; Gunasekaran, S.; Seshadri, S.

    2014-03-01

    This work presents the characterization of p-bromoacetanilide (PBA) by quantum chemical calculations and spectral techniques. The spectroscopic properties were investigated by FT-IR, FT-Raman and UV-Vis techniques. The structural and spectroscopic data of the molecule were obtained from B3LYP/6-311++ G(d,p) and MPW1PW91/6-311++G(d,p) basis set calculations. The theoretical wavenumbers were scaled and compared with experimental FT-IR and FT-Raman spectra. The complete assignments were performed on the basis of the normal co-ordinate analysis (NCA), experimental results and potential energy distribution (PED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method, interpreted in terms of fundamental modes. The stability of molecule has been analyzed by NBO/NLMO analysis. The molecular orbital contributions were studied by using the density of states. The electronic properties like UV-Vis spectral analysis and HOMO-LUMO energies were reported. The calculated HOMO and LUMO energies shows that charge transfer interactions taking place within the molecule. Mulliken population analysis on atomic charges, Statistical thermodynamic properties at various temperatures of the PBA is also calculated.

  5. DFT computations and spectroscopic analysis of p-bromoacetanilide.

    PubMed

    Gnanasambandan, T; Gunasekaran, S; Seshadri, S

    2014-03-25

    This work presents the characterization of p-bromoacetanilide (PBA) by quantum chemical calculations and spectral techniques. The spectroscopic properties were investigated by FT-IR, FT-Raman and UV-Vis techniques. The structural and spectroscopic data of the molecule were obtained from B3LYP/6-311++ G(d,p) and MPW1PW91/6-311++G(d,p) basis set calculations. The theoretical wavenumbers were scaled and compared with experimental FT-IR and FT-Raman spectra. The complete assignments were performed on the basis of the normal co-ordinate analysis (NCA), experimental results and potential energy distribution (PED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method, interpreted in terms of fundamental modes. The stability of molecule has been analyzed by NBO/NLMO analysis. The molecular orbital contributions were studied by using the density of states. The electronic properties like UV-Vis spectral analysis and HOMO-LUMO energies were reported. The calculated HOMO and LUMO energies shows that charge transfer interactions taking place within the molecule. Mulliken population analysis on atomic charges, Statistical thermodynamic properties at various temperatures of the PBA is also calculated. PMID:24334018

  6. Spectroscopic study of solar twins and analogues

    NASA Astrophysics Data System (ADS)

    Datson, Juliet; Flynn, Chris; Portinari, Laura

    2015-02-01

    Context. Many large stellar surveys have been and are still being carried out, providing huge amounts of data, for which stellar physical parameters will be derived. Solar twins and analogues provide a means to test the calibration of these stellar catalogues because the Sun is the best-studied star and provides precise fundamental parameters. Solar twins should be centred on the solar values. Aims: This spectroscopic study of solar analogues selected from the Geneva-Copenhagen Survey (GCS) at a resolution of 48 000 provides effective temperatures and metallicities for these stars. We test whether our spectroscopic parameters, as well as the previous photometric calibrations, are properly centred on the Sun. In addition, we search for more solar twins in our sample. Methods: The methods used in this work are based on literature methods for solar twin searches and on methods we developed in previous work to distinguish the metallicity-temperature degeneracies in the differential comparison of spectra of solar analogues versus a reference solar reflection spectrum. Results: We derive spectroscopic parameters for 148 solar analogues (about 70 are new entries to the literature) and verify with a-posteriori differential tests that our values are well-centred on the solar values. We use our dataset to assess the two alternative calibrations of the GCS parameters; our methods favour the latest revision. We show that the choice of spectral line list or the choice of asteroid or time of observation does not affect the results. We also identify seven solar twins in our sample, three of which are published here for the first time. Conclusions: Our methods provide an independent means to differentially test the calibration of stellar catalogues around the values of a well-known benchmark star, which makes our work interesting for calibration tests of upcoming Galactic surveys. Based on observations made with ESO Telescopes at the La Silla Observatory under programme ID 077.D-0525 and 090.D-0133.Table 1 is also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/574/A124Full Table 5 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/574/A124

  7. Spectroscopic analysis of the superluminous HD327083

    NASA Astrophysics Data System (ADS)

    Machado, M. A. D.; de Araujo, F. X.

    2003-08-01

    New optical high-resolution (R»50 000) spectra of the star HD 327083 are reported in this work. The Balmer and Fe ii lines show P Cygni profiles, while He i lines are all in pure absorption, ressembling the spectra of the Luminous Blue Variable HR Carinae. However, the blue absorption components of the Balmer lines are more pronounced in HD 327083 than in HR Carinae, indicating a more intense mass loss. We performed a spectroscopic analysis of the Balmer lines (Ha, Hb, Hg and Hd) with a non-LTE code to analyse extended atmospheres. The basic assumptions are: spherical symmetry, stationary and homogeneity. The density structure r(r) is related to the mass loss rate and the velocity field via the equation of continuity. The velocity field is pre-specified in an ad-hoc way as a b-type law. The statistical equilibrium equations are solved using the escape probability method for calculating the source function while the transfer equation is solved using the "SEI" - Sobolev Exact Integration - method. Due the large number of "free" parameters we constructed a primary grid of models (theoretical profiles) based on the results provided by theoretical evolutionary paths. In other words, the input parameters L«, T«, and AHe are those provided as output data of the evolutive models. We chose the tracks of the Geneve group since they are available in the WEB in the range of initial masses from Mi = 25 M¤ to 120 M¤. The derived stellar parameters for HD 327083 are: log(L«/L¤) = 6.0, T« = 11500 K, = 8.0´10-5 M¤/yr and He/H = 0.2 (by number). From these results and considering the similarity with HR Carinae we concluded that HD 327083 is a superluminous object in an evolved phase of an evolutive track of MZAMS~ 60 M¤. It might be a B[e] Supergiant but it is most likely to be about to enter in a typical LBV phase.

  8. Spectroscopic study of natural quartz samples

    NASA Astrophysics Data System (ADS)

    Nunes, Eduardo H. M.; Lameiras, Fernando S.; Houmard, Manuel; Vasconcelos, Wander L.

    2013-09-01

    In this work we performed a spectroscopic characterization of natural amethyst, citrine, and prasiolite samples from different localities. These materials were examined by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-visible spectroscopy (UV-vis), electron paramagnetic resonance (EPR), and inductively coupled plasma atomic emission spectrometry (ICP-AES). Samples were used in this study in as-received, gamma-irradiated, UV-irradiated, and heat-treated conditions. We observed the changes in the FTIR, UV-vis, and EPR spectra of these samples as a function of the condition they were analyzed. We noticed that gamma radiation had a great effect on the color of amethyst and citrine samples used in this work. It was observed that light colored samples showed a deepening of their colors upon gamma-irradiation and a bleaching upon heat treatment at 450 °C. However, we observed that gamma radiation had a slight effect on the color of citrine. UV-irradiations revealed that the coloration of both amethyst and prasiolite can be bleached by UV radiation. On the other hand, the color of citrine was not affected by UV radiation.

  9. Spectroscopic studies of tantalum doped borate glasses

    NASA Astrophysics Data System (ADS)

    Sharada, M.; Suresh Babu, D.

    2012-10-01

    Glasses with formula 30Li2O 60B2O3xTa2O5 (10-x) Bi2O3 for x=0, 2, 4, 6 and 8 were prepared via normal melt quenching technique and characterized by refractive index and MDSC. Refractive index (?) and glass transition temperature (Tg) are found to increase with increase in dopant concentration. Impedance spectra of the samples were recorded in the frequency range 100 Hz-5 MHz in the temperature range 175-275 °C. The plots are typical of those recorded for disordered systems. Conductivities and relaxation times are found to follow Arrhenius type of relation and activation energies are calculated. Optical absorption spectra were recorded in the wavelength range 200-900 nm range from which cutoff wavelength (?c) and optical band gap energy (Eg) are evaluated. ?c is found to decrease while Eg to increase with increase in composition. FTIR spectra of the samples were recorded in the frequency range 400-1500 cm-1 which exhibit characteristic bands corresponding to BO3, BO4 stretching vibrations and BO bending vibration. Tightening of the structure is indicated by increase in the vibration of BO3 at the cost of BO4 for 8 mol% of Ta2O5. This is in support of the highest value of Tg for this sample among the series. Raman spectra of the samples were recorded in the frequency range 200-1200 cm-1. With successive addition of Ta2O5, increase in the vibration of Ta-O groups TaO6 groups to be responsible for observed increase in ? and Tg. An attempt is made to prepare tantalum doped borate glasses and study them by spectroscopic techniques.

  10. Indentation device for in situ Raman spectroscopic and optical studies.

    PubMed

    Gerbig, Y B; Michaels, C A; Forster, A M; Hettenhouser, J W; Byrd, W E; Morris, D J; Cook, R F

    2012-12-01

    Instrumented indentation is a widely used technique to study the mechanical behavior of materials at small length scales. Mechanical tests of bulk materials, microscopic, and spectroscopic studies may be conducted to complement indentation and enable the determination of the kinetics and physics involved in the mechanical deformation of materials at the crystallographic and molecular level, e.g., strain build-up in crystal lattices, phase transformations, and changes in crystallinity or orientation. However, many of these phenomena occurring during indentation can only be observed in their entirety and analyzed in depth under in situ conditions. This paper describes the design, calibration, and operation of an indentation device that is coupled with a Raman microscope to conduct in situ spectroscopic and optical analysis of mechanically deformed regions of Raman-active, transparent bulk material, thin films or fibers under contact loading. The capabilities of the presented device are demonstrated by in situ studies of the indentation-induced phase transformations of Si thin films and modifications of molecular conformations in high density polyethylene films. PMID:23278025

  11. Indentation device for in situ Raman spectroscopic and optical studies

    NASA Astrophysics Data System (ADS)

    Gerbig, Y. B.; Michaels, C. A.; Forster, A. M.; Hettenhouser, J. W.; Byrd, W. E.; Morris, D. J.; Cook, R. F.

    2012-12-01

    Instrumented indentation is a widely used technique to study the mechanical behavior of materials at small length scales. Mechanical tests of bulk materials, microscopic, and spectroscopic studies may be conducted to complement indentation and enable the determination of the kinetics and physics involved in the mechanical deformation of materials at the crystallographic and molecular level, e.g., strain build-up in crystal lattices, phase transformations, and changes in crystallinity or orientation. However, many of these phenomena occurring during indentation can only be observed in their entirety and analyzed in depth under in situ conditions. This paper describes the design, calibration, and operation of an indentation device that is coupled with a Raman microscope to conduct in situ spectroscopic and optical analysis of mechanically deformed regions of Raman-active, transparent bulk material, thin films or fibers under contact loading. The capabilities of the presented device are demonstrated by in situ studies of the indentation-induced phase transformations of Si thin films and modifications of molecular conformations in high density polyethylene films.

  12. Spectroscopic analysis of cinnamic acid using quantum chemical calculations

    NASA Astrophysics Data System (ADS)

    Vinod, K. S.; Periandy, S.; Govindarajan, M.

    2015-02-01

    In this present study, FT-IR, FT-Raman, 13C NMR and 1H NMR spectra for cinnamic acid have been recorded for the vibrational and spectroscopic analysis. The observed fundamental frequencies (IR and Raman) were assigned according to their distinctiveness region. The computed frequencies and optimized parameters have been calculated by using HF and DFT (B3LYP) methods and the corresponding results are tabulated. On the basis of the comparison between computed and experimental results assignments of the fundamental vibrational modes are examined. A study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies, were performed by HF and DFT methods. The alternation of the vibration pattern of the pedestal molecule related to the substitutions was analyzed. The 13C and 1H NMR spectra have been recorded and the chemical shifts have been calculated using the gauge independent atomic orbital (GIAO) method. The Mulliken charges, UV spectral analysis and HOMO-LUMO analysis of have been calculated and reported. The molecular electrostatic potential (MEP) was constructed.

  13. Applications of Linear Systems Theory to Spectroscopic Instrumentation and Multivariate Analysis

    Microsoft Academic Search

    Chris L. Erickson

    1993-01-01

    This research employs linear systems theory to design novel spectroscopic instruments, explain their operation, and provide insight into methods of data analysis. The first study examines the relationship between digital filtering, a technique based on linear systems theory, and multivariate regression, a statistical method. The study focuses on quantitative property estimation for one -sided, repetitive, linear, shift-invariant systems, and compares

  14. Raman spectroscopic study of “The Malatesta”: A Renaissance painting?

    NASA Astrophysics Data System (ADS)

    Edwards, Howell G. M.; Vandenabeele, Peter; Benoy, Timothy J.

    2015-02-01

    Raman spectroscopic analysis of the pigments on an Italian painting described as a "Full Length Portrait of a Gentleman", known also as the "Malatesta", and attributed to the Renaissance period has established that these are consistent with the historical research provenance undertaken earlier. Evidence is found for the early 19th Century addition of chrome yellow to highlighted yellow ochre areas in comparison with a similar painting executed in 1801 by Sir Thomas Lawrence of John Kemble in the role of Hamlet, Prince of Denmark. The Raman data are novel in that no analytical studies have previously been made on this painting and reinforces the procedure whereby scientific analyses are accompanied by parallel historical research.

  15. Raman spectroscopic study of "The Malatesta": a Renaissance painting?

    PubMed

    Edwards, Howell G M; Vandenabeele, Peter; Benoy, Timothy J

    2015-02-25

    Raman spectroscopic analysis of the pigments on an Italian painting described as a "Full Length Portrait of a Gentleman", known also as the "Malatesta", and attributed to the Renaissance period has established that these are consistent with the historical research provenance undertaken earlier. Evidence is found for the early 19th Century addition of chrome yellow to highlighted yellow ochre areas in comparison with a similar painting executed in 1801 by Sir Thomas Lawrence of John Kemble in the role of Hamlet, Prince of Denmark. The Raman data are novel in that no analytical studies have previously been made on this painting and reinforces the procedure whereby scientific analyses are accompanied by parallel historical research. PMID:25194320

  16. [Studies on metal allergy in the field of dentistry--treatment with application of X-ray fluorescence spectroscope analysis in detection of allergen metals].

    PubMed

    Suzuki, N

    1994-03-01

    The most effective method to treat metal allergy may be allergen elimination. Information on the exact location of the allergens becomes essential for this treatment. An XRFS (X-ray fluorescence spectroscope) was used for the detection of such elements and applied for the treatment of these patients. 1. Evaluation of the apparatus preceding its clinical application proved that the reliability and the detection limit for pure elements were comparative to those of the Electron Probe Microanalyzer. A notable decrease in the emitted X-ray intensity was observed when a sample was analyzed through a medium with thickness of more than 5 mm. 2. The analysis results of the restorations showed that the most frequently used alloys were Ag-Sn-Hg amalgams, Au-Ag-Pd alloys and Ag alloys. Some of the elements with high prevalence rates were Ag, Cu, Zn, Au, Pd, Sn, and Hg. 3. Personal and household items suspected of containing allergen metals were analyzed. Some of the frequently detected elements were Fe, Cu, Mn, Zn, Ni, Cr, and Au. 4. With XRFS, analysis of bulk metals and those samples in various forms became possible. A clinical case with the lesion resolved after the allergen elimination was reported. This proved that the use of XRFS enabled us to deal more definitely and effectively towards metal allergy. PMID:8163875

  17. Optical trapping and binding in air: Imaging and spectroscopic analysis

    SciTech Connect

    Guillon, Marc [Laboratoire d'Interferometrie Stellaire et Exoplanetaire, Observatoire de Haute Provence, 04870 Saint Michel l'Observatoire (France); Stout, Brian [Case 161, Institut Fresnel, Faculte des Sciences et Techniques de St. Jerome, 13397 Marseille cedex 20 (France)

    2008-02-15

    We report on an experimental study of direct and spectroscopic imaging of optically trapped Mie droplets in air. The scattering of the trapping beams gives glare points at the droplets' azimuths. Spectroscopic measurements involving polarized light are performed to precisely determine both the droplet sizes and refraction index using Mie scattering theory. Experimental pictures are compared to rigorous numerical simulations. We also include some results on imaging of whispering gallery resonances and conclude with a brief discussion on the possibility of efficiently exciting whispering gallery resonances via radiative coupling.

  18. ALS 2883: Analysis of spectroscopic features

    NASA Astrophysics Data System (ADS)

    Silva, A. R.; Levenhagen, R. S.; Künzel, R.; Leister, N. V.

    2014-10-01

    ALS 2883 (RA 13^{h} 02^{m} 47^{s}, DEC -63^{o} 50' 08'', M_{v} 10.1) is the first known radio pulsar with an emission B-type companion system, discovered in 1992. The Be companion of ALS 2883 has all line profiles in the visible range in emission. This emission is a common hallmark among many Be stars, and this effect is thought to be due to the presence of a circumstellar environment. Also, the star is orbiting a X-ray source as has been detected by the XMM-Newton Science Operation Center. In this study, we present the observations of ALS 2883 made at the OPD/LNA 1.60 m telescope with the Coudé spectrograph in the range 4000 to 5000 Å and S/N simeq 200, performed in April 2011. First-order estimations of T_{eff} and log g parameters have been performed through Johnson's UBV and JHK photometric calibrations. Projected rotation velocity V sin i has been estimated through the mean of the first zeroes of the Fourier transforms of neutral helium rotation profiles adopting linear, quadratic and square-root limb-darkening laws. The physical conditions of the circumstellar envelope were estimated through the solution of the radiative transport equation assuming local thermodynamic equilibrium within a disk-shaped circumstellar environment with a Keplerian velocity field. The radiative transport equation is solved assuming the Roche model as a boundary condition in the circumstellar environment. Iterating the computations with a downhill-simplex algorithm, this analysis leads to a best solution for an envelope with T simeq 9500 K, gas density ? simeq 2 × 10^{-15} g.cm^{-3}, internal radius r_{i} simeq 8 R_{odot} and external radius r_e simeq 30 R_{odot}, rotating with V_{rot} simeq 140 km.s^{-1} and expanding with V_{exp} simeq 90 km.s^{-1}.

  19. Absorption spectroscopic study of EDA complexes of.

    PubMed

    Bhattacharya, S; Nayak, S K; Chattopadhyay, S K; Banerjee, M; Mukherjee, A K

    2001-02-01

    [70]Fullerene has been shown to form 1:1 molecular complexes with toluene, p-xylene, m-xylene, 1,2,4,5-tetramethyl benzene (durene) and pentamethyl benzene (PMB) in CCl4 medium by absorption spectroscopic method. Isosbestic points have been detected in case of complexes with PMB and durene. Charge transfer absorption band could not be detected but the intensity of the broad absorption band of C70 in CCl4 decreases systematically with increase in the concentration of the added methylbenzenes. From this trend the formation constants (Kc) of the complexes have been determined at three different wavelengths. The constancy of Kc with respect to change in the wavelength of measurement supports the view that complex of a single stoichiometry (1:1) is formed in each case. PMID:11206565

  20. Comparative Analysis of Atmospheric Parameters Obtained from the Photometric and Spectroscopic Techniques

    NASA Astrophysics Data System (ADS)

    Genest-Beaulieu, C.; Bergeron, P.; Darveau-Bernier, A.

    2015-06-01

    We present a comparative analysis of atmospheric parameters obtained with the so-called photometric and spectroscopic techniques using the DA white dwarfs identified in the Data Release 7 of the Sloan Digital Sky Survey. We also exploit the sensitivity of the Balmer jump to surface gravity, using the (u–g) color index, to study the well known high-log g problem.

  1. Nonplanar property study of antifungal agent tolnaftate-spectroscopic approach

    NASA Astrophysics Data System (ADS)

    Arul Dhas, D.; Hubert Joe, I.; Roy, S. D. D.; Balachandran, S.

    2011-09-01

    Vibrational analysis of the thionocarbamate fungicide tolnaftate which is antidermatophytic, antitrichophytic and antimycotic agent, primarily inhibits the ergosterol biosynthesis in the fungus, was carried out using NIR FT-Raman and FTIR spectroscopic techniques. The equilibrium geometry, various bonding features, harmonic vibrational wavenumbers and torsional potential energy surface (PES) scan studies have been computed using density functional theory method. The detailed interpretation of the vibrational spectra has been carried out with the aid of VEDA.4 program. Vibrational spectra, natural bonding orbital (NBO) analysis and optimized molecular structure show the clear evidence for electronic interaction of thionocarbamate group with aromatic ring. Predicted electronic absorption spectrum from TD-DFT calculation has been compared with the UV-vis spectrum. The Mulliken population analysis on atomic charges and the HOMO-LUMO energy were also calculated. Vibrational analysis reveals that the simultaneous IR and Raman activation of the C-C stretching mode in the phenyl and naphthalene ring provide evidence for the charge transfer interaction between the donor and acceptor groups and is responsible for its bioactivity as a fungicide.

  2. Nonplanar property study of antifungal agent tolnaftate-spectroscopic approach.

    PubMed

    Dhas, D Arul; Joe, I Hubert; Roy, S D D; Balachandran, S

    2011-09-01

    Vibrational analysis of the thionocarbamate fungicide tolnaftate which is antidermatophytic, antitrichophytic and antimycotic agent, primarily inhibits the ergosterol biosynthesis in the fungus, was carried out using NIR FT-Raman and FTIR spectroscopic techniques. The equilibrium geometry, various bonding features, harmonic vibrational wavenumbers and torsional potential energy surface (PES) scan studies have been computed using density functional theory method. The detailed interpretation of the vibrational spectra has been carried out with the aid of VEDA.4 program. Vibrational spectra, natural bonding orbital (NBO) analysis and optimized molecular structure show the clear evidence for electronic interaction of thionocarbamate group with aromatic ring. Predicted electronic absorption spectrum from TD-DFT calculation has been compared with the UV-vis spectrum. The Mulliken population analysis on atomic charges and the HOMO-LUMO energy were also calculated. Vibrational analysis reveals that the simultaneous IR and Raman activation of the C-C stretching mode in the phenyl and naphthalene ring provide evidence for the charge transfer interaction between the donor and acceptor groups and is responsible for its bioactivity as a fungicide. PMID:21565546

  3. Spectroscopic and Electrochemical Analysis of Psychotropic Drugs

    PubMed Central

    Puzanowska-Tarasiewicz, H.; Misiuk, W.; Mielech-?ukasiewicz, K.; Ku?micka, L.

    2009-01-01

    Psychotropic drugs are an important family of compounds from a medical point of view. Their application in therapy requires methods for the determination in pharmaceutical dosage forms and body fluids. Several methods for their analysis have been reported in the literature. Among the methods, spectrophotometric and electrochemical are very useful for the determination of the drugs. Some of the spectrophotometric methods are based on the formation of the binary and ternary compounds with complexes of metals. The formed compounds are sparingly soluble in water, but quantitatively extracted from aqueous phase into organic solvents and the extracts are intensely colored and stable for a few days. These complexes have been employed in pharmaceutical analysis. The electrochemical procedures are very useful in determination of the psychotropic substances in pharmaceutical preparations. PMID:20177449

  4. A SPECTROSCOPIC ANALYSIS OF WHITE DWARFS IN THE KISO SURVEY

    SciTech Connect

    Limoges, M.-M.; Bergeron, P., E-mail: limoges@astro.umontreal.c, E-mail: bergeron@astro.umontreal.c [Departement de Physique, Universite de Montreal, C.P. 6128, Succ. Centre-Ville, Montreal, Quebec H3C 3J7 (Canada)

    2010-05-10

    We present a spectroscopic analysis of white dwarfs found in the Kiso survey. Spectroscopic observations at high signal-to-noise ratio have been obtained for all DA and DB stars in the Kiso Schmidt ultraviolet excess survey (KUV stars). These observations led to the reclassification of several KUV objects, including the discovery of three unresolved DA+DB double-degenerate binaries. The atmospheric parameters (T{sub eff} and log g) are obtained from detailed model atmosphere fits to optical spectroscopic data. The mass distribution of our sample is characterized by a mean value of 0.606 M{sub sun} and a dispersion of 0.135 M{sub sun} for DA stars, and 0.758 M{sub sun} and a dispersion of 0.192 M{sub sun} for DB stars. Absolute visual magnitudes obtained from our spectroscopic fits allow us to derive an improved luminosity function for the DA and DB stars identified in the Kiso survey. Our luminosity function is found to be significantly different from earlier estimates based on empirical photometric calibrations of M{sub V} for the same sample. The results for the DA stars now appear entirely consistent with those obtained for the PG survey using the same spectroscopic approach. The space density for DA stars with M{sub V} {<=} 12.75 is 2.80 x 10{sup -4} pc{sup -3} in the Kiso survey, which is 9.6% smaller than the value found in the PG survey. The completeness of both surveys is briefly discussed.

  5. Mössbauer spectroscopic analysis of ancient Egyptian pottery

    NASA Astrophysics Data System (ADS)

    Stevens, John G.; Zhu, Wenjun

    1986-02-01

    Ten pieces of Egyptian pottery ware and eleven silt samples collected at Hierakonopolis (Nile River, Egypt) were studied by Mössbauer spectroscopy. Three Nile silt samples and three pottery sherds were test fired and refired in an oxidized atmosphere up to 1100°C. Changes of the Mössbauer parameters depend upon the firing temperatures as well as the firing atmosphere. Three kinds of pottery were studied: Plum Red Ware, Straw Tempered Ware, and Orange Ware.

  6. In situ spectroscopic studies in hydroformylation of olefins

    SciTech Connect

    Horvath, I.T. [Exxon Research & Engineering Co., Annandale, NJ (United States)

    1995-12-01

    Since most hydroformylation (or oxo) processes are performed above atmospheric pressure, high pressure IR and NMR have been extensively for mechanistic studies. The initial goal of these studies is to develop a molecular snapshot of reactions which are part of or connected to the catalytic cycle. A generalized catalytic cycle and relevant spectroscopic opportunities will be described. The in situ spectroscopic data combined with other mechanistic information could lead to the design of novel catalyst system(s) targeting strict process requirements. The application of in situ IR and/or NMR will be demonstrated for cobalt and rhodium based catalyst systems modified by various phosphines.

  7. Spectroscopic Studies in X-ray Astronomy

    NASA Astrophysics Data System (ADS)

    Choi, Chul-Sung

    2000-09-01

    X-ray astronomy deals with measurements of the electromagnetic radiation in the energy range of E 0.1- 100 keV. The wavelength of X-ray is comparable to the size of atoms, so that the photons in the X-ray range are usually produced and absorbed by the atomic processes. Since the launch of the first X-ray astronomy satellite "Uhuru" in 1970, technological advances in a launch capability and a detection capability make X-ray astronomy one of the most rapidly evolving fields of astronomical research. Particularly, a spectral resolving power E/Delta E has been increased by an order of 2 - 3 (in the energy range of 0,1 - 10 keV) during the past 30 years. In this paper, I briefly review a developing process of the resolving power and spectroscopic techniques. Then I describe important emission/absorption lines in X-ray astronomy, as well as diagnostics of gas property with line parameters.

  8. Spectroscopic analysis of biologically synthesized silver nanoparticles under clinorotation

    NASA Astrophysics Data System (ADS)

    Jagtap, Sagar; Vidyasagar, Pandit; Ghemud, Vipul; Dixit, Jyotsana

    Nanoparticles are one of the hot topics of research due to their size dependent optical, electrical and magnetic properties & their anti-bacterial and anti-fungal nature. Synthesis of nano particles can be done by various physical and chemical methods. However, Biosynthesis of nanoparticles is environment friendly, can take place around room temperature, and require little intervention or input of energy. In the present study, the synthesis of silver nanoparticles (AgNPs) using bacteria and the effect of clinorotation on rate of synthesis is discussed. The freshly grown bacterial isolate was inoculated in to 250-ml Erlenmeyer flask containing 50 ml sterile nutrient broth (LB). The cultured flasks were incubated in a shaker at 120 rpm for 24 h at 370C. Culture was centrifuged at 10,000 rpm for 10 min. The supernatant was used for carrying extracellular production of silver nanoparticles by mixing it with 5mM AgNO3 solution. The above solution was clinorotated at 2 rpm for 24 h. The synthesis was carried out at 60oC. Visual observation was conducted periodically to check for the nanoparticles formation in normal gravity as well as under clinorotation. UV-visible spectroscopic analysis showed that rate of synthesis was faster in case of clinorotated sample than control. Further, the results of FTIR and XRD characterization will be discussed.

  9. Spectroscopic Analysis of Unbound Asteroid Pairs

    NASA Astrophysics Data System (ADS)

    Duddy, S. R.; Lowry, S. C.; Wolters, S. D.; Rozitis, B.; Green, S. F.; Christou, A.; Weissman, P.

    2011-10-01

    We have begun a survey of the asteroids in these pairs to determine whether they share a similar composition, expected if they have originated from the same parent body. We have conducted optical, low-resolution spectroscopy of the asteroids in several unbound pairs. Observations were obtained in January and March 2011 using the 3.6m NTT+EFOSC2 covering the wavelength range 0.4- 0.95 microns, and in May 2011 using the 4.2m WHT+ACAM, covering the wavelength range 0.5- 0.95 microns. The observations of the components in each pair were kept as consistent as possible to reduce spurious effects introduced to the spectra. For example, the same solar analog was observed to remove the solar spectrum from the spectra of each component. Chi-squared fitting of the extracted spectra to the Bus-DeMeo taxonomy [1] allowed taxonomic classifications to be assigned to each asteroid. A chi-squared test was then used to determine the similarity of the spectra of the asteroids in each pair. Initial results suggest that the asteroids in the unbound pair (7343) Ockeghem - (154634) 2003 XX38 exhibit an S-type spectrum. The spectra of these asteroids are excellent matches, with the same spectral slope and apparent silicate-absorption band depth. This information will allow us to use further optical and thermal observations obtained using the Palomar Observatory 200" Hale Telescope and 8m VLT to conduct a thorough dynamical analysis to further constrain the likely formation time of these objects. We will also present the optical spectra of several other unbound pairs obtained during recent observations using the 4.2m WHT and the 8m VLT.

  10. Spectroscopic study of low-lying {sup 16}N levels

    SciTech Connect

    Bardayan, D. W.; Nesaraja, C. D.; Pain, S. D.; Smith, M. S. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); O'Malley, P. D.; Cizewski, J. A.; Hatarik, R.; Peters, W. A. [Department of Physics and Astronomy, Rutgers University, New Brunswick, New Jersey 08903 (United States); Blackmon, J. C. [Deptartment of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Chae, K. Y.; Jones, K. L.; Moazen, B. H.; Paulauskas, S.; Pittman, S. T.; Schmitt, K. T. [Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996 (United States); Chipps, K. A. [Department of Physics, Colorado School of Mines, Golden, Colorado 80401 (United States); Kozub, R. L.; Shriner, J. F. Jr. [Physics Department, Tennessee Technological University, Cookeville, Tennessee 38505 (United States); Matei, C. [Oak Ridge Associated Universities, Oak Ridge, Tennessee 37830 (United States)

    2008-11-15

    The magnitude of the {sup 15}N(n,{gamma}){sup 16}N reaction rate in asymptotic giant branch stars depends directly on the neutron spectroscopic factors of low-lying {sup 16}N levels. A new study of the {sup 15}N(d,p){sup 16}N reaction is reported populating the ground and first three excited states in {sup 16}N. The measured spectroscopic factors are near unity as expected from shell model calculations, resolving a long-standing discrepancy with earlier measurements that had never been confirmed or understood. Updated {sup 15}N(n,{gamma}){sup 16}N reaction rates are presented.

  11. [FTIR spectroscopic study on carcinoma cells].

    PubMed

    Du, Jun-Kai; Shi, Jing-Sen; Xu, Yi-Zhuang; Zhang, Yuan-Fu; Sun, Xue-Jun; Wang, Jian-Sheng; Weng, Shi-Fu; Wu, Jin-Guang

    2008-01-01

    The aim of this research is to establish the cell basis for the carcinoma tissue diagnosis by exploring a method to obtain the FTIR (Fourier transform infrared) spectra of the cultured carcinoma cells with FTIR spectroscopy and investigating the special spectral features of the carcinoma cells compared with the carcinoma tissues. In the present paper, the gastric carcinoma tissues confirmed by histology were measured using a Nicolet Magna750-II FTIR spectrometer and the corresponding FTIR spectra were obtained. The cultured gastric carcinoma cells (SGC7901) were centrifuged to provide a small pellet of cells for FTIR analysis. The cell pellet was then placed on a specially designed salt plate made of BaF2. Then the infrared spectra were recorded by the same equipment. Based on the previously established criteria, a comparative study was subsequently carried out between the spectra of the cultured carcinoma cells (SGC7901) and that of the corresponding gastric tissues. Several infrared spectral features of the carcinoma cells were obtained: the different bands between cells and tissues locate in the range of 3 000-3 600 cm(-1) and 1 640 cm(-1) which are the range of the hydroxy stretching and blending bands of H2O. There are more H2O out of carcinoma cells in carcinoma tissues, so the strong bands of H2O cover the distinctive bands of carcinoma cells in carcinoma tissues. Although the carcinoma tissue is more complicated, which might originate from the intrinsic complexity of the tissue, the results suggest that the spectral features of the carcinoma cells can be well reflected by that of the carcinoma tissue. This study shows that the diagnosis of carcinoma tissue by FTIR method exhibits sufficient cell basis. PMID:18422118

  12. Adsorption and Optical Properties of Ferritin Layers on Gold Studied with Spectroscopic Ellipsometry

    Microsoft Academic Search

    Jan Mårtensson; Hans Arwin; Håkan Nygren; Ingemar Lundström

    1995-01-01

    Thin layers of ferritin adsorbed on gold substrates were studied in situ in buffer with spectroscopic ellipsometry. A four-phase model was used to determine their optical properties. The top layer was the protein layer and the bottom layer an effective medium layer used to model interaction between the protein molecules and the gold substrate. An analysis of the time dependence

  13. Halo Nucleus Be11: A Spectroscopic Study via Neutron Transfer

    NASA Astrophysics Data System (ADS)

    Schmitt, K. T.; Jones, K. L.; Bey, A.; Ahn, S. H.; Bardayan, D. W.; Blackmon, J. C.; Brown, S. M.; Chae, K. Y.; Chipps, K. A.; Cizewski, J. A.; Hahn, K. I.; Kolata, J. J.; Kozub, R. L.; Liang, J. F.; Matei, C.; Matoš, M.; Matyas, D.; Moazen, B.; Nesaraja, C.; Nunes, F. M.; O'Malley, P. D.; Pain, S. D.; Peters, W. A.; Pittman, S. T.; Roberts, A.; Shapira, D.; Shriner, J. F., Jr.; Smith, M. S.; Spassova, I.; Stracener, D. W.; Villano, A. N.; Wilson, G. L.

    2012-05-01

    The best examples of halo nuclei, exotic systems with a diffuse nuclear cloud surrounding a tightly bound core, are found in the light, neutron-rich region, where the halo neutrons experience only weak binding and a weak, or no, potential barrier. Modern direct-reaction measurement techniques provide powerful probes of the structure of exotic nuclei. Despite more than four decades of these studies on the benchmark one-neutron halo nucleus Be11, the spectroscopic factors for the two bound states remain poorly constrained. In the present work, the Be10(d,?p) reaction has been used in inverse kinematics at four beam energies to study the structure of Be11. The spectroscopic factors extracted using the adiabatic model were found to be consistent across the four measurements and were largely insensitive to the optical potential used. The extracted spectroscopic factor for a neutron in an n?j=2s1/2 state coupled to the ground state of Be10 is 0.71(5). For the first excited state at 0.32 MeV, a spectroscopic factor of 0.62(4) is found for the halo neutron in a 1p1/2 state.

  14. Halo Nucleus 11Be: A Spectroscopic Study via Neutron Transfer

    SciTech Connect

    Schmitt, Kyle [University of Tennessee, Knoxville (UTK); Jones, K. L. [University of Tennessee, Knoxville (UTK); Bey, A. [University of Tennessee, Knoxville (UTK); Ahn, S.H. [University of Tennessee, Knoxville (UTK); Bardayan, Daniel W [ORNL; Blackmon, Jeffery C [Louisiana State University; Brown, S. [University of Surrey, UK; Chae, Kyung Yuk [ORNL; Chipps, K. [Colorado School of Mines, Golden; Cizewski, J. A. [Rutgers University; Kozub, R. L. [Tennessee Technological University; Liang, J Felix [ORNL; Matei, Catalin [Oak Ridge Associated Universities (ORAU); Matos, M. [Louisiana State University; Moazen, Brian H [ORNL; Nesaraja, Caroline D [ORNL; Nunes, F. M. [Michigan State University, East Lansing; O'Malley, Patrick [Rutgers University; Pain, Steven D [ORNL; Peters, W. A. [Rutgers University; Pittman, S. T. [University of Tennessee, Knoxville (UTK); Wilson, G. [University of Surrey, UK

    2012-01-01

    The best examples of halo nuclei, exotic systems with a diffuse nuclear cloud surrounding a tightly bound core, are found in the light, neutron-rich region, where the halo neutrons experience only weak binding and a weak, or no, potential barrier. Modern direct-reaction measurement techniques provide powerful probes of the structure of exotic nuclei. Despite more than four decades of these studies on the benchmark one-neutron halo nucleus 11Be, the spectroscopic factors for the two bound states remain poorly constrained. In the present work, the 10Be d;p reaction has been used in inverse kinematics at four beam energies to study the structure of 11Be. The spectroscopic factors extracted using the adiabatic model were found to be consistent across the four measurements and were largely insensitive to the optical potential used. The extracted spectroscopic factor for a neutron in an n j 2s1=2 state coupled to the ground state of 10Be is 0.71(5). For the first excited state at 0.32 MeV, a spectroscopic factor of 0.62(4) is found for the halo neutron in a 1p1=2 state.

  15. Halo nucleus Be-11: A spectroscopic study via neutron transfer

    E-print Network

    K. T. Schmitt; K. L. Jones; A. Bey; S. H. Ahn; D. W. Bardayan; J. C. Blackmon; S. M. Brown; K. Y. Chae; K. A. Chipps; J. A. Cizewski; K. I. Hahn; J. J. Kolata; R. L. Kozub; J. F. Liang; C. Matei; M. Matoš; D. Matyas; B. Moazen; C. Nesaraja; F. M. Nunes; P. D. O'Malley; S. D. Pain; W. A. Peters; S. T. Pittman; A. Roberts; D. Shapira; J. F. Shriner Jr; M. S. Smith; I. Spassova; D. W. Stracener; A. N. Villano; G. L. Wilson

    2012-03-19

    The best examples of halo nuclei, exotic systems with a diffuse nuclear cloud surrounding a tightly-bound core, are found in the light, neutron-rich region, where the halo neutrons experience only weak binding and a weak, or no, potential barrier. Modern direct reaction measurement techniques provide powerful probes of the structure of exotic nuclei. Despite more than four decades of these studies on the benchmark one-neutron halo nucleus Be-11, the spectroscopic factors for the two bound states remain poorly constrained. In the present work, the Be-10(d,p) reaction has been used in inverse kinematics at four beam energies to study the structure of Be-11. The spectroscopic factors extracted using the adiabatic model, were found to be consistent across the four measurements, and were largely insensitive to the optical potential used. The extracted spectroscopic factor for a neutron in a nlj = 2s1/2 state coupled to the ground state of Be-10 is 0.71(5). For the first excited state at 0.32 MeV, a spectroscopic factor of 0.62(4) is found for the halo neutron in a 1p1/2 state.

  16. Spectroscopic and thermal study of Er-doped oxysulfide crystal powders

    NASA Astrophysics Data System (ADS)

    Fernández, Joaquín.; Balda, Rolindes; Barredo-Zuriarrain, Macarena; Merdrignac-Conanec, Odile; Hakmeh, Noha; García-Revilla, Sara; Arriandiaga, M. A.

    2015-03-01

    The present investigation explores the upconversion properties of Er3+- doped La2O2S crystal powder as well as its potentiality for anti-Stokes cooling. A detailed study of the wavelength and pumping power dependence of the spectroscopic properties and of the temperature field of samples with various erbium concentrations is presented. The analysis of both spectroscopic and thermal measurements shows that after a transient heating induced by the background absorption, cooling can be attained by means of anti-Stokes processes.

  17. Spectroscopic study of coal structure and reactivity

    SciTech Connect

    Rabenstein, D.L.

    1990-09-07

    The aim of this project is to perform quantitative analysis of the Fourier transform infrared (FT-IR) spectra of coals and coal extracts. The major difficulty encountered in the analysis of the FT-IR spectra of coals is the complexity of the bands, which consist of many closely overlapped peaks. Two techniques that are commonly used for the quantitative analysis of complex FT-IR spectra are deconvolution and curve-fitting. Deconvolution is a mathematical technique that narrows the speaks in a spectrum, thereby improving the effective resolution. Curve-fitting optimizes a set of ban parameters, using a least squares criterion, to simulate the true spectrum. We have recently completed work on optimizing the combination of these two techniques with the aim of applying this to the spectra of coals and coal extracts. Two types of deconvolution were investigated in this context: Fourier self-deconvolution (FSD) and maximum likelihood restoration (MLR). It was concluded that for noisy spectra MLR gave superior results. 3 refs., 7 figs.

  18. A Spectroscopic and Photometric Study of Gravitational Microlensing Events

    NASA Astrophysics Data System (ADS)

    Kane, Stephen R.

    2000-08-01

    Gravitational microlensing has generated a great deal of scientific interest over recent years. This has been largely due to the realization of its wide-reaching applications, such as the search for dark matter, the detection of planets, and the study of Galactic structure. A significant observational advance has been that most microlensing events can be identified in real-time while the source is still being lensed. More than 400 microlensing events have now been detected towards the Galactic bulge and Magellanic Clouds by the microlensing survey teams EROS, MACHO, OGLE, DUO, and MOA. The real-time detection of these events allows detailed follow-up observations with much denser sampling, both photometrically and spectroscopically. The research undertaken in this project on photometric studies of gravitational microlensing events has been performed as a member of the PLANET (Probing Lensing Anomalies NETwork) collaboration. This is a worldwide collaboration formed in the early part of 1995 to study microlensing anomalies - departures from an achromatic point source, point lens light curve - through rapidly-sampled, multi-band, photometry. PLANET has demonstrated that it can achieve 1% photometry under ideal circumstances, making PLANET observations sensitive to detection of Earth-mass planets which require characterization of 1%--2% deviations from a standard microlensing light curve. The photometric work in this project involved over 5 months using the 1.0 m telescope at Canopus Observatory in Australia, and 3 separate observing runs using the 0.9 m telescope at the Cerro Tololo Inter-American Observatory (CTIO) in Chile. Methods were developed to reduce the vast amount of photometric data using the image analysis software MIDAS and the photometry package DoPHOT. Modelling routines were then written to analyse a selection of the resulting light curves in order to detect any deviation from an achromatic point source - point lens light curve. The photometric results presented in this thesis are from observations of 34 microlensing events over three consecutive bulge seasons. These results are presented along with a discussion of the observations and the data reduction procedures. The colour-magnitude diagrams indicate that the microlensed sources are main sequence and red clump giant stars. Most of the events appear to exhibit standard Paczynski point source - point lens curves whilst a few deviate significantly from the standard model. Various microlensing models that include anomalous structure are fitted to a selection of the observed events resulting in the discovery of a possible binary source event. These fitted events are used to estimate the sensitivity to extra-solar planets and it is found that the sampling rate for these events was insufficient by about a factor of 7.5 for detecting a Jupiter-mass planet. This result assumes that deviations of 5% can be reliably detected. If microlensing is caused predominantly by bulge stars, as has been suggested by Kiraga and Paczynski, the lensed stars should have larger extinction than other observed stars since they would preferentially be located at the far side of the Galactic bulge. Hence, spectroscopy of Galactic microlensing events may be used as a tool for studying the kinematics and extinction effects in the Galactic bulge. The spectroscopic work in this project involved using Kurucz model spectra to create theoretical extinction effects for various spectral classes towards the Galactic centre. These extinction effects are then used to interpret spectroscopic data taken with the 3.6 m ESO telescope. These data consist of a sample of microlensed stars towards the Galactic bulge and are used to derive the extinction offsets of the lensed source with respect to the average population and a measurement of the fraction of bulge-bulge lensing is made. Hence, it is shown statistically that the microlensed sources are generally located on the far side of the Galactic bulge. Measurements of the radial velocities of these sources are used to determine the kinematic properti

  19. Spectroscopic analysis technique for arc-welding process control

    NASA Astrophysics Data System (ADS)

    Mirapeix, Jesús; Cobo, Adolfo; Conde, Olga; Quintela, María Ángeles; López-Higuera, José-Miguel

    2005-09-01

    The spectroscopic analysis of the light emitted by thermal plasmas has found many applications, from chemical analysis to monitoring and control of industrial processes. Particularly, it has been demonstrated that the analysis of the thermal plasma generated during arc or laser welding can supply information about the process and, thus, about the quality of the weld. In some critical applications (e.g. the aerospace sector), an early, real-time detection of defects in the weld seam (oxidation, porosity, lack of penetration, ...) is highly desirable as it can reduce expensive non-destructive testing (NDT). Among others techniques, full spectroscopic analysis of the plasma emission is known to offer rich information about the process itself, but it is also very demanding in terms of real-time implementations. In this paper, we proposed a technique for the analysis of the plasma emission spectrum that is able to detect, in real-time, changes in the process parameters that could lead to the formation of defects in the weld seam. It is based on the estimation of the electronic temperature of the plasma through the analysis of the emission peaks from multiple atomic species. Unlike traditional techniques, which usually involve peak fitting to Voigt functions using the Levenberg-Marquardt recursive method, we employ the LPO (Linear Phase Operator) sub-pixel algorithm to accurately estimate the central wavelength of the peaks (allowing an automatic identification of each atomic species) and cubic-spline interpolation of the noisy data to obtain the intensity and width of the peaks. Experimental tests on TIG-welding using fiber-optic capture of light and a low-cost CCD-based spectrometer, show that some typical defects can be easily detected and identified with this technique, whose typical processing time for multiple peak analysis is less than 20msec. running in a conventional PC.

  20. Spectroscopic studies of metal growth on oxides 

    E-print Network

    Luo, Kai

    2000-01-01

    of metal clusters on well-defined oxide surfaces. In this work, the nucleation and growth modes of Ag on TiO?(110)(1x1) and (1x2) surfaces, Ag on ultra-thin Al?O? films, and Au on ultra-thin SiO? films were studied by scanning tunneling microscopy (STM...

  1. Raman spectroscopic studies in supercritical water

    SciTech Connect

    Bowman, L.E.; Fulton, J.L.

    1994-10-01

    Reaction studies have been carried out on the destruction of nitrogen-containing compounds such as ammonium, nitrates, and species containing aromatic nitro functionality. The destruction of ammonium ion in near-critical and supercritical water using Raman spectroscopy is the subject of this presentation. Reaction rates were determined from Raman spectra and from measurements of system pressure. Concentrations of key species in the reactor effluent were determined via off-line assay. The effects of temperature, pressure, and concomitants on reaction rate were determined. The reaction half-life is below ten seconds at 400 C with better than 95% conversion. Oxides of nitrogen were not generated in detectable quantities. The studied system is a model for the destruction of ammonium in municipal wastes.

  2. Integrated Spectroscopic Studies of Hydrous Sulfate Minerals

    NASA Technical Reports Server (NTRS)

    Dyar, M. D.; Lane, M. D.; Bishop, J. L.; OConnor, V.; Cloutis, E.; Hiroi, T.

    2005-01-01

    Sulfate minerals have been identified in Martian meteorites and on Mars using a suite of instruments aboard the MER rovers. These results have confirmed previous groundbased observations and orbital measurements that suggested their presence. The orbiting OMEGA instrument on Mars Express is also finding evidence for sulfate. In order to better interpret remote-sensing data, we present here the results of a coordinated visible/near infrared (VNIR) reflectance, Moussbauer (MB), and thermal emittance study of wellcharacterized hydrous sulfate minerals.

  3. Progress report on nuclear spectroscopic studies

    SciTech Connect

    Bingham, C.R.; Guidry, M.W.; Riedinger, L.L.; Sorensen, S.P.

    1994-02-18

    The Nuclear Physics group at the University of Tennessee, Knoxville (UTK) is involved in several aspects of heavy-ion physics including both nuclear structure and reaction mechanisms. While the main emphasis is on experimental problems, the authors have maintained a strong collaboration with several theorists in order to best pursue the physics of their measurements. During the last year they have had several experiments at the ATLAS at Argonne National Laboratory, the GAMMASPHERE at the LBL 88 Cyclotron, and with the NORDBALL at the Niels Bohr Institute Tandem. Also, they continue to be very active in the WA93/98 collaboration studying ultra-relativistic heavy ion physics utilizing the SPS accelerator at CERN in Geneva, Switzerland and in the PHENIX Collaboration at the RHIC accelerator under construction at Brookhaven National Laboratory. During the last year their experimental work has been in three broad areas: (1) the structure of nuclei at high angular momentum, (2) the structure of nuclei far from stability, and (3) ultra-relativistic heavy-ion physics. The results of studies in these particular areas are described in this document. These studies concentrate on the structure of nuclear matter in extreme conditions of rotational motion, imbalance of neutrons and protons, or very high temperature and density. Another area of research is heavy-ion-induced transfer reactions, which utilize the transfer of nucleons to states with high angular momentum to learn about their structure and to understand the transfer of particles, energy, and angular momentum in collisions between heavy ions.

  4. Progress report on nuclear spectroscopic studies

    SciTech Connect

    Bingham, C.R.; Riedinger, L.L.; Sorensen, S.P.

    1996-01-16

    The experimental program in nuclear physics at the University of Tennessee, Knoxville, is led by Professors Carrol Bingham, Lee Riedinger, and Soren Sorenseni who respectively lead the studies of the exotic decay modes of nuclei far from stability, the program of high-spin research, and our effort in relativistic heavy-ion physics. Over the years, this broad program of research has been successful partially because of the shared University resources applied to this group effort. The proximity of the Oak Ridge National Laboratory has allowed us to build extremely strong programs of joint research, and in addition to play an important leadership role in the Joint Institute for Heavy Ion Research (JIHIR). Our experimental program is also very closely linked with those at other national laboratories: Argonne (collaborations involving the Fragment Mass Analyzer (FMA) and {gamma}-ray arrays), Brookhaven (the RHIC and Phenix projects), and Berkeley (GAMMASPHERE). We have worked closely with a variety of university groups in the last three years, especially those in the UNISOR and now UNIRIB collaborations. And, in all aspects of our program, we have maintained close collaborations with theorists, both to inspire the most exciting experiments to perform and to extract the pertinent physics from the results. The specific areas discussed in this report are: properties of high-spin states; study of low-energy levels of nuclei far from stability; and high energy heavy-ion physics.

  5. Terahertz spectroscopic study of benzodiazepine sedative hypnotics

    NASA Astrophysics Data System (ADS)

    Deng, Fusheng; Shen, Jingling; Wang, Xianfeng

    2011-08-01

    Terahertz time domain spectroscopy (THz-TDS) is used to the pure active ingredient of three benzodiazepine sedative hypnotics with similar molecular structure. The absorption spectra of them are studied in the range of 0.2~2.6THz. Based on the experiment, the theoretical simulation results of diazepam, nitrazepam and clonazepam are got by the Gaussian03 package of DFT/B3LYP/6-31G* method in single-molecule models. The experimental results show that even if the molecular structure and medicine property of them are similar, the accurate identification of them can still be done with their characteristic absorption spectra. Theoretical simulation results are well consistent with the experimental results. It demonstrates that absorption peaks of them in THz range mainly come from intra-molecular forces and are less affected by the intermolecular interaction and crystal effects.ô

  6. Spectroscopic analysis of vermicompost for determination of nutritional quality.

    PubMed

    Subhash Kumar, M; Rajiv, P; Rajeshwari, Sivaraj; Venckatesh, Rajendran

    2015-01-25

    Spectroscopic analysis has been carried out to examine the compost quality, maturity and nutritional levels of vermicompost and compost of Eichhornia. 50% Eichhorniacrassipes and 50% cow dung mixtures were vermicomposted using earthworms (Eudrilus eugeniae) and collected on different days' time intervals. Fourier transform infrared spectroscopy (FT-IR) spectra reveal the presence of humic substance from compost and vermicompost, which improves the soil fertility. Gas chromatography-mass spectroscopy (GC-MS) analysis shows maximum level of Benzene propanoic acid (95.98%) and by 2-Propanone, 1-Phenyl-, OXIM (10.10%) from vermicompost through earthworms activity. Atomic absorption spectroscopy (AAS) results reported high level of micronutrient from Eichhornia mediated compost and vermicompost. PMID:25068838

  7. Spectroscopic analysis of vermicompost for determination of nutritional quality

    NASA Astrophysics Data System (ADS)

    Subhash Kumar, M.; Rajiv, P.; Rajeshwari, Sivaraj; Venckatesh, Rajendran

    2015-01-01

    Spectroscopic analysis has been carried out to examine the compost quality, maturity and nutritional levels of vermicompost and compost of Eichhornia. 50% Eichhorniacrassipes and 50% cow dung mixtures were vermicomposted using earthworms (Eudrilus eugeniae) and collected on different days' time intervals. Fourier transform infrared spectroscopy (FT-IR) spectra reveal the presence of humic substance from compost and vermicompost, which improves the soil fertility. Gas chromatography-mass spectroscopy (GC-MS) analysis shows maximum level of Benzene propanoic acid (95.98%) and by 2-Propanone, 1-Phenyl-, OXIM (10.10%) from vermicompost through earthworms activity. Atomic absorption spectroscopy (AAS) results reported high level of micronutrient from Eichhornia mediated compost and vermicompost.

  8. Interactions of Isophorone Derivatives with DNA: Spectroscopic Studies

    PubMed Central

    Deiana, Marco; Matczyszyn, Katarzyna; Massin, Julien; Olesiak-Banska, Joanna; Andraud, Chantal; Samoc, Marek

    2015-01-01

    Interactions of three new isophorone derivatives, Isoa Isob and Isoc with salmon testes DNA have been investigated using UV-Vis, fluorescence and circular dichroism spectroscopic methods. All the studied compounds interact with DNA through intercalative binding mode. The stoichiometry of the isophorone/DNA adducts was found to be 1:1. The fluorescence quenching data revealed a binding interaction with the base pairs of DNA. The CD data indicate that all the investigated isophorones induce DNA modifications. PMID:26069963

  9. Hypernuclear Spectroscopic Study at TJNAF II

    NASA Astrophysics Data System (ADS)

    Miyoshi, Toshinobu

    2001-10-01

    Experiment E89-009, which employs the Hypernuclear Spectrometer System (HNSS), was carried out at Thomas Jefferson National Accelerator Facility (JLab) from March to May 2000. This was the first hypernuclear study using the (e,e ' K^+) reaction at JLab. The high quality electron beam of JLab in conjunction with HNSS enabled us to measure hypernuclear spectra with below 1 MeV (FWHM) energy resolution. E89-009 was designed to make use of the peaking of the virtual photon flux at very forward angles. Scattered electrons were detected at 0 degrees, and positive kaons were detected at near 0 degrees where the ? photo-production cross section reaches the maximum. The overall performance of the spectrometer and detector systems will be presented. From the spectra obtained with CH2 target, a preliminary differential cross section for elementary process H(e,e ' K^+)? was extracted near the real photon limit at the four-momentum squared Q^2 ~= 1 (MeV/c)^2 for the first time. Differential cross sections for the ^12C(e,e ' K^+)^12_?B reaction were also measured for several states of ^12_?B. The results will be compared to theoretical predictions and previous ^12_?C spectra obtained from meson beams.

  10. Fluorescence spectroscopic studies of DNA dynamics

    SciTech Connect

    Scalettar, B.A.

    1987-04-01

    Random solvent induced motions of DNA are manifest as nanosecond torsional oscillations of the helix backbone, nanosecond through millisecond bending deformations and overall rotational and translational diffusion of the polymer. Fluorescence spectroscopy is used to study this spectrum of DNA motions while ethidium monoazide was covalently bounded. The steady state fluorescence depolarization data indicate that the covalent monoazide/DNA complex exhibits internal motions characterized by an average angular amplitude of 26 degrees confirming reports of fast torsional oscillations in noncovalent ethidium bromide/DNA systems. Data obtained by use of a new polarized photobleaching recovery technique (FPR) reflect both the rotational dynamics of the polymer and the reversible photochemistry of the dye. To isolate the reorientational motion of the DNA, the FPR experiments were ran in two modes that differ only in the polarization of the bleaching light. A quotient function constructed from the data obtained in these two modes monitors only the rotational component of the FPR recovery. In specific applications those bending deformations of long DNA molecules that have characteristic relaxation times on the order of 100 microseconds have been resolved. A fluorescence correlation technique that relates fluctuations in particle number to center-of-mass motion was used to measure translational diffusion on coefficients of the plasmid PBR322 and a short oligomeric DNA. A theory that describes angular correlation in systems exhibiting cyclic, biologically directed reorientation and random Brownian rotation is developed.

  11. Quantum chemical studies on molecular structure, spectroscopic (IR, Raman, UV-Vis), NBO and Homo-Lumo analysis of 1-benzyl-3-(2-furoyl) thiourea

    NASA Astrophysics Data System (ADS)

    Gil, Diego M.; Defonsi Lestard, M. E.; Estévez-Hernández, O.; Duque, J.; Reguera, E.

    2015-06-01

    Vibrational and electronic spectra for 1-benzyl-3-(2-furoyl) thiourea were calculated by using density functional method (B3LYP) with different basis sets. The complete assignment of all vibrational modes was performed on basis of the calculated frequencies and comparing with the reported IR and Raman spectra for that thiourea derivative. UV-visible absorption spectra of the compound dissolved in methanol were recorded and analyzed using time dependent density functional theory (TD-DFT). The calculated values for the geometrical parameters of the title compound are consistent with the ones reported from XRD studies. The stability of the molecule, related to hyper-conjugative interactions, and electron delocalization were evaluated using natural bond orbital (NBO) analysis. Intra-molecular interactions were studied by AIM approach. The HOMO and LUMO analysis are used to determine the charge transfer within the molecule. Molecular electrostatic potential map was performed by the DFT method.

  12. Spectroscopic Studies of High Temperature Superconductors.

    NASA Astrophysics Data System (ADS)

    Chang, Chinglin

    The electronic properties of the high temperature superconducting materials play a crucial role in understanding the high superconducting transition temperature (T _{rm c}) which they exhibit. To investigate these electronic properties, we have made a number of core level X-ray photoemission spectroscopy (XPS) and near edge X-ray absorption fine structures (NEXAFS) measurements of superconducting and nonsuperconducting modified perovskites with the general formula RBa _2Cu_3O_ {rm x}, in which R = Y, Yb, Ce, Pr and Eu. The Cu 2p core level photoemission spectra show many body shakedown features, which are indicative of the presence of divalent Cu, appear only in superconducting materials. These features are absent in nonsuperconducting perovskites. Therefore, at least in the surface region, Cu is divalent in superconducting materials and monovalent in nonsuperconductors. However, due to the surface sensitivity of this technique, the results may not be representative of the bulk properties. Photoemission measurements of O and Ba also showed surface effect including the loss of oxygen after baking in vacuum. Our Cu 1s X-ray absorption measurements on superconducting materials indicate that the Cu valence is 2+, and in nonsuperconducting perovskites the Cu valence is only slightly less than 2+. This link between the Cu valence and superconductivity was further investigated by examining the Cu 1s absorption edges of a series of EuBa_2Cu_3 O_{rm 7-x} materials. It is clear that the Cu valence and the O content are closely correlated, and these factors are essential to superconductivity. To examine the effect on Cu valence when Zn is doped, we have studied a series of EuBa _2(Cu_{rm 1-y} Zn_{rm y})_3 O_7 materials. Although doping with Zn does not affect the electronic state of the Cu, it brings the Zn^{2+ } ions with filled d shell to the system. These Zn ions are similar to Cu^{1+} ions in magnetic property. Neutron scattering measurements indicate that in oxygen deficient samples, there is an antiferromagnetic ground state which precludes the superconductivity. To investigate the relationship between the valence of the rare earth and superconductivity, we measured the rare earth 2p_{3/2} absorption edges of superconducting YbBa_2Cu _3O_7, and nonsuperconducting Ce and Pr based 1-2-3 compounds. We found that the Yb valence in YbBa_2Cu _3O_7 is 3+, as in Yb_2O_3. (Abstract shortened with permission of author.).

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

    SciTech Connect

    Jellison, G.E. Jr.

    1997-05-01

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

  14. Caput mortuum: spectroscopic and structural studies of an ancient pigment.

    PubMed

    de Oliveira, Luiz F C; Edwards, Howell G M; Frost, Ray L; Kloprogge, J Theo; Middleton, Paul S

    2002-04-01

    The use of a pigment variously described as caput mortuum, usta or ostrum to provide a deep purple colour in ancient wall-paintings was highly prized, despite the technical difficulties associated with its application. With the Raman spectroscopic characterization of pigments in ancient frescoes and wall-paintings becoming more widespread, it is timely to consider the identification of this material either as a generic haematite alone or in admixture with contemporary blue pigments. Here, Raman and infrared spectroscopic, X-ray diffractometric and scanning electron microscopic structural studies have been undertaken to characterize caput mortuum and to identify a specimen of Roman wall-painting dating from the 3rd century. PMID:12022655

  15. Spectroscopic studies of protein folding: Linear and nonlinear methods

    PubMed Central

    Serrano, Arnaldo L; Waegele, Matthias M; Gai, Feng

    2012-01-01

    Although protein folding is a simple outcome of the underlying thermodynamics, arriving at a quantitative and predictive understanding of how proteins fold nevertheless poses huge challenges. Therefore, both advanced experimental and computational methods are continuously being developed and refined to probe and reveal the atomistic details of protein folding dynamics and mechanisms. Herein, we provide a concise review of recent developments in spectroscopic studies of protein folding, with a focus on new triggering and probing methods. In particular, we describe several laser-based techniques for triggering protein folding/unfolding on the picosecond and/or nanosecond timescales and various linear and nonlinear spectroscopic techniques for interrogating protein conformations, conformational transitions, and dynamics. PMID:22109973

  16. Synthesis, structure, spectroscopic studies (FT-IR, FT-Raman and UV), normal coordinate, NBO and NLO analysis of salicylaldehyde p-chlorophenylthiosemicarbazone

    NASA Astrophysics Data System (ADS)

    Muthu, S.; Elamurugu Porchelvi, E.; Karabacak, M.; Asiri, A. M.; Swathi, Sushmita S.

    2015-02-01

    The thiosemicarbazone compound, salicylaldehyde p-chlorophenylthiosemicarbazone (abbreviated as SCPTSC) was synthesized by refluxing equimolar amounts of 4-(4-methyl phenyl)-3-thiosemicarbazide and salicylaldehyde in presence of one drop of conc. H2SO4 in ethanolic medium for one hour and recrystallised from alcohol. The SCPTSC was characterized by FT-IR, FT-Raman, UV spectroscopy and thermal analysis. By using density functional theory (DFT) using B3LYP method with 6-31+G(d,p) and 6-311++G(d,p) basis sets, molecular geometry and vibrational frequencies were calculated and compared with the experimental data. The detailed interpretation of the vibrational spectra was carried out with aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology. The electronic dipole moment (?D) and the first hyperpolarizability (?tot) values of the investigated molecule were computed by using DFT/B3LYP method with 6-31+G(d,p) and 6-311++G(d,p) basis sets. The stability and charge delocalization of the title molecule were studied by natural bond orbital (NBO) analysis. Mulliken population analysis on atomic charges is also calculated. The molecule orbital contributions were investigated by using the total density of states (TDOS), sum of ? and ? electron density of states (??DOS). Thermodynamic properties (heat capacity, entropy and enthalpy) of the title compound at different temperatures were calculated.

  17. Spectroscopic and dynamical studies of highly energized small polyatomic molecules

    NASA Astrophysics Data System (ADS)

    Stimulated emission pumping (SEP) spectroscopy was used on acetylene and on formyl radical. An attempt was made for pattern recognition based on statistics; a method was invented that combined CNPI (complete nuclear permutation-inversion) group theory and SCC (spectral cross-correlation). But the direction away from statistical pattern recognition back to traditional spectroscopic pattern recognition was taken. Vibrational states and quantum numbers are discussed. For the formyl radical, the fluorescence excitation spectrum was recorded and a rotational analysis of the 0(sup 0)(sub 0) band performed.

  18. MULTI-OBJECTIVE SPECTROSCOPIC DATA ANALYSIS OF INERTIAL CONFINEMENT FUSION IMPLOSION CORES

    E-print Network

    Louis, Sushil J.

    MULTI-OBJECTIVE SPECTROSCOPIC DATA ANALYSIS OF INERTIAL CONFINEMENT FUSION IMPLOSION CORES: PLASMA confinement fusion implosion cores based on the self-consistent analysis of simultaneous narrow-band X is illustrated with spectroscopic data recorded in a series of stable and spherically symmetric implosion

  19. Surface gravity analysis of the NIRSPEC Brown Dwarf Spectroscopic Survey

    NASA Astrophysics Data System (ADS)

    Martin, Emily; McLean, Ian S.; Mace, Gregory N.; Logsdon, Sarah E.; Rice, Emily L.

    2015-01-01

    We present an analysis of J band spectra for over two hundred M, L, and T dwarfs obtained from the Brown Dwarf Spectroscopic Survey (BDSS) using NIRSPEC on the Keck II Telescope. This R~2000 sample includes spectra presented in McLean et al. (2003), as well as many new, unpublished spectra observed for the BDSS, more than doubling the size of the original survey. We determine surface gravity-sensitive spectral indices from the literature, which probe K I and FeH absorption, and we estimate uncertainties using a Monte Carlo iterative method. With these indices we characterize surface gravities of our targets in order to disentangle temperature and age of brown dwarfs and low mass stars of various masses.

  20. Effects of essential oil treatments on the secondary protein structure of Vicia faba: A mid-infrared spectroscopic study supported by two-dimensional correlation analysis

    NASA Astrophysics Data System (ADS)

    Mecozzi, Mauro; Sturchio, Elena

    2015-02-01

    In this study we investigated the effects of essential oil treatments on the secondary protein structure of the Vicia faba roots, a bioindicator plant, in order to obtain information for the potential allelopathic uses of these oils as alternative to the use of pesticides in agriculture. We tested two mixtures of essential oils consisting of Tween 20-emulsions of tea tree oil (TTO) and Tween 20-emulsion of Clove and Rosemary (GARROM) essential oils respectively at three different oil concentrations each. The molecular modifications caused in Vicia faba by exposure to oil emulsions were investigated by FTIR spectroscopy in diffuse reflectance (DRIFT) mode. We considered the specific Amide I, Amide II and Amide VI bands by ordinary and second derivative spectroscopy and the results showed that both Tween 20-emulsion of GARROM and Tween 20-emulsion of TTO oils cause transitions among the secondary (?-helix, ?-sheet and ?-turn) structures with in addition the appearance of random coil structures in exposed samples. The Amide VI bands, placed between 500 and 600 cm-1, confirmed the structural transitions observed for the Amide I bands. In addition we observed the presence of a protein oxidation effect for TTO treated samples, oxidation which resulted negligible instead for the GARROM oil samples. At last, FTIR spectra were also submitted to two-dimensional correlation analysis (2DCORR) and double two-dimensional correlation analysis (D2DCORR); the results confirmed the different effects caused by the two typologies of essential oils on the secondary protein structures of Vicia faba roots.

  1. How specific Raman spectroscopic models are: a comparative study between different cancers

    NASA Astrophysics Data System (ADS)

    Singh, S. P.; Kumar, K. Kalyan; Chowdary, M. V. P.; Maheedhar, K.; Krishna, C. Murali

    2010-02-01

    Optical spectroscopic methods are being contemplated as adjunct/ alternative to existing 'Gold standard' of cancer diagnosis, histopathological examination. Several groups are actively pursuing diagnostic applications of Ramanspectroscopy in cancers. We have developed Raman spectroscopic models for diagnosis of breast, oral, stomach, colon and larynx cancers. So far, specificity and applicability of spectral- models has been limited to particular tissue origin. In this study we have evaluated explicitly of spectroscopic-models by analyzing spectra from already developed spectralmodels representing normal and malignant tissues of breast (46), cervix (52), colon (25), larynx (53), and oral (47). Spectral data was analyzed by Principal Component Analysis (PCA) using scores of factor, Mahalanobis distance and Spectral residuals as discriminating parameters. Multiparametric limit test approach was also explored. The preliminary unsupervised PCA of pooled data indicates that normal tissue types were always exclusive from their malignant counterparts. But when we consider tissue of different origin, large overlap among clusters was found. Supervised analysis by Mahalanobis distance and spectral residuals gave similar results. The 'limit test' approach where classification is based on match / mis-match of the given spectrum against all the available spectra has revealed that spectral models are very exclusive and specific. For example breast normal spectral model show matches only with breast normal spectra and mismatch to rest of the spectra. Same pattern was seen for most of spectral models. Therefore, results of the study indicate the exclusiveness and efficacy of Raman spectroscopic-models. Prospectively, these findings might open new application of Raman spectroscopic models in identifying a tumor as primary or metastatic.

  2. Spectroscopic investigation (FT-IR, FT-Raman), HOMO-LUMO, NBO analysis and molecular docking study of 4-chlorophenyl quinoline-2-carboxylate

    NASA Astrophysics Data System (ADS)

    Fazal, E.; Panicker, C. Yohannan; Varghese, Hema Tresa; Nagarajan, S.; Sudha, B. S.; War, Javeed Ahamad; Srivastava, S. K.; Harikumar, B.; Anto, P. L.

    2015-06-01

    FT-IR and FT-Raman spectra of 4-chlorophenyl quinoline-2-carboxylate were recorded and analyzed. The vibrational wavenumbers were computed using DFT quantum chemical calculations. The data obtained from wavenumber calculations are used to assign vibrational bands obtained experimentally. Potential energy distribution was done using GAR2PED program. The geometrical parameters obtained theoretically are in agreement with the XRD data. NBO analysis, HOMO-LUMO, first hyperpolarizability and molecular electrostatic potential results are also reported. The calculated hyperpolarizability of the title compound is 77.53 times that of the standard NLO material urea and the title compound and its derivatives are attractive object for future studies of nonlinear optical properties. Molecular docking results suggest that the compound might exhibit inhibitory activity against GPb.

  3. Spectroscopic investigation (FT-IR, FT-Raman), HOMO-LUMO, NBO analysis and molecular docking study of 4-chlorophenyl quinoline-2-carboxylate.

    PubMed

    Fazal, E; Panicker, C Yohannan; Varghese, Hema Tresa; Nagarajan, S; Sudha, B S; War, Javeed Ahamad; Srivastava, S K; Harikumar, B; Anto, P L

    2015-06-15

    FT-IR and FT-Raman spectra of 4-chlorophenyl quinoline-2-carboxylate were recorded and analyzed. The vibrational wavenumbers were computed using DFT quantum chemical calculations. The data obtained from wavenumber calculations are used to assign vibrational bands obtained experimentally. Potential energy distribution was done using GAR2PED program. The geometrical parameters obtained theoretically are in agreement with the XRD data. NBO analysis, HOMO-LUMO, first hyperpolarizability and molecular electrostatic potential results are also reported. The calculated hyperpolarizability of the title compound is 77.53 times that of the standard NLO material urea and the title compound and its derivatives are attractive object for future studies of nonlinear optical properties. Molecular docking results suggest that the compound might exhibit inhibitory activity against GPb. PMID:25791883

  4. Effects of essential oil treatments on the secondary protein structure of Vicia faba: a mid-infrared spectroscopic study supported by two-dimensional correlation analysis.

    PubMed

    Mecozzi, Mauro; Sturchio, Elena

    2015-02-25

    In this study we investigated the effects of essential oil treatments on the secondary protein structure of the Vicia faba roots, a bioindicator plant, in order to obtain information for the potential allelopathic uses of these oils as alternative to the use of pesticides in agriculture. We tested two mixtures of essential oils consisting of Tween 20-emulsions of tea tree oil (TTO) and Tween 20-emulsion of Clove and Rosemary (GARROM) essential oils respectively at three different oil concentrations each. The molecular modifications caused in Vicia faba by exposure to oil emulsions were investigated by FTIR spectroscopy in diffuse reflectance (DRIFT) mode. We considered the specific Amide I, Amide II and Amide VI bands by ordinary and second derivative spectroscopy and the results showed that both Tween 20-emulsion of GARROM and Tween 20-emulsion of TTO oils cause transitions among the secondary (?-helix, ?-sheet and ?-turn) structures with in addition the appearance of random coil structures in exposed samples. The Amide VI bands, placed between 500 and 600 cm(-1), confirmed the structural transitions observed for the Amide I bands. In addition we observed the presence of a protein oxidation effect for TTO treated samples, oxidation which resulted negligible instead for the GARROM oil samples. At last, FTIR spectra were also submitted to two-dimensional correlation analysis (2DCORR) and double two-dimensional correlation analysis (D2DCORR); the results confirmed the different effects caused by the two typologies of essential oils on the secondary protein structures of Vicia faba roots. PMID:25203214

  5. Spectroscopic investigation (FT-IR, FT-Raman and SERS), vibrational assignments, HOMO-LUMO analysis and molecular docking study of Opipramol.

    PubMed

    Mary, Y Sheena; Panicker, C Yohannan; Kavitha, C N; Yathirajan, H S; Siddegowda, M S; Cruz, Sandra M A; Nogueira, Helena I S; Al-Saadi, Abdulaziz A; Van Alsenoy, Christian; War, Javeed Ahmad

    2015-02-25

    FT-IR and FT-Raman spectra of Opipramol were recorded and analyzed. SERS spectrum was recorded in silver colloid. The vibrational wave numbers were computed using DFT quantum chemical calculations. The data obtained from wave number calculations are used to assign vibrational bands obtained in infrared and Raman spectra as well as in SERS of the studied molecule. Potential energy distribution was done using GAR2PED program. The geometrical parameters (DFT) of the title compound are in agreement with the XRD results. The presence of CH2 stretching modes in the SERS spectrum indicates the close of piperazine ring with the metal surface and the interaction of the silver surface with this moiety. NBO analysis, HOMO-LUMO, first hyperpolarizability and molecular electrostatic potential results are also reported. The inhibitor Opipramol forms a stable complex with P4502C9 as is evident from the ligand-receptor interactions and a -9.0 kcal/mol docking score and may be an effective P4502C9 inhibitor if further biological explorations are carried out. PMID:25240828

  6. Spectroscopic investigation (FT-IR, FT-Raman and SERS), vibrational assignments, HOMO-LUMO analysis and molecular docking study of Opipramol

    NASA Astrophysics Data System (ADS)

    Mary, Y. Sheena; Panicker, C. Yohannan; Kavitha, C. N.; Yathirajan, H. S.; Siddegowda, M. S.; Cruz, Sandra M. A.; Nogueira, Helena I. S.; Al-Saadi, Abdulaziz A.; Van Alsenoy, Christian; War, Javeed Ahmad

    2015-02-01

    FT-IR and FT-Raman spectra of Opipramol were recorded and analyzed. SERS spectrum was recorded in silver colloid. The vibrational wave numbers were computed using DFT quantum chemical calculations. The data obtained from wave number calculations are used to assign vibrational bands obtained in infrared and Raman spectra as well as in SERS of the studied molecule. Potential energy distribution was done using GAR2PED program. The geometrical parameters (DFT) of the title compound are in agreement with the XRD results. The presence of CH2 stretching modes in the SERS spectrum indicates the close of piperazine ring with the metal surface and the interaction of the silver surface with this moiety. NBO analysis, HOMO-LUMO, first hyperpolarizability and molecular electrostatic potential results are also reported. The inhibitor Opipramol forms a stable complex with P4502C9 as is evident from the ligand-receptor interactions and a -9.0 kcal/mol docking score and may be an effective P4502C9 inhibitor if further biological explorations are carried out.

  7. Continuous spectroscopic analysis of vanadous and vanadic ions

    SciTech Connect

    Bishop, J.V.; Dutcher, R.A.; Fisher, M.S.; Kottle, S.; Stowe, R.A. [Omni Tech International Ltd., Midland, MI (United States)

    1993-10-01

    Spectroscopic methods were investigated for the determination of vanadium ions in aqueous solutions arising in the production of vanadium (11) formate and its use in the LOMI (Low Oxidation-state Metal Ion) process for the chemical decontamination of systems in nuclear power plants. In the LOMI process, a dilute solution of vanadous formate and picolinic acid is used. The vanadous formate n reduces metal oxides in the scale on the equipment, causing the scale to break up and become suspended. The picolinic acid chelates these materials and makes them soluble. During the decontamination the progress is followed by analyses of the metal ions and of the radioactivity. When the values stop increasing, the decontamination is terminated. At present, it cannot be determined if the values are no longer changing due to all the scale being removed or due to the vanadous ion being spent. Infrared and ultraviolet-visible analysis were investigated as the means of analyzing for vanadium species. It was found that the complex formed by V(II) with picolinic acid could be used for colorimetric analysis for V(II) in the range of 0 {minus} 0.011 moles/liter, which encompasses the concentration range used in the LOMI process. The findings will be used to develop an on-line instrument for continuously monitoring V(II) during decontamination.

  8. Conformational analysis, spectroscopic study (FT-IR, FT-Raman, UV, 1H and 13C NMR), molecular orbital energy and NLO properties of 5-iodosalicylic acid.

    PubMed

    Karaca, Caglar; Atac, Ahmet; Karabacak, Mehmet

    2015-02-01

    In this study, 5-iodosalicylic acid (5-ISA, C7H5IO3) is structurally characterized by FT-IR, FT-Raman, NMR and UV spectroscopies. There are eight conformers, Cn, n=1-8 for this molecule therefore the molecular geometry for these eight conformers in the ground state are calculated by using the ab-initio density functional theory (DFT) B3LYP method approach with the aug-cc-pVDZ-PP basis set for iodine and the aug-cc-pVDZ basis set for the other elements. The computational results identified that the most stable conformer of 5-ISA is the C1 form. The vibrational spectra are calculated DFT method invoking the same basis sets and fundamental vibrations are assigned on the basis of the total energy distribution (TED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method with PQS program. Total density of state (TDOS) and partial density of state (PDOS) and also overlap population density of state (COOP or OPDOS) diagrams analysis for C1 conformer were calculated using the same method. The energy and oscillator strength are calculated by time-dependent density functional theory (TD-DFT) results complement with the experimental findings. Besides, charge transfer occurring in the molecule between HOMO and LUMO energies, frontier energy gap, molecular electrostatic potential (MEP) are calculated and presented. The NMR chemical shifts ((1)H and (13)C) spectra are recorded and calculated using the gauge independent atomic orbital (GIAO) method. Mulliken atomic charges of the title molecule are also calculated, interpreted and compared with salicylic acid. The optimized bond lengths, bond angles and calculated NMR and UV, vibrational wavenumbers showed the best agreement with the experimental results. PMID:25448933

  9. Raman spectroscopic study of a genetically altered kidney cell

    NASA Astrophysics Data System (ADS)

    Joshi, Joel; Garcia, Francisco; Centeno, Silvia P.; Joshi, N. V.

    2008-02-01

    A Raman spectroscopic investigation of a genetically altered Human Embryonic Kidney Cell (HEK293) along with a pathologically normal cell has been carried out by a conventional method. The genetic alteration was carried out with a standard protocol by using a Green Fluorescence Protein (GFP). Raman spectra show that there are dramatic differences between the spectrum obtained from a genetically altered cell and that obtained from a pathologically normal cell. The former shows three broad bands; meanwhile the latter shows several sharp peaks corresponding to the ring vibrational modes of Phen, GFP and DNA. The present analysis provides an indication that the force field near Phen located at 64, 65 and 66 was altered during the genetic transformation. The Raman spectrum could be a direct experimental evidence for substantial modifications triggered due to the expression of specific genes.

  10. Millimeter and Submillimeter Spectroscopic Studies of HO_3

    NASA Astrophysics Data System (ADS)

    Zou, Luyao; Widicus Weaver, Susanna L.

    2014-06-01

    HO_3 is a radical species of atmospheric and astrophysical chemical importance. While the microwave spectrum of this radical is known, its rotational spectrum has not been measured at higher frequencies. Studies of HO_3 in the millimeter and submillimeter ranges would provide the information needed to further refine its structural determination, as well as provide additional spectroscopic guidance for observational searches. In order to study the rotational spectrum of HO_3 at higher frequencies, we have coupled a pulsed supersonic expansion discharge source with a multipass direct absorption millimeter and submillimeter spectrometer. Initial experiments focused on the optimization of the HO_2 radical, which has a known rotational spectrum and is the intermediate species in the production of HO_3. Searches for lines of HO_3 are currently underway. The spectrometer design, results of the HO_2 studies, and initial results for HO_3 will be presented.

  11. Spectroscopic studies of interactions involving horseradish peroxidase and Tb3+.

    PubMed

    Guo, Shaofen; Zhou, Qing; Lu, Tianhong; Ding, Xiaolan; Huang, Xiaohua

    2008-09-01

    The spectroscopic properties of interactions involving horseradish peroxidase (HRP) and Tb3+ in the simulated physiological solution was investigated with some electrochemical and spectroscopic methods, such as cyclic voltammetry (CV), circular dichroism (CD), X-ray photoelectron spectroscopy (XPS) and synchronous fluorescence (SF). It was found that Tb3+ can coordinate with oxygen atoms in carbonyl groups in the peptide chain of HRP, form the complex of Tb3+ and HRP (Tb-HRP), and then lead to the conformation change of HRP. The increase in the random coil content of HRP can disturb the microstructure of the heme active center of HRP, in which the planarity of the porphyrin cycle in the heme group is increased and then the exposure extent of the electrochemical active center is decreased. Thus Tb3+ can inhibit the electrochemical reaction of HRP and its electrocatalytic activity for the reduction of H2O2 at the Au/Cys/GC electrode. The changes in the microstructure of HRP obstructed the electron transfer of Fe(III) in the porphyrin cycle of the heme group, thus HRP catalytic activity is inhibited. The inhibition effect of Tb3+ on HRP catalytic activity is increased with the increasing of Tb3+ concentration. This study would provide some references for better understanding the rare earth elements and heavy metals on peroxidase toxicity in living organisms. PMID:18024195

  12. Photometric and Spectroscopic Analysis for the Determination of Physical Parameters of an Eclipsing Binary Star System

    NASA Astrophysics Data System (ADS)

    Reid, Piper

    2013-01-01

    A binary star system is a pair of stars that are bound together by gravity. Most of the stars that we see in the night sky are members of multiple star systems. A system of stars where one star passes in front of the other (as observed from Earth) on a periodic basis is called an eclipsing binary. Eclipsing binaries can have very short rotational periods and in all cases these pairs of stars are so far away that they can only be resolved from Earth as a single point of light. The interaction of the two stars serves to produce physical phenomena that can be observed and used to study stellar properties. By careful data collection and analysis is it possible for an amateur astronomer using commercial, low cost equipment (including a home built spectroscope) to gather photometric (brightness versus time) and spectroscopic (brightness versus wavelength) data, analyze the data, and calculate the physical properties of a binary star system? Using a CCD camera, tracking mount and telescope photometric data of BB Pegasi was collected and a light curve produced. 57 Cygni was also studied using a spectroscope, tracking mount and telescope to prove that Doppler shift of Hydrogen Balmer absorption lines can be used to determine radial velocity. The orbital period, orbital velocity, radius of each star, separation of the two stars and mass of each star was calculated for the eclipsing binary BB Pegasi using photometric and spectroscopic data and Kepler’s 3rd Law. These data were then compared to published data. By careful use of consumer grade astronomical equipment it is possible for an amateur astronomer to determine an array of physical parameters of a distant binary star system from a suburban setting.

  13. Exploring AGN Unification through Mid-Infrared Spectroscopic Analysis

    NASA Astrophysics Data System (ADS)

    Thompson, Grant D.; Macnamara, Murray E.

    2015-01-01

    The emission of silicate dust and species of low- and high-ionization dominate the mid-infrared (MIR) spectra of active galactic nuclei (AGN). The dust, expected to be in a toroidal distribution about a central, supermassive black hole, may or may not obscure optical broad-line emission emanating from within, providing the type 2 and type 1 AGN classes, respectively. In the context of AGN unification, type 1 and 2 AGN may inherently be similar objects which are distinguished by the viewing angle of the observer. Many avenues have been explored to decipher AGN unification, or the lack thereof. We present the findings of a two method approach analyzing an archival sample of AGN observed by the Infrared Spectrograph aboard the Spitzer Space Telescope. The first approach implements MIR spectral energy distributions to determine the arrangement of dust within the torus and if there are similarities between the AGN classes. The second is a comparative analysis of prominent MIR ionization lines between the two AGN classes. We also discuss implications of the star formation present in the MIR spectroscopic observations and their potential influence on the premise of AGN unification.

  14. Quantum mechanical study and spectroscopic (FT-IR, FT-Raman, UV-Visible) study, potential energy surface scan, Fukui function analysis and HOMO-LUMO analysis of 3-tert-butyl-4-methoxyphenol by DFT methods

    NASA Astrophysics Data System (ADS)

    Saravanan, S.; Balachandran, V.

    2014-09-01

    This study represents an integral approach towards understanding the electronic and structural aspects of 3-tert-butyl-4-methoxyphenol (TBMP). Fourier-transform Infrared (FT-IR) and Fourier-transform Raman (FT-Raman) spectra of TBMP was recorded in the region 4000-400 cm-1 and 3500-100 cm-1, respectively. The molecular structures, vibrational wavenumbers, infrared intensities and Raman activities were calculated using DFT (B3LYP and LSDA) methods using 6-311++G (d,p) basis set. The most stable conformer of TBMP was identified from the computational results. The assignments of vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The first order hyperpolarizability (?0) and related properties (?, ?0 and ??) of TBMP have been discussed. The stability and charge delocalization of the molecule was studied by Natural Bond Orbital (NBO) analysis. UV-Visible spectrum and effects of solvents have been discussed and the electronic properties such as HOMO and LUMO energies were determined by time-dependent TD-DFT approach with B3LYP/6-311++G (d,p) level of theory. The molecule orbital contributions are studied by density of energy states (DOSs). The reactivity sites are identified by mapping the electron density into electrostatic potential surface (MEP). Mulliken analysis of atomic charges is also calculated. The thermodynamic properties at different temperatures were calculated, revealing the correlations between standard heat capacities, standard entropy and standard enthalpy changes with temperatures. Global hardness, global softness, global electrophilicity and ionization potential of the title compound are determined.

  15. Quantum mechanical study and spectroscopic (FT-IR, FT-Raman, UV-Visible) study, potential energy surface scan, Fukui function analysis and HOMO-LUMO analysis of 3-tert-butyl-4-methoxyphenol by DFT methods.

    PubMed

    Saravanan, S; Balachandran, V

    2014-09-15

    This study represents an integral approach towards understanding the electronic and structural aspects of 3-tert-butyl-4-methoxyphenol (TBMP). Fourier-transform Infrared (FT-IR) and Fourier-transform Raman (FT-Raman) spectra of TBMP was recorded in the region 4000-400 cm(-1) and 3500-100 cm(-1), respectively. The molecular structures, vibrational wavenumbers, infrared intensities and Raman activities were calculated using DFT (B3LYP and LSDA) methods using 6-311++G (d,p) basis set. The most stable conformer of TBMP was identified from the computational results. The assignments of vibrational spectra have been carried out with the help of normal co-ordinate analysis (NCA) following the scaled quantum mechanical force field (SQMFF) methodology. The first order hyperpolarizability (?0) and related properties (?, ?0 and ??) of TBMP have been discussed. The stability and charge delocalization of the molecule was studied by Natural Bond Orbital (NBO) analysis. UV-Visible spectrum and effects of solvents have been discussed and the electronic properties such as HOMO and LUMO energies were determined by time-dependent TD-DFT approach with B3LYP/6-311++G (d,p) level of theory. The molecule orbital contributions are studied by density of energy states (DOSs). The reactivity sites are identified by mapping the electron density into electrostatic potential surface (MEP). Mulliken analysis of atomic charges is also calculated. The thermodynamic properties at different temperatures were calculated, revealing the correlations between standard heat capacities, standard entropy and standard enthalpy changes with temperatures. Global hardness, global softness, global electrophilicity and ionization potential of the title compound are determined. PMID:24813291

  16. DFT electronic structure calculations, spectroscopic studies, and normal coordinate analysis of 2-[(5-nitro-1,3-thiazol-2-yl)carbamoyl]phenyl acetate.

    PubMed

    Muthu, S; Elamuruguporchelvi, E; Varghese, Anitha

    2015-03-01

    The solid phase FTIR and FT-Raman spectra of 2-[(5-nitro-1,3-thiazol-2-yl)carbamoyl]phenyl acetate (25N2LCPA) have been recorded 450-4000cm(-1) and 100-4000cm(-1) respectively. The normal coordinate analysis was carried out to confirm the precision of the assignments. DFT calculations have been performed giving energies, optimized structures, harmonic vibrational frequencies and IR intensities. The structure of the molecule was optimized and the structural characteristics were determined by density functional theory (DFT) using B3LYP method with 6-31+G(d,p) basis set. The detailed interpretation of the vibrational spectra has been carried out with aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology. The Vibrational frequencies are calculated in the above method and are compared with experimental frequencies which yield good agreement between observed and calculated frequencies. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. In addition, Frontiers molecular orbital and molecular electrostatic potential were computed by using Density Functional Theory (DFT) B3LYP/6-31+G(d,p) basis set. The calculated HOMO and LUMO energies show that charge transfer occurs in the molecule. PMID:25544190

  17. DFT electronic structure calculations, spectroscopic studies, and normal coordinate analysis of 2-[(5-nitro-1,3-thiazol-2-yl)carbamoyl]phenyl acetate

    NASA Astrophysics Data System (ADS)

    Muthu, S.; Elamuruguporchelvi, E.; Varghese, Anitha

    2015-03-01

    The solid phase FTIR and FT-Raman spectra of 2-[(5-nitro-1,3-thiazol-2-yl)carbamoyl]phenyl acetate (25N2LCPA) have been recorded 450-4000 cm-1 and 100-4000 cm-1 respectively. The normal coordinate analysis was carried out to confirm the precision of the assignments. DFT calculations have been performed giving energies, optimized structures, harmonic vibrational frequencies and IR intensities. The structure of the molecule was optimized and the structural characteristics were determined by density functional theory (DFT) using B3LYP method with 6-31+G(d,p) basis set. The detailed interpretation of the vibrational spectra has been carried out with aid of normal coordinate analysis (NCA) following the scaled quantum mechanical force field methodology. The Vibrational frequencies are calculated in the above method and are compared with experimental frequencies which yield good agreement between observed and calculated frequencies. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. In addition, Frontiers molecular orbital and molecular electrostatic potential were computed by using Density Functional Theory (DFT) B3LYP/6-31+G(d,p) basis set. The calculated HOMO and LUMO energies show that charge transfer occurs in the molecule.

  18. A Planetary Environment and Analysis Chamber Equipped with Multiple Spectroscopic Sensors

    NASA Astrophysics Data System (ADS)

    Sobron, P.; Wang, A.

    2010-03-01

    A Planetary Environment and Analysis Chamber (PEACH) has been developed at Washington University in St. Louis, in order to conduct co-registered spectroscopic measurements on geological samples under planetary relevant environmental conditions.

  19. Spectroscopic study of the open cluster NGC 6811

    NASA Astrophysics Data System (ADS)

    Molenda-?akowicz, J.; Brogaard, K.; Niemczura, E.; Bergemann, M.; Frasca, A.; Arentoft, T.; Grundahl, F.

    2014-12-01

    The NASA space telescope Kepler has provided unprecedented time series observations which have revolutionized the field of asteroseismology, i.e. the use of stellar oscillations to probe the interior of stars. The Kepler-data include observations of stars in open clusters, which are particularly interesting for asteroseismology. One of the clusters observed with Kepler is NGC 6811, which is the target of this paper. However, apart from high-precision time series observations, sounding the interiors of stars in open clusters by means of asteroseismology also requires accurate and precise atmospheric parameters as well as cluster membership indicators for the individual stars. We use medium-resolution (R ˜ 25 000) spectroscopic observations, and three independent analysis methods, to derive effective temperatures, surface gravities, metallicities, projected rotational velocities and radial velocities, for 15 stars in the field of the open cluster NGC 6811. We discover two double-lined and three single-lined spectroscopic binaries. Eight stars are classified as either certain or very probable cluster members, and three stars are classified as non-members. For four stars, cluster membership could not been assessed. Five of the observed stars are G-type giants which are located in the colour-magnitude diagram in the region of the red clump of the cluster. Two of these stars are surely identified as red clump stars for the first time. For those five stars, we provide chemical abundances of 31 elements. The mean radial velocity of NGC 6811 is found to be +6.68 ± 0.08 km s-1 and the mean metallicity and overall abundance pattern are shown to be very close to solar with an exception of Ba which we find to be overabundant.

  20. Vibrational spectroscopic (FT-IR and FT-Raman) studies, natural bond orbital analysis and molecular electrostatic potential surface of 3-hydroxy-6-methyl-2-nitropyridine

    NASA Astrophysics Data System (ADS)

    Karnan, M.; Balachandran, V.; Murugan, M.

    2012-10-01

    The optimized molecular structure and corresponding vibrational assignments of 3-hydroxy-6-methyl-2-nitropyridine have been investigated using density functional theory (DFT) B3LYP method with 6-311++G(d,p), 6-311++G(2d,2p) and 6-311++G(3d,3p) basis sets. Investigation of the relative orientation of the hydroxyl group with respect to the nitro group has shown that two conformers (O-cis) and (O-trans) exist. The vibrational analysis of the stable conformer of the title compound is performed by means of infrared absorption and Raman spectroscopy in combination with theoretical simulations. The molecular stability and bond strength were investigated by applying the natural bond orbital (NBO) analysis. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecule has been obtained by mapping electron density isosurface with electrostatic potential (ESP). The isotropic chemical shift computed by 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the HMNP calculated using the gauge invariant atomic orbital (GIAO) method also shows good agreement with experimental observations.

  1. Spectroscopic study of Gd nanostructures quantum confined in Fe corrals.

    PubMed

    Cao, R X; Sun, L; Miao, B F; Li, Q L; Zheng, C; Wu, D; You, B; Zhang, W; Han, P; Bader, S D; Zhang, W Y; Ding, H F

    2015-01-01

    Low dimensional nanostructures have attracted attention due to their rich physical properties and potential applications. The essential factor for their functionality is their electronic properties, which can be modified by quantum confinement. Here the electronic states of Gd atom trapped in open Fe corrals on Ag(111) were studied via scanning tunneling spectroscopy. A single spectroscopic peak above the Fermi level is observed after Gd adatoms are trapped inside Fe corrals, while two peaks appear in empty corrals. The single peak position is close to the higher energy peak of the empty corrals. These findings, attributed to quantum confinement of the corrals and Gd structures trapped inside, are supported by tight-binding calculations. This demonstrates and provides insights into atom trapping in open corrals of various diameters, giving an alternative approach to modify the properties of nano-objects. PMID:26160318

  2. Spectroscopic study of Gd nanostructures quantum confined in Fe corrals

    PubMed Central

    Cao, R. X.; Sun, L.; Miao, B. F.; Li, Q. L.; Zheng, C.; Wu, D.; You, B.; Zhang, W.; Han, P.; Bader, S. D.; Zhang, W. Y.; Ding, H. F.

    2015-01-01

    Low dimensional nanostructures have attracted attention due to their rich physical properties and potential applications. The essential factor for their functionality is their electronic properties, which can be modified by quantum confinement. Here the electronic states of Gd atom trapped in open Fe corrals on Ag(111) were studied via scanning tunneling spectroscopy. A single spectroscopic peak above the Fermi level is observed after Gd adatoms are trapped inside Fe corrals, while two peaks appear in empty corrals. The single peak position is close to the higher energy peak of the empty corrals. These findings, attributed to quantum confinement of the corrals and Gd structures trapped inside, are supported by tight-binding calculations. This demonstrates and provides insights into atom trapping in open corrals of various diameters, giving an alternative approach to modify the properties of nano-objects. PMID:26160318

  3. Detection and Monitoring of Neurotransmitters - a Spectroscopic Analysis

    NASA Astrophysics Data System (ADS)

    Manciu, Felicia; Lee, Kendall; Durrer, William; Bennet, Kevin

    2012-10-01

    In this work we demonstrate the capability of confocal Raman mapping spectroscopy for simultaneously and locally detecting important compounds in neuroscience such as dopamine, serotonin, and adenosine. The Raman results show shifting of the characteristic vibrations of the compounds, observations consistent with previous spectroscopic studies. Although some vibrations are common in these neurotransmitters, Raman mapping was achieved by detecting non-overlapping characteristic spectral signatures of the compounds, as follows: for dopamine the vibration attributed to C-O stretching, for serotonin the indole ring stretching vibration, and for adenosine the adenine ring vibrations. Without damage, dyeing, or preferential sample preparation, confocal Raman mapping provided positive detection of each neurotransmitter, allowing association of the high-resolution spectra with specific micro-scale image regions. Such information is particularly important for complex, heterogeneous samples, where modification of the chemical or physical composition can influence the neurotransmission processes. We also report an estimated dopamine diffusion coefficient two orders of magnitude smaller than that calculated by the flow-injection method.

  4. A Spectroscopic-Based Laboratory Experiment for Protein Conformational Studies

    ERIC Educational Resources Information Center

    Ramos, Carlos Henrique I.

    2004-01-01

    This article describes a practical experiment for teaching basic spectroscopic techniques to introduce the topic of protein conformational change to students in the field of molecular biology, biochemistry, or structural biology. The spectroscopic methods employed in the experiment are absorbance, for protein concentration measurements, and…

  5. Vibrational spectroscopic (FT-IR and FT-Raman) studies, natural bond orbital analysis and molecular electrostatic potential surface of Isoxanthopterin

    NASA Astrophysics Data System (ADS)

    Prabavathi, N.; Nilufer, A.; Krishnakumar, V.

    2013-10-01

    The FTIR and FT-Raman spectra of Isoxanthopterin have been recorded in the region 4000-450 and 4000-100 cm-1, respectively. The optimized geometry, frequency and intensity of the vibrational bands of Isoxanthopterin were obtained by the density functional theory (DFT) using 6-311++G(d,p) basis set. The harmonic vibrational frequencies were scaled and compared with experimental values. The observed and the calculated frequencies are found to be in good agreement. The 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were also calculated using the gauge independent atomic orbital (GIAO) method. The UV-visible spectrum was also recorded and compared with the theoretical values. The calculated HOMO and LUMO energies show that charge transfer occurs within molecule. The first order hyperpolarizability (?0), related properties (?, ?0 and ??) and the Mulliken charges of the molecule were also computed using DFT calculations. Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The results show that charge in electron density (ED) in the ?* and ?* antibonding orbitals and second order delocalization energies (E2) confirms the occurrence of intramolecular charge transfer (ICT) within the molecule. Information about the charge density distribution of the molecule and its chemical reactivity has been obtained by mapping molecular electrostatic potential surface. In addition, the non-linear optical properties were discussed from the dipole moment values and excitation wavelength in the UV-visible region.

  6. Vibrational spectroscopic (FT-IR and FT-Raman) studies, natural bond orbital analysis and molecular electrostatic potential surface of Isoxanthopterin.

    PubMed

    Prabavathi, N; Nilufer, A; Krishnakumar, V

    2013-10-01

    The FTIR and FT-Raman spectra of Isoxanthopterin have been recorded in the region 4000-450 and 4000-100 cm(-1), respectively. The optimized geometry, frequency and intensity of the vibrational bands of Isoxanthopterin were obtained by the density functional theory (DFT) using 6-311++G(d,p) basis set. The harmonic vibrational frequencies were scaled and compared with experimental values. The observed and the calculated frequencies are found to be in good agreement. The (1)H and (13)C nuclear magnetic resonance chemical shifts of the molecule were also calculated using the gauge independent atomic orbital (GIAO) method. The UV-visible spectrum was also recorded and compared with the theoretical values. The calculated HOMO and LUMO energies show that charge transfer occurs within molecule. The first order hyperpolarizability (?0), related properties (?, ?0 and ??) and the Mulliken charges of the molecule were also computed using DFT calculations. Stability of the molecule arising from hyperconjugative interactions, charge delocalization have been analyzed using natural bond orbital (NBO) analysis. The results show that charge in electron density (ED) in the ?* and ?* antibonding orbitals and second order delocalization energies (E2) confirms the occurrence of intramolecular charge transfer (ICT) within the molecule. Information about the charge density distribution of the molecule and its chemical reactivity has been obtained by mapping molecular electrostatic potential surface. In addition, the non-linear optical properties were discussed from the dipole moment values and excitation wavelength in the UV-visible region. PMID:23751224

  7. Vibrational spectroscopic (FTIR and FT Raman) studies, first order hyperpolarizabilities and HOMO, LUMO analysis of p-toluenesulfonyl isocyanate using ab initio HF and DFT methods.

    PubMed

    Parimala, K; Balachandran, V

    2011-10-15

    The Fourier transform infrared (FTIR) and FT Raman spectra of p-toluenesulfonyl isocyanate (p-tosyl isocyanate) have been measured. The molecular geometry, vibrational frequencies, infrared intensities, Raman activities and atomic charges have been calculated by using ab initio HF and density functional theory calculation (B3LYP) with 6-311+G(d,p) basis set. Complete vibrational assignment and analysis of the fundamental modes of the compound were carried out using the observed FTIR and FT Raman data. The thermodynamic functions of the title compound were also performed with the aid of HF/6-311+G(d,p) and B3LYP/6-311+G(d,p) levels of theory. Simulated FTIR and FT Raman spectra for p-tosyl isocyanate showed good agreement with the observed spectra. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. The dipole moment (?), polarizability (?) and the hyperpolarizability (?) values of the investigated molecule have been computed using HF and B3LYP methods. PMID:21795105

  8. Spectroscopic, electronic structure and natural bond analysis of 2-aminopyrimidine and 4-aminopyrazolo[3,4-d]pyrimidine: a comparative study.

    PubMed

    Prabavathi, N; Nilufer, A; Krishnakumar, V; Akilandeswari, L

    2012-10-01

    The FTIR and FT-Raman spectra of 2-aminopyrimidine (2-AP) and 4-aminopyrazolo[3,4-d]pyrimidine (4-APP) has been recorded in the region 4000-400 and 3500-100 cm(-1), respectively. The tautomeric stability, optimized geometry, frequency and intensity of the vibrational bands of 2-AP and 4-APP were obtained by the DFT level using 6-31G(d) and 6-31G(d,p) basis sets. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FTIR and FT-Raman spectra. A detailed interpretation of the infrared and Raman spectra of 2-AP and 4-APP are also reported based on total energy distribution (TED). The observed and the calculated frequencies are found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theoretically simulated spectra. The (1)H and (13)C NMR spectra have been simulated using the gauge independent atomic orbital (GIAO) method. The theoretical UV-Vis spectrum of the compound using CIS method and the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The calculated HOMO and LUMO energies show that charge transfer occurs within molecule. The first order hyperpolarizability (?(0)) of these novel molecular system and related properties (?, ?(0) and ??) of 2-AP and 4-APP are calculated using DFT/6-31G(d) method on the finite-field approach. The Mulliken charges, the values of electric dipole moment (?) of the molecule were computed using DFT calculations. The change in electron density (ED) in the ?(?) antibonding orbitals and stabilization energies E(2) have been calculated by natural bond (NBO) analysis to give clear evidence of stabilization originating in the hyper conjugation of hydrogen-bonded interactions. PMID:22683558

  9. Spectroscopic, electronic structure and natural bond analysis of 2-aminopyrimidine and 4-aminopyrazolo[3,4-d]pyrimidine: A comparative study

    NASA Astrophysics Data System (ADS)

    Prabavathi, N.; Nilufer, A.; Krishnakumar, V.; Akilandeswari, L.

    2012-10-01

    The FTIR and FT-Raman spectra of 2-aminopyrimidine (2-AP) and 4-aminopyrazolo[3,4-d]pyrimidine (4-APP) has been recorded in the region 4000-400 and 3500-100 cm-1, respectively. The tautomeric stability, optimized geometry, frequency and intensity of the vibrational bands of 2-AP and 4-APP were obtained by the DFT level using 6-31G(d) and 6-31G(d,p) basis sets. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FTIR and FT-Raman spectra. A detailed interpretation of the infrared and Raman spectra of 2-AP and 4-APP are also reported based on total energy distribution (TED). The observed and the calculated frequencies are found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theoretically simulated spectra. The 1H and 13C NMR spectra have been simulated using the gauge independent atomic orbital (GIAO) method. The theoretical UV-Vis spectrum of the compound using CIS method and the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The calculated HOMO and LUMO energies show that charge transfer occurs within molecule. The first order hyperpolarizability (?0) of these novel molecular system and related properties (?, ?0 and ??) of 2-AP and 4-APP are calculated using DFT/6-31G(d) method on the finite-field approach. The Mulliken charges, the values of electric dipole moment (?) of the molecule were computed using DFT calculations. The change in electron density (ED) in the ?? antibonding orbitals and stabilization energies E(2) have been calculated by natural bond (NBO) analysis to give clear evidence of stabilization originating in the hyper conjugation of hydrogen-bonded interactions.

  10. Diagnostic Chemical Analysis of Exhaled Human Breath Using a Novel Sub-Millimeter Spectroscopic Approach

    NASA Astrophysics Data System (ADS)

    Fosnight, Alyssa M.; Moran, Benjamin L.; Branco, Daniela R.; Thomas, Jessica R.; Medvedev, Ivan R.

    2013-06-01

    As many as 3000 chemicals are reported to be found in exhaled human breath. Many of these chemicals are linked to certain health conditions and environmental exposures. Present state of the art techniques used for analysis of exhaled human breath include mass spectrometry based methods, infrared spectroscopic sensors, electro chemical sensors and semiconductor oxide based testers. Some of these techniques are commercially available but are somewhat limited in their specificity and exhibit fairly high probability of false alarm. Here, we present the results of our most recent study which demonstrated a novel application of a terahertz high resolutions spectroscopic technique to the analysis of exhaled human breath, focused on detection of ethanol in the exhaled breath of a person which consumed an alcoholic drink. This technique possesses nearly ``absolute'' specificity and we demonstrated its ability to uniquely identify ethanol, methanol, and acetone in human breath. This project is now complete and we are looking to extend this method of chemical analysis of exhaled human breath to a broader range of chemicals in an attempt to demonstrate its potential for biomedical diagnostic purposes.

  11. Spectroscopic study of early-type multiple stellar systems. I. Orbits of spectroscopic binary subsystems

    NASA Astrophysics Data System (ADS)

    Veramendi, M. E.; González, J. F.

    2014-03-01

    Context. The present knowledge of stellar properties and dynamical structure of early-type multiple stellar systems is insufficient to offer useful statistical constraints for stellar formation models. Aims: To increase the amount of observational information about the characteristics of early-type multiples, we carried out a spectroscopic monitoring to search for new spectroscopic components and to determine their orbits. Methods: We observed 30 early-type multiple systems using the 2.15 m telescope and REOSC echelle spectrograph at the Complejo Astronómico El Leoncito (CASLEO) during 10 observing runs between 2008 and 2013. We measured radial velocities by cross-correlations and applied a spectral disentangling method to double-lined systems. We calculated orbital elements for the inner subsystem of each analysed multiple. Results: In this first paper we present calculated orbits for six previously catalogued subsystems. Three subsystems had no previously published parameters, while we obtained more accurate orbits for the other three. In one case we found absolute masses and radii for the components by using available photometric data. Conclusions: The long-term spectroscopic monitoring of multiple systems is a useful method of investigating the companions in intermediate hierarchical levels, particularly those that could affect the dynamical evolution of a close inner binary subsystem. Reduced spectra are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/563/A138 Warning, no authors found for 2014A&A...564A..12.

  12. A photometric and spectroscopic study of BG Canis Minoris.

    NASA Astrophysics Data System (ADS)

    de Martino, D.; Mouchet, M.; Bonnet-Bidaud, J. M.; Vio, R.; Rosen, S. R.; Mukai, K.; Augusteijn, T.; Garlick, M. A.

    1995-06-01

    The photometric and spectroscopic analysis presented here has revealed new observational features in the Intermediate Polar BG CMi. We have found a strong variability of the dominant light pulsations, rotational (913s) and orbital (3.23hr), on a timescale of years. Variations in the amplitude of the spin pulsation with epoch generally appear to be anti-correlated with that of the orbital modulation with the former decreasing while the latter increases. We do not find stable periodic signals at other frequencies as well as no indication of periodicity at the 847s X-ray period. UV and optical orbital continuum modulations reveal two components at different temperatures. The hot contribution is identified with the bulge (the heated face of the hot-spot) and the cool one with the hot-spot itself eclipsed by the secondary star. Orbital phase resolved spectroscopy reveals a rotational disturbance in the HeII emission line, indicating a partial eclipse of circulating material around the white dwarf, possibly in the form of a ring. From the orbital motion of the white dwarf, we also infer that BG CMi is a moderate inclination system (i~55^o^-75^o^).

  13. FT-IR spectroscopic, thermal analysis of human urinary stones and their characterization.

    PubMed

    Selvaraju, R; Raja, A; Thiruppathi, G

    2015-02-25

    In the present study, FT-IR, XRD, TGA-DTA spectral methods have been used to investigate the chemical compositions of urinary calculi. Multi-components of urinary calculi such as calcium oxalate, hydroxyl apatite, struvite and uric acid have been studied. The chemical compounds are identified by FT-IR spectroscopic technique. The mineral identification was confirmed by powder X-ray diffraction patterns as compared with JCPDS reported values. Thermal analysis techniques are considered the best techniques for the characterization and detection of endothermic and exothermic behaviors of the urinary stones. The percentages of each hydrate (COM and COD) are present together, in the presences of MAPH or UA. Finally, the present study suggests that the Urolithiasis is significant health problem in children, and is very common in some parts of the world, especially in India. So that present study is so useful and helpful to the scientific community for identification of latest human health problems and their remedies using spectroscopic techniques. PMID:25306135

  14. X-ray diffraction and vibrational spectroscopic studies of indolecarboxylic acids and their metal complexes

    Microsoft Academic Search

    Barbara Morzyk-Ociepa

    2008-01-01

    In the present studies the novel catena-poly[(di-?3-aqua)(?2-:-?2-indole-3-propionato-O,O?:-O)(?3-indole-3-propionato-O)disodium], [Na2(I3PA)2(H2O)2]n has been synthesized and characterized by X-ray diffraction analysis and infrared and Raman spectroscopic methods. In the [Na2(I3PA)2(H2O)2]n, there are two different crystallographic sites for the Na+ ions, which are coordinated by six and seven oxygen atoms. Moreover, two O-deprotonated I3PA ions exhibit different coordination modes. One I3PA ion acts as a

  15. Hemoglobin-silver interaction and bioconjugate formation: a spectroscopic study.

    PubMed

    Mahato, Mrityunjoy; Pal, Prabir; Kamilya, Tapanendu; Sarkar, Ratan; Chaudhuri, Avinanda; Talapatra, G B

    2010-05-27

    In this article, we report the results of the extent of interaction as well as the formation of a bioconjugate of human hemoglobin (Hb) with silver (Ag). The complexation process and conformational changes are characterized using different spectroscopic and microscopic techniques. The UV-vis study demonstrates the perturbation of the soret/heme band and generates conformational heterogeneity within the heme group in the presence of silver. A fluorescence study suggests that the Tryptophan (Trp) residues of Hb are in a more polar environment after conjugation. Initial fluorescence enhancement with addition of silver is due to metal-enhanced fluorescence. Moreover, the fluorescence quenching after the formation of the Hb-Ag bioconjugate follows the modified Stern-Volmer (S-V) plot. The S-V plot along with the time-resolved fluorescence study indicates the presence of both static and dynamic types of quenching. In addition, the reduction potential values of the entities (Hb-heme, Ag(+), and Trp) indicate the possible electron transfer. The secondary structure calculation from CD and FTIR spectra indicate alpha-helix to beta-sheet conversion, and unfolding of Hb is also responsible for the bioconjugate formation. In addition, FE-SEM, phase contrast inverted microscopy (PCIM) images demonstrate the formation of the silver-protein bioconjugate. The overall data show that there is a change in the secondary as well as the tertiary structure of Hb after conjugation with silver. PMID:20433184

  16. Particle in a Disk: A Spectroscopic and Computational Laboratory Exercise Studying the Polycyclic Aromatic Hydrocarbon Corannulene

    ERIC Educational Resources Information Center

    Frey, E. Ramsey; Sygula, Andrzej; Hammer, Nathan I.

    2014-01-01

    This laboratory exercise introduces undergraduate chemistry majors to the spectroscopic and theoretical study of the polycyclic aromatic hydrocarbon (PAH), corannulene. Students explore the spectroscopic properties of corannulene using UV-vis and Raman vibrational spectroscopies. They compare their experimental results to simulated vibrational…

  17. New homotrinuclear lanthanide complexes: synthesis, characterization and spectroscopic study.

    PubMed

    Silva, Wagner E; Belian, Mônica Freire; Freire, Ricardo O; de Sá, Gilberto F; Alves, Severino

    2010-09-23

    This work presents the synthesis and spectroscopic study of new homotrinuclear (TRI) systems for photonics applications. The luminescence spectroscopy shows characteristics transitions of Eu(III) and Tb(III) ions. For the Gd(III) complexes, the triplets states were determined by phosphorescence measurement. The complexes’ coordination geometries were calculated using the Sparkle/AM1 model. For the europium systems, the Sparkle/AM1 geometries were used to calculate all details involved in the energy transfer process, and the theoretical quantum yields were determined. From an energy diagram, that estimates triplet levels, it was possible to understand some experimental phenomenon, such as weak luminescence for precursor complex (without heterocyclics ligands), and ligands emission in terbium complexes. Some of these observations can also be explained by the Jablonski diagrams that describe, based on theoretical calculations, all luminescent process. The synthesized complexes showed high values of quantum yield in ethanolic environment: 50% for EuTRIDipy, 26% EuTRITerpy, and 56% for EuTRIPhen complexes. PMID:20738128

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

  19. Quantum mechanical study and spectroscopic (FT-IR, FT-Raman, (13)C, (1)H) study, first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis of 2-acetoxybenzoic acid by density functional methods.

    PubMed

    Bhavani, K; Renuga, S; Muthu, S; Sankara Narayanan, K

    2014-10-15

    In this work, colorless crystals of 2-acetoxybenzoic acid were grown by slow evaporation method and the FT-IR and FT-Raman spectra of the sample were recorded in the region 4000-500cm(-1) and 4000-100cm(-1) respectively. Molecular structure is optimized with the help of density functional theory method (B3LYP) with 6-31+G(d,p), 6-311++G(d,p) basis sets. Stability of the molecule arising from hyperconjugation and charge delocalization is confirmed by the natural bond orbital analysis (NBO). The results show that electron density (ED) in the ?(?) antibonding orbitals and E(2) energies confirms the occurrence of intramolecular charge transfer (ICT) within the molecule. The assignments of the vibrational spectra have been carried out with the help of normal coordinate analysis following the scaled quantum mechanical force field (SQMFF) methodology. The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The (1)H and (13)C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by GIAO method. Mulliken population analysis on atomic charges is also calculated. The calculated HOMO and LUMO energy gap shows that charge transfer occurs within the molecule. PMID:25456668

  20. Quantum mechanical study and spectroscopic (FT-IR, FT-Raman, 13C, 1H) study, first order hyperpolarizability, NBO analysis, HOMO and LUMO analysis of 2-acetoxybenzoic acid by density functional methods

    NASA Astrophysics Data System (ADS)

    Bhavani, K.; Renuga, S.; Muthu, S.; Sankara narayanan, K.

    2015-02-01

    In this work, colorless crystals of 2-acetoxybenzoic acid were grown by slow evaporation method and the FT-IR and FT-Raman spectra of the sample were recorded in the region 4000-500 cm-1 and 4000-100 cm-1 respectively. Molecular structure is optimized with the help of density functional theory method (B3LYP) with 6-31+G(d,p), 6-311++G(d,p) basis sets. Stability of the molecule arising from hyperconjugation and charge delocalization is confirmed by the natural bond orbital analysis (NBO). The results show that electron density (ED) in the ?? antibonding orbitals and E(2) energies confirms the occurrence of intramolecular charge transfer (ICT) within the molecule. The assignments of the vibrational spectra have been carried out with the help of normal coordinate analysis following the scaled quantum mechanical force field (SQMFF) methodology. The results of the calculations were applied to simulated spectra of the title compound, which show excellent agreement with observed spectra. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecule were calculated by GIAO method. Mulliken population analysis on atomic charges is also calculated. The calculated HOMO and LUMO energy gap shows that charge transfer occurs within the molecule.

  1. A Spectroscopic Study of the Close Binary AG Virginis

    NASA Astrophysics Data System (ADS)

    Kim, Ho-Il; Lee, Chung-Uk; Lee, Jae Woo; Sohn, Mi Rim

    2005-12-01

    We performed a new high-resolution spectroscopy of AG Vir for 4 nights from 25 March 2004 using the BOES (Bohyunsan Optical Echelle Spectrograph) attached to the 1.8-m reflector at Bohyunsan Optical Astronomy Observatory, and obtained a total of 59 spectra where all orbital phases are covered. To get the radial velocities of the binary system, both method of the CCF (Cross-Correlation Function)and the BF (Broadening Function) were applied to the analysis of all the observed spectra. From these, the CCF could calculate the radial velocities of the primary star alone, while the BF could determine those of the primary and the secondary components. New absolute dimensions were deduced with the combination of our spectroscopic orbital elements (K1=90.5km/s-1 K2=258.8) and the photometric solutions of Bell, Rainger, & Hilditch (1990): M1=1.99 M?, M2=0.62 M?, R1=2.21 R?, R2=1.36 R?, L1=13.17 L?, and L2= 3.47 L?. Our absolute parameters are larger and brighter than those derived from Bell, Rainger, & Hilditch (1990). We re-analyzed all the previous radial-velocity curves of AG Vir and, as a result, can see that its system velocity scatters largely up to ± 8km/s. However, we, at present, cannot determine this as the light-time effect due to the third body, which was suggested as a cause of the orbital period changes by Qian (2001)

  2. Comprehensive processing, display and analysis for in vivo MR spectroscopic imaging

    E-print Network

    Hall, Lawrence O.

    Comprehensive processing, display and analysis for in vivo MR spectroscopic imaging A. A. Maudsley and spectral data processing methods and benefits from the use of several sources of prior information processing and analysis can involve multiple processing steps and several different data types. In this paper

  3. Effect of temperature on the methotrexate BSA interaction: Spectroscopic study

    NASA Astrophysics Data System (ADS)

    Su?kowska, A.; Maci??ek, M.; Równicka, J.; Bojko, B.; Pentak, D.; Su?kowski, W. W.

    2007-05-01

    Rheumatoid arthritis (RA) is an autoimmune and chronic inflammatory illness which affects about one percent of the world's population. Methotrexate (4-amino-10-methylfolic acid) (MTX) also known as amethopterin is commonly used to treat rheumatoid arthritis (RA). It is transported in the circulary system as a complex with serum albumin. The aim of this study was to investigate the interactions of MTX with transporting protein with the use of spectroscopic methods. The binding of MTX to bovine serum albumin (BSA) was studied by monitoring the changes in the emission fluorescence spectra of protein in the presence of MTX at excitation wavelength of 280 nm and 295 nm. The quenching of protein fluorescence at temperature range from 298 K to 316 K was observed. Energy transfer between methotrexate and fluorophores contained in the serum albumin structure was found at the molar ratio MTX:BSA 7.5:1. The relative fluorescence intensity of BSA decreases with increase of temperature. Similar results were observed for BSA excited with 280 nm and 295 nm at the same temperature range. The presence of MTX seems to prevent these changes. Temperature dependence of the binding constant has been presented. The binding and quenching constants for equilibrium complex were calculated using Scatchard and Stern-Volmer method, respectively. The results show that MTX forms ?-? complex with aromatic amino acid residues of BSA. The binding site for MTX on BSA was found to be situated in the hydrophobic IIA or IB subdomain where the Trps were located. The spontaneity of MTX-BSA complex formation in the temperature range 298-316 K was ascertained.

  4. A Far Ultraviolet Spectroscopic Analysis of the Old Nova Q Cygni

    NASA Astrophysics Data System (ADS)

    Kolobow, Craig; Sion, E. M.

    2011-01-01

    Q Cygni (Nova Cygni 1876) is one of the oldest old novae with a long orbital period of 10.08 hours and spectroscopic peculiarities in the optical including the presence of variable wind outflow revealed by optical P Cygni profiles in the He I lines and Halpha (Kafka et al.2003). There has never been a far UV spectroscopic analysis of this system. Therefore, we have carried out a synthetic spectral analysis of a far ultraviolet IUE archival spectrum of Q Cygni using our optically thick, steady state, accretion disk models and model white dwarf photospheres. We report the results of our spectroscopic analysis and compare the physical parameters we derive with those of other old novae. We gratefully acknowledge the support of this by NSF grant 0807892 to Villanova University.

  5. Spectroscopic studies (FTIR, FT-Raman and UV), potential energy surface scan, normal coordinate analysis and NBO analysis of (2R,3R,4R,5S)-1-(2-hydroxyethyl)-2-(hydroxymethyl) piperidine-3,4,5-triol by DFT methods

    NASA Astrophysics Data System (ADS)

    Isac Paulraj, E.; Muthu, S.

    2013-05-01

    This work presents the characterization of (2R,3R,4R,5S)-1-(2-hydroxyethyl)-2-(hydroxymethyl)piperidine-3,4,5-triol (abbreviated as HEHMPT) by quantum chemical calculations and spectral techniques. The spectroscopic properties were investigated by FT-IR, FT-Raman and UV-Vis techniques. The FT-IR spectrum (4000-400 cm-1) and FT-Raman spectrum (4000-100 cm-1) in solid phase was recorded for HEHMPT. The UV-Vis absorption spectrum of the HEHMPT that dissolved in water was recorded in the range of 100-400 nm. The structural and spectroscopic data of the molecule were obtained from B3LYP and M06-2X with 6-31G(d,p) basis set calculations. The theoretical wavenumbers were scaled and compared with experimental FT-IR and FT-Raman spectra. The complete assignments were performed on the basis of the normal co-ordinate analysis (NCA), experimental results and potential energy distribution (PED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method, interpreted in terms of fundamental modes. The stable geometry of the compound has been determined from the potential energy surface scan. The stability of molecule has been analyzed by NBO analysis. The molecule orbital contributions were studied by using the total (TDOS), partial (PDOS), and overlap population (OPDOS) density of states. The electronic properties like UV spectral analysis and HOMO-LUMO energies were reported. The calculated HOMO and LUMO energies shows that charge transfer interactions taking place within the molecule. Mulliken population analysis on atomic charges is also calculated.

  6. Spectroscopic studies (FTIR, FT-Raman and UV), potential energy surface scan, normal coordinate analysis and NBO analysis of (2R,3R,4R,5S)-1-(2-hydroxyethyl)-2-(hydroxymethyl) piperidine-3,4,5-triol by DFT methods.

    PubMed

    Isac Paulraj, E; Muthu, S

    2013-05-01

    This work presents the characterization of (2R,3R,4R,5S)-1-(2-hydroxyethyl)-2-(hydroxymethyl)piperidine-3,4,5-triol (abbreviated as HEHMPT) by quantum chemical calculations and spectral techniques. The spectroscopic properties were investigated by FT-IR, FT-Raman and UV-Vis techniques. The FT-IR spectrum (4000-400 cm(-1)) and FT-Raman spectrum (4000-100 cm(-1)) in solid phase was recorded for HEHMPT. The UV-Vis absorption spectrum of the HEHMPT that dissolved in water was recorded in the range of 100-400 nm. The structural and spectroscopic data of the molecule were obtained from B3LYP and M06-2X with 6-31G(d,p) basis set calculations. The theoretical wavenumbers were scaled and compared with experimental FT-IR and FT-Raman spectra. The complete assignments were performed on the basis of the normal co-ordinate analysis (NCA), experimental results and potential energy distribution (PED) of the vibrational modes, calculated with scaled quantum mechanics (SQM) method, interpreted in terms of fundamental modes. The stable geometry of the compound has been determined from the potential energy surface scan. The stability of molecule has been analyzed by NBO analysis. The molecule orbital contributions were studied by using the total (TDOS), partial (PDOS), and overlap population (OPDOS) density of states. The electronic properties like UV spectral analysis and HOMO-LUMO energies were reported. The calculated HOMO and LUMO energies shows that charge transfer interactions taking place within the molecule. Mulliken population analysis on atomic charges is also calculated. PMID:23454843

  7. Albumin adsorption on oxide thin films studied by spectroscopic ellipsometry

    Microsoft Academic Search

    P. Silva-Bermudez; S. E. Rodil; S. Muhl

    Thin films of tantalum, niobium, zirconium and titanium oxides were deposited by reactive magnetron sputtering and their wettability and surface energy, optical properties, roughness, chemical composition and microstructure were characterized using contact angle measurements, spectroscopic ellipsometry, profilometry, X-ray photoelectron spectroscopy and X-ray diffraction, respectively. The purpose of the work was to correlate the surface properties of the films to the

  8. Fluorescence Spectroscopic Studies of (Amide + Electrolyte) Deep Eutectic Systems Biswajit Guchhait and Ranjit Biswas*

    E-print Network

    Biswas, Ranjit

    glass transition. Keywords: deep eutectic solvents, fluorescence measurements, viscosity decoupling Refs liquid at or near room temperature. These systems are known as deep eutectic solvents (DES) and exhibit1 Fluorescence Spectroscopic Studies of (Amide + Electrolyte) Deep Eutectic Systems Biswajit

  9. Solid-State NMR Spectroscopic Study of Phosphate Sorption Mechanisms on Aluminum (Hydr)oxides

    E-print Network

    Sparks, Donald L.

    Solid-State NMR Spectroscopic Study of Phosphate Sorption Mechanisms on Aluminum (Hydr)oxides Wei the mechanism of phosphate sorption on aluminum hydroxides under different environ- mental conditions, including

  10. LOOKING FOR SO2: A SPECTROSCOPIC STUDY OF MARTIAN UV ALBEDO USING SPICAM.

    E-print Network

    Paris-Sud XI, Université de

    LOOKING FOR SO2: A SPECTROSCOPIC STUDY OF MARTIAN UV ALBEDO USING SPICAM. E. Marcq, LATMOS, 11 Bd d'Alembert, Guyancourt, France (emmanuel.marcq@latmos.ipsl.fr), F. Montmessin, F. Lef`evre, A. Reberac, LATMOS

  11. [Spectroscopic analysis of substituted tetraphenylporphyrin iron, manganese, cobalt, copper and zinc complexes].

    PubMed

    Wang, Lan-zhi; She, Yuan-bin

    2008-10-01

    A full IR, UV-Vis, FIR, spectroscopic analysis on substituted porphyrin iron, manganese, cobalt, copper and Zinc complexes was performed, and the spectroscopic patterns were found for the metalloporphyrin compounds with various structures. Base on molecular structures theory, the reasons for the spectroscopic patterns were discussed deeply. Considering the inconsistency of the far-infrared spectra of the Fe-Cl axial bonds in chloro-iron tetraphenylporphyrins reported in the literature. Their far-infrared absorptions were investigated by using both theoretical analysis and experimental determination, and the results showing that their vibrational frequencies of the Fe--Cl bonds in different substitution chloro-iron tetraphenylporphyrins were associated with their structures, and were linearly related to the length of Fe--Cl bonds. PMID:19123396

  12. Spectroscopic studies of uranium species for environmental decontamination applications

    NASA Astrophysics Data System (ADS)

    Eng, Charlotte

    After the Cold War, Department of Energy began to concentrate its efforts on cleanup of former nuclear material processing facilities, especially uranium-contaminated groundwater and soil. This research aims to study uranium association to both organic and inorganic compounds found in the contaminated environment in the hopes that the information gathered can be applied to the development and optimization of cost-effective remediation techniques. Spectroscopic and electrochemical methods will be employed to examine the behavior of uranium in given conditions to further our understanding of its impact on the environment. Uranium found in groundwater and soil bind with various ligands, especially organic ligands present in the environment due to natural sources (e.g. metabolic by-products or degradation of plants and animals) or man-made sources (e.g. chelating agents used in operating or cleanup of uranium processing facilities). We selected reasonable analogs of naturally occurring matter and studied their structure, chemical and electrochemical behavior and found that the structure of uranyl complexes depends heavily on the nature of the ligand and environmental factors such as pH. Association of uranium-organic complexes with anaerobic bacteria, Clostridium sp. was studied to establish if the bacteria can effectively bioreduce uranium while going through normal bacterial activity. It was found that the nature of the organic ligand affected the bioavailability and toxicity of the uranium on the bacteria. In addition, we have found that the type of iron corrosion products and uranyl species present on the surface of corroded steel depended on various environmental factors, which subsequently affected the removal rate of uranium by a citric acid/hydrogen peroxide/deionized water cleaning process. The method was found to remove uranium from only the topmost corrosion layers and residual uranium could be found (a) deeper in the corrosion layers where it is occluded by the steel corrosion products or (b) in areas where the dissolved uranium/iron species, the products generated by the dissolution power of citric acid, was not properly rinsed away.

  13. Photoelectron spectroscopic study of the cleaned, thermally treated and oxidized Zr??Ni?? amorphaus alloy 

    E-print Network

    Liang, Guiping

    1987-01-01

    PHOTOELECTRON SPECTROSCOPIC STUDY OF THE CLEANED, THERMALLY TREATED AND OXIDIZED ZrssNi34 AMORPHOUS ALLOY A Thesis by GUIPING LIANG Submitted to the Graduate College of Texas A & 51 University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE May 1987 Major Subject: Physics PHOTOELECTRON SPECTROSCOPIC STUDY OF THE CLEANED, THERMALLY TREATED AND OXIDIZED ZrssNi34 AMORPHOUS ALLOY A Thesis by GUIPING LIANG Approved as to style and content by: Donald G...

  14. A microwave spectroscopic study of the reaction of cyanogen bromide and hydrogen selenide 

    E-print Network

    Gardner, John Berten

    1958-01-01

    UBRARy A 4 At COLLEGE OF TEXAS A MICROWAVE SPECTROSCOPIC STUDY OF THE REACTION OF CYANOGEN BROMIDE AND HYDROGEN SELENIDE A Thesis By Johnny Berten Gardner Submitted to the Graduate School of The Agricultural and Mechanical College of Texas... in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1958 Major Subject: Chemistry A MICROWAVE SPECTROSCOPIC STUDY OF THE REACTION OF CYANOGEN BROMIDE AND HYDROGEN SELENIDE A Thesis By Johnny Berten Gardner Approved...

  15. Improved protocols for vibrational spectroscopic analysis of body fluids.

    PubMed

    Bonnier, Franck; Petitjean, François; Baker, Matthew J; Byrne, Hugh J

    2014-04-01

    The applications of vibrational spectroscopy to the examination of human blood serum are explored. Although FTIR spectra can be recorded in aqueous solutions at (gelatin) concentrations as low as 100 mg/L, the high-wavenumber region remains obscured by water absorption. Using Raman spectroscopy, high quality spectra of gelatine solutions as low as 10 mg/L can be achieved, also covering the high-wavenumber regions. In human serum, spectral profiles are weak and partially obscured by water features. Dried deposits are shown to be physically and chemically inhomogeneous resulting in reduced measurement reproducibility. Concentration of the serum using commercially available centrifugal filter devices results in an improvement in the spectral intensity and quality. Additionally, in Raman spectroscopy, reduced background and significantly enhanced signal collection is achievable by measurement in an inverted geometry. The improved protocols for spectroscopic measurement of human serum are applicable to a range of bodily fluids and should accelerate potential clinical applications. PMID:24132993

  16. Spectroscopic Analysis of Impurity Precipitates in CdS Films

    SciTech Connect

    Webb, J. D.; Keane, J.; Ribelin, R.; Gedvilas, L.; Swartzlander, A.; Ramanathan, K.; Albin, D. S.; Noufi, R.

    1999-10-31

    Impurities in cadmium sulfide (CdS) films are a concern in the fabrication of copper (indium, gallium) diselenide (CIGS) and cadmium telluride (CdTe) photovoltaic devices. Devices incorporating chemical-bath-deposited (CBD) CdS are comparable in quality to devices incorporating purer CdS films grown using vacuum deposition techniques, despite the higher impurity concentrations typically observed in the CBD CdS films. In this paper, we summarize and review the results of Fourier transform infrared (FTIR), Auger, electron microprobe, and X-ray photoelectron spectroscopic (XPS) analyses of the impurities in CBD CdS films. We show that these impurities differ as a function of substrate type and film deposition conditions. We also show that some of these impurities exist as 10{sup 2} micron-scale precipitates.

  17. Investigation on interaction of prulifloxacin with pepsin: A spectroscopic analysis

    NASA Astrophysics Data System (ADS)

    Huang, Yabei; Yan, Jie; Liu, Benzhi; Yu, Zhang; Gao, Xiaoyan; Tang, Yingcai; Zi, Yanqin

    2010-03-01

    The interaction between prulifloxacin, a kind of new oral taking antibiotic and pepsin, a kind of enzyme in the stomach has been investigated in vitro under a simulated physiological condition by different spectroscopic methods. The intrinsic fluorescence of pepsin was strongly quenched by prulifloxacin. This effect was rationalized in terms of a static quenching procedure. The binding parameters have been evaluated by fluorescence quenching methods. The negative value of ? G0 reveals that the binding process is a spontaneous process. The binding distance R between donor (pepsin) and acceptor (prulifloxacin) was obtained according to the Förster's resonance energy transfer theory and found to be 0.95 nm. The results obtained herein will be of biological significance in pharmacology and clinical medicine.

  18. SPECTROSCOPIC STUDY OF THE GLOBULAR CLUSTERS IN M31

    Microsoft Academic Search

    S. C. Kim; M. G. Lee; H. S. Park; H. S. Hwang; D. Geisler; A. Sarajedini; W. E. Harris; J. C. Seguel

    2007-01-01

    We have performed a new systematic globular cluster (GC) survey of M31 for 3 3 area centered on M31. Using photometric data obtained from observations using the KPNO 0.9-m telescope + Washington CMT1 lters, and spectroscopic data obtained from observations using the KPNO\\/WIYN 3.5-m telescope + Hydra multib er spectrograph, we have conrmed 544 previously known GCs and found over

  19. Spectroscopic Study of the Globular Clusters in M31

    Microsoft Academic Search

    S. C. Kim; M. G. Lee; H. S. Park; H. S. Hwang; D. Geisler; A. Sarajedini; W. E. Harris; J. C. Seguel

    2007-01-01

    We have performed a new systematic globular cluster (GC) survey of M31 for ˜ 3° × 3° area centered on M31. Using photometric data obtained from observations using the KPNO 0.9-m telescope + Washington CMT1 filters, and spectroscopic data obtained from observations using the KPNO\\/WIYN 3.5-m telescope + Hydra multifiber spectrograph, we have confirmed 544 previously known GCs and found

  20. Temperature Dependent Spectroscopic studies of HiPco SWNT composites

    Microsoft Academic Search

    Sinead Keogh; T. G. Heddermann; Garrett Farrell; M. Ruether; Elizabeth Gregan; Mary McNamara; Gordon Chambers; Hugh J. Byrne

    2005-01-01

    Hybrid systems of the conjugated organic polymer poly(p-phenylene vinylene-co-2,5-dioctyIoxy-m-phenylene vinylene)(PmPV) and HiPco SWNTs are explored using spectroscopic and thermal techniques to determine specific interactions. Vibrational spectroscopy indicates a weak interaction and this is further elucidated using Differential Scanning Calorimetry, Temperature Dependent Raman Spectroscopy and Temperature Dependent Infrared Spectroscopy of the raw materials and the composite. An endothermic transition is observed

  1. Study of various spectroscopic properties of the Ds meson

    NASA Astrophysics Data System (ADS)

    Kher, Virendrasinh H.; Devlani, Nayneshkumar; Rai, Ajay Kumar

    2015-05-01

    Spectroscopic parameters of the Ds (cs¯) meson are obtained using phenomenological quark antiquark potential(coulomb plus power) model consisting of O(1/m) correction to the potential. Within Variational scheme Gaussian wave function is employed with a hamiltonian incorporating kinematic relativistic corrections to obtain various properties such as the mass spectra, decay constants, electromagnetic transitions. The results are compared with various experimental measurement as well as other theoretical predictions.

  2. Structural, spectroscopic and theoretical study of novel ephedrinum salt

    NASA Astrophysics Data System (ADS)

    Ivanova, B.; Kolev, T.; Lamshöft, M.; Mayer-Figge, H.; Seidel, R.; Sheldrick, W. S.; Spiteller, M.

    2010-05-01

    Ephedrinum violurate dihydrate was synthesized, spectroscopically and structural elucidated. The data are compared with those of the free-base ephedrine hemihydrate. Discussion on the stable conformer of the ephedrinum cation is carried out. Quantum chemical calculations were performed for the theoretical elucidation of the conformational preference of the ephedrinum cation and its vibrational properties. The model systems neutral ephedrine hemihydrate ( 1) and violurate salt dihydrate ( 2) are elucidated.

  3. The ARAUCARIA project: Grid-based quantitative spectroscopic study of massive blue stars in NGC 55

    NASA Astrophysics Data System (ADS)

    Castro, N.; Urbaneja, M. A.; Herrero, A.; Garcia, M.; Simón-Díaz, S.; Bresolin, F.; Pietrzy?ski, G.; Kudritzki, R.-P.; Gieren, W.

    2012-06-01

    Context. The quantitative study of the physical properties and chemical abundances of large samples of massive blue stars at different metallicities is a powerful tool to understand the nature and evolution of these objects. Their analysis beyond the Milky Way is challenging, nonetheless it is doable and the best way to investigate their behavior in different environments. Fulfilling this task in an objective way requires the implementation of automatic analysis techniques that can perform the analyses systematically, minimizing at the same time any possible bias. Aims: As part of the ARAUCARIA project we carry out the first quantitative spectroscopic analysis of a sample of 12 B-type supergiants in the galaxy NGC 55 at 1.94 Mpc away. By applying the methodology developed in this work, we derive their stellar parameters, chemical abundances and provide a characterization of the present-day metallicity of their host galaxy. Methods: Based on the characteristics of the stellar atmosphere/line formation code fastwind, we designed and created a grid of models for the analysis of massive blue supergiant stars. Along with this new grid, we implemented a spectral analysis algorithm. Both tools were specially developed to perform fully consistent quantitative spectroscopic analyses of low spectral resolution of B-type supergiants in a fast and objective way. Results: We present the main characteristics of our fastwind model grid and perform a number of tests to investigate the reliability of our methodology. The automatic tool is applied afterward to a sample of 12 B-type supergiant stars in NGC 55, deriving the stellar parameters, Si , C , N , O and Mg abundances. The results indicate that our stars are part of a young population evolving towards a red supergiant phase. For half of the sample we find a remarkable agreement between spectroscopic and evolutionary masses, whilst for the rest larger discrepancies are present, but still within the uncertainties. The derived chemical composition hints to an average metallicity similar to the one of the Large Magellanic Cloud, with no indication of a spatial trend across the galaxy. Conclusions: The consistency between the observed spectra and our stellar models supports the reliability of our methodology. This objective and fast approach allows us to deal with large samples in an accurate and more statistical way. These are two key issues to achieve an unbiased characterization of the stars and their host galaxies. Based on observations obtained at the ESO VLT Large Programme 171.D-0004.

  4. Raman spectroscopic methods for classification of normal and malignant hypopharyngeal tissues: an exploratory study.

    PubMed

    Pujary, Parul; Maheedhar, K; Krishna, C Murali; Pujary, Kailesh

    2011-01-01

    Laryngeal cancer is more common in males. The present study is aimed at exploration of potential of conventional Raman spectroscopy in classifying normal from a malignant laryngopharyngeal tissue. We have recorded Raman spectra of twenty tissues (aryepiglottic fold) using an in-house built Raman setup. The spectral features of mean malignant spectrum suggests abundance proteins whereas spectral features of mean normal spectrum indicate redundancy of lipids. PCA was employed as discriminating algorithm. Both, unsupervised and supervised modes of analysis as well as match/mismatch "limit test" methodology yielded clear classification among tissue types. The findings of this study demonstrate the efficacy of conventional Raman spectroscopy in classification of normal and malignant laryngopharyngeal tissues. A rigorous evaluation of the models with development of suitable fibreoptic probe may enable real-time Raman spectroscopic diagnosis of laryngopharyngeal cancers in future. PMID:21804932

  5. Laser Spectroscopic Studies of Europium-Doped Glasses and Emerald

    Microsoft Academic Search

    Gregory James Quarles

    1987-01-01

    Scope of study. High-power, picosecond-pulse excitation was used in the first part of this work to study the dynamics of the pumping and decay processes in Eu ^{3+}-doped fluoride and oxide glasses. Time resolved spectroscopy techniques are used to determine the absorption cross sections of the intermediate state and a Judd-Ofelt analysis of the absorption spectrum is used to determine

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  7. Spectroscopic Observations and Analysis of the Peculiar SN 1999aa

    E-print Network

    G. Garavini; G. Folatelli; A. Goobar; S. Nobili; G. Aldering; A. Amadon; R. Amanullah; P. Astier; C. Balland; G. Blanc; M. S. Burns; A. Conley; T. Dahlen; S. E. Deustua; R. Ellis; S. Fabbro; X. Fan; B. Frye; E. L. Gates; R. Gibbons; G. Goldhaber; B. Goldman; D. E. Groom; J. Haissinski; D. Hardin; I. M. Hook; D. A. Howell; D. Kasen; S. Kent; A. G. Kim; R. A. Knop; B. C. Lee; C. Lidman; J. Mendez; G. J. Miller; M. Moniez; A. Mourao; H. Newberg; P. E. Nugent; R. Pain; O. Perdereau; S. Perlmutter; V. Prasad; R. Quimby; J. Raux; N. Regnault; J. Rich; G. T. Richards; P. Ruiz-Lapuente; G. Sainton; B. E. Schaefer; K. Schahmaneche; E. Smith; A. L. Spadafora; V. Stanishev; N. A. Walton; L. Wang; W. M. Wood-Vasey

    2004-04-20

    We present an extensive new time-series of spectroscopic data of the peculiar SN 1999aa in NGC 2595. Our data set includes 25 optical spectra between -11 and +58 days with respect to B-band maximum light, providing an unusually complete time history. The early spectra resemble those of a SN 1991T-like object but with a relatively strong Ca H&K absorption feature. The first clear sign of Si II 6355, characteristic of Type Ia supernovae, is found at day -7 and its velocity remains constant up to at least the first month after B-band maximum light. The transition to normal-looking spectra is found to occur earlier than in SN 1991T suggesting SN 1999aa as a possible link between SN 1991T-like and Branch-normal supernovae. Comparing the observations with synthetic spectra, doubly ionized Fe, Si and Ni are identified at early epochs. These are characteristic of SN 1991T-like objects. Furthermore, in the day -11 spectrum, evidence is found for an absorption feature which could be identified as high velocity C II 6580 or H-alpha. At the same epoch C III 4648.8 at photospheric velocity is probably responsible for the absorption feature at 4500 A. High velocity Ca is found around maximum light together with Si II and Fe II confined in a narrow velocity window. Implied constraints on supernovae progenitor systems and explosion hydrodynamical models are briefly discussed.

  8. Raman spectroscopic analysis of atypical proliferative lesions of the breast

    NASA Astrophysics Data System (ADS)

    Subramanian, K.; Kendall, C.; Stone, N.; Brown, J. C.; McCarthy, K.; Bristol, J.; Chan, Y. H.

    2006-02-01

    Atypical lesions of the breast have potential to turn malignant. The diagnosis of these lesions has increased considerably with screening mammography. A good understanding of their progression to invasive cancer is yet to be proved. Using Raman spectroscopy to study their chemical finger printing at different stages of proliferation a clear picture of whether a progression exists between lesions could be made. At present there is no clear recognition of the biochemical changes that distinguish between the different proliferative lesions of the breast. Our aim is to understand these changes through Raman mapping studies. Raman spectroscopy is a highly sensitive and specific technique for demonstration of biochemical changes in different atypical proliferative lesions of the breast. The technique could be used to classify the different grades and analyse progression of pathology in the proliferative lesions of the breast. Breast pathologists carefully marked 50 ducts and classified the different pathology on H and E sections from biopsy samples. Raman spectra were measured, using a Renishaw Raman Spectrometer, on a 20-micron thick consecutive frozen section. Principal component analysis was undertaken using Matlab. Pseudocolor maps of the principal components scores have been generated. The peaks of the corresponding loads were identified enabling visualisation of the biochemical changes associated with proliferative lesions. Proliferative lesions of the duct were grouped according to the existing standard pathological classification and formed four major groups-HUT, ADH, DCIS and IDC. Spectra of biochemical constituents were fitted to mean spectra from selected regions, taken from maps of each pathology, to identify the relative concentration of the constituents. The study gave an insight into chemical make up of the ducts in each pathology group and showed similar results to earlier studies in progression but no clear-cut demarcation or continuum of the proliferative disease.

  9. Micro-Ft Spectroscopic Studies of Breast Tissues

    NASA Astrophysics Data System (ADS)

    Anastassopoulou, J.; Arapantoni, P.; Boukaki, E.; Konstadoudakis, S.; Theophanides, T.; Valavanis, C.; Conti, C.; Ferraris, P.; Giorgini, G.; Sabbatini, S.; Tosi, G.

    Micro-FT-IR spectroscopy was used to study breast cancer tissues and, in particular osteosarcoma tissue. By analysing the spectra, we have found characteristic bands in the infrared regions, where the main components of these signature bands are located. In the region between 1680-1660 cm-1 are found the characteristic bands of Amide I and II of proteins. The bands, which correspond to the vibrations of the phosphate groups, are found in the region near 1140-900 cm-1. These characteristic bands have been monitored as a function of the degree of cancer progression. The results have been obtained with chemometric methods, such as cluster analysis, principal component analysis and custom analysis in order to distinguish the neoplastic zones from the normal zones.

  10. Picosecond flash spectroscopic studies on ultraviolet stabilizers and stabilized polymers

    NASA Technical Reports Server (NTRS)

    Scott, G. W.

    1982-01-01

    Spectroscopic and excited state decay kinetics are reported for monomeric and polymeric forms of ultraviolet stabilizers in the 2-(2'-hydroxyphenyl)-benzotriazole and 2-hydroxybenzophenone classes. For some of these molecules in various solvents at room temperature, (1) ground state absorption spectra, (2) emission spectra, (3) picosecond time-resolved transient absorption spectra, (4) ground state absorption recovery kinetics, (5) emission kinetics, and (6) transient absorption kinetics are reported. In the solid state at low temperatures, emission spectra and their temperature dependent kinetics up to approximately 200K as well as, in one case, the 12K excitation spectra of the observed dual emission are also reported.

  11. IR spectroscopic study of the chemical composition of epiphytic lichens

    NASA Astrophysics Data System (ADS)

    Meysurova, A. F.; Khizhnyak, S. D.; Pakhomov, P. M.

    2011-11-01

    Changes in the chemical composition of lichens exposed to pollutants are investigated by means of FTIR spectroscopy. According to model experiments, alkyl nitrates, ammonium salts, amines, and sulfones develop in the lichen thallus through the action of ammonia and nitric and sulfuric acids. Spectroscopic data of modeling experiments enabled nitrogen- and sulfur-containing substances to be identified as the main air pollutants in the vicinity of a pig-breeding complex and information to be obtained on the content of the pollutants and their impact on the lichens.

  12. Spectroscopic studies on gallic acid and its azo derivatives and their iron(III) complexes.

    PubMed

    Masoud, Mamdouh S; Ali, Alaa E; Haggag, Sawsan S; Nasr, Nessma M

    2014-01-01

    Azo gallic derivatives and their iron(III) complexes were synthesized and characterized. The stereochemistry and the mode of bonding of the complexes were achieved based on elemental analysis, UV-Vis and IR. The thermal behaviors of the complexes were studied. The effect of pH on the electronic absorption spectra of gallic acid and its azo derivatives are discussed. Different spectroscopic methods (molar ratio, straight line method, continuous variation, slope ratio and successive method) are applied for determination of stoichiometry and pK values for the complex formation of gallic acid with iron(III) in aqueous media. Iron(III) complexes of gallic acid is formed with different ratio: 1:1, 1:2, 1:3 and 1:4 (M:L). PMID:24211811

  13. Quantitative comparison of analysis methods for spectroscopic optical coherence tomography: reply to comment

    PubMed Central

    Bosschaart, Nienke; van Leeuwen, Ton G.; Aalders, Maurice C.G.; Faber, Dirk J.

    2014-01-01

    We reply to the comment by Kraszewski et al on “Quantitative comparison of analysis methods for spectroscopic optical coherence tomography.” We present additional simulations evaluating the proposed window function. We conclude that our simulations show good qualitative agreement with the results of Kraszewski, in support of their conclusion that SOCT optimization should include window shape, next to choice of window size and analysis algorithm. PMID:25401016

  14. Structural and spectroscopic studies of a commercial glassy carbon

    NASA Astrophysics Data System (ADS)

    Parker, Stewart F.; Imberti, Silvia; Callear, Samantha K.; Albers, Peter W.

    2013-12-01

    Glassy carbon is a form of carbon made by heating a phenolic resin to high temperature in an inert atmosphere. It has been suggested that it is composed of fullerene-like structures. The aim of the present work was to characterize the material using both structural (neutron diffraction and transmission electron microscopy) and spectroscopic (inelastic neutron scattering, Raman and X-ray photoelectron spectroscopies) methods. We find no evidence to support the suggestion of fullerene-like material being present to a significant extent, rather the model that emerges from all of the techniques is that the material is very like amorphous carbon, consisting of regions of small graphite-like basic structural units of partly stacked but mismatched structure with the edges terminated by hydrogen or hydroxyls. We do find evidence for the presence of a small quantity of water trapped in the network and suggest that this may account for batch-to-batch variation in properties that may occur.

  15. Microwave spectra of some chlorine and fluorine compounds. [spectroscopic analysis

    NASA Technical Reports Server (NTRS)

    White, W. F.

    1975-01-01

    A computer-controlled microwave spectrometer was used to catalog reference spectra for chemical analysis. Tables of absorption frequencies, peak absorption intensities, and integrated intensities are shown for 21 organic compounds which contain chlorine, fluorine, or both.

  16. Chemical and spectroscopic analysis of organic matter transformations during composting of pig manure

    Microsoft Academic Search

    Jenn-Hung Hsu; Shang-Lien Lo

    1999-01-01

    Composting of separated pig manure (SPM) was studied in an attempt to elaborate upon organic matter (OM) transformation during the process and define parameters for product maturity using both chemical and spectroscopical methods. Composting was performed in two piles and the following parameters were measured in 10 samples during 122 days of composting: temperature, ash content, C\\/N ratio, water-soluble organic

  17. FTIR-ATR-spectroscopic analysis of Bis-Crown ether based PVC-membranes

    Microsoft Academic Search

    K. Tóth; E. Lindner; E. Pungor; E. Zippel; R. Kellner

    1988-01-01

    To get more information on the phase boundary and bulk membrane processes, the short and long time behaviour of potassium selective solvent polymeric membranes was studied. In parallel with the measurement of the dynamic response of model membranes, in situ spectroscopic measurements applying the Attenuated Total Reflection (ATR) technique in the infrared region, were carried out in solutions containing anions

  18. Structure and spectroscopic properties of neutral and cationic tetratomic [C,H,N,Zn] isomers: A theoretical study

    NASA Astrophysics Data System (ADS)

    Redondo, Pilar; Largo, Antonio; Vega-Vega, Álvaro; Barrientos, Carmen

    2015-05-01

    The structure and spectroscopic parameters of the most relevant [C,H,N,Zn] isomers have been studied employing high-level quantum chemical methods. For each isomer, we provide predictions for their molecular structure, thermodynamic stabilities as well as vibrational and rotational spectroscopic parameters which could eventually help in their experimental detection. In addition, we have carried out a detailed study of the bonding situations by means of a topological analysis of the electron density in the framework of the Bader's quantum theory of atoms in molecules. The analysis of the relative stabilities and spectroscopic parameters suggests two linear isomers of the neutral [C,H,N,Zn] composition, namely, cyanidehydridezinc HZnCN (1?) and hydrideisocyanidezinc HZnNC (1?), as possible candidates for experimental detections. For the cationic [C,H,N,Zn]+ composition, the most stable isomers are the ion-molecule complexes arising from the direct interaction of the zinc cation with either the nitrogen or carbon atom of either hydrogen cyanide or hydrogen isocyanide, namely, HCNZn+ (2?) and HCNZn+ (2?).

  19. Comment on “Quantitative comparison of analysis methods for spectroscopic optical coherence tomography”

    PubMed Central

    Kraszewski, Maciej; Trojanowski, Micha?; Str?kowski, Marcin R.

    2014-01-01

    In a recent paper by Bosschaart et al. [Biomed. Opt. Express 4, 2570 (2013)] various algorithms of time-frequency signal analysis have been tested for their performance in blood analysis with spectroscopic optical coherence tomography (sOCT). The measurement of hemoglobin concentration and oxygen saturation based on blood absorption spectra have been considered. Short time Fourier transform (STFT) was found as the best method for the measurement of blood absorption spectra. STFT was superior to other methods, such as dual window Fourier transform. However, the algorithm proposed by Bosschaart et al. significantly underestimates values of blood oxygen saturation. In this comment we show that this problem can be solved by thorough design of STFT algorithm. It requires the usage of a non-gaussian shape of STFT window that may lead to an excellent reconstruction of blood absorption spectra from OCT interferograms. Our study shows that sOCT can be potentially used for estimating oxygen saturation of blood with the accuracy below 1% and the spatial resolution of OCT image better than 20 ?m. PMID:25401015

  20. Chemical factor analysis of skin cancer FTIR-FEW spectroscopic data

    NASA Astrophysics Data System (ADS)

    Bruch, Reinhard F.; Sukuta, Sydney

    2002-03-01

    Chemical Factor Analysis (CFA) algorithms were applied to transform complex Fourier transform infrared fiberoptical evanescent wave (FTIR-FEW) normal and malignant skin tissue spectra into factor spaces for analysis and classification. The factor space approach classified melanoma beyond prior pathological classifications related to specific biochemical alterations to health states in cluster diagrams allowing diagnosis with more biochemical specificity, resolving biochemical component spectra and employing health state eigenvector angular configurations as disease state sensors. This study demonstrated a wealth of new information from in vivo FTIR-FEW spectral tissue data, without extensive a priori information or clinically invasive procedures. In particular, we employed a variety of methods used in CFA to select the rank of spectroscopic data sets of normal benign and cancerous skin tissue. We used the Malinowski indicator function (IND), significance level and F-Tests to rank our data matrices. Normal skin tissue, melanoma and benign tumors were modeled by four, two and seven principal abstract factors, respectively. We also showed that the spectrum of the first eigenvalue was equivalent to the mean spectrum. The graphical depiction of angular disparities between the first abstract factors can be adopted as a new way to characterize and diagnose melanoma cancer.

  1. Analysis of Spectroscopic Radiation Portal Monitor Data Using Principal Components Analysis

    SciTech Connect

    Runkle, Robert C.; Tardiff, Mark F.; Anderson, K K.; Carlson, Deborah K.; Smith, L E.

    2006-06-01

    Many international border crossings screen cargo for illicit nuclear material using radiation portal monitors (RPMs) that measure the gamma-ray flux emitted by vehicles. Screening often consists of primary, which acts as a trip-wire for suspect vehicles, and secondary, which locates the radiation source and performs isotopic identification. The authors present a method of anomaly detection for primary screening that uses past observations of gamma-ray signatures to define an expected benign vehicle population. Newly acquired spectra are then compared to this expected population using statistical criteria that reflect acceptable alarm rates and probabilities of detection. Shown here is an analysis of spectroscopic RPM data collected at an international border crossing using this technique. The raw data were analyzed to develop an expected benign vehicle population by decimating the original pulse-height channels, extracting composite variables with principal components analysis, and estimating variance-weighted distances from the ''mean vehicle spectra'' with the Mahalanobis distance metric. The following analysis considers data acquired with both NaI(Tl)-based and plastic scintillator-based RPMs. For each system, performance estimates for anomaly sources are compared to common nuisance sources. The algorithm reported here shows promising results in that it is more sensitive to the anomaly sources than common nuisance sources for both RPM types.

  2. Spectroscopic optical coherence tomography with graphics processing unit based analysis of three dimensional data sets

    NASA Astrophysics Data System (ADS)

    Jaedicke, Volker; A?caer, Semih; Goebel, Sebastian; Gerhardt, Nils C.; Welp, Hubert; Hofmann, Martin R.

    2013-02-01

    Spectroscopic optical coherence tomography (OCT) is an extension of the standard backscattering intensity analysis of OCT. It enables depth resolved monitoring of molecular and structural differences of tissue. One drawback of most methods to calculate the spectroscopic data is the long processing time. Also systematic and stochastic errors make the interpretation of the results challenging. Our approach combines modern signal processing tools with powerful graphics processing unit (GPU) programming. The processing speed for the spectroscopic analysis is nearly 3 mega voxel per second. This allows us to analyze multiple B-Scans in a few seconds and to display the results as a three dimensional data set. Our algorithm contains the following steps in addition to the conventional processing for frequency domain OCT: a quality map to exclude noisy parts of the data, spectral analysis by short time Fourier transform, feature reduction by Principal Component Analysis, unsupervised pattern recognition with K-means and rendering of the gray scale backscattering OCT data which is superimposed with a color map that is based on the results of the pattern recognition algorithm. Our set up provides a spectral range from 650-950nm and is optimized to suppress chromatic errors. In a proof-of-principle attempt, we already achieved additional spectroscopic contrast in phantom samples including scattering microspheres of different sizes and ex vivo biological tissue. This is an important step towards a system for real time spectral analysis of OCT data, which would be a powerful diagnosis tool for many diseases e.g. cancer detection at an early stage.

  3. RAMAN SPECTROSCOPIC ANALYSIS OF FERTILIZERS AND PLANT TISSUE FOR PERCHLORATE

    EPA Science Inventory

    Raman spectroscopy, without the need for prior chromatographic separation, was used for qualitative and quantitative analysis of 59 samples of fertilizers for perchlorate (ClO4-). These primarily lawn and garden products had no known link to Chile saltpeter, which is known to con...

  4. An integrated spectroscopic approach for the non-invasive study of modern art materials and techniques

    NASA Astrophysics Data System (ADS)

    Rosi, F.; Miliani, C.; Clementi, C.; Kahrim, K.; Presciutti, F.; Vagnini, M.; Manuali, V.; Daveri, A.; Cartechini, L.; Brunetti, B. G.; Sgamellotti, A.

    2010-09-01

    A non-invasive study has been carried out on 18 paintings by Alberto Burri (1915-1995), one of Italy’s most important contemporary painters. The study aims to demonstrate the appropriate and suitable use of portable non-invasive instrumentation for the characterization of materials and techniques found in works dating from 1948 to 1975 belonging to the Albizzini Collection. Sampling of any kind has been forbidden, in order to maintain the integrity of the paintings. Furthermore, the material heterogeneity of each single artwork could potentially result in a poorly representative sampling campaign. Therefore, a non-invasive and in situ analytical approach has been deemed mandatory, notwithstanding the complexity of modern materials and challenging data interpretation. It is the non-invasive nature of the study that has allowed for the acquisition of vast spectral data (a total of about 650 spectra including XRF, mid and near FTIR, micro-Raman and UV-vis absorption and emission spectroscopies). In order to better handle and to extrapolate the most meaningful information from these data, a statistical multivariate analysis, namely principal component analysis (PCA), has been applied to the spectral results. In particular, the possibility of combining elemental and molecular information has been explored by uniting XRF and infrared spectra in one PCA dataset. The combination of complementary spectroscopic techniques has allowed for the characterization of both inorganic and organic pigments, extenders, fillers, and binders employed by Alberto Burri.

  5. Spectroscopic investigation and hydrogen-bonding analysis of triazinones.

    PubMed

    Dhas, Devadhas Arul; Joe, Isaac Hubert; Roy, Solomon Dawn Dharma; Balachandran, Sreedharan

    2012-08-01

    NIR FT-Raman, FTIR and UV-vis spectra of the herbicide metamitron were recorded and analyzed. The aromaticities, equilibrium geometries, bonding features, electrostatic potentials, and harmonic vibrational wavenumbers of the monomers and dimers of triazinone derivatives were also investigated with the aid of BLYP/6-311 G(df, p) density functional theory. Features in the vibrational spectra were assigned with the aid of the VEDA.4 program. The calculated results were a good match to the experimental data obtained from FTIR, Raman, and electronic absorption spectra. Mulliken population analysis was performed on the atomic charges and the HOMO-LUMO energies were also calculated. NBO analysis highlighted the intra- and intermolecular N-H…O and C-H…O hydrogen bonds in the crystal structures of the triazinones. The solvent effect was calculated using time-dependent density functional theory in combination with the polarizable continuum model. PMID:22350295

  6. Spectroscopic studies on the interaction of ofloxacin with metals

    NASA Astrophysics Data System (ADS)

    Sagdinc, S.; Bayar?, S.

    2004-03-01

    Several coordination compounds (1:1) formed between alkaline earth metal cations [Mg(II), Ca(II) and Ba(II)] and transition metal ions [Co(II), Ni(II) and Zn(II)] with oflocaxin were synthesized. The compounds have been characterized using elemental analysis, Fourier transform infrared (FT-IR) spectroscopy and 1H NMR spectra. The solid state samples of all complexes have been measured within the range 4000-400 cm -1. Based on normal mode calculations for complexes, the assignments of bands observed in FT-IR spectra of studied compounds have been done. Some significant differences in vibrational structure have been observed and discussed. The frequencies and intensities of some bands of the ofloxacin depend systematically on the second ionization potential of the metals.

  7. Spectroscopic and microscopic study of vanadium oxide nanotubes

    SciTech Connect

    Gloskovskii, A.; Nepijko, S. A.; Schoenhense, G.; Therese, H. A.; Reiber, A.; Kandpal, H. C.; Fecher, G. H.; Felser, C.; Tremel, W.; Klimenkov, M. [Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, 55099 Mainz (Germany); Institut fuer Anorganische und Analytische Chemie, Johannes Gutenberg-Universitaet Mainz, 55099 Mainz (Germany); Institut fuer Materialforschung I, Forschungszentrum Karlsruhe GmbH, Postfach 3640, 76021 Karlsruhe (Germany)

    2007-04-15

    V{sub 2}O{sub 5} nanotubes synthesized via the sol-gel route has been studied by electron energy loss spectroscopy (EELS), x-ray absorption spectroscopy (XAS), and energy dispersive x-ray analysis, in order to understand the local structure of vanadium in the nanotubes. Contrary to our expectation, all the features of the XAS and EELS spectra of the V{sub 2}O{sub 5} nanotubes are in line with that of bulk layered vanadium oxide revealing that vanadium is present in the 5{sup +} oxidation state in the nanotubes. However, V{sub 2}O{sub 5} nanotubes exhibit additional surface states in their electronic structure in comparison with bulk V{sub 2}O{sub 5}. A comparison of measured and calculated spectra allows us to distinguish single-wall from multiwall V{sub 2}O{sub 5} nanotubes.

  8. Photometric and spectroscopic study of low mass embedded star clusters in reflection nebulae

    NASA Astrophysics Data System (ADS)

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

    2005-02-01

    An analysis of the candidate embedded stellar systems in the reflection nebulae vdBH-RN 26, vdBH-RN} 38, vdBH-RN} 53a, GGD 20, ESO 95-RN 18 and NGC 6595 is presented. Optical spectroscopic data from CASLEO (Argentina) in conjunction with near infrared photometry from the 2MASS Point Source Catalogue were employed. The analysis is based on source surface density, colour-colour and colour-magnitude diagrams together with theoretical pre-main sequence isochrones. We take into account the field population affecting the analysis by carrying out a statistical subtraction. The fundamental parameters for the stellar systems were derived. The resulting ages are in the range 1-4 Myr and the objects are dominated by pre-main sequence stars. The observed masses locked in the clusters are less than 25 M?. The studied systems have no stars of spectral types earlier than B, indicating that star clusters do not necessarily evolve through an HII region phase. The relatively small locked mass combined with the fact that they are not numerous in catalogues suggests that these low mass clusters are not important donors of stars to the field populations. Based on observations made at Complejo Astronómico El Leoncito, which is operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina and the National Universities of La Plata, Córdoba and San Juan, Argentina.

  9. Electrical Conductivity, Near-Infrared Absorption, and Thermal Lens Spectroscopic Studies of Percolation of Microemulsions

    E-print Network

    Reid, Scott A.

    Electrical Conductivity, Near-Infrared Absorption, and Thermal Lens Spectroscopic Studies studied below and above the percolation thresholds by electrical conductivity, near-infrared absorption quenching, neutron and light scattering, and electrical conductivity.1,2 However, in spite of these numerous

  10. FTIR Spectroscopic Study of an Organic/mineral Composite for Bone and Dental Substitute Materials.

    E-print Network

    Boyer, Edmond

    conditions, two types of degradation of cellulose material can occur. First, alkaline degradation can produce1 FTIR Spectroscopic Study of an Organic/mineral Composite for Bone and Dental Substitute Materials. The purpose of this study was to detect possible polymer degradation which may have been caused

  11. Laser Spectroscopic Studies of Europium-Doped Glasses and Emerald.

    NASA Astrophysics Data System (ADS)

    Quarles, Gregory James

    1987-05-01

    Scope of study. High-power, picosecond-pulse excitation was used in the first part of this work to study the dynamics of the pumping and decay processes in Eu ^{3+}-doped fluoride and oxide glasses. Time resolved spectroscopy techniques are used to determine the absorption cross sections of the intermediate state and a Judd-Ofelt analysis of the absorption spectrum is used to determine the branching ratios, radiative and nonradiative decay rates. Nondegenerate four-wave mixing and time-resolved site-selection spectroscopy were used to study energy migration processes in Be_3Al_2 (SiO_3)_6:Cr ^{3+}. Site-selection spectroscopy probed the short range spectral energy transfer among nonresonant Cr^{3+} ions in emerald. Four -wave mixing techniques were used to study the long range spatial diffusion of energy among resonant Cr^ {3+} ions. Findings and conclusions. From the study of the europium-doped glasses, it was possible to determine fluorescence lifetimes, branching ratios, radiative and nonradiative decay rates, and the two-phonon absorption cross sections for the fluoride glass. The oxide glass showed no transitions associated with two-photon absorption. From studies of the variations in the emission intensities of Eu ^{3+} in the fluoride glass versus laser power, it was possible to conclude that the excitation processes are either virtual two-photon excitation processes or are coherent sequential two-photon excitation processes in which fast phonon dephasing processes play a key role. From the studies of energy migration in emerald, it was found that there are two distinct types of energy transfer processes taking place. Using site-selection spectroscopy, short range spectral energy transfer was observed between Cr^{3+} ions in slightly different crystal field sites in emerald. It was found that the appropriate model for spectral energy transfer in emerald is one in which the excitation undergoes multistep migration among sensitizers before transfer takes place to the activator. Spatial energy migration was observed among resonant Cr^{3+} sites in emerald using nondegenerate four-wave mixing spectroscopy. The appropriate model for this transfer indicates that a long range, partially coherent exciton migration takes place. Estimations of the nonradiative decay rate from the ^4 T_2 to ^2 E states were made through calculations of the dephasing time of the excited state from the four-wave mixing scattering efficiency data.

  12. Interaction of an aluminum atom with a closed subshell metal atom: Spectroscopic analysis of AlZn

    E-print Network

    Morse, Michael D.

    Interaction of an aluminum atom with a closed subshell metal atom: Spectroscopic analysis of Al-block main group element, aluminum, and the 3d series of transi- tion metal atoms. Although the bonding in Al

  13. [Infrared spectroscopic study on leaf senescence of evergreen tree].

    PubMed

    Li, Lun; Zhou, Xiang-Ping; Liu, Gang; Zhang, Li; Ou, Quan-Hong; Hao, Jian-Ming

    2013-02-01

    In order to investigate plant physiological process of leaf senescence and aging, Fourier transform infrared (FTIR) spectroscopy was used to study the young, mature, and old yellow leaves from seven species of evergreen trees. The spectra of the leaves from different growing period are different in the region of 1 800-700 cm(-1). The absorption ratios A1 070/A2 927, A1 070/A1 160 were used to evaluate the relative changes of polysaccharides, and A1 318/A2 922 was used to estimate the change of calcium oxalate during leaf senescence. Decomposition and curve-fitting analysis was performed in the region of 1 800 -1 500 cm(-1). The sub-band absorption ratio H1 650/H1 740 was used to evaluate the relative changes of protein in the leaves. The results show that the accumulation and mobilization of polysaccharides, protein, and calcium oxalate during leaf growing period were different in different plant species. This study demonstrates the potential of mid-infrared spectroscopy for investigation of plants senescence, as well as physiological and biochemical changes of plants. PMID:23697107

  14. Raman spectroscopic study of Lactarius spores (Russulales, Fungi)

    NASA Astrophysics Data System (ADS)

    De Gussem, Kris; Vandenabeele, Peter; Verbeken, Annemieke; Moens, Luc

    2005-10-01

    Fungi are important organisms in ecosystems, in industrial and pharmaceutical production and are valuable food sources as well. Classical identification is often time-consuming and specialistic. In this study, Raman spectroscopy is applied to the analysis of fungal spores of Lactarius, an economically and ecologically important genus of Basidiomycota. Raman spectra of spores of Lactarius controversus Pers.: Fr., Lactarius lacunarum (Romagn.) ex Hora, Lactarius quieticolor Romagn. and Lactarius quietus (Fr.: Fr.) Fr. are reported for the first time. The spectra of these species show large similarity. These spectra are studied and compared with the Raman spectra of reference substances known to occur in macrofungi, including saccharides, lipids and some minor compounds that may serve as specific biomarkers (adenine, ergosterol and glycine). Most Raman bands could be attributed to specific components. In agreement with the biological role of fungal spores, high amounts of lipids were observed, the main fatty acid being oleate. In addition to different types of lipids and phospholipids, the polysaccharides chitin and amylopectin could be detected as well. The presence of trehalose is not equivocally shown, due to overlapping bands. Raman band positions are reported for the observed bands of the different species and reference products.

  15. Breath Analysis Using Laser Spectroscopic Techniques: Breath Biomarkers, Spectral Fingerprints, and Detection Limits

    PubMed Central

    Wang, Chuji; Sahay, Peeyush

    2009-01-01

    Breath analysis, a promising new field of medicine and medical instrumentation, potentially offers noninvasive, real-time, and point-of-care (POC) disease diagnostics and metabolic status monitoring. Numerous breath biomarkers have been detected and quantified so far by using the GC-MS technique. Recent advances in laser spectroscopic techniques and laser sources have driven breath analysis to new heights, moving from laboratory research to commercial reality. Laser spectroscopic detection techniques not only have high-sensitivity and high-selectivity, as equivalently offered by the MS-based techniques, but also have the advantageous features of near real-time response, low instrument costs, and POC function. Of the approximately 35 established breath biomarkers, such as acetone, ammonia, carbon dioxide, ethane, methane, and nitric oxide, 14 species in exhaled human breath have been analyzed by high-sensitivity laser spectroscopic techniques, namely, tunable diode laser absorption spectroscopy (TDLAS), cavity ringdown spectroscopy (CRDS), integrated cavity output spectroscopy (ICOS), cavity enhanced absorption spectroscopy (CEAS), cavity leak-out spectroscopy (CALOS), photoacoustic spectroscopy (PAS), quartz-enhanced photoacoustic spectroscopy (QEPAS), and optical frequency comb cavity-enhanced absorption spectroscopy (OFC-CEAS). Spectral fingerprints of the measured biomarkers span from the UV to the mid-IR spectral regions and the detection limits achieved by the laser techniques range from parts per million to parts per billion levels. Sensors using the laser spectroscopic techniques for a few breath biomarkers, e.g., carbon dioxide, nitric oxide, etc. are commercially available. This review presents an update on the latest developments in laser-based breath analysis. PMID:22408503

  16. Spectroscopic analysis of solar and cosmic X-ray spectra. 1: The nature of cosmic X-ray spectra and proposed analytical techniques

    NASA Technical Reports Server (NTRS)

    Walker, A. B. C., Jr.

    1975-01-01

    Techniques for the study of the solar corona are reviewed as an introduction to a discussion of modifications required for the study of cosmic sources. Spectroscopic analysis of individual sources and the interstellar medium is considered. The latter was studied via analysis of its effect on the spectra of selected individual sources. The effects of various characteristics of the ISM, including the presence of grains, molecules, and ionization, are first discussed, and the development of ISM models is described. The expected spectral structure of individual cosmic sources is then reviewed with emphasis on supernovae remnants and binary X-ray sources. The observational and analytical requirements imposed by the characteristics of these sources are identified, and prospects for the analysis of abundances and the study of physical parameters within them are assessed. Prospects for the spectroscopic study of other classes of X-ray sources are also discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2008-02-01

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

  18. Spectroscopic analysis of the interaction of lomustine with calf thymus DNA.

    PubMed

    Agarwal, Shweta; Jangir, Deepak Kumar; Singh, Parul; Mehrotra, Ranjana

    2014-01-01

    Investigation of drug-DNA interaction is important for understanding the drug action at molecular level and for designing specific DNA targeted drug. Lomustine (CCNU=1-[2-chloroethyl]-3-cyclohexyl-1-nitroso-urea) is an alkylating antineoplastic nitrosourea derivative, used to treat different types of cancer. In the present study, conformational and structural effects of lomustine on DNA are investigated using different spectroscopic approaches. Different drug/DNA molar ratios are analyzed to determine the binding sites and binding mode of lomustine with DNA. Fourier transform infrared spectroscopic (FTIR) results suggest binding of lomustine with nitrogenous bases guanine and cytosine along with weak interaction to the sugar-phosphate backbone of DNA. Circular dichroism (CD) spectroscopic results show perturbation in the local conformation of DNA upon binding of lomustine with DNA helix. These local conformational changes may act as recognition site for alkylating enzymes that further causes alkylation of DNA. Spectroscopic results confirm the formation of an intermediate stage of DNA that occurs during the transition of B-conformation into A-conformation. PMID:24368412

  19. Photometric and Spectroscopic Analysis of Warm DQ White Dwarfs

    NASA Astrophysics Data System (ADS)

    Fortier, Alexandre; Dufour, Patrick

    2015-06-01

    The "Hot DQ" white dwarfs, a new class of stars showing a surface composition dominated by carbon (Dufour et al. 2007), represent a challenge to stellar evolution. Little is known on how exactly they form or evolve. The first few stars discovered in the SDSS survey were all found in a narrow range of effective temperature (18,000-24,000 K). It has been suggested at the last workshop that these stars may evolve into warm (Teff = 12,000-18,000 K) and highly polluted (log C/He > -3.0) DQ white dwarfs with atomic CI lines (Dufour et al. 2013). We present an analysis of a sample of such "warm DQ" white dwarfs, filling the gap between the Hot DQ and the cooler DQ with molecular bands.

  20. Fourier transform infrared spectroscopic analysis of cell differentiation

    NASA Astrophysics Data System (ADS)

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

    2007-02-01

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

  1. A spectroscopic study of field BHB star candidates

    E-print Network

    T. Kinman; F. Castelli; C. Cacciari; A. Bragaglia; D. Harmer; F. Valdes

    2000-06-13

    New spectroscopic observations (R=15000 and 40000) are given for 31 nearby (V < 11) BHB star candidates. IUE low-resolution spectra are available for most of them. New determinations of temperature, gravity, reddening and abundances were obtained from these data using models computed by Castelli with an updated version of the ATLAS9 code. A summary of the visual photometry for these stars (including new photometry obtained at Kitt Peak) is also given. All 31 candidates are halo stars. We classify 28 as BHB stars because: (1) They lie close to the ZAHB (in a similar position to globular cluster BHB stars) in the Teff vs. log g plot. (2) Their distribution of vsini (less than 40 km/s) is similar to that found for the BHB stars in globular clusters. (3) Their [Fe/H] lies between -0.99 and -2.95 (mean [Fe/H] -1.67, dispersion 0.42 dex) which is similar to that found for field halo RR Lyrae and red HB stars but more metal- poor than for halo globular clusters. Field BHB stars with Teff greater than 8500 K show the He I (4471 A) line corresponding to solar abundance. (4) They show a similar average enhancement of the alpha-elements ([Mg/Fe] = +0.43 +/- 0.04 and [Ti/Fe] = +0.44 +/- 0.02) to that found for other halo field stars of similar metallicity. Comments are given on a further 25 stars that have previously been suggested to be BHB stars; these were not included in our sample because they did not fulfil one or more of the above criteria.

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

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

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

  3. Spectroscopic Analysis of Ultraviolet Lamps for Disinfection of Air in Hospitals

    Microsoft Academic Search

    Syed Hussain Shah

    2009-01-01

    In order to have feasibility study of ultraviolet lamps for air disinfection in hospitals, a number of lamps were studied\\u000a spectroscopically. It was required to understand if these lamps really emitted 253.7 nm. Was the radiation intense enough\\u000a to disinfect the surrounding air in the hospital? And to know about the percent transmission of the UV rays through the glass\\u000a of

  4. Spectroscopic study on binding of rutin to human serum albumin

    NASA Astrophysics Data System (ADS)

    Pastukhov, Alexander V.; Levchenko, Lidiya A.; Sadkov, Anatoli P.

    2007-10-01

    Steady-state and time-resolved fluorescence spectroscopy techniques were used to study the interaction of the flavonoid rutin with human serum albumin (HSA) as well as spectral properties of the protein-bound flavonoid. Both quenching of the intrinsic fluorescence of the protein (Trp214) and the ligand fluorescence, appearing upon complexation with HSA, were used to determine binding parameters. The binding constant determined from the quenching of the Trp214 fluorescence by rutin is equal to 6.87 ± 0.22 × 10 4 M -1 and that obtained from the fluorescence of HSA-bound rutin is 3.8 ± 0.4 × 10 4 M -1. Based on the Job plot analysis, the 1:1 binding stoichiometry for the HSA-rutin complex was determined. The efficient quenching of the Trp214 fluorescence by rutin, fluorescence resonance energy transfer from excited Trp214 to rutin, and competitive binding of warfarin indicate that the binding site for the flavonoid is situated within subdomain IIA of HSA. The presence of the sugar moiety in the flavonoid molecule reduces affinity of rutin for binding to HSA but does not affect the binding stoichiometry and location of the binding site compared with aglycone analogues.

  5. Application of Spectroscopic Methods for Structural Analysis of Chitin and Chitosan

    PubMed Central

    Kumirska, Jolanta; Czerwicka, Ma?gorzata; Kaczy?ski, Zbigniew; Bychowska, Anna; Brzozowski, Krzysztof; Thöming, Jorg; Stepnowski, Piotr

    2010-01-01

    Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad range of applications in medicine, agriculture and the food industry. Two of the main reasons for this are firstly the unique chemical, physicochemical and biological properties of chitin and chitosan, and secondly the unlimited supply of raw materials for their production. These polymers exhibit widely differing physicochemical properties depending on the chitin source and the conditions of chitosan production. The presence of reactive functional groups as well as the polysaccharide nature of these biopolymers enables them to undergo diverse chemical modifications. A complete chemical and physicochemical characterization of chitin, chitosan and their derivatives is not possible without using spectroscopic techniques. This review focuses on the application of spectroscopic methods for the structural analysis of these compounds. PMID:20559489

  6. Application of spectroscopic methods for structural analysis of chitin and chitosan.

    PubMed

    Kumirska, Jolanta; Czerwicka, Ma?gorzata; Kaczy?ski, Zbigniew; Bychowska, Anna; Brzozowski, Krzysztof; Thöming, Jorg; Stepnowski, Piotr

    2010-01-01

    Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad range of applications in medicine, agriculture and the food industry. Two of the main reasons for this are firstly the unique chemical, physicochemical and biological properties of chitin and chitosan, and secondly the unlimited supply of raw materials for their production. These polymers exhibit widely differing physicochemical properties depending on the chitin source and the conditions of chitosan production. The presence of reactive functional groups as well as the polysaccharide nature of these biopolymers enables them to undergo diverse chemical modifications. A complete chemical and physicochemical characterization of chitin, chitosan and their derivatives is not possible without using spectroscopic techniques. This review focuses on the application of spectroscopic methods for the structural analysis of these compounds. PMID:20559489

  7. A COMPREHENSIVE SPECTROSCOPIC ANALYSIS OF DB WHITE DWARFS

    SciTech Connect

    Bergeron, P.; Wesemael, F.; Dufour, Pierre; Beauchamp, A.; Hunter, C.; Gianninas, A.; Limoges, M.-M.; Dufour, Patrick; Fontaine, G. [Departement de Physique, Universite de Montreal, C.P. 6128, Succ. Centre-Ville, Montreal, QC H3C 3J7 (Canada); Saffer, Rex A. [Strayer University, 234 Mall Boulevard, Suite G-50, King of Prussia, PA 19406 (United States); Ruiz, M. T. [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile); Liebert, James, E-mail: bergeron@astro.umontreal.ca, E-mail: wesemael@astro.umontreal.ca, E-mail: gianninas@astro.umontreal.ca, E-mail: limoges@astro.umontreal.ca, E-mail: dufourpa@astro.umontreal.ca, E-mail: fontaine@astro.umontreal.ca, E-mail: alain.beauchamp@fti-ibis.com, E-mail: chris.hunter@yale.edu, E-mail: rex.saffer@strayer.edu, E-mail: mtruiz@das.uchile.cl [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

    2011-08-10

    We present a detailed analysis of 108 helium-line (DB) white dwarfs based on model atmosphere fits to high signal-to-noise optical spectroscopy. We derive a mean mass of 0.67 M{sub sun} for our sample, with a dispersion of only 0.09 M{sub sun}. White dwarfs also showing hydrogen lines, the DBA stars, comprise 44% of our sample, and their mass distribution appears similar to that of DB stars. As in our previous investigation, we find no evidence for the existence of low-mass (M < 0.5 M{sub sun}) DB white dwarfs. We derive a luminosity function based on a subset of DB white dwarfs identified in the Palomar-Green Survey. We show that 20% of all white dwarfs in the temperature range of interest are DB stars, although the fraction drops to half this value above T{sub eff} {approx} 20,000 K. We also show that the persistence of DB stars with no hydrogen features at low temperatures is difficult to reconcile with a scenario involving accretion from the interstellar medium, often invoked to account for the observed hydrogen abundances in DBA stars. We present evidence for the existence of two different evolutionary channels that produce DB white dwarfs: the standard model where DA stars are transformed into DB stars through the convective dilution of a thin hydrogen layer and a second channel where DB stars retain a helium atmosphere throughout their evolution. We finally demonstrate that the instability strip of pulsating V777 Her white dwarfs contains no non-variables, if the hydrogen content of these stars is properly accounted for.

  8. A mass spectroscopic analysis of {gamma}-GPS films

    SciTech Connect

    Dillingham, R.G.; Boerio, F.J.; Bertelsen, C. [Univ. of Cincinnati, OH (United States); Savina, M.R.; Lykke, K.; Calaway, W. [Univ. of Cincinnati, OH (United States)

    1996-12-31

    Preparation of substrates for painting or adhesive bonding frequently includes roughening through sanding, chemical etching, or gritblasting. Increased roughness can improve interfacial strength and durability due to increased mechanical interlocking, increased surface area, and improved wettability of the substrate. The chemical reactivity of the surface with the organic phase may be affected as well, perhaps related to the strain energy stored in the surface regions through the intense plastic deformation that occurs. Unfortunately, the chemistry of interactions taking place near a surface that has been roughened is difficult to access analytically by some of the more useful techniques such as infrared spectroscopy. This paper discusses analysis of nonreflective grit-blasted surfaces using mass spectroscopy of species which were either sputtered off using an ion beam (Static Secondary Ion Mass Spectroscopy, or SSIMS) or thermally desorbed as neutrals using a pulsed laser and then post-ionized using a secondary laser (Laser Desorption-Laser Ionization Mass Spectroscopy, or LDLIMS). Both of these techniques exhibit sub-nanometer sensitivity and provide significant information as to the chemistry and structure of the surface regions. In a current application of {gamma}-glycidoxypropyltrimethoxysilane ({gamma}-GPS) for the pre-treatment of grit-blasted aluminum before adhesive bonding, certain factors related to the handling of the primer solution and to the application technique were found to significantly affect the performance of the adhesive bond under long-term aging conditions including stress and humidity. To understand why these parameters are important and to potentially improve the pretreatment process even further, the authors have been investigating how the structure and reactivity of these silane films are related to the application techniques.

  9. A Spectroscopic Survey and Analysis of Bright, Hydrogen-rich White Dwarfs

    NASA Astrophysics Data System (ADS)

    Gianninas, A.; Bergeron, P.; Ruiz, M. T.

    2011-12-01

    We have conducted a spectroscopic survey of over 1300 bright (V <= 17.5), hydrogen-rich white dwarfs based largely on the last published version of the McCook & Sion catalog. The complete results from our survey, including the spectroscopic analysis of over 1100 DA white dwarfs, are presented. High signal-to-noise ratio optical spectra were obtained for each star and were subsequently analyzed using our standard spectroscopic technique where the observed Balmer line profiles are compared to synthetic spectra computed from the latest generation of model atmospheres appropriate for these stars. First, we present the spectroscopic content of our sample, which includes many misclassifications as well as several DAB, DAZ, and magnetic white dwarfs. Next, we look at how the new Stark broadening profiles affect the determination of the atmospheric parameters. When necessary, specific models and analysis techniques are used to derive the most accurate atmospheric parameters possible. In particular, we employ M dwarf templates to obtain better estimates of the atmospheric parameters for those white dwarfs that are in DA+dM binary systems. Certain unique white dwarfs and double-degenerate binary systems are also analyzed in greater detail. We then examine the global properties of our sample including the mass distribution and their distribution as a function of temperature. We then proceed to test the accuracy and robustness of our method by comparing our results to those of other surveys such as SPY and Sloan Digital Sky Survey. Finally, we revisit the ZZ Ceti instability strip and examine how the determination of its empirical boundaries is affected by the latest line profile calculations. Based on observations made with ESO Telescopes at the La Silla or Paranal Observatories under program ID 078.D-0824(A).

  10. A SPECTROSCOPIC SURVEY AND ANALYSIS OF BRIGHT, HYDROGEN-RICH WHITE DWARFS

    SciTech Connect

    Gianninas, A.; Bergeron, P. [Departement de Physique, Universite de Montreal, C.P. 6128, Succ. Centre-Ville, Montreal, Quebec H3C 3J7 (Canada); Ruiz, M. T., E-mail: gianninas@astro.umontreal.ca, E-mail: bergeron@astro.umontreal.ca, E-mail: mtruiz@das.uchile.cl [Departamento de Astronomia, Universidad de Chile, Casilla 36-D, Santiago (Chile)

    2011-12-20

    We have conducted a spectroscopic survey of over 1300 bright (V {<=} 17.5), hydrogen-rich white dwarfs based largely on the last published version of the McCook and Sion catalog. The complete results from our survey, including the spectroscopic analysis of over 1100 DA white dwarfs, are presented. High signal-to-noise ratio optical spectra were obtained for each star and were subsequently analyzed using our standard spectroscopic technique where the observed Balmer line profiles are compared to synthetic spectra computed from the latest generation of model atmospheres appropriate for these stars. First, we present the spectroscopic content of our sample, which includes many misclassifications as well as several DAB, DAZ, and magnetic white dwarfs. Next, we look at how the new Stark broadening profiles affect the determination of the atmospheric parameters. When necessary, specific models and analysis techniques are used to derive the most accurate atmospheric parameters possible. In particular, we employ M dwarf templates to obtain better estimates of the atmospheric parameters for those white dwarfs that are in DA+dM binary systems. Certain unique white dwarfs and double-degenerate binary systems are also analyzed in greater detail. We then examine the global properties of our sample including the mass distribution and their distribution as a function of temperature. We then proceed to test the accuracy and robustness of our method by comparing our results to those of other surveys such as SPY and Sloan Digital Sky Survey. Finally, we revisit the ZZ Ceti instability strip and examine how the determination of its empirical boundaries is affected by the latest line profile calculations.

  11. Infrared spectroscopic study of rovibrational states of methane trapped in parahydrogen crystal

    E-print Network

    Oka, Takeshi

    Infrared spectroscopic study of rovibrational states of methane trapped in parahydrogen crystal observed by using Fourier transform infrared and high resolution laser spectroscopy. The observed spectrum broader lines of a width of 1 cm 1 . The infrared selection rules derived from an extended group theory

  12. Spectroscopic studies of lanthanide (Ce, Eu) chlorides in ethane-1,2-diol

    Microsoft Academic Search

    Barbara Keller; Janina Legendziewicz; Jan Przybylski; Ma?gorzata Guzik; Jacek Gli?ski

    2002-01-01

    This paper is a consequence of our earlier studies on the structure of solutions of anhydrous and hydrated lanthanide chlorides in different types of alcohols. Such investigations are important mainly in understanding the spectroscopic behavior of silica gels and glasses obtained by alcohol methods and codoped with Ce3+ and other lanthanide ions. Our work focuses on the spectroscopy of Ce(III)

  13. Millimeter-Wave Spectroscopic and Collisional Studies of Molecules and Molecular Ions

    Microsoft Academic Search

    John Christoffersen Pearson

    1995-01-01

    Molecular spectroscopy in the millimeter- and submillimeter-wave regions is an important tool in molecular physics. Information on molecular motions and interactions is obtained from spectroscopic studies of energy levels and collisions. This information and the data from which it is derived are essential in remote sensing of the atmosphere and the interstellar medium. Remote sensing at submillimeter wavelengths is now

  14. A Spectroscopic Study of the Solar Corona from Norikura and SOHO data

    Microsoft Academic Search

    K. P. Raju; T. Sakurai; K. Ichimoto

    2001-01-01

    We report the results from a spectroscopic study of the solar corona, wherein, we examine some of the current problems in the corona, such as the plume-interplume differences in coronal holes, coronal loops in active regions and wave propagation in the corona. The distribution of emission line intensities, Doppler velocities and line widths in the corona were obtained from the

  15. Melting of Rodlike Molecules on Pt(111). Infrared Spectroscopic Studies of Isotopically Labeled n-Alkanes

    E-print Network

    Girolami, Gregory S.

    Melting of Rodlike Molecules on Pt(111). Infrared Spectroscopic Studies of Isotopically Labeled n 61801 ReceiVed: May 12, 1998; In Final Form: August 24, 1998 The melting of monolayers of isotopically labeled n-alkanes on Pt(111) surfaces has been followed by reflection-absorption infrared (RAIR

  16. STM and Raman spectroscopic study of graphite irradiated by heavy ions

    E-print Network

    Gao, Hongjun

    ; Heavy ions; Scanning tunnel microscopy; Raman spectroscopy 1. Introduction When a swift heavy ion on the presentation of new Raman scattering results on ion irradiation because it is sensitive to structural disorderSTM and Raman spectroscopic study of graphite irradiated by heavy ions J. Liu a,*, M.D. Hou a , C

  17. Pb(II) binding to humic substances: an equilibrium and spectroscopic study.

    PubMed

    Orsetti, Silvia; Marco-Brown, Jose L; Andrade, Estela M; Molina, Fernando V

    2013-08-01

    The binding of Pb(II) to humic acids is studied through an approach combining equilibrium and spectroscopic measurements. The methods employed are potentiometric and fluorometric titrations, fluorescence excitation-emission matrices (EEM) and IR spectroscopy. Potentiometric titration curves are analyzed using the NICA equations and an electrostatic model treating the humic particles as an elastic polyelectrolyte network. EEMs are analyzed using parallel factor analysis, decomposing the signal in its independent components and finding their dependence on Pb(II) activity. Potentiometric results are consistent with bimodal affinity distributions for Pb(II) binding, whereas fluorometric titrations are explained by monomodal distributions. EEM analysis is consistent with three independent components in the humic fluorescence response, which are assigned to moieties with different degree of aromaticity. All three components show a similar quenching behavior upon Pb(II) binding, saturating at relatively low Pb(II) concentrations. This is attributed to metal ion induced aggregation of humic molecules, resulting in the interaction between the aromatic groups responsible for fluorescence; this is also consistent with IR spectroscopy results. The observed behavior is interpreted considering that initial metal binding (observed as strongly binding sites), correspond to bi- or multidentate complexation to carboxylate groups, including binding between groups of different humic molecules, promoting aggregation; further metal ions (observed as weakly binding sites) bind to single ligand groups. PMID:23805795

  18. {sup 1}H NMR spectroscopic studies establish that heparanase is a retaining glycosidase

    SciTech Connect

    Wilson, Jennifer C., E-mail: jennifer.wilson@griffith.edu.au [Institute for Glycomics, Griffith University Gold Coast Campus, QLD 4222 (Australia); Laloo, Andrew Elohim [School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 (Australia)] [School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 (Australia); Singh, Sanjesh [Institute for Glycomics, Griffith University Gold Coast Campus, QLD 4222 (Australia)] [Institute for Glycomics, Griffith University Gold Coast Campus, QLD 4222 (Australia); Ferro, Vito, E-mail: v.ferro@uq.edu.au [School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 (Australia)] [School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD 4072 (Australia)

    2014-01-03

    Highlights: •{sup 1}H and {sup 13}C NMR chemical shifts of fondaparinux were fully assigned by 1D and 2D NMR techniques. •Hydrolysis of fondaparinux by heparanase was monitored by {sup 1}H NMR spectroscopy. •Heparanase is established to be a retaining glycosidase. -- Abstract: Heparanase is an endo-?-glucuronidase that cleaves heparan sulfate side chains of proteoglycans in basement membranes and the extracellular matrix (ECM). Heparanase is implicated in several diverse pathological processes associated with ECM degradation such as metastasis, inflammation and angiogenesis and is thus an important target for anti-cancer and anti-inflammatory drug discovery. Heparanase has been classed as belonging to the clan A glycoside hydrolase family 79 based on sequence analysis, secondary structure predictions and mutagenic analysis, and thus it has been inferred that it is a retaining glycosidase. However, there has been no direct experimental evidence to support this conclusion. Herein we describe {sup 1}H NMR spectroscopic studies of the hydrolysis of the pentasaccharide substrate fondaparinux by heparanase, and provide conclusive evidence that heparanase hydrolyses its substrate with retention of configuration and is thus established as a retaining glycosidase. Knowledge of the mechanism of hydrolysis may have implications for future design of inhibitors for this important drug target.

  19. Spectroscopic and molecular modeling studies on the interactions of N-Methylformamide with superoxide dismutase.

    PubMed

    Kalyani, Durai; Jyothi, Kanagaraj; Sivaprakasam, Chinnarasu; Nachiappan, Vasanthi

    2014-04-24

    N-Methylformamide, a polar solvent has a wide industrial applications and it is well-known for hepatotoxicity. The interaction between NMF with superoxide dismutase, an antioxidant defense enzyme has been studied for the first time using spectroscopic methods including Fourier transform infrared (FT-IR) spectroscopy, Circular dichroism (CD) spectroscopy and UV-visible spectroscopy under simulative physiological conditions and also by molecular modelling. Fourier Transform Infra Red analysis showed that the change in peak positions and shapes revealed that the secondary structure of SOD had been changed by the interaction with NMF. The data of CD spectra also confirmed that NMF decreased the degree of secondary structure of SOD, which directly resulted in destabilization of enzyme. We studied the inhibitory effect of NMF on enzyme kinetics by pyrogallol autoxidation revealed that protein-ligand complex caused structural unfolding which resulted in enzymatic inhibition. Thus the spectral behaviour of superoxide dismutase provides data concerning its conformational changes in the presence of NMF. Furthermore, molecular docking was applied to explore the binding mode between the protein-ligand complex. This suggested that Asn54 and Val302 residues of dimeric protein were predicted to interact with NMF. The present study provides direct evidence at a molecular level to show that exposure to NMF cause perturbation in its structure and function. PMID:24473177

  20. Laser apparatus and method for microscopic and spectroscopic analysis and processing of biological cells

    DOEpatents

    Gourley, Paul L. (12508 Loyola, NE., Albuquerque, NM 87112); Gourley, Mark F. (7509 Spring Lake Dr., Apt. B1, Bethesda, MD 20817)

    1997-01-01

    An apparatus and method for microscopic and spectroscopic analysis and processing of biological cells. The apparatus comprises a laser having an analysis region within the laser cavity for containing one or more biological cells to be analyzed. The presence of a cell within the analysis region in superposition with an activated portion of a gain medium of the laser acts to encode information about the cell upon the laser beam, the cell information being recoverable by an analysis means that preferably includes an array photodetector such as a CCD camera and a spectrometer. The apparatus and method may be used to analyze biomedical cells including blood cells and the like, and may include processing means for manipulating, sorting, or eradicating cells after analysis thereof.

  1. Laser apparatus and method for microscopic and spectroscopic analysis and processing of biological cells

    DOEpatents

    Gourley, P.L.; Gourley, M.F.

    1997-03-04

    An apparatus and method are disclosed for microscopic and spectroscopic analysis and processing of biological cells. The apparatus comprises a laser having an analysis region within the laser cavity for containing one or more biological cells to be analyzed. The presence of a cell within the analysis region in superposition with an activated portion of a gain medium of the laser acts to encode information about the cell upon the laser beam, the cell information being recoverable by an analysis means that preferably includes an array photodetector such as a CCD camera and a spectrometer. The apparatus and method may be used to analyze biomedical cells including blood cells and the like, and may include processing means for manipulating, sorting, or eradicating cells after analysis. 20 figs.

  2. Static and time-resolved spectroscopic studies of low-symmetry Ru(II) polypyridyl complexes

    SciTech Connect

    Curtright, A.E.; McCusker, J.K.

    1999-09-02

    The spectroscopic and electrochemical properties of a series of four Ru{sup II} polypyridyl complexes are reported. Compounds of the form [Ru(dmb){sub x}(dea){sub 3{minus}x}]{sup 2+} (x = 0--3), where dmb is 4,4{prime}-dimethyl-2,2{prime}-bipyridine and dea is 4,4{prime}-bis(diethylamino)-2,2{prime}-bipyridine, have been prepared and studied using static and time-resolved electronic and vibrational spectroscopies as a prelude to femtosecond spectroscopic studies of excited-state dynamics. Static electronic spectra in CH{sub 3}CN solution reveal a systematic shift of the MLCT absorption envelope from a maximum of 458 nm in the case of [Ru(dmb){sub 3}]{sup 2+} to 518 nm for [Ru(dea){sub 3}]{sup 2+} with successive substitutions of dea for dmb, suggesting a dea-based chromophore as the lowest-energy species. However, analysis of static and time-resolved emission data indicates an energy gap ordering of [Ru(dmb){sub 3}]{sup 2+} > [Ru(dmb){sub 2}(dea)]{sup 2+} > [Ru(dea){sub 3}]{sup 2+} > [Ru(dmb)(DEA){sub 2}]{sup 2+}, at variance with the electronic structures inferred from the absorption spectra. Nanosecond time-resolved electronic absorption and time-resolved step-scan infrared data are used to resolve this apparent conflict and confirm localization of the long-lived {sup 3}MLCT state on dmb in all three complexes where this ligand is present, thus making the dea-based excited state unique to [Ru(dea){sub 3}]{sup 2+}. Electrochemical studies further reveal the origin of this result, where a strong influence of the dea ligand on the oxidative Ru{sup II/III} couple, due to {pi} donation from the diethylamino substituent, is observed. The electronic absorption spectra are then reexamined in light of the now well-determined excited-state electronic structure. The results serve to underscore the importance of complete characterization of the electronic structures of transition metal complexes before embarking on ultrafast studies of their excited-state properties.

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

    SciTech Connect

    Wang, Han; Fu, Kan [Department of Materials Science and Engineering, University of Connecticut, Storrs, Connecticut 06269. (United States)] [Department of Materials Science and Engineering, University of Connecticut, Storrs, Connecticut 06269. (United States)

    2013-11-15

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

  4. a Negative Ion Photoelectron Spectroscopic and Computational Study of Mo_{2} and Mo_{2}^{-}

    NASA Astrophysics Data System (ADS)

    Barker, Beau J.; Baidar, Sunil; Casey, Sean M.; Leopold, Doreen G.

    2009-06-01

    We report the 488 and 514 nm anion photoelectron spectra of Mo_{2}^{-}. Neutral Mo_{2} has been described in recent ab initio studies as having a bond order of six, predicted to be the highest of any homonuclear diatomic, exceeding even that of Cr_{2}(five). The photoelectron spectrum of Mo_{2}^{-}confirms the previously measured vibrational frequency of gas phase Mo_{2} and displays transitions to vibrational levels up to v=7 in its ^{1}?_{g}^{+} ground state. The electron affinity of Mo_{2} is measured to be 0.732 ± 0.010 eV. The Mo_{2}^{-} ground state is assigned as a ^{2}?_{u}^{+} state, in which the extra electron occupies a formally antibonding ?_{u} orbital of primarily 5s atomic parentage. A Franck-Condon analysis of the vibrational band intensities indicates a change in the equilibrium bond length of only 0.03 ± 0.02 Å upon electron detachment. These results, and the similar vibrational frequencies measured for Mo_{2} and Mo_{2}^{-}, suggest that the anion HOMO is essentially nonbonding. Weak photodetachment transitions to excited states of Mo_{2} lying within 1.2 eV of its ground state are also observed. DFT calculations using the BPW91/SDD method show good agreement with experiment for the electron affinity of Mo_{2} and the bond lengths in the anion and neutral molecule ground states. It is hoped that these spectroscopic results will motivate and assist high level theoretical studies of the Mo_{2}^{-} anion.

  5. A Combined Remote LIBS and Raman Spectroscopic Study of Minerals

    NASA Technical Reports Server (NTRS)

    Hubble, H. W.; Ghosh, M.; Sharma, S. K.; Horton, K. A.; Lucey, P. G.; Angel, S. M.; Wiens, R. C.

    2002-01-01

    In this paper, we explore the use of remote LIBS combined with pulsed-laser Raman spectroscopy for mineral analysis at a distance of 10 meters. Samples analyzed include: carbonates (both biogenic and abiogenic), silicates, and sulfates. Additional information is contained in the original extended abstract.

  6. Analysis of heavy metals during composting of the tannery sludge using physicochemical and spectroscopic techniques.

    PubMed

    Haroun, Mahdi; Idris, Azni; Omar, Syed

    2009-06-15

    The major limitation of direct application of tannery sludge compost in agriculture is the total heavy metal contents and their bioavailability to the soil-plant system. This study focused on the heavy metal characterization and the influence of changing the physicochemical properties of the medium throughout the composting on the concentrations, bioavailability or chemical forms of Cr, Cu, Zn, Pb and Cd in tannery sludge. The study shows that throughout the 60 days of composting, physicochemical analysis and Fourier-transformed infrared (FTIR) spectroscopic characterization show that all parameters elaborated and reached relatively stable levels reflecting the stability and maturity of the final product, and revealed the biodegradation of components that can be easily assimilated by microorganism. The C/N ratio reaches the optimal range of stable compost; inorganic nitrogen is transformed into stable organic forms. The total concentration of Cr, Zn, Cu, Pb and Cd is very low rendering final compost acceptable for agricultural use. The germination index for both Chinese cabbage and lettuce was 97% after 60 days of composting, showing that the final compost was not phytotoxic. Furthermore, in using a sequential extraction method in sludge compost at different phases of treatment, a less than 2% of metals bound to bioavailable fractions X-(KNO(3)+H(2)O). A large proportion of the heavy metals were associated to the residual fraction (75-85%) and more resistant fractions to extraction X-NaOH, X-EDTA, X-HNO(3) (15-25%). Mobile fractions of metals are poorly predictable from the total content. Bioavailability of all fractions of elements tends to decrease. PMID:18990495

  7. Comparative performance analysis of time-frequency distributions for spectroscopic optical coherence tomography.

    PubMed

    Xu, Chenyang; Kamalabadi, Farzad; Boppart, Stephen A

    2005-04-01

    The analysis of spectroscopic optical coherence tomography (SOCT) signals suffers the trade-off between time resolution and frequency resolution. Various joint time-frequency distributions (TFDs) can optimize this trade-off. Synthesized signals were generated and experimentally acquired data were obtained to compare and validate several different TFDs under different SOCT imaging schemes. Specific criteria were designed to quantify the TFD performance. We found that different SOCT imaging schemes require different optimal TFDs. Cohen's class TFDs generate the most compact time-frequency (TF) analysis, while linear TFDs offer the most reliable TF analysis. In both cases, if some prior information is known, model-based TF analysis can improve the performance. PMID:15813517

  8. Temporal correlation scheme for spectroscopic gas analysis using multimode diode lasers

    SciTech Connect

    Somesfalean, G.; Sjoeholm, M.; Persson, L.; Gao, H.; Svensson, T.; Svanberg, S. [Department of Physics, Lund Institute of Technology, P.O. Box 118, SE-221 00 Lund (Sweden)

    2005-05-02

    The reliability of diode lasers used in spectroscopic applications is limited by their intrinsic multimode and mode-jump behavior when wavelength-tuned by current or temperature. We report on a scheme for gas analysis based on temporal correlation between absorption signals from an unknown external and a known reference gas concentration, simultaneously recorded when the diode laser wavelength is temperature-tuned across absorption features of the gas of interest. This procedure, which does not require any knowledge of the exact spectrum, also eliminates light intensity fluctuations due to mode competition. The method is illustrated for atmospheric oxygen absorption applied to diffusion measurements.

  9. Multipass annular mirror system for spectroscopic studies in shock tubes

    Microsoft Academic Search

    Semen M. Chernin

    2004-01-01

    A fundamentally new multipass reflecting mirror system for studies in shock tubes is designed. Conducting optical absorption measurements in shock tubes when modelling processes of controlled combustion is necessary. The results of these optical studies facilitate working out recommendations on efficient and non-polluting burning of natural fuels in industry. The basic component of the suggested multipass optical system is an

  10. Vibrational spectroscopic studies of the isotope effects in polyaniline

    Microsoft Academic Search

    S. Quillard; G. Louam; J. P. Buisson; M. Boyer; M. Lapkowski; A. Pron; S. Lefrant

    1997-01-01

    Comparative Raman spectroscopy studies of nondeuterated polyaniline and polyaniline deuterated on the ring and on the nitrogen enabled us to confirm the assignments of principal Raman modes. Spectroelectrochemical studies carried out for these two isotopically different polymers indicate the creation of two types of structures upon electrochemical doping, namely polaron lattice and bipolaronic structure.

  11. Raman spectroscopic study of four isotopically substituted lithium hydroxide monohydrates

    Microsoft Academic Search

    Yoshiyuki Hase

    1981-01-01

    Raman spectral data of polycrystals of four isotopically substituted lithium hydroxide monohydrates,6LiOH·H2O,7LiOH·H2O,6LiOD·D2O and7LiOD·D2O, have been investigated in the 4,000–50 cm-1 region. The observed spectra have been analyzed and discussed taking into account the results of the factor group analysis and the H\\/D and6Li\\/7Li isotope effects on the fundamental wavenumbers.

  12. Spectroscopic Binary Star Studies with the Palomar Testbed Interferometer II

    E-print Network

    for which we will present new orbit mod- els are: 12 Boo (HD 123999), 75 Cnc (HD 78418), 47 And (HD 8374.4 1.6 27.1 #6; 0.4 27.3 #6; 0.8 BY Dra K6 V 4.4 24 65.8 #6; 5.4 60.9 #6; 0.9 75 Cnc G5 IV 5.9 4.6 31 completed our analysis or have solid provisional solutions: 12 Boo (HD 123999), 75 Cnc (HD 78418), 47

  13. Structural, spectroscopic and DFT study of 4-methoxybenzohydrazide Schiff bases. A new series of polyfunctional ligands

    NASA Astrophysics Data System (ADS)

    Ferraresi-Curotto, Verónica; Echeverría, Gustavo A.; Piro, Oscar E.; Pis-Diez, Reinaldo; González-Baró, Ana C.

    2015-02-01

    Five Schiff bases obtained from condensation of 4-methoxybenzohydrazide with related aldehydes, namely o-vanillin, vanillin, 5-bromovanillin, 5-chlorosalicylaldehyde and 5-bromosalicylaldehyde were prepared. A detailed structural and spectroscopic study is reported. The crystal structures of four members of the family were determined and compared with one another. The hydrazones obtained from 5-chlorosalicylaldehyde and 5-bromosalicylaldehyde resulted to be isomorphic to each other. The solid-state structures are stabilized by intra-molecular Osbnd H⋯N interactions in salicylaldehyde derivatives between the Osbnd H moiety from the aldehyde and the hydrazone nitrogen atom. All crystals are further stabilized by inter-molecular H-bonds mediated by the crystallization water molecule. A comparative analysis between experimental and theoretical results is presented. The conformational space was searched and geometries were optimized both in gas phase and including solvent effects. The structure is predicted for the compound for which the crystal structure was not determined. Infrared and electronic spectra were measured and assigned with the help of data obtained from computational methods based on the Density Functional Theory.

  14. A Raman spectroscopic study of thermally treated glushinskite—the natural magnesium oxalate dihydrate

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.; Adebajo, Moses; Weier, Matt L.

    2004-02-01

    Raman spectroscopy has been used to study the thermal transformations of natural magnesium oxalate dihydrate known in mineralogy as glushinskite. The data obtained by Raman spectroscopy was supplemented with that of infrared emission spectroscopy. The vibrational spectroscopic data was complimented with high resolution thermogravimetric analysis combined with evolved gas mass spectrometry. TG-MS identified two mass loss steps at 146 and 397 °C. In the first mass loss step water is evolved only, in the second step carbon dioxide is evolved. The combination of Raman microscopy and a thermal stage clearly identifies the changes in the molecular structure with thermal treatment. Glushinskite is the dihydrate phase in the temperature range up to the pre-dehydration temperature of 146 °C. Above 397 °C, magnesium oxide is formed. Infrared emission spectroscopy shows that this mineral decomposes at around 400 °C. Changes in the position and intensity of the CO and CC stretching vibrations in the Raman spectra indicate the temperature range at which these phase changes occur.

  15. WIYN open cluster study. LX. Spectroscopic binary orbits in NGC 6819

    SciTech Connect

    Milliman, Katelyn E.; Mathieu, Robert D.; Gosnell, Natalie M. [Department of Astronomy, University of Wisconsin-Madison, 475 North Charter Street Madison, WI 53706 (United States); Geller, Aaron M. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA), Northwestern University, 2145 Sheridan Road, Evanston, IL 60208 (United States); Meibom, Søren [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Platais, Imants, E-mail: milliman@astro.wisc.edu [Department of Physics and Astronomy, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)

    2014-08-01

    We present the current state of the WOCS radial-velocity (RV) survey for the rich open cluster NGC 6819 (2.5 Gyr) including 93 spectroscopic binary orbits with periods ranging from 1.5 to 8000 days. These results are the product of our ongoing RV survey of NGC 6819 using the Hydra Multi-Object Spectrograph on the WIYN 3.5 m telescope. We also include a detailed analysis of multiple prior sets of optical photometry for NGC 6819. Within a 1° field of view, our stellar sample includes the giant branch, the red clump, and blue straggler candidates, and extends to almost 2 mag below the main sequence (MS) turnoff. For each star observed in our survey we present all RV measurements, the average RV, and velocity variability information. Additionally, we discuss notable binaries from our sample, including eclipsing binaries (WOCS 23009, WOCS 24009, and WOCS 40007), stars noted in Kepler asteroseismology studies (WOCS 4008, WOCS 7009, and WOCS 8007), and potential descendants of past blue stragglers (WOCS 1006 and WOCS 6002). We find the incompleteness-corrected binary fraction for all MS binaries with periods less than 10{sup 4} days to be 22% ± 3% and a tidal circularization period of 6.2{sub ?1.1}{sup +1.1} days for NGC 6819.

  16. Solvatochromism of 9,10-phenanthrenequinone: an electronic and resonance Raman spectroscopic study.

    PubMed

    Ravi Kumar, Venkatraman; Rajkumar, Nagappan; Umapathy, Siva

    2015-01-14

    Solvent effects play a vital role in various chemical, physical, and biological processes. To gain a fundamental understanding of the solute-solvent interactions and their implications on the energy level re-ordering and structure, UV-VIS absorption, resonance Raman spectroscopic, and density functional theory calculation studies on 9,10-phenanthrenequinone (PQ) in different solvents of diverse solvent polarity has been carried out. The solvatochromic analysis of the absorption spectra of PQ in protic dipolar solvents suggests that the longest (1n-?(1)*; S1 state) and the shorter (1?-?(1)*; S2 state) wavelength band undergoes a hypsochromic and bathochromic shift due to intermolecular hydrogen bond weakening and strengthening, respectively. It also indicates that hydrogen bonding plays a major role in the differential solvation of the S2 state relative to the ground state. Raman excitation profiles of PQ (400-1800 cm(-1)) in various solvents followed their corresponding absorption spectra therefore the enhancements on resonant excitation are from single-state rather than mixed states. The hyperchromism of the longer wavelength band is attributed to intensity borrowing from the nearby allowed electronic transition through vibronic coupling. Computational calculation with C2? symmetry constraint on the S2 state resulted in an imaginary frequency along the low-frequency out-of-plane torsional modes involving the C=O site and therefore, we hypothesize that this mode could be involved in the vibronic coupling. PMID:25591351

  17. Solvatochromism of 9,10-phenanthrenequinone: An electronic and resonance Raman spectroscopic study

    NASA Astrophysics Data System (ADS)

    Ravi Kumar, Venkatraman; Rajkumar, Nagappan; Umapathy, Siva

    2015-01-01

    Solvent effects play a vital role in various chemical, physical, and biological processes. To gain a fundamental understanding of the solute-solvent interactions and their implications on the energy level re-ordering and structure, UV-VIS absorption, resonance Raman spectroscopic, and density functional theory calculation studies on 9,10-phenanthrenequinone (PQ) in different solvents of diverse solvent polarity has been carried out. The solvatochromic analysis of the absorption spectra of PQ in protic dipolar solvents suggests that the longest (1n-?1*; S1 state) and the shorter (1?-?1*; S2 state) wavelength band undergoes a hypsochromic and bathochromic shift due to intermolecular hydrogen bond weakening and strengthening, respectively. It also indicates that hydrogen bonding plays a major role in the differential solvation of the S2 state relative to the ground state. Raman excitation profiles of PQ (400-1800 cm-1) in various solvents followed their corresponding absorption spectra therefore the enhancements on resonant excitation are from single-state rather than mixed states. The hyperchromism of the longer wavelength band is attributed to intensity borrowing from the nearby allowed electronic transition through vibronic coupling. Computational calculation with C2? symmetry constraint on the S2 state resulted in an imaginary frequency along the low-frequency out-of-plane torsional modes involving the C=O site and therefore, we hypothesize that this mode could be involved in the vibronic coupling.

  18. A combined spectroscopic and theoretical study of propofol·(H2O)3.

    PubMed

    León, Iker; Cocinero, Emilio J; Millán, Judith; Rijs, Anouk M; Usabiaga, Imanol; Lesarri, Alberto; Castaño, Fernando; Fernández, José A

    2012-08-21

    Propofol (2,6-di-isopropylphenol) is probably the most widely used general anesthetic. Previous studies focused on its complexes containing 1 and 2 water molecules. In this work, propofol clusters containing three water molecules were formed using supersonic expansions and probed by means of a number of mass-resolved laser spectroscopic techniques. The 2-color REMPI spectrum of propofol[middle dot](H(2)O)(3) contains contributions from at least two conformational isomers, as demonstrated by UV/UV hole burning. Using the infrared IR/UV double resonance technique, the IR spectrum of each isomer was obtained both in ground and first excited electronic states and interpreted in the light of density functional theory (DFT) calculations at M06-2X/6-311++G(d,p) and B3LYP/6-311++G(d,p) levels. The spectral analysis reveals that in both isomers the water molecules are forming cyclic hydrogen bond networks around propofol's OH moiety. Furthermore, some evidences point to the existence of isomerization processes, due to a complicated conformational landscape and the existence of multiple paths with low energy barriers connecting the different conformers. Such processes are discussed with the aid of DFT calculations. PMID:22920116

  19. Toward High Performance Graphene-based Solar Cells: Spectroscopic Study on Doped Graphene

    NASA Astrophysics Data System (ADS)

    Chang, Jan-Kai; Hsu, Chen-Chih; Lin, Wei-Hsiang; Wu, Chih-I.; Yeh, Nai-Chang

    2015-03-01

    A polymer-free transfer method with in situ doping process for graphene, aiming at simple and efficient doping of residue-free graphene, has been developed to achieve stacked graphene/dopant intercalation films. The proposed facile strategy led to a tunable work function from 3.25 eV to 5.10 eV, enabling graphene anode and cathode for solar cell devices. Both hybrid and organic photovoltaics using graphene electrodes have been carried out with a series of optimization based on spectroscopic characterizations. Since aging of doped graphene is crucial to the lifetime of graphene-based solar cells, the doping-induced electronic state variation with time has been investigated via X-ray and ultra-violet photoemission spectroscopy analysis to gain insight in its electronic properties and stability. The doping effect developed in graphene has also been studied via Raman spectroscopy, including time evolution of the Raman D, G and 2D bands under normal and humid conditions for up to 30 days. This systematic investigation of aging effect provides better understanding and helps optimize the stacking of doped graphene films for achieving high performance graphene-based devices. This work is supported by NSC of R.O.C. (Dragon Gate Program) and NSF for the work at Caltech.

  20. Spectroscopic investigations, molecular interactions, and molecular docking studies on the potential inhibitor "thiophene-2-carboxylicacid".

    PubMed

    Karthick, T; Balachandran, V; Perumal, S

    2015-04-15

    Thiophene derivatives have been focused in the past decades due to their remarkable biological and pharmacological activities. In connection with that the conformational stability, spectroscopic characterization, molecular (inter- and intra-) interactions, and molecular docking studies on thiophene-2-carboxylicacid have been performed in this work by experimental FT-IR and theoretical quantum chemical computations. Experimentally recorded FT-IR spectrum in the region 4000-400 cm(-1) has been compared with the scaled theoretical spectrum and the spectral peaks have been assigned on the basis of potential energy distribution results obtained from MOLVIB program package. The conformational stability of monomer and dimer conformers has been examined. The presence of inter- and intramolecular interactions in the monomer and dimer conformers have been explained by natural bond orbital analysis. The UV-Vis spectra of the sample in different solvents have been simulated and solvent effects were predicted by polarisable continuum model with TD-DFT/B3LYP/6-31+G(d,p) method. To test the biological activity of the sample, molecular docking (ligand-protein) simulations have been performed using SWISSDOCK web server. The full fitness (FF) score and binding affinity values revealed that thiophene-2-carboxylicacid can act as potential inhibitor against inflammation. PMID:25677530

  1. Spectroscopic study on sorption of hydrogen sulfide by means of red soil.

    PubMed

    Ko, T H; Chu, H

    2005-07-01

    This paper reports the results of the characterization of red soils in relation to the sorption of H2S from coal gas at 500 degrees C by spectroscopic techniques in order to provide more information on red soils' structural change both before and after reaction. In addition, by-products analysis has also been studied using Fourier transform infrared (FTIR) spectroscopy. Before and after the experiments the red soils were characterized with X-ray powder diffraction (XRPD), energy dispersion spectrum (EDS), X-ray photoelectron spectroscopy (XPS) and FTIR spectroscopy. XRPD results indicate that iron oxide species disappear from the original to reacted red soil. EDS analysis shows that a significant amount of sulfur is present in the reacted red soil, which is in agreement with the results of the elemental analysis and the calculated value based on breakthrough curve. XPS regression fitting results further indicate that sulfur retention may be associated with the iron oxides. S 2p XPS fittings point out that the major sulfur species present in the reacted red soil are composed of S(-2), elemental sulfur, polysulfide, sulfite and sulfate. Additionally, the binding energy of iron shifts to a lower position for the reacted red soil, which indicates that iron oxides in the original red soil have been converted into iron sulfide. Appreciable amounts of the by-products CO2, SO2 and COS are detected by on-line FTIR spectroscopy during the initial and later stages of the sorption process. The formation of CO2 is related to the water-shift reaction, and SO2 is probably attributable to the reaction of organic matters and H2S. The concentration of COS is quantified by GC/FPD and found it to be about 350 ppm, which is close to the equilibrium concentration of the reaction of inlet CO and H2S at a temperature of 500 degrees C. PMID:15911419

  2. Spectroscopic study on sorption of hydrogen sulfide by means of red soil

    NASA Astrophysics Data System (ADS)

    Ko, T. H.; Chu, H.

    2005-07-01

    This paper reports the results of the characterization of red soils in relation to the sorption of H 2S from coal gas at 500 °C by spectroscopic techniques in order to provide more information on red soils' structural change both before and after reaction. In addition, by-products analysis has also been studied using Fourier transform infrared (FTIR) spectroscopy. Before and after the experiments the red soils were characterized with X-ray powder diffraction (XRPD), energy dispersion spectrum (EDS), X-ray photoelectron spectroscopy (XPS) and FTIR spectroscopy. XRPD results indicate that iron oxide species disappear from the original to reacted red soil. EDS analysis shows that a significant amount of sulfur is present in the reacted red soil, which is in agreement with the results of the elemental analysis and the calculated value based on breakthrough curve. XPS regression fitting results further indicate that sulfur retention may be associated with the iron oxides. S 2p XPS fittings point out that the major sulfur species present in the reacted red soil are composed of S -2, elemental sulfur, polysulfide, sulfite and sulfate. Additionally, the binding energy of iron shifts to a lower position for the reacted red soil, which indicates that iron oxides in the original red soil have been converted into iron sulfide. Appreciable amounts of the by-products CO 2, SO 2 and COS are detected by on-line FTIR spectroscopy during the initial and later stages of the sorption process. The formation of CO 2 is related to the water-shift reaction, and SO 2 is probably attributable to the reaction of organic matters and H 2S. The concentration of COS is quantified by GC/FPD and found it to be about 350 ppm, which is close to the equilibrium concentration of the reaction of inlet CO and H 2S at a temperature of 500 °C.

  3. Laser-induced breakdown spectroscopic study of ammonium nitrate plasma

    SciTech Connect

    Hanif, M., E-mail: drhanif-mcs@nust.edu.pk [MCS, National University of Sciences and Technology (Pakistan); Salik, M. [Beijing Jiaotong University, Institute of Optoelectronics (China); Baig, M. A. [Quaid-E-Azam University Campus, National Center for Physics (Pakistan)

    2013-12-15

    We present the optical emission studies of the ammonium nitrate plasma produced by the fundamental (1064 nm) and second (532 nm) harmonics of a Q-switched Nd: YAG laser. The target material was placed in front of the laser beam in an open atmospheric air. The spectrum reveals numerous transitions of neutral nitrogen. We have studied the spatial behavior of the plasma temperature (T{sub e}) and electron number density (N{sub e}) determined using the Boltzmann plot method and Stark broadened line profiles, respectively. Besides, we have studied the variation of the plasma parameters as a function of the laser irradiance.

  4. Spectroscopic and dynamical studies of highly energized small polyatomic molecules

    NASA Astrophysics Data System (ADS)

    Field, Robert W.; Silbey, Robert J.

    The formyl radical and the acetylene molecule were chosen for these studies. The visible and fluorescence spectra of the formyl radical were recorded, and the spectral results are used as a basis to explain the electronic structure. Optical-optical double resonance studies of acetylene were recorded, and the spectral results are interpreted. The results of Zeeman and Stark anticrossing and quantum beat studies of acetylene are reported, and they provide an unusually detailed view of both Intersystem Crossing and Internal Conversion in small polyatomic molecules. Twenty-two references are cited as resulting from Department of Energy sponsorship of this project.

  5. SPECTROSCOPIC STUDIES OF MATERIALS FOR ELECTROCHEMICAL ENERGY STORAGE

    SciTech Connect

    Greenbaum, Steven G.

    2014-03-01

    Several battery materials research projects were undertaken, suing NMR spectroscopy as a primary analytical tool. These include transport proerties of liquid and solid electrolytes and structural studies of Li ion electrodes.

  6. Synthesis and spectroscopical study of rhodanine derivative using DFT approaches

    NASA Astrophysics Data System (ADS)

    Anbarasan, R.; Dhandapani, A.; Manivarman, S.; Subashchandrabose, S.; Saleem, H.

    2015-07-01

    The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of (E)-5-benzylidene-2-thioxothiazolidine-4-one (E5BTTO) have been investigated experimentally and theoretically based on Density Functional Theory (DFT) approach. The FT-Raman and FT-IR spectra of E5BTTO were recorded in solid phase. Theoretical calculations were performed at the DFT level using the Gaussian 03 program. The experimental bands were assigned and characterized on the basis of the scaled theoretical wavenumber by their Total Energy Distribution (TED). The results of the calculation were applied to simulate infrared and raman spectra of the title compound which showed good agreement with the observed spectra. The calculated HOMO and LUMO energies show that charge transfer occur within the molecule. Stability arising from hyperconjugative interactions leading to its NLO activity and charge delocalization were analyzed using Natural Bond Orbital (NBO) analysis.

  7. Raman spectroscopic studies of carbon in extra-terrestrial materials

    Microsoft Academic Search

    John Macklin; Donald Brownlee; Sherwood Chang; Ted Bunch

    1990-01-01

    The measurements obtained here indicate ways in which micro-Raman spectroscopy can be used to elucidate structural characteristics and distribution of carbon in meteorites and interplanetary dust particles (IDPs). Existing information about structurally significant aspects of Raman measurements of graphite is combined with structurally relevant findings from the present micro-Raman studies of carbons prepared by carbonization of polyvinylidine chloride (PVDC) at

  8. Photoacoustic FTIR spectroscopic study of undisturbed nacre from red abalone

    Microsoft Academic Search

    Devendra Verma; Kalpana Katti; Dinesh Katti

    2006-01-01

    In this work, photoacoustic Fourier transform infrared (PA-FTIR) spectroscopy has been utilized to study interfacial interactions of undisturbed nacre and nacre powder from red abalone shell. The spectra of both undisturbed nacre and nacre powder showed characteristic bands of aragonite and proteins. Although nacre powder and undisturbed nacre are chemically identical, PA-FTIR spectrum of undisturbed nacre is found to be

  9. FT-Raman spectroscopic studies of guarana and some extracts

    Microsoft Academic Search

    Howell G. M. Edwards; Dennis W. Farwell; Luiz F. C. de Oliveira; Jose-Maria Alia; Mireille Le Hyaric; Mauro V. de Ameida

    2005-01-01

    The Raman spectrum of guarana, an important product of the Amazonian rain forest, has been investigated; the therapeutic properties of guarana and it's extracts have been realised for some time and have been attributed to guaranine, which could be a complex of caffeine and tannins or to a new xanthine natural product. The purpose of this study is two-fold: firstly,

  10. Phase transition in ethylenetetrafluoroethylene (ETFE) alternating copolymer. A spectroscopic study

    Microsoft Academic Search

    G. Zerbi

    1997-01-01

    The study of temperature dependent infrared (i.r.) and Raman spectra of alternating ethylenetetrafluoroethylene (ETFE) copolymer suggests that the transition from orthorhombic to hexagonal phases may be driven by the generation and propagation of conformational solitons (gentle mobile chain twist).

  11. Photoemission Spectroscopic Study of Cesium Telluride Thin Film Photocathode

    SciTech Connect

    Sugiyama, Harue; Ogawa, Koji; Azuma, Junpei; Takahashi, Kazutoshi; Kamada, Masao [Synchrotron Light Application Center, Saga University, 1 Honjo, Saga 840-8502 (Japan)

    2009-08-04

    The photoemission spectroscopy using synchrotron radiation has been carried out to study the high quantum efficiency and long working lifetime of cesium telluride (Cs{sub x}Te{sub y}) thin film photocathode. The electron affinity derived from the observed energy-distribution curves provides an important hint for long persistency of the photocathode.

  12. Spectroscopic studies of terrestrial impact materials: Preparation for Popigai expedition

    NASA Astrophysics Data System (ADS)

    Evdokimova, N. A.; Rodin, A. V.; Masaitis, V. L.; Timofeev, I. S.; Roste, O. Z.; Korablev, O. I.; Dolnikov, G. G.

    2011-10-01

    Terrestrial craters give us an excellent opportunity of direct analisys as opposed to craters out of the E arth. However, on the Earth there are only few sites where traces of strong impacts event could be studied in the fi eld. The traces of ancient impacts are better preserved in the frozen subsoil at subpolar latitudes. One of such sites is Popigai crater, located in subpolar Siberia, Russia, presumably caused by a giant impactor 35 Ma ago. This astrobleme gives a good chance to observe in situ the asteroid crater, impact materials and other consequenses of great energy deposition. T he crater was thoroughly studied during last few decades due to impact diamond inventories associated with it [1]. However a number of problems remain unresolved and wait for further studies: the physics and chemistry of impactites and impact breccias; mineral components with metamorphic rocks affected by great shock and impactites; material ejecta; structural forms invoked by crater formation; problems of remote sensing studies and problems related to comparative planetology. In the framework o f Europlanet program, we plan the expedition to Popigai site scheduled to 2012.

  13. Structural and spectroscopic study of adsorption of naphthalene on silver

    NASA Astrophysics Data System (ADS)

    Rekha, T. N.; Umadevi, M.; Rajkumar, Beulah J. M.

    2015-01-01

    Adsorption characteristics of naphthalene on silver are investigated using methods based on Density Functional Theory (DFT) and Surface Enhanced Raman Spectroscopy (SERS). Variations in bond angles and dihedral angles of the optimized geometry of naphthalene after adsorption on silver indicate distorted hexagonal structure of the ring nearer to Ag atoms and deviations in co-planarity of carbon atoms. Theoretical computations establish binding interactions through ? electrons as natural bond orbital analysis confirms intramolecular charge transfers originating from the orbital overlap between ?(Csbnd C) to ??(Csbnd C) and ?(Csbnd C) to ??(Agsbnd Ag) orbitals. Higher polarization values resulting from charge transfers on adsorption, indicated by DFT calculations, account for Raman enhancement of selective vibrational modes and band shifts. Silver nanoparticles (Ag NPs) were prepared using solution combustion method and were characterized by X-ray diffraction (XRD) and High Resolution Transmission Electron Microscopy (HRTEM). Surface plasmon resonance peak observed around 412 nm in the optical absorption spectrum of Ag NPs after adsorption of naphthalene is in good agreement with the theoretically simulated UV spectra derived using Time-Dependent Density Functional Theory (TDDFT) calculations. Theoretical and experimental SERS are correlating well, strongly confirming the process of adsorption, the tilted orientation of naphthalene on silver surface and the adsorption mechanism reported. Localization of electron density resulting from redistribution of electrostatic potential after adsorption on silver together with the reduction in bandgap of naphthalene suggests its utility in the design of electro active organic molecular devices.

  14. Magnetic resonance and optical spectroscopic studies of carotenoids

    SciTech Connect

    Kispert, L.D.

    1991-05-01

    It is our goal to study the role of a host lattice in the formation of radicals and excited singlet and triplet states that are relevant to photosynthesis. Particular emphasis is being placed on determining what is special about carotenoids that natural photosynthetic systems require them as antennae as well as for protection. We are thus manipulating the host matrix so as to understand the carotenoid function (protection, quenching, energy transfer and antenna) and the structure of carotenoid cations. To characterize their properties, we have carried out EPR, ENDOR, optical, molecular orbital and electrochemical studies of carotenoids and carotenoid cations produced chemically, electrochemically, radiolytically (x-ray irradiated freon matrices) and photolytically (solution photolysis by excimer radiation) as a function of the host matrix. 36 refs.

  15. Studies of tropical fruit ripening using three different spectroscopic techniques.

    PubMed

    Zhang, Hao; Huang, Jing; Li, Tianqi; Wu, Xiuxiang; Svanberg, Sune; Svanberg, Katarina

    2014-06-01

    We present a noninvasive method to study fruit ripening. The method is based on the combination of reflectance and fluorescence spectroscopies, as well as gas in scattering media absorption spectroscopy (GASMAS). Chlorophyll and oxygen are two of the most important constituents in the fruit ripening process. Reflectance and fluorescence spectroscopies were used to quantify the changes of chlorophyll and other chromophores. GASMAS, based on tunable diode laser absorption spectroscopy, was used to measure free molecular oxygen in the fruit tissue at 760 nm, based on the fact that the free gases have much narrower spectral imprints than those of solid materials. The fruit maturation and ripening processes can be followed by studying the changes of chlorophyll and oxygen contents with these three techniques. PMID:24887745

  16. Studies of tropical fruit ripening using three different spectroscopic techniques

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Huang, Jing; Li, Tianqi; Wu, Xiuxiang; Svanberg, Sune; Svanberg, Katarina

    2014-06-01

    We present a noninvasive method to study fruit ripening. The method is based on the combination of reflectance and fluorescence spectroscopies, as well as gas in scattering media absorption spectroscopy (GASMAS). Chlorophyll and oxygen are two of the most important constituents in the fruit ripening process. Reflectance and fluorescence spectroscopies were used to quantify the changes of chlorophyll and other chromophores. GASMAS, based on tunable diode laser absorption spectroscopy, was used to measure free molecular oxygen in the fruit tissue at 760 nm, based on the fact that the free gases have much narrower spectral imprints than those of solid materials. The fruit maturation and ripening processes can be followed by studying the changes of chlorophyll and oxygen contents with these three techniques.

  17. Spectroscopic and computational study of a new isomer of salinomycin

    NASA Astrophysics Data System (ADS)

    Pankiewicz, Rados?aw

    2013-09-01

    A new derivative of polyether ionophore salinomycin was obtained as a result of a rearrangement catalysed by sulphuric acid in two-phase medium of water/methylene chloride solution. The new isomer was fully characterized by multinuclear 2D NMR, NOESY and MALDI-TOF. The properties of the new compound were additionally study by semiempirical (PM5) and DFT (B3LYP) methods. A potential mechanism of the rearrangement was also proposed.

  18. Raman and infrared spectroscopic study of turquoise minerals

    NASA Astrophysics Data System (ADS)

    ?ejka, Ji?í; Sejkora, Ji?í; Macek, Ivo; Malíková, Radana; Wang, Lina; Scholz, Ricardo; Xi, Yunfei; Frost, Ray L.

    2015-10-01

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

  19. Spectroscopic studies on Si-phthalocyanines and Si-naphthalocyanines

    NASA Astrophysics Data System (ADS)

    von Schoenermark, C.; Volkmer, Andreas; Mueller, Silke; Woehrle, Dieter; Roeder, Beate

    1995-01-01

    Some photophysical properties (steady-state absorption, fluorescence and phosphorescence, fluorescence decay times and singlet oxygen quantum yields) of silicon phthalocyanines with methoxypolyethylene glycol (MPEG)-substituents of various chain length at the silicon atom [SiPc(OCH2CH2)n-OCH3; n equals 1,2,3,12], silicon phthalocyanine covalently bound to the water soluble polymer methoxypolyethylene glycol [SiPc(-O-MPEG 5000)2] and silicon naphthalocyanine [SiNc(CH2CH2OCH3)2] have been studied. The aim of these investigations was to get information about the influence of methoxypolyethylene-glycol-coupling on photophysical sensitizer parameters.

  20. CD Spectroscope

    NSDL National Science Digital Library

    2012-06-26

    In this activity, learners use an old CD to construct a spectroscope, a device that separates light into its component colors. Learners will hold it up to various light sources to examine how different light has different color strengths. Use this activity to introduce learners to the color spectrum and the tools scientists use to study it.

  1. Photoacoustic FTIR spectroscopic study of undisturbed nacre from red abalone.

    PubMed

    Verma, Devendra; Katti, Kalpana; Katti, Dinesh

    2006-07-01

    In this work, photoacoustic Fourier transform infrared (PA-FTIR) spectroscopy has been utilized to study interfacial interactions of undisturbed nacre and nacre powder from red abalone shell. The spectra of both undisturbed nacre and nacre powder showed characteristic bands of aragonite and proteins. Although nacre powder and undisturbed nacre are chemically identical, PA-FTIR spectrum of undisturbed nacre is found to be significantly different from that of nacre powder. A broad and strong band is observed at around 1485 cm(-1) in nacre powder. The intensity of this band is notably reduced in undisturbed nacre. This result is explained on the basis of interfacial interactions between aragonite platelets and acidic proteins. It is also observed that band at around 1788 cm(-1) originates from three overlapping bands 1797, 1787 and 1778 cm(-1). The band at around 1787 cm(-1) is assigned to CO stretching of carboxylate groups of acidic proteins. The other two bands at 1797 and 1778 cm(-1), originate from aragonite and have been assigned to combination bands, nu(3)+nu(4a) and nu(3)+nu(4b), respectively. For the study of stratification in undisturbed nacre, PA-FTIR spectra have been collected in step scan mode. The variation in spectra with depth can be attributed to changes in conformation of proteins as well as interfacial interactions. PMID:16332453

  2. Nuclear shapes from spectroscopic studies of fission fragments

    SciTech Connect

    Ahmad, I.; Emling, H.; Holzmann, R.; Janssens, R.V.F.; Khoo, T.L.; Phillips, W.R.; Drigert, M.W.

    1989-01-01

    Partial level schemes for several neutron-rich Ba and Ce nuclei have been determined from the study of gamma-gamma coincidences in /sup 252/Cf fission fragments. The experiment was performed with the Argonne-Notre Dame gamma ray facility, which consisted of 7 Compton- suppressed Ge detectors, a low-energy photon spectrometer and an inner ball of fourteen hexagonal BGO detectors. Gamma-gamma coincidence events between the Ge detectors, which were accompanied by a gamma in BGO detectors, were accepted. The triple coincidence requirement eliminated most of the beta-decay background. Transitions in individual Ba and Ce nuclei were identified by gating on the known 2/sup +/ ..-->.. O/sup +/ gamma rays. Level schemes deduced from these studies indicate interleaved negative and positive parity levels in /sup 144/Ba, /sup 146/Ba and /sup 146/Ce which are connected by fast E1 transitions. Both these features are signature of octupole deformation (reflection asymmetric shape) and are reproduced by recent theoretical calculations. 4 refs., 1 fig., 1 tab.

  3. Spectroscopic study of blue compact galaxies III. Empirical population synthesis

    E-print Network

    Xu Kong; Stephane Charlot; Achim Weiss; Fuzhen Cheng

    2003-03-24

    This is the third paper of a series dedicated to the study of the star formation rates, star formation histories, metallicities and dust contents of a sample of blue compact galaxies (BCGs). We constrain the stellar contents of 73 blue compact galaxies by analyzing their continuum spectra and the equivalent widths of strong stellar absorption features using a technique of empirical population synthesis based on a library of observed star-cluster spectra. Our results indicate that blue compact galaxies are typically age-composite stellar systems; in addition to young stars, intermediate-age and old stars contribute significantly to the 5870 A continuum emission of most galaxies in our sample. The stellar populations of blue compact galaxies also span a variety of metallicities. The ongoing episodes of star formation started typically less than a billion years ago. Some galaxies may be undergoing their first global episode of star formation, while for most galaxies in our sample, older stars are found to contribute up to half the optical emission. Our results suggest that BCGs are primarily old galaxies with discontinuous star formation histories. The absorption equivalent widths measured in the synthetic spectra range from typically 1.5 A for Halpha, to 2 -- 5 A for Hbeta, Hgamma, and Hdelta. The implied accurate measurements of emission-line intensities will be used in a later study to constrain the star formation rates and gas-phase chemical element abundances of blue compact galaxies.

  4. Thermo-active polymer nanocomposites: a spectroscopic study

    NASA Astrophysics Data System (ADS)

    Winter, A. Douglas; Larios, Eduardo; Jaye, Cherno; Fischer, Daniel A.; Omastová, Mária; Campo, Eva M.

    2014-09-01

    Photo- and thermo-mechanical actuation behaviour in specific polymer-carbon nanotube composites has been observed in recent years and studied at the macroscale. These systems may prove to be suitable components for a wide range of applications, from MOEMs and nanotechnology to neuroscience and tissue engineering. Absence of a unified model for actuation behaviour at a molecular level is hindering development of such smart materials. We observed thermomechanical actuation of ethylene-vinyl acetate | carbon nanotube composites through in situ near-edge X-ray absorption fine structure spectroscopy to correlate spectral trends with macroscopic observations. This paper presents spectra of composites and constituents at room temperature to identify resonances in a building block model, followed by spectra acquired during thermo-actuation. Effects of strain-induced filler alignment are also addressed. Spectral resonances associated with C=C and C=O groups underwent synchronised intensity variations during excitation, and were used to propose a conformational model of actuation based on carbon nanotube torsion. Future actuation studies on other active polymer nanocomposites will verify the universality of the proposed model.

  5. Ligand exchange in quaternary alloyed nanocrystals--a spectroscopic study.

    PubMed

    Gabka, Grzegorz; Bujak, Piotr; Giedyk, Kamila; Kotwica, Kamil; Ostrowski, Andrzej; Malinowska, Karolina; Lisowski, Wojciech; Sobczak, Janusz W; Pron, Adam

    2014-11-14

    Exchange of initial, predominantly stearate ligands for pyridine in the first step and butylamine (BA) or 11-mercaptoundecanoic acid (MUA) in the second one was studied for alloyed quaternary Cu-In-Zn-S nanocrystals. The NMR results enabled us to demonstrate, for the first time, direct binding of the pyridine labile ligand to the nanocrystal surface as evidenced by paramagnetic shifts of the three signals attributed to its protons to 7.58, 7.95 and 8.75 ppm. XPS investigations indicated, in turn, a significant change in the composition of the nanocrystal surface upon the exchange of initial ligands for pyridine, which being enriched in indium in the 'as prepared' form became enriched in zinc after pyridine binding. This finding indicated that the first step of ligand exchange had to involve the removal of the surface layer enriched in indium with simultaneous exposure of a new, zinc-enriched layer. In the second ligand exchange step (replacement of pyridine with BA or MUA) the changes in the nanocrystal surface compositions were much less significant. The presence of zinc in the nanocrystal surface layer turned out necessary for effective binding of pyridine as shown by a comparative study of ligand exchange in Cu-In-Zn-S, Ag-In-Zn-S and CuInS2, carried out by complementary XPS and NMR investigations. PMID:25252174

  6. Comparison of different metrics for analysis and visualization in spectroscopic optical coherence tomography

    PubMed Central

    Jaedicke, Volker; Agcaer, Semih; Robles, Francisco E.; Steinert, Marian; Jones, David; Goebel, Sebastian; Gerhardt, Nils C.; Welp, Hubert; Hofmann, Martin R.

    2013-01-01

    Spectroscopic Optical Coherence Tomography (S-OCT) extracts depth resolved spectra that are inherently available from OCT signals. The back scattered spectra contain useful functional information regarding the sample, since the light is altered by wavelength dependent absorption and scattering caused by chromophores and structures of the sample. Two aspects dominate the performance of S-OCT: (1) the spectral analysis processing method used to obtain the spatially-resolved spectroscopic information and (2) the metrics used to visualize and interpret relevant sample features. In this work, we focus on the second aspect, where we will compare established and novel metrics for S-OCT. These concepts include the adaptation of methods known from multispectral imaging and modern signal processing approaches such as pattern recognition. To compare the performance of the metrics in a quantitative manner, we use phantoms with microsphere scatterers of different sizes that are below the system’s resolution and therefore cannot be differentiated using intensity based OCT images. We show that the analysis of the spectral features can clearly separate areas with different scattering properties in multi-layer phantoms. Finally, we demonstrate the performance of our approach for contrast enhancement in bovine articular cartilage. PMID:24409393

  7. Enhanced Raman spectroscopic study of rotational isomers on metal surfaces

    NASA Technical Reports Server (NTRS)

    Loo, B. H.; Lee, Y. G.; Frazier, D. O.

    1986-01-01

    Surfaced-enhanced Raman spectroscopy has been used to study rotational isomers of succinonitrile and N-methyl-thioacetamide on Cu and Ag surfaces. Both the gauche and trans conformers of succinonitrile are found to chemisorb on the metal surface. The doubly degenerate nu(C-triple bond-N) in the free molecules is removed when succinonitrile adsorbs on copper, which indicates that the two (C-triple bond-N) groups are no longer chemically equivalent. Both conformers are found to coordinate to the copper surface through the pi system of one of the two (C-triple bond-N) groups. In the case of N-methyl-thioacetamide, the population of the cis isomer is greatly increased on Cu and Ag surfaces. This is probably due to surface-induced cis-trans isomerization, in which the predominant trans isomer is converted to the cis isomer.

  8. [Raman spectroscopic studies on methanol under high pressure].

    PubMed

    Qiao, Er-wei; Zheng, Hai-fei; Sun, Qiang

    2004-12-01

    This paper studies Raman spectra of methanol atpressures from 169.2 MPa up to 713.8 MPa and at ambient temperature. The result shows that the spectral profile of stretching vibrational modes of CH and OH gradually changes and Raman shift moves to higher and lower frequency respectively with increasing pressure, which indicates that the energy of C-H bonding increases with pressure, and the influence of hydrogen bonding on O-H function group is greater than that of pressure. In addition, the relative peak area of O-H stretch band decreases with pressure, showing that the total intensity of O-H bonding is weaker compared with C-H bonding. PMID:15828333

  9. Raman spectroscopic studies of beta-turn-containing cyclic peptides

    NASA Astrophysics Data System (ADS)

    Seaton, B. A.

    Two cyclic nonapeptides, cyclo(glycine- S-benzyl- L-cysteine-glycine) 3 and cyclo(glycine- S-methoxybenzyl- L-cysteine- L-proline) 3, and a cyclic hexapeptide, cyclo( D-alanine- L-proline- D-alanine) 2, were studied by Raman spectroscopy to determine the effects of conformation on their amide frequencies. The first and third of these peptides are known to contain three repeating type-II beta turns in solution. The second is also known to contain three repeating turns, but the turn type has not been established. Depending upon solubility properties of individual peptides, amide assignments were made either through H?D exchange or by evaluating spectra of constituent amino acids. The results suggest that, at least in these systems, beta turn types may be distinguished more readily by amide III rather than amide I vibration frequencies.

  10. Raman spectroscopic study of plasma-treated salmon DNA

    SciTech Connect

    Lee, Geon Joon; Kim, Yong Hee; Choi, Eun Ha [Plasma Bioscience Research Center, Kwangwoon University, Seoul 139-701 (Korea, Republic of)] [Plasma Bioscience Research Center, Kwangwoon University, Seoul 139-701 (Korea, Republic of); Kwon, Young-Wan [Department of Chemistry, Korea University, Seoul 136-701 (Korea, Republic of)] [Department of Chemistry, Korea University, Seoul 136-701 (Korea, Republic of)

    2013-01-14

    In this research, we studied the effect of plasma treatment on the optical/structural properties of the deoxyribonucleic acid (DNA) extracted from salmon sperm. DNA-cetyltrimethylammonium (CTMA) films were obtained by complexation of DNA with CTMA. Circular dichroism (CD) and Raman spectra indicated that DNA retained its double helical structure in the solid film. The Raman spectra exhibited several vibration modes corresponding to the nuclear bases and the deoxyribose-phosphate backbones of the DNA, as well as the alkylchains of CTMA. Dielectric-barrier-discharge (DBD) plasma treatment induced structural modification and damage to the DNA, as observed by changes in the ultraviolet-visible absorption, CD, and Raman spectra. The optical emission spectra of the DBD plasma confirmed that DNA modification was induced by plasma ions such as reactive oxygen species and reactive nitrogen species.

  11. Preparations and spectroscopic studies of organotin complexes of diclofenac*1

    NASA Astrophysics Data System (ADS)

    Kourkoumelis, Nikolaos; Demertzis, Mavroudis A.; Kovala-Demertzi, Dimitra; Koutsodimou, Aglaia; Moukarika, Alice

    2004-08-01

    The reactions of the potent and widely used anti-inflammatory drug diclofenac, HL, with diorganotin(IV) oxides were studied. The dimeric tetraorganodistannoxane complexes [Me 2LSnOSnLMe 2] 2, [Bu 2LSnOSnLBu 2] 2, [Ph 2LSnOSnLPh 2] 2 and the dibutyltin complex [Bu 2SnL 2], have been prepared and structurally characterized in the solid state by means of vibrational and 119Sn Mössbauer spectroscopy. Determination of lattice dynamics by temperature-dependent 119Sn Mössbauer spectroscopy. From the variable-temperature Mössbauer effect, the Debye temperature was determined. The complexes have been characterized in solution by NMR ( 1H and 13C) spectroscopy. Vibrational, Mössbauer, and NMR data are discussed in terms of the proposed structures.

  12. Spectroscopic study of low-temperature hydrogen absorption in palladium

    NASA Astrophysics Data System (ADS)

    Ienaga, K.; Takata, H.; Onishi, Y.; Inagaki, Y.; Tsujii, H.; Kimura, T.; Kawae, T.

    2015-01-01

    We report real-time detection of hydrogen (H) absorption in metallic palladium (Pd) nano-contacts immersed in liquid H2 using inelastic electron spectroscopy (IES). After introduction of liquid H2, the spectra exhibit the time evolution from the pure Pd to the Pd hydride, indicating that H atoms are absorbed in Pd nano-contacts even at the temperature where the thermal process is not expected. The IES time and bias voltage dependences show that H absorption develops by applying bias voltage 30 ˜ 50 mV, which can be explained by quantum tunneling. The results represent that IES is a powerful method to study the kinetics of high density H on solid surface.

  13. Microparticle electrodes and single particle microbatteries: electrochemical and in situ microRaman spectroscopic studies.

    PubMed

    Jebaraj, Adriel Jebin Jacob; Scherson, Daniel A

    2013-05-21

    Studies of the intrinsic electrochemical, structural, and electronic propertiesof microparticles of energy storage materials can provide much needed insight into the factors that control various aspects of the performance of technical electrodes for battery applications. This Account summarizes efforts made in our laboratories toward the development and implementation of methods for the in situ electrical, optical, and spectroscopic characterization of microparticles of a variety of such materials, including Ni hydroxide, Zn, carbon, and lithiated Mn and Co oxides. In the case of Ni hydroxide, the much darker appearance of NiOOH compared to the virtually translucent character of virgin Ni(OH)2 allowed for the spatial and temporal evolution of charge flow within spherical microparticles of Ni(OH)2 to be monitored in real time during the first scan toward positive potentials using computer-controlled video imaging. In situ Raman scattering measurements involving single microparticles of Zn harvested from a commercial Zn|MnO2 battery revealed that passive films formed in strongly alkaline solutions by stepping the potential from 1.55 V to either 0.7 or 0.8 V vs SCE displayed a largely enhanced feature at ca. 565 cm(-1) ascribed to a longitudinal optical phonon mode of ZnO, an effect associated with the presence of interstitial Zn and oxygen deficiencies in the lattice. In addition, significant amounts of crystalline ZnO could be detected only for passive films formed at the same two potentials after the electrodes had been roughened by a single passivation-reduction step. Quantitative correlations were found in the case of LiMn2O4 and KS-44 graphite between the Raman spectral properties and the state of charge. In the case of KS-44, a chemometrics analysis of the spectroscopic data in the potential region in which the transition between dilute phase 1 and phase 4 of lithiated graphite is known to occur made it possible to determine independently the fraction of each of the two phases present as a function of potential without relying on the coulometric information. Also featured in this Account are methods we developed for the assembly and electrochemical characterization of Zn|MnO2 and nickel|metal-hydride Ni|MH alkaline batteries incorporating single microparticles of the active materials. As evidenced from the data collected, the voltage-time profiles for constant current operation for both types of devices were found to be similar to those of commercially available batteries involving the same chemistries. The ability to monitor the state of charge of individual particles based strictly on spectroscopic data is expected to open exciting new prospects for visualizing the flow of charge within electrodes in Li-ion batteries, an area that is being vigorously pursued in our laboratories. PMID:23530836

  14. Mid-infrared spectroscopic studies of alkali-activated fly ash structure

    Microsoft Academic Search

    A. Fernández-Jiménez; A. Palomo

    2005-01-01

    Infrared spectroscopic techniques were used in the present study to acquire a deeper understanding of mid-range order in the alkaline aluminosilicate (zeolite precursor) formed in the alkali activation of fly ash. Experiments were conducted with three type F fly ashes containing different proportions of vitreous and crystalline (primarily mullite and quartz) phases, activated with an 8M solution of NaOH. All

  15. Raman Spectroscopic Studies of Pressure-induced Glassy Phase Transitions on cyclohexene

    Microsoft Academic Search

    ZHANGYI HU; HAIFEI ZHENG

    Raman spectroscopic study of cyclohexene was conducted in a moissanite anvil cell up to 1.5 GPa at 26?. Two new solid phases were observed. The phase formed at around 0.9 GPa is confirmed as a glassy phase (termed as Phase A). The other solid phase (termed as Phase B) is formed at 1.5GPa, with a first-order transition from Phase A

  16. Spectroscopic study of excited-state densities in a Zn vacuum-arc plasma

    Microsoft Academic Search

    S. Goldsmith; Y. Bresler; R. L. Boxman

    1983-01-01

    A spectroscopic study of the excited-state densities in the interelectrode plasma of a Zn multi-cathode-spot vacuum arc is presented. The plasma was produced by a 1.2-kA peak current, 0.65-ms full-width half-amplitude discharge between Zn butt electrodes, 14 mm in diameter, spaced 4-mm apart. Absolute time and space resolved line intensities were measured using a calibrated lens-monochromator-photomultiplier system. Peak excited-state densities

  17. Raman spectroscopic study of a post-medieval wall painting in need of conservation

    Microsoft Academic Search

    Howell G. M. Edwards; Dennis W. Farwell; Christopher J. Brooke

    2005-01-01

    Raman spectroscopic studies of four specimens from an important angel wall painting in need of conservation work in a medieval\\u000a church have provided some information about the pigments and pigment compositions which will influence possible future preservation\\u000a and restoration strategies. Excitation of the Raman spectra at 1,064 nm in macroscopic mode and at 785 nm in microscopic mode\\u000a revealed that the white

  18. Chemical and spectroscopic studies of metal oxide surfaces D. W. Goodman

    E-print Network

    Goodman, Wayne

    Chemical and spectroscopic studies of metal oxide surfaces D. W. Goodman Department of Chemistry Thin oxide films e.g., 5­10 nm of SiO2, Al2O3, NiO, MgO supported on a refractory metal substrate e.g., Mo, W, Ta, Re have been prepared by deposition of the oxide metal precursor in a background of oxygen

  19. HF and NH4OH-treated (111)Si surfaces studied by spectroscopic ellipsometry

    Microsoft Academic Search

    Katsuyuki Utani; Takahiro Suzuki; Sadao Adachi

    1993-01-01

    Spectroscopic ellipsometry has been used to study HF- and NH4OH-treated (111)Si surfaces. The ellipsometric data indicate that aqueous HF etching results in the removal of the surface oxide and leaves behind Si surfaces terminated by atomic hydrogen. Chemical treatment by aqueous NH4OH solution provides a bare Si surface, but further etching of Si leads to roughening of the sample surfaces.

  20. A spectroscopic and photometric study of the planetary nebulae Kn 61 and Pa 5

    SciTech Connect

    García-Díaz, Ma. T.; González-Buitrago, D.; López, J. A.; Zharikov, S.; Tovmassian, G. [Instituto de Astronomía, Universidad Nacional Autónoma de México. Km 103 Carretera Tijuana-Ensenada, 22860 Ensenada, Baja California (Mexico); Borisov, N.; Valyavin, G., E-mail: tere@astro.unam.mx, E-mail: dgonzalez@astro.unam.mx, E-mail: jal@astro.unam.mx, E-mail: zhar@astro.unam.mx, E-mail: gag@astro.unam.mx, E-mail: borisov@sao.ru, E-mail: gvalyavin@gmail.com [Special Astrophysical Observatory of the RAS, 369167, Nizhny Arkhyz, Karachaevo-Cherkesia (Russian Federation)

    2014-09-01

    We present the first morpho-kinematical analysis of the planetary nebulae Kn 61 and Pa 5 and explore the nature of their central stars. Our analysis is based on high-resolution and medium-resolution spectroscopic observations, deep narrow-band imaging, and integral photometry. This material allows us to identify the morphological components and study their kinematics. The direct images and spectra indicate an absence of the characteristic [N II] and [S II] emission lines in both nebulae. The nebular spectrum of Kn 61 suggests a hydrogen deficient planetary nebula and the stellar spectrum of the central star reveals a hydrogen-deficient PG 1159-type star. The [O III] position velocity diagram reveals that Kn 61 is a closed, empty, spherical shell with a thin border and a filamentary surface expanding at 67.6 km s{sup –1} and the shell is currently not expanding isotropically. We derived a kinematic age of ?1.6 × 10{sup 4} yr for an assumed distance of 4 kpc. A photometric period of ?5.7(±0.4) days has been detected for Kn 61, indicating the presence of a possible binary system at its core. A possible link between filamentary spherical shells and PG 1159-type stars is noted. The morphology of Pa 5 is dominated by an equatorial toroid and faint polar extensions. The equatorial region of this planetary nebula is expanding at 45.2 km s{sup –1}. The stellar spectrum corresponds to a very hot star and is dominated by a steep blue rising continuum and He II, Balmer, and Ca II photospheric lines.

  1. A vibrational spectroscopic study of the silicate mineral ardennite-(As).

    PubMed

    Frost, Ray L; López, Andrés; Xi, Yunfei; Scholz, Ricardo; Gandini, Antonio Luciano

    2014-01-24

    We have used a combination of scanning electron microscopy with EDX and vibrational spectroscopy to study the mineral ardennite-(As). The mineral ardennite-(As) of accepted formula Mn4(2+)(Al,Mg)6(Si3O10)(SiO4)2(AsO4,VO4)(OH)6 is a silicate mineral which may contain arsenate and/or vanadates anions. Because of the oxyanions present, the mineral lends itself to analysis by Raman and infrared spectroscopy. Qualitative chemical analysis shows a homogeneous phase, composed by Si, Mn, Al and As. Ca and V were also observed in partial substitution for Mn and As. Raman bands at 1197, 1225, 1287 and 1394 cm(-1) are assigned to SiO stretching vibrations. The strong Raman bands at 779 and 877 cm(-1) are assigned to the AsO4(3-) antisymmetric and symmetric stretching vibrations. The Raman band at 352 cm(-1) is assigned to the ?2 symmetric bending vibration. The series of Raman bands between 414 and 471 cm(-1)are assigned to the ?4 out of plane bending modes of the AsO4(3-) units. Intense Raman bands observed at 301 and 314 cm(-1) are attributed to the MnO stretching and bending vibrations. Raman bands at 3041, 3149, 3211 and 3298 cm(-1) are attributed to the stretching vibrations of OH units. There is vibrational spectroscopic evidence for the presence of water adsorbed on the ardennite-(As) surfaces. PMID:24161862

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

    NASA Astrophysics Data System (ADS)

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

    2008-04-01

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

  3. Synthesis, growth and vibrational spectroscopic study of a novel coumarinoylthiazole

    NASA Astrophysics Data System (ADS)

    Reshmy, R.; Sajan, D.; Kurien Thomas, K.; Sulekha, A.; Rajasekharan, K. N.; Selvanayagam, S.; Alver, Ö.

    2012-11-01

    An efficient route was developed for the synthesis of novel 3-(2-morpholinyl-4-phenylthiazol-5-oyl)coumarin (MPTC). FT-IR spectrum of MPTC was recorded and analyzed. The crystal structure data are also described. The vibrational wavenumbers were computed theoretically using the Gaussian03 package of programs using HF/6-31G(d) and B3LYP/6-31G(d) levels of theory. The data obtained from vibrational wave number calculations are used to assign vibrational bands observed in the infrared spectra of MPTC. The first hyperpolarizability, infrared absorption band intensities and intensities of raman active bands are reported. The calculated first hyperpolarizability is comparable with the values reported for compounds of similar structure. The structural parameters of MPTC obtained from XRD studies are in agreement with the calculated values. The unit cell parameters of crystals of MPTC are: a = 8.6017(10) Å, b = 9.9735(5) Å, c = 13.3870(13) Å, ? = 111.123(6)°, ? = 90.102(9)°, ? = 110.246(6)°, and Z = 2,1.397 Mg/m3.

  4. An infrared and Raman spectroscopic study of the uranyl micas

    NASA Astrophysics Data System (ADS)

    Frost, Ray L.

    2004-06-01

    Vibrational spectroscopy using a combination of infrared and Raman spectroscopy has been used to study the uranyl micas also known as the autunite minerals, of general formula M(UO 2) 2(XO 4) 2·8-12H 2O where M may be Ba, Ca, Cu, Fe 2+, Mg, Mn 2+ or 1/2(HAl) and X is As or P. Included in these minerals are autunite, metautunite, torbernite, meta-torbernite, meta-zeunerite, saléeite and sabugalite. Compared with the results of infrared spectroscopy, Raman microscopy shows excellent band separation enabling the separation and identification of bands attributed to (UO 2) 2+ units, PO 4 and AsO 4 units. Common to all spectra were bands at around 900 and 818 cm -1, attributed to the antisymmetric and symmetric stretching vibrations of the (UO 2) 2+ units. Water in autunites is in a highly structured arrangement in the interlayer of the uranyl micas. Water molecules are differentiated according to the strength of the hydrogen bonds formed between the water and the adjacent uranyl-phosphate or uranyl-arsenate surfaces and the hydration sphere of the interlayer cation.

  5. Synchronous fluorescence spectroscopic study of solvatochromic curcumin dye

    NASA Astrophysics Data System (ADS)

    Patra, Digambara; Barakat, Christelle

    2011-09-01

    Curcumin, the main yellow bioactive component of turmeric, has recently acquired attention by chemists due its wide range of potential biological applications as an antioxidant, an anti-inflammatory, and an anti-carcinogenic agent. This molecule fluoresces weakly and poorly soluble in water. In this detailed study of curcumin in thirteen different solvents, both the absorption and fluorescence spectra of curcumin was found to be broad, however, a narrower and simple synchronous fluorescence spectrum of curcumin was obtained at ? ? = 10-20 nm. Lippert-Mataga plot of curcumin in different solvents illustrated two sets of linearity which is consistent with the plot of Stokes' shift vs. the ET30. When Stokes's shift in wavenumber scale was replaced by synchronous fluorescence maximum in nanometer scale, the solvent polarity dependency measured by ?SFSmax vs. Lippert-Mataga plot or ET30 values offered similar trends as measured via Stokes' shift for protic and aprotic solvents for curcumin. Better linear correlation of ?SFSmax vs. ?* scale of solvent polarity was found compared to ?absmax or ?emmax or Stokes' shift measurements. In Stokes' shift measurement both absorption/excitation as well as emission (fluorescence) spectra are required to compute the Stokes' shift in wavenumber scale, but measurement could be done in a very fast and simple way by taking a single scan of SFS avoiding calculation and obtain information about polarity of the solvent. Curcumin decay properties in all the solvents could be fitted well to a double-exponential decay function.

  6. Surface spectroscopic study of sulfided molybdena-alumina catalysts

    SciTech Connect

    Li, C.P.; Hercules, D.M.

    1984-02-02

    X-ray photoelectron spectroscopy (ESCA), low-energy ion-scattering spectroscopy (ISS), and X-ray diffraction have been used to characterize a series of sulfided and reduced MoO/sub 3//..gamma..-Al/sub 2/O/sub 3/ catalysts. X-ray diffraction has shown the presence of small MoS/sub 2/ crystallites on a catalyst prepared by impregnation of ammonium thiomolybdate in ..gamma..-alumina with subsequent calcination. ESCA and ISS have identified the presence of both MoS/sub 2/ and Mo(V) on a MoO/sub 3//..gamma..-Al/sub 2/O/sub 3/ catalyst sulfided with 15% H/sub 2/S/H/sub 2/. The octahedrally and tetrahedrally coordinated molybdenum on an oxidic MoO/sub 3//..gamma..-Al/sub 2/O/sub 3/ precursor catalyst show different sulfidation behavior. At low Mo concentrations, tetrahedrally coordinated molybdenum is reduced mostly to Mo(V) and only partially sulfided to MoS/sub 2/. Increasing the MoO/sub 3/ loading above 8% MoO/sub 3/ caused formation of excess octahedrally coordinated molybdenum which leads to a significant increase of MoS/sub 2/ on the sulfided catalyst. After monolayer coverage has been reached, formation of Al/sub 2/(MoO/sub 4/)/sub 3/ and MoO/sub 3/ result in prominent MoS/sub 2/ formation and a small amount of Mo(V) on the sulfided catalyst. The effect of calcination temperature has been studied; it was found that decreased calcination temperatures favor formation of MoS/sub 2/ on sulfided MoO/sub 3//..gamma..-Al/sub 2/O/sub 3/ catalysts.

  7. Comparative vibrational spectroscopic studies, HOMO-LUMO and NBO analysis of 5,7-dibromo-8-hydroxyquinoline and 5,7-dichloro-8-hydroxyquinoline based on Density Functional Theory

    NASA Astrophysics Data System (ADS)

    Lakshmi, A.; Balachandran, V.; Janaki, A.

    2011-10-01

    Comparative studies of the Raman and infrared spectra, the geometry, frequency and intensity of the vibrational bands of 5,7-dibromo-8-hydroxyquinoline (DBHQ) and 5,7-dichloro-8-hydroxyquinoline (DCHQ) were obtained by using Density Functional Theory calculations (DFT) with B3LYP functional and 6-311++G ** basis set. The effects of bromine and chlorine substituents on the vibrational frequencies of 8-hydroxyquinoline have been investigated. The assignments have been proposed with aid of the results of normal coordinate analysis. Coupling of vibrations have been determined by calculating potential energy distributions (PEDs). The molecular stability and bond strength was investigated by applying the Natural Bond Orbital analysis (NBO). The other molecular properties like Mulliken population analysis, thermodynamic functions and polarizabilities of the title compounds have been reported. The calculated HOMO and LUMO energies show that charge transfer occur in the molecules. Information about the size, shape, charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping electron density isosurface with electrostatic potential (ESP).

  8. Spectroscopic studies of Synechococcus sp PCC 7002 phycobilisome core mutants

    SciTech Connect

    Gindt, Y.M.

    1993-04-01

    The role of the L[sub cm] (I), [beta][sup 18] (II), and [alpha][sup AP-B] (III) chromoproteins in the phycobilisome (PBS) core was investigated using genetically engineered strains of Synechococcus missing different polypeptides. Intact cells, isolated PBS, and subcore preparations for each mutant were studied to determine the effect of that mutation on energy transfer within the PBS core and to the reaction centers. Three mutants lacked the II and/or III polypeptides, while the I chromophore was altered in others. A lower energy absorbing chromophore, A[sub max] = 695 nm, was substituted for the I chromophore. The deletion of the II and III subunits had no discernible effect on energy transfer from the PBS to PSII. In cells and isolated PBS, the altered I chromophore acts to quench the PBS complex and to redirect the energy which would be transferred to PSII. In the PBS and subcore preparations, deletion of the III subunit did not alter energy transfer within the core. The deletion of the II subunit from the PBS caused a small decrease in the excited state lifetimes of the final emitters indicating more disorder within the core. The I chromophore was found to absorb at 670nm and to emit at 683nm within the intact PBS. The II chromophore emits at 679nm while the III chromophore emits at 682nm. A strong interaction exists between the I chromophore and the II subunit. Upon deletion of the II subunit from the PBS core, the I chromophore emits at a higher energy. The II subunit could act to stabilize the I chromophore-binding pocket, or exciton coupling could be occurring between the two. The role of the III chromophore is still unclear at this time. The III chromophore does contribute to the RT emission of the isolated PBS, but it transfers energy to I at 77 K. One can conclude that the III subunit is adjacent to the trimer containing the I polypeptide.

  9. Spectroscopic studies of Synechococcus sp PCC 7002 phycobilisome core mutants

    SciTech Connect

    Gindt, Y.M.

    1993-04-01

    The role of the L{sub cm} (I), {beta}{sup 18} (II), and {alpha}{sup AP-B} (III) chromoproteins in the phycobilisome (PBS) core was investigated using genetically engineered strains of Synechococcus missing different polypeptides. Intact cells, isolated PBS, and subcore preparations for each mutant were studied to determine the effect of that mutation on energy transfer within the PBS core and to the reaction centers. Three mutants lacked the II and/or III polypeptides, while the I chromophore was altered in others. A lower energy absorbing chromophore, A{sub max} = 695 nm, was substituted for the I chromophore. The deletion of the II and III subunits had no discernible effect on energy transfer from the PBS to PSII. In cells and isolated PBS, the altered I chromophore acts to quench the PBS complex and to redirect the energy which would be transferred to PSII. In the PBS and subcore preparations, deletion of the III subunit did not alter energy transfer within the core. The deletion of the II subunit from the PBS caused a small decrease in the excited state lifetimes of the final emitters indicating more disorder within the core. The I chromophore was found to absorb at 670nm and to emit at 683nm within the intact PBS. The II chromophore emits at 679nm while the III chromophore emits at 682nm. A strong interaction exists between the I chromophore and the II subunit. Upon deletion of the II subunit from the PBS core, the I chromophore emits at a higher energy. The II subunit could act to stabilize the I chromophore-binding pocket, or exciton coupling could be occurring between the two. The role of the III chromophore is still unclear at this time. The III chromophore does contribute to the RT emission of the isolated PBS, but it transfers energy to I at 77 K. One can conclude that the III subunit is adjacent to the trimer containing the I polypeptide.

  10. Photometric and Spectroscopic Analysis of CP Stars Under Indo-Russian Collaboration

    NASA Astrophysics Data System (ADS)

    Joshi, S.; Semenko, E.; Moiseeva, A.; Joshi, G. C.; Joshi, Y. C.; Sachkov, M.

    2015-04-01

    The Indo-Russian collaboration is a joint venture between the astronomers of India (ARIES) and Russia (SAO and INASAN) to develop scientific and technical interactions by making use of observational facilities. Here we present the results obtained after the “Magnetic Conference” that was held in the Special Astrophysical Observatory, Russia in 2010. The analysis of time-series photometric CCD observations of HD 98851 shows a pulsation period of 1fh55, which is consistent with the period reported previously. We have also found a signature of short-term periodic variability in HD 207561. The analysis of high-resolution spectroscopic and spectropolarimetric observations of the sample stars revealed characteristics similar to Am stars, hence the excitation of the low-overtone pulsations are expected in these stars.

  11. Synthesis, crystal structures and spectroscopic properties of triazine-based hydrazone derivatives; a comparative experimental-theoretical study.

    PubMed

    Arshad, Muhammad Nadeem; Bibi, Aisha; Mahmood, Tariq; Asiri, Abdullah M; Ayub, Khurshid

    2015-01-01

    We report here a comparative theoretical and experimental study of four triazine-based hydrazone derivatives. The hydrazones are synthesized by a three step process from commercially available benzil and thiosemicarbazide. The structures of all compounds were determined by using the UV-Vis., FT-IR, NMR (1H and 13C) spectroscopic techniques and finally confirmed unequivocally by single crystal X-ray diffraction analysis. Experimental geometric parameters and spectroscopic properties of the triazine based hydrazones are compared with those obtained from density functional theory (DFT) studies. The model developed here comprises of geometry optimization at B3LYP/6-31G (d, p) level of DFT. Optimized geometric parameters of all four compounds showed excellent correlations with the results obtained from X-ray diffraction studies. The vibrational spectra show nice correlations with the experimental IR spectra. Moreover, the simulated absorption spectra also agree well with experimental results (within 10-20 nm). The molecular electrostatic potential (MEP) mapped over the entire stabilized geometries of the compounds indicated their chemical reactivates. Furthermore, frontier molecular orbital (electronic properties) and first hyperpolarizability (nonlinear optical response) were also computed at the B3LYP/6-31G (d, p) level of theory. PMID:25854752

  12. Applications of Linear Systems Theory to Spectroscopic Instrumentation and Multivariate Analysis

    NASA Astrophysics Data System (ADS)

    Erickson, Chris L.

    This research employs linear systems theory to design novel spectroscopic instruments, explain their operation, and provide insight into methods of data analysis. The first study examines the relationship between digital filtering, a technique based on linear systems theory, and multivariate regression, a statistical method. The study focuses on quantitative property estimation for one -sided, repetitive, linear, shift-invariant systems, and compares matched filtering, Kalman innovation filtering, classical least-squares regression, and principal components regression. Kalman innovation filters, which are derived by making signals independent of interferences via orthogonalization, are similar to the respective columns of the pseudo-inverse of the pure signal matrix in classical least-squares regression, and to the regression vectors of principal components least -squares regression, which are derived via calibration. Inverse regression methods, such as principal components regression, are advantageous in that if the experiment is carefully designed, interferences need not be explicitly defined and properties that depend on multiple components can be estimated. In the second study, an absorption spectrophotometer based on a novel stationary interferometer is described. A major advantage of the interferometer is that it requires few optical components: minimally a slit, a collimator, a planar mirror, a magnification lens, and a photodiode array detector. The interferometer images a linear spatial interferogram on a photodiode array. Fourier transformation of the detected interferogram yields the desired spectrum. Equations describing interferometer operation are derived using electromagnetic wave theory and linear systems theory. Systems theory is also used to model and correct systematic errors. The interferometer's baseline noise, resolution, dynamic range and precision are assessed and compared to those of a modern grating-based photodiode-array spectrograph. Finally, the theory of grating-based optical spectrometers is explored using linear systems theory. This theory explains how diffraction gratings transform a polychromatic spectral input to an angularly-dependent output. Using the system transfer functions, a Fourier relationship is shown to exist between the wavenumber and spatial domains of the grating. This domain connectivity can be exploited to design diffraction gratings in the spatial domain that perform specific analytical tasks in the spectral domain.

  13. Classification of malignant gliomas by infrared spectroscopic imaging and linear discriminant analysis.

    PubMed

    Krafft, Christoph; Sobottka, Stephan B; Geiger, Kathrin D; Schackert, Gabriele; Salzer, Reiner

    2007-03-01

    Infrared (IR) spectroscopy provides a sensitive molecular fingerprint for tissue without external markers. Supervised classification models can be trained to identify the tissue type based on the spectroscopic fingerprint. Infrared imaging spectrometers equipped with multi-channel detectors combine the spectral and spatial information. Tissue areas of 4 x 4 mm(2) can be analyzed within a few minutes in the macroscopic imaging mode. An approach is described to apply this methodology to human astrocytic gliomas, which are graded according to their malignancy from one to four. Multiple IR images of three tissue sections from one patient with a malignant glioma are acquired and assigned to the six classes normal brain tissue, astrocytoma grade II, astrocytoma grade III, glioblastoma multiforme grade IV, hemorrhage, and other tissue by a linear discriminant analysis model which was trained by data from a single-channel detector. Before the model is applied here, the spectra are shown to be virtually identical. The first specimen contained approximately 95% malignant glioma regions, that means astrocytoma grade III or glioblastoma. The smaller percentage of 12-34% malignant glioma in the second specimen is consistent with its location at the tumor periphery. The detection of less than 0.2% malignant glioma in the third specimen points to a location outside the tumor. The results were correlated with the cellularity of the tissue which was obtained from the histopathologic gold standard. Potential applications of IR spectroscopic imaging as a rapid tool to complement established diagnostic methods are discussed. PMID:17103151

  14. [Spectroscopic and dynamical studies of highly energized small polyatomic molecules]. [Stimulated emission pumping

    SciTech Connect

    Not Available

    1992-01-01

    Stimulated emission pumping (SEP) spectroscopy was used on acetylene and on formyl radical. An attempt was made for pattern recognition based on statistics; a method was invented that combined CNPI (complete nuclear permutation-inversion) group theory and SCC (spectral cross-correlation). But the direction away from statistical pattern recognition back to traditional spectroscopic pattern recognition was taken. Vibrational states and quantum numbers are discussed. For the formyl radical, the fluorescence excitation spectrum was recorded and a rotational analysis of the 0[sup 0][sub 0] band performed.

  15. Spectroscopic investigation (FT-IR and FT-Raman), vibrational assignments, HOMO-LUMO, NBO, MEP analysis and molecular docking study of 2-(4-hydroxyphenyl)-4,5-dimethyl-1H-imidazole 3-oxide

    NASA Astrophysics Data System (ADS)

    Benzon, K. B.; Varghese, Hema Tresa; Panicker, C. Yohannan; Pradhan, Kiran; Tiwary, Bipransh Kumar; Nanda, Ashis Kumar; Alsenoy, C. Van

    2015-07-01

    In this work, the vibrational spectral analysis was carried out using FT-IR and FT-Raman spectroscopy of 2-(4-hydroxyphenyl)-4,5-dimethyl-1H-imidazole 3-oxide. The computations were performed at DFT levels of theory to get the optimized geometry and vibrational frequencies of the normal modes of the title compound using Gaussian09 software. The complete vibrational assignments of frequencies were made on the basis of potential energy distribution. The calculated HOMO and LUMO energies show the chemical activity of the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The hyperpolarizability values are reported and the first hyperpolarizability of the title compound is 19.61 times that of standard NLO material urea. From the MEP plot, the negative charge covers the nitro group and the positive region is over the hydroxyl group and N-H part of the imidazole ring. The calculated 1H NMR results are in good agreement with experimental data. Molecular docking study is also reported.

  16. Molecular orbital studies (hardness, chemical potential, electronegativity and electrophilicity), vibrational spectroscopic investigation and normal coordinate analysis of 5-{1-hydroxy-2-[(propan-2-yl)amino]ethyl}benzene-1,3-diol.

    PubMed

    Muthu, S; Renuga, S

    2014-01-24

    FT-IR and FT-Raman spectra of 5-{1-hydroxy-2-[(propan-2-yl) amino] ethyl} benzene-1,3-diol (abbrevi- 54 ated as HPAEBD) were recorded in the region 4000-450 cm(-1) and 4000-100 cm(-1) respectively. The structure of the molecule was optimized and the structural characteristics were determined by density functional theory (B3LYP) and HF method with 6-31 G(d,p) as basis set. The theoretical wave numbers were scaled and compared with experimental FT-IR and FT-Raman spectra. A detailed interpretation of the vibrational spectra of this compound has been made on the basis of the calculated Potential energy distribution (PED). Stability of the molecule arising from hyperconjugation and charge delocalization is confirmed by the natural bond orbital analysis (NBO). The results show that electron density (ED) in the ? antibonding orbitals and E (2) energies confirm the occurrence of intra molecular charge transfer (ICT) within the molecule. The molecule orbital contributions were studied by using the total (TDOS), sum of ? and ? electron (??DOS) density of States. Mulliken population analysis of atomic charges is also calculated. The calculated HOMO and LUMO energy gap shows that charge transfer occurs within the molecule. The electron density-based local reactivity descriptors such as Fukui functions were calculated to explain the chemical selectivity or reactivity site in this compound. On the basis of vibrational analyses, the thermodynamic properties of title compound at different temperatures have been calculated. PMID:24096064

  17. Molecular orbital studies (hardness, chemical potential, electronegativity and electrophilicity), vibrational spectroscopic investigation and normal coordinate analysis of 5-{1-hydroxy-2-[(propan-2-yl)amino]ethyl}benzene-1,3-diol

    NASA Astrophysics Data System (ADS)

    Muthu, S.; Renuga, S.

    2014-01-01

    FT-IR and FT-Raman spectra of 5-{1-hydroxy-2-[(propan-2-yl) amino] ethyl} benzene-1,3-diol (abbrevi- 54 ated as HPAEBD) were recorded in the region 4000-450 cm-1 and 4000-100 cm-1 respectively. The structure of the molecule was optimized and the structural characteristics were determined by density functional theory (B3LYP) and HF method with 6-31 G(d,p) as basis set. The theoretical wave numbers were scaled and compared with experimental FT-IR and FT-Raman spectra. A detailed interpretation of the vibrational spectra of this compound has been made on the basis of the calculated Potential energy distribution (PED). Stability of the molecule arising from hyperconjugation and charge delocalization is confirmed by the natural bond orbital analysis (NBO). The results show that electron density (ED) in the ? antibonding orbitals and E (2) energies confirm the occurrence of intra molecular charge transfer (ICT) within the molecule. The molecule orbital contributions were studied by using the total (TDOS), sum of ? and ? electron (??DOS) density of States. Mulliken population analysis of atomic charges is also calculated. The calculated HOMO and LUMO energy gap shows that charge transfer occurs within the molecule. The electron density-based local reactivity descriptors such as Fukui functions were calculated to explain the chemical selectivity or reactivity site in this compound. On the basis of vibrational analyses, the thermodynamic properties of title compound at different temperatures have been calculated.

  18. Spectroscopic investigation (FT-IR and FT-Raman), vibrational assignments, HOMO-LUMO, NBO, MEP analysis and molecular docking study of 2-(4-hydroxyphenyl)-4,5-dimethyl-1H-imidazole 3-oxide.

    PubMed

    Benzon, K B; Varghese, Hema Tresa; Panicker, C Yohannan; Pradhan, Kiran; Tiwary, Bipransh Kumar; Nanda, Ashis Kumar; Van Alsenoy, C

    2015-07-01

    In this work, the vibrational spectral analysis was carried out using FT-IR and FT-Raman spectroscopy of 2-(4-hydroxyphenyl)-4,5-dimethyl-1H-imidazole 3-oxide. The computations were performed at DFT levels of theory to get the optimized geometry and vibrational frequencies of the normal modes of the title compound using Gaussian09 software. The complete vibrational assignments of frequencies were made on the basis of potential energy distribution. The calculated HOMO and LUMO energies show the chemical activity of the molecule. The stability of the molecule arising from hyper-conjugative interaction and charge delocalization has been analyzed using NBO analysis. The hyperpolarizability values are reported and the first hyperpolarizability of the title compound is 19.61 times that of standard NLO material urea. From the MEP plot, the negative charge covers the nitro group and the positive region is over the hydroxyl group and N-H part of the imidazole ring. The calculated (1)H NMR results are in good agreement with experimental data. Molecular docking study is also reported. PMID:25819320

  19. Synthesis, spectroscopic characterization of novel 16?-(3-acetyl phenyl amino)-3?-hydroxy pregn-5-ene-20-one, its molecular structure, NBO analysis, intramolecular interactions studied by DFT and AIM approach

    NASA Astrophysics Data System (ADS)

    Sethi, Arun; Shukla, Dolly; Singh, Ranvijay Pratap

    2014-09-01

    A novel compound 16?-(3-acetyl phenyl amino)-3?-hydroxy pregn-5-ene-20-one was synthesized by Michael addition reaction and characterized with the aid of 1H, 13C NMR, IR, UV and mass spectrometry. The molecular geometry of synthesized compound was calculated in the ground state by density functional theory (DFT/B3LYP) using 6-31G(d,p) basis set. 1H and 13C NMR chemical shifts were calculated using Gauge-Including Atomic Orbital (GIAO) approach and these values were correlated with the experimental observations. The electronic properties such as HOMO and LUMO energies were calculated using time dependent density functional theory (TD-DFT). Stability of the molecule as a result of hyperconjugative interactions and electron delocalization were analyzed using natural bond orbital (NBO) analysis. Intramolecular interactions were analyzed by AIM approach. Local reactivity descriptors were calculated to study the reactive site within the molecule.

  20. Can spectroscopic analysis improve our understanding of biogeochemical processes in agricultural streams?

    NASA Astrophysics Data System (ADS)

    Bieroza, Magdalena; Heathwaite, Ann Louise

    2015-04-01

    In agricultural catchments diffuse fluxes of nutrients, mainly nitrogen (N) and phosphorus (P) from arable land and livestock are responsible for pollution of receiving waters and their eutrophication. Organic matter (OM) can play an important role in mediating a range of biogeochemical processes controlling diffuse pollution in streams and at their interface with surrounding land in the riparian and hyporheic zones. Thus, a holistic and simultaneous monitoring of N, P and OM fractions can help to improve our understanding of biogeochemical functioning of agricultural streams. In this study we build on intensive in situ monitoring of diffuse pollution in a small agricultural groundwater-fed stream in NW England carried out since 2009. The in situ monitoring unit captures high-frequency (15 minutes to hourly) responses of water quality parameters including total phosphorus, total reactive phosphorus and nitrate-nitrogen to changing flow conditions. For two consecutive hydrological years we have carried out additional spectroscopic water analyses to characterise organic matter components and their interactions with nutrient fractions. Automated and grab water samples have been analysed using ultraviolet-visible (UV-Vis) absorbance and excitation-emission (EEM) fluorescence spectroscopy. In addition, a tryptophan sensor was trialled to capture in situ fluorescence dynamics. Our paper evaluates patterns in nutrient and OM responses to baseflow and storm flow conditions and provides an assessment of storage-related changes of automated samples and temperature and turbidity effects on in situ tryptophan measurements. The paper shows the value of spectroscopic measurements to understand biogeochemical and hydrological nutrient dynamics and quantifies analytical uncertainty associated with both laboratory-based and in situ spectroscopic measurements.

  1. An in-depth spectroscopic analysis of RR Lyr Variations over the pulsation cycle?

    NASA Astrophysics Data System (ADS)

    Fossati, L.; Kolenberg, K.; Shulyak, D. V.; Elmasli, A.; Tsymbal, V.; Barnes, T. G.; Guggenberger, E.; Kochukhov, O.

    2014-12-01

    The stellar parameters of RR Lyrae stars vary considerably over a pulsation cycle, and their determination is crucial for stellar modelling. We present a detailed spectroscopic analysis of the pulsating star RR Lyr, the prototype of its class, over a complete pulsation cycle, based on high-resolution spectra collected at the 2.7-m telescope of McDonald Observatory. We used simultaneous photometry to determine the accurate pulsation phase of each spectrum and determined the effective temperature, the shape of the depth-dependent microturbulent velocity, and the abundance of several elements, for each phase. The surface gravity was fixed to 2.4. Element abundances resulting from our analysis are stable over the pulsation cycle. However, a variation in ionization equilibrium is observed around minimum radius. We attribute this mostly to a dynamical acceleration contributing to the surface gravity. Variable turbulent convection on time-scales longer than the pulsation cycle has been proposed as a cause for the Blazhko effect. We test this hypothesis to some extent by using the derived variable depth-dependent microturbulent velocity profiles to estimate their effect on the stellar magnitude. These effects turn out to be wavelength dependent and much smaller than the observed light variations over the Blazhko cycle: if variations in the turbulent motions are entirely responsible for the Blazhko effect, they must surpass the scales covered by the microturbulent velocity. This work demonstrates the possibility of a self-consistent spectroscopic analysis over an entire pulsation cycle using static atmosphere models, provided one takes into account certain features of a rapidly pulsating atmosphere.

  2. Spectroscopic and Structural Study of Proton and Halide Ion Cooperative Binding to GFP

    PubMed Central

    Arosio, Daniele; Garau, Gianpiero; Ricci, Fernanda; Marchetti, Laura; Bizzarri, Ranieri; Nifosì, Riccardo; Beltram, Fabio

    2007-01-01

    This study reports the influence of halogens on fluorescence properties of the Aequorea victoria Green Fluorescent Protein variant S65T/T203Y (E2GFP). Halide binding forms a specific nonfluorescent complex generating a substantial drop of the fluorescence via static quenching. Spectroscopic analysis under different solution conditions reveals high halogen affinity, which is strongly dependent on the pH. This evidences the presence in E2GFP of interacting binding sites for halide ions and for protons. Thermodynamic link and cooperative interaction are assessed demonstrating that binding of one halide ion is associated with the binding of one proton in a cooperative fashion with the formation, in the pH range 4.5–10, of a single fully protonated E2GFP·halogen complex. To resolve the structural determinants of E2GFP sensitivity to halogens, high-resolution crystallographic structures were obtained for the halide-free and I?, Br?, and Cl? bound E2GFP. Remarkably the first high-resolution (1.4 Å) crystallographic structure of a chloride-bound GFP is reported. The chloride ion occupies a specific and unique binding pocket in direct contact (3.4 Å) with the chromophore imidazolidinone aromatic ring. Unanticipated flexibility, strongly modulated by halide ion interactions, is observed in the region surrounding the chromophore. Furthermore molecular dynamics simulations identified E222 residue (along with the chromophore Y66 residue) being in the protonated state when E2GFP·halogen complex is formed. The impact of these results on high-sensitivity biosensor design will be discussed. PMID:17434942

  3. A Far-UV Spectroscopic Analysis of the Central Star of the Planetary Nebula Longmore 1

    E-print Network

    J. E. Herald; L. Bianchi

    2004-02-26

    We have performed a non-LTE spectroscopic analysis using far-UV and UV data of the central star of the planetary nebula K1-26 (Longmore 1), and found Teff = 120+/-10 kK, logg = 6.7 +0.3/-0.7, and y = 0.10. The temperature is significantly hotter than previous results based on optical line analyses, highlighting the importance of analyzing the spectra of such hot objects at shorter wavelengths. The spectra show metal lines (from, e.g, carbon, oxygen, sulfur, and iron). The signatures of most elements can be fit adequately using solar abundances, confirming the classification of Longmore 1 as a high gravity O(H) object. Adopting a distance of 800 pc, we derive R = 0.04 Rsun, L = 250 Lsun, and M = 0.6 Msun. This places the object on the white dwarf cooling sequence of the evolutionary tracks with an age of ~= 65 kyr.

  4. A comparison of microscopic and spectroscopic identification methods for analysis of microplastics in environmental samples.

    PubMed

    Song, Young Kyoung; Hong, Sang Hee; Jang, Mi; Han, Gi Myung; Rani, Manviri; Lee, Jongmyoung; Shim, Won Joon

    2015-04-15

    The analysis of microplastics in various environmental samples requires the identification of microplastics from natural materials. The identification technique lacks a standardized protocol. Herein, stereomicroscope and Fourier transform infrared spectroscope (FT-IR) identification methods for microplastics (<1mm) were compared using the same samples from the sea surface microlayer (SML) and beach sand. Fragmented microplastics were significantly (p<0.05) underestimated and fiber was significantly overestimated using the stereomicroscope both in the SML and beach samples. The total abundance by FT-IR was higher than by microscope both in the SML and beach samples, but they were not significantly (p>0.05) different. Depending on the number of samples and the microplastic size range of interest, the appropriate identification method should be determined; selecting a suitable identification method for microplastics is crucial for evaluating microplastic pollution. PMID:25682567

  5. Spectroscopic study of sub-barrier quasi-elastic nuclear reactions

    SciTech Connect

    Pass, C.N.; Evans, P.M.; Smith, A.E.; Stuttge, L.; Betts, R.R.; Lilley, J.S.; Connell, K.A.; Simpson, J.; Smith, J.R.; James, A.N.

    1988-01-01

    The technique developed in this paper is particularly well suited to the detailed spectroscopic study of low energy quasi-elastic nuclear reactions and by overcoming the limitations of conventional procedure, the prospect of detailed studies of inclusive reaction mechanism may be realised. With only limited statistics we find evidence for strong multistep character in the transfer of a single nucleon from spherical vibrational target to spherical projectile nuclei. The suggestive measurements reported here may be made definitive through extended runs based on this technique and experiments planned for the future offer the real prospect of developing a quantified interpretation of the reaction process. 9 refs. 5 figs.

  6. Mössbauer spectroscopic studies of glass ceramics with hexagonal barium and strontium ferrites

    Microsoft Academic Search

    U. C. Johri; R. M. Singru; D. Bahadur

    1992-01-01

    Mössbauer spectroscopic studies have been performed on glass ceramics in which barium and strontium hexaferrites have been crystallized as a major magnetic phase. The crystallization process of the different magnetic phases has been studied by suitable heat treatments of the initial glass compositions 35BaO-40B2O3-25Fe2O2, 35SrO-40B2O3-25Fe2O3 and 47SrO-28B2O3-25Fe2O3. The nucleation and growth times have been varied and Mössbauer spectra of differently

  7. Detailed spectroscopic analysis of SN 1987A: The distance to the LMC using the SEAM method

    SciTech Connect

    Mitchell, Robert C.; Baron, E.; Branch, David; Hauschildt, Peter H.; Nugent, Peter E.; Lundqvist, Peter; Blinnikov, Sergei; Pun, Chun S.J.

    2002-05-21

    Supernova 1987A remains the most well-studied supernova to date. Observations produced excellent broad-band photometric and spectroscopic coverage over a wide wavelength range at all epochs. We model the observed spectra from Day 1 to Day 81 using a hydrodynamical model. We show that good agreement can be obtained at times up to about 60 days, if we allow for extended nickel mixing. Later than about 60 days the observed Balmer lines become stronger than our models can reproduce. We show that this is likely due to a more complicated distribution of gamma-rays than we allow for in our spherically symmetric calculations. We present synthetic light curves in UBVRIJHK and a synthetic bolometric light curve. Using this broad baseline of detailed spectroscopic models we find a distance modulus mu = 18.5 +/- 0.2 using the SEAM method of determining distances to supernovae. We find that the explosion time agrees with that of the neutrino burst and is constrained at 68 percent confidence to within +/- 0.9 days. We argue that the weak Balmer lines of our detailed model calculations casts doubt on the accuracy of the purely photometric EPM method. We also suggest that Type IIP supernovae will be most useful as distance indicators at early times due to a variety of effects.

  8. Spectroscopic investigation (FT-IR and FT-Raman), vibrational assignments, HOMO-LUMO analysis and molecular docking study of 2-(Adamantan-1-yl)-5-(4-nitrophenyl)-1,3,4-oxadiazole.

    PubMed

    Haress, Nadia G; Al-Omary, Fatmah; El-Emam, Ali A; Mary, Y Sheena; Panicker, C Yohannan; Al-Saadi, Abdulaziz A; War, Javeed Ahmad; Van Alsenoy, Christian

    2015-01-25

    FT-IR and FT-Raman spectra of 2-(Adamantan-1-yl)-5-(4-nitrophenyl)-1,3,4-oxadiazole were recorded and analyzed. The vibrational wavenumbers were computed using DFT quantum chemical calculations. The data obtained from wavenumber calculations are used to assign vibrational bands obtained experimentally. The energy barriers of the internal rotations about the C-C bonds connecting the oxadiazole to the adamantane and benzene rings are reported. The geometrical parameters (DFT) of the title compound are in agreement with the XRD results. The calculated HOMO and LUMO energies allow the calculations of atomic and molecular properties and they also showed that charge transfer occurs in the molecule. A detailed molecular picture of the title compound and its interactions were obtained from NBO analysis. As can be seen from the MEP map of the title compound, which regions having the negative potential are over the electro negative atoms, the region having the positive potential are over the phenyl and adamantine rings and the remaining species are surrounded by zero potential. The molecular docking studies reveal that the adamantyl derivative may exhibit C-South African HIV-proteas inhibitory activity. PMID:25168235

  9. SPECTROSCOPIC ANALYSIS OF AN EIT WAVE/DIMMING OBSERVED BY HINODE/EIS

    SciTech Connect

    Chen, F.; Ding, M. D.; Chen, P. F., E-mail: dmd@nju.edu.c [Department of Astronomy, Nanjing University, Nanjing 210093 (China)

    2010-09-10

    EUV Imaging Telescope (EIT) waves are a wavelike phenomenon propagating outward from the coronal mass ejection source region, with expanding dimmings following behind. We present a spectroscopic study of an EIT wave/dimming event observed by the Hinode/Extreme-ultraviolet Imaging Spectrometer. Although the identification of the wave front is somewhat affected by the pre-existing loop structures, the expanding dimming is well defined. We investigate the line intensity, width, and Doppler velocity for four EUV lines. In addition to the significant blueshift implying plasma outflows in the dimming region as revealed in previous studies, we find that the widths of all four spectral lines increase at the outer edge of the dimmings. We illustrate that this feature can be well explained by the field line stretching model, which claims that EIT waves are apparently moving brightenings that are generated by the successive stretching of the closed field lines.

  10. Infrared spectroscopic analysis of the effects of simulated space radiation on a polyimide

    NASA Technical Reports Server (NTRS)

    Ferl, J. E.; Long, E. R., Jr.

    1981-01-01

    Infrared spectroscopic techniques have been used to study the effects of electron radiation on the polyimide PMDA-p,p-prime- ODA. The radiation exposures were made at various dose rates, for a total dose approximately equal to that for 30 years of exposure to electron radiation in geosynchronous earth orbit. At high dose rates the major effect was probably the formation of a polyisoimide or a charged quaternary amine, and at the low dose rates the effect was a reduction in the amount or aromatic ether linkage. In addition, the effects of dose rate for a small total dose were studied. Elevated temperatures occurred at high dose rates and were, in part, probably the cause of the radiation product. The data suggest that dose rates for accelerated simulations of the space environment should not exceed 100,000 rads/sec.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  12. Spectroscopic Studies of Electronically Active Defects in Transition Metal Oxides for Advanced Si Devices

    SciTech Connect

    Lucovsky, G.; Luning, J.

    2009-06-04

    Based on spectroscopic studies, and guided by ab initio theory, the electron and hole traps in HfO2 and other transition metal elemental oxides e.g., TiO2, are assigned to O-atom divacancies, clustered at internal grain boundaries. Engineering solutions for defect reduction are identified: (i) deposition of ultra-thin, < 2 nm HfO2 and phase separated Hf silicate dielectrics, in which grain boundary formation is suppressed by effectively eliminating inter-primitive unit cell {pi}-bonding interactions, and (ii) non-crystalline Zr/Hf Si oxynitrides without nanocrystalline grain boundaries.

  13. Electrode materials for lithium rechargeable batteries: Synthesis, spectroscopic studies and electrochemical performance

    NASA Astrophysics Data System (ADS)

    Zhang, Xulong

    The lithium rechargeable battery is the newest member of the rechargeable battery family and is best known for its high energy density, long battery life, low self-discharge rate and light weight. This battery may become one of the most important energy sources in consumer market, industrial and military applications. Intercalation compounds play a critical role in determining the overall performance of a lithium rechargeable battery. The common intercalation materials for battery applications are layered structure Lisb{x}CoOsb2, spinel Lisb{x}Mnsb2Osb4 and lithium vanadium oxides, Lisb{x}Vsb2Osb5 and Lisb{x}Vsb3Osb8. Three distinct Lisb{x}Vsb2Osb5 phases, delta,\\ varepsilon, and gamma-Lisb{x}Vsb2Osb5, were obtained through a chemical intercalation reaction and solid state reactions. Infrared and Raman spectra were recorded for the three phases. The spectral changes were interpreted in terms of the local structural changes of the vanadium-oxygen polyhedra. Although the delta and varepsilon phases have very similar powder x-ray diffraction patterns, IR and Raman studies showed these two phases adopt distinctive local structural environments. These results demonstrate that IR and Raman spectroscopy are important techniques for the structural analysis of intercalation materials. Single crystals of Lisb{1.1}Vsb3Osb8 and sp6Lisb{1.1}Vsb3Osb8 were prepared using solid state synthesis techniques. IR spectra and polarized Raman spectra were recorded on the Lisb{1.1}Vsb3Osb8 and sp6Lisb{1.1}Vsb3Osb8 crystals and a lithiated phase, Lisb4Vsb3Osb8. Factor group analysis method was used to interpret the spectral changes. These spectroscopic results provide insight into the structural modifications originating from lithium intercalation/deintercalation processes. In situ Raman spectra of Lisb{x}Vsb2Osb5 were successfully recorded on a operating lithium rechargeable battery. Distinctive spectral changes were observed at different lithium intercalation levels and interpreted in terms of the slight rearrangements of the V-O structural units. The results show that in situ Raman spectroscopy may become an important nondestructive technique in investigating the irreversible structural changes in electrode materials and evaluating battery performance. For the first time novel mesostructural materials were synthesized as electrode materials for the lithium rechargeable battery. The well-ordered mesostructural materials provide an ideal host for lithium transport processes. The preliminary results on the manganese oxide-based cathode and tin oxide-based anode show that the templating synthesis technique may provide important electrode materials for battery applications.

  14. Spectroscopic study of the light-harvesting protein C-phycocyanin associated with colorless linker peptides

    SciTech Connect

    Pizarro, Shelly A.

    2000-05-12

    The phycobilisome (PBS) light-harvesting antenna is composed of chromophore-containing biliproteins and 'colorless' linker peptides and is structurally designed to support unidirectional transfer of excitation energy from the periphery of the PBS to its core. The linker peptides have a unique role in this transfer process by modulating the spectral properties of the associated biliprotein. There is only one three-dimensional structure of a biliprotein/linker complex available to date (APC/LC7.8) and the mechanism of interaction between these two proteins remains unknown. This study brings together a detailed spectroscopic characterization of C-Phycocyanin (PC)-linker complexes (isolated from Synechococcus sp. PCC 7002) with proteomic analysis of the linker amino acid sequences to produce a model for biliprotein/linker interaction. The amino acid sequences of the rod linkers [LR8.9, LR32.3 and LRC28.5] were examined to identify evolutionarily conserved regions important to either the structure or function of this protein family. Although there is not one common homologous site among all the linkers, there are strong trends across each separate subset (LC, LR and LRC) and the N-terminal segments of both LR32.3 and LRC28.5 display multiple regions of similarity with other linkers. Predictions of the secondary structure of LR32.3 and LRC28.5, and comparison to the crystal structure of LC7.8, further narrowed the candidates for interaction sites with the PC chromophores. Measurements of the absorption, fluorescence, CD and excitation anisotropy of PC trimer, PC/LR32.3, and PC/LRC28.5, document the spectroscopic effect of each linker peptide on the PC chromophores at a series of temperatures (298 to 77 K). Because LR32.3 and LRC28.5 modulate the PC trimer spectral properties in distinct manners, it suggests different chromophore-interaction mechanisms for each linker. The low temperature absorbance spectrum of the PC trimer is consistent with an excitonic coupling interaction between neighboring a84 and b84 chromophores. Association with LR32.3 does not greatly alter this band shape but the absorbance of the PC/LRC28.5 complex is dramatically different. This indicates that LRC28.5 is disrupting the a84 - b84 relation established in the PC trimer. From these, and other polarized spectroscopy measurements, we conclude that both LR32.3 and LRC28.5 affect the spectral properties of the terminally emitting PC trimer chromophore (b84), and that LRC28.5 is additionally perturbing the relationship between the a84 and b84 chromophores to either disrupt or enhance their coupling interaction. The linker can perturb the PC chromophores through either specific aromatic residues or a concentration of electrostatically charged residues. Structurally, the linker disrupts the C3 symmetry of the associated biliprotein and this asymmetric interaction can serve to guide the transfer of excitation energy in one direction.

  15. Spectroscopic studies on the interaction between novel polyvinylthiol-functionalized silver nanoparticles with lysozyme

    NASA Astrophysics Data System (ADS)

    Ali, Mohd. Sajid; Al-Lohedan, Hamad A.; Rafiquee, M. Z. A.; Atta, Ayman M.; Ezzat, Abdurrahman O.

    2015-01-01

    Silver nanoparticles were functionalized with polyvinylthiol (Ag-PVT) and their effect on the conformation of hen-egg white lysozyme was seen by means of spectroscopic techniques, viz., UV visible, fluorescence (intrinsic and synchronous), resonance Rayleigh scattering and circular dichroism. UV absorption spectra of lysozyme show a hyperchromic shift on the addition of Ag-PVT nanoparticles indicating the complex formation between the two. The interaction between lysozyme and Ag-PVT nanoparticles was takes place via static quenching with 1:1 binding ratio as revealed by the analysis of fluorescence measurements. Circular dichroism spectroscopic data show a decrease in ?-helical content of lysozyme on interaction with Ag-PVT nanoparticles which was due to the partial unfolding of the protein. Synchronous fluorescence spectroscopy disclosed that the microenvironments of both tryptophan and tyrosine residues were perturbed in the presence of Ag-PVT nanoparticles and perturbation in the tryptophan environment was more prominent. Rayleigh scattering (RRS) intensity increases on increasing the Ag-PVT nanoparticles concentration till it reaches to the saturation. The RRS intensity increases four times as compared to the native protein indicating the possibility of protein aggregation at higher concentrations of nanoparticles.

  16. Spectroscopic ellipsometry analysis of silicon nanotips obtained by electron cyclotron resonance plasma etching.

    PubMed

    Mendoza-Galván, Arturo; Järrendahl, Kenneth; Arwin, Hans; Huang, Yi-Fan; Chen, Li-Chyong; Chen, Kuei-Hsien

    2009-09-10

    Silicon nanotips fabricated by electron cyclotron resonance plasma etching of silicon wafers are studied by spectroscopic ellipsometry. The structure of the nanotips is composed of columns 100-140 nm wide and spaced by about 200 nm. Ellipsometry data covering a wide spectral range from the midinfrared to the visible are described by modeling the nanotip layer as a graded uniaxial film using the Bruggeman effective medium approximation. The ellipsometry data in the infrared range reveal two absorption bands at 754 and 955 cm(-1), which cannot be resolved with transmittance measurements. These bands indicate that the etching process is accompanied with formation of carbonaceous SiC and CH(n) species that largely modify the composition of the original crystalline silicon material affecting the optical response of the nanotips. PMID:19745863

  17. Structural, spectroscopic, optical, dielectric and mechanical study of pure and l-Proline doped ammonium dihydrogen phosphate single crystals.

    PubMed

    Hasmuddin, Mohd; Singh, Preeti; Shkir, Mohd; Abdullah, M M; Vijayan, N; Bhagavannarayana, G; Wahab, M A

    2014-04-01

    Single crystals of pure and l-Proline (LP) C5H9NO2 doped ammonium dihydrogen phosphate (ADP) (NH4) H2PO4 were grown by slow evaporation solution technique (SEST) at ambient conditions. Powder X-ray diffraction (PXRD) analysis was carried out to confirm the crystal structure and no additional phase was observed due to doping except a systematic variation in peak intensities. FT-Raman analysis also confirms that there is no additional phase formation due to doping. Fourier transform infrared spectral analysis was done to examine the presence of various functional groups in the grown crystals. UV-VIS-NIR spectroscopic analysis was carried out to see the change in optical transparency of pure ADP and crystals due to LP with different doping concentrations. The high-resolution X-ray diffraction (HRXRD) analysis was carried out to examine the crystalline perfection and observed reasonable changes with LP doping. Second harmonic generation (SHG) efficiency measurement was done to examine the enhancement in the nonlinear optical characteristics of the grown crystals. The dielectric behavior of the samples shows that the dielectric constant decreased with increase the value of frequency. The effect of LP dopant on crystal morphology, mechanical properties of ADP has also been presented in this paper. The above studies reveal the effect of incorporation of LP into the lattice of ADP crystals. PMID:24412791

  18. The June 6 2012 transit of Venus: Imaging and spectroscopic analysis of the upper atmosphere emission

    NASA Astrophysics Data System (ADS)

    Bazin, C.; Zhi, X.; Valls-Gabaud, D.; Koutchmy, S.; Rocher, P.; Zin, Z. Y.; Fu, Y.; Yang, L.; Liu, G. Q.; Liu, Z.; Ji, K.; Goodarzi, H.

    2014-12-01

    In the context of transiting exoplanets, the last June 6, 2012 Venus transit was a unique opportunity to address important questions regarding its atmosphere. The transit of Venus is indeed a particular case of an Earth-like planet transit, and the inference one can make about the upper layers of its atmosphere can be applied to other exoplanets. To this aim, we designed a small spectrograph that we placed at the focus of the New Vacuum Solar Telescope of Yunnan Observatory in China (45 m focus and 1 m of aperture), coupled to a 4K×2K 14 bit CCD detector, to measure low-resolution optical spectra of the refracted, scattered and transmitted solar radiation in the upper layers of the planet. It covered the 385-780 nm range when Venus was over the disc, and 540-680 nm (including the O_2 terrestrial bands) during the 18 minutes-long egress. The H? and He I D3 lines were recorded repeatedly. The atmospheric Lomonossov arc of Venus was simultaneously imaged using H? and TiO filters, allowing us to check the slit position on the images of Venus and to locate the spectroscopic features on its disc. The spectra show the signature of the Northern Pole horn part; a second part was evidenced on the spectra taken near but outside the limb. We studied the O_2, H_2O and H? line profiles searching for signatures arising from Venus and we compared the observed spectra with synthetic models. The spectroscopic dataset can now be used by a large community for discussing the properties of the upper atmosphere of Venus and the future detection of Venus-like exoplanets. Finally, the study is completed using a unique very high resolution deconvolved image of the arc and Venus silhouetted at the limb of the Sun, from the SOT of the Hinode space mission.

  19. Spectroscopic and Computational Studies of a Series of High-Spin Ni(II) Thiolate Complexes

    PubMed Central

    Van Heuvelen, Katherine M.; Cho, Jaeheung; Dingee, Timothy; Riordan, Charles G.; Brunold, Thomas C.

    2010-01-01

    The electronic structures of a series of high-spin Ni(II)-thiolate complexes of the form [PhTttBu]Ni(SR) (R = CPh3, 2; C6F5, 3; C6H5, 4; PhTttBu = phenyltris((tert-butylthio)methyl)borate) have been characterized using a combined spectroscopic and computational approach. Resonance Raman (rR) spectroscopic data reveal that the ?Ni–SR vibrational feature occurs between 404 and 436 cm?1 in these species. The corresponding rR excitation profiles display a striking de-enhancement behavior due to interference effects involving energetically proximate electronic excited states. These data were analyzed in the framework of time-dependent Heller theory to obtain quantitative insight into excited state nuclear distortions. The electronic absorption and magnetic circular dichroism spectra of 2 – 4 are characterized by numerous charge transfer (CT) transitions. The dominant absorption feature, which occurs at ~18,000 cm?1 in all three complexes, is assigned as a thiolate-to-Ni CT transition involving molecular orbitals that are of ?-symmetry with respect to the Ni–S bond, reminiscent of the characteristic absorption feature of blue copper proteins. Density functional theory computational data provide molecular orbital descriptions for 2 – 4 and allow for detailed assignments of the key spectral features. A comparison of the results obtained in this study to those reported for similar Ni-thiolate species reveals that the supporting ligand plays a secondary role in determining the spectroscopic properties, as the electronic structure is primarily determined by the metal–thiolate bonding interaction. PMID:20565082

  20. The Distance to the Massive Galactic Cluster Westerlund 2 from a Spectroscopic and HST Photometric Study

    NASA Astrophysics Data System (ADS)

    Vargas Álvarez, Carlos A.; Kobulnicky, Henry A.; Bradley, David R.; Kannappan, Sheila J.; Norris, Mark A.; Cool, Richard J.; Miller, Brendan P.

    2013-05-01

    We present a spectroscopic and photometric determination of the distance to the young Galactic open cluster Westerlund 2 using WFPC2 imaging from the Hubble Space Telescope (HST) and ground-based optical spectroscopy. HST imaging in the F336W, F439W, F555W, and F814W filters resolved many sources previously undetected in ground-based observations and yielded photometry for 1136 stars. We identified 15 new O-type stars, along with two probable binary systems, including MSP 188 (O3 + O5.5). We fit reddened spectral energy distributions based on the Padova isochrones to the photometric data to determine individual reddening parameters RV and AV for O-type stars in Wd2. We find average values langRV rang = 3.77 ± 0.09 and langAV rang = 6.51 ± 0.38 mag, which result in a smaller distance than most other spectroscopic and photometric studies. After a statistical distance correction accounting for close unresolved binaries (factor of 1.08), our spectroscopic and photometric data on 29 O-type stars yield that Westerlund 2 has a distance langdrang = 4.16 ± 0.07 (random) +0.26 (systematic) kpc. The cluster's age remains poorly constrained, with an upper limit of 3 Myr. Finally, we report evidence of a faint mid-IR polycyclic aromatic hydrocarbon ring surrounding the well-known binary candidate MSP 18, which appears to lie at the center of a secondary stellar grouping within Westerlund 2. Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the Ministério da Ciência, Tecnologia, e Inovação (MCTI) da República Federativa do Brasil, the U.S. National Optical Astronomy Observatory (NOAO), the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).

  1. Spectroscopic analysis of binary systems with HgMn components. (Spanish Title: Análisis espectroscópico de sistemas binarios con componentes peculiares del tipo HgMn)

    NASA Astrophysics Data System (ADS)

    Gonzalez, E. J.; González, J. F.

    We present a spectroscopic analysis of two double-lined binary systems with HgMn components belonging to open clusters. The observations have been carried out at the Complejo Astronómico El Leoncito (CASLEO) with the Echelle REOSC spectrograph. We identify spectral lines, determine the spectroscopic orbit, and estimate the physical parameters of both systems, assuming cluster membership.

  2. Spectroscopic and TSDC analysis of 100 MeV Ag ion irradiated polyetherimide

    NASA Astrophysics Data System (ADS)

    Goyal, Geetika; Garg, Maneesha; Quamara, J. K.

    The energetic heavy ion irradiation effects in polymers have drawn considerable attention for the application of polymers in radioactive environment. In the present paper, we report the Fourier transform infrared (FTIR) and UV-visible spectroscopic analysis and thermally stimulated depolarization current (TSDC) investigations in polyetherimide (PEI) samples (25 ?m) irradiated with 100 MeV Ag ion at different fluences (5.6×1010, 1.8×1011, 1.8×1012 ions/cm2). The FTIR spectra of irradiated samples show an overall decrease in the intensity of all the typical bands, whereas the UV-visible spectra show a hyperchromic and bathochromic shift attributed to the formation of new defect sites. The radiation induced dehydrogenation of the methyl pendent group, opening of imide rings and the formation of carbonyl radicals and unsaturated C = C bonds are the major conclusion drawn from the FTIR analysisE The TSDC spectra of pristine PEI comprises two current maxima termed as ?- and ?-peak with their respective locations around 80° and 190 °C. These are attributed to dipole-orientation and space charge relaxation, respectively. A significant effect of irradiation is observed on the whole TSDC spectrum. The ?-peak vanishes due to demerization of carbonyl groups. Enhancement in the ?-peak has been associated to the formation of new deep traps. Some new radiation induced relaxation processes have also been identified.

  3. Spectroscopic and quantum chemical analysis of a natural product - Hayatin hydrochloride

    NASA Astrophysics Data System (ADS)

    Mishra, Rashmi; Srivastava, Anubha; Tandon, Poonam; Jain, Sudha

    2015-08-01

    Majority of drugs in use today are natural products, natural product mimics or semi synthetic derivatives. Therefore in recent times, focus on plant research has increased all over the world and large body of evidence has been collected to show immense potential of medicinal plants used in various traditional systems. Therefore, in the present communication to aid that research, structural and spectroscopic analysis of a natural product, an alkaloid Hayatin hydrochloride was performed. Both ab initio Hartree-Fock and density functional theory employing B3LYP with complete relaxation in the potential energy surface using 6-311G (d,p) basis set were used for the calculations. The vibrational frequencies were calculated and scaled values were compared with experimental FT-IR and micro-Raman spectra. The complete assignments were performed on the basis of potential energy distribution. The structure-activity relationship has also been interpreted by mapping electrostatic potential surface, which are valuable information for the quality control of medicines and drug-receptor interactions. Electronic properties have been analysed employing TD-DFT for both gaseous and solvent phase. The calculated HOMO and LUMO energies show that charge transfer occurs within the molecule. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis.

  4. Spectroscopic study and structure of ( E)-2-[(2-chlorobenzylimino)methyl]methoxyphenol

    NASA Astrophysics Data System (ADS)

    Ünver, Hüseyin; Y?ld?z, Mustafa; Özay, Hava; Durlu, Tahsin Nuri

    2009-12-01

    ( E)-2-[(2-Chlorobenzylimino)methyl]methoxyphenol has been synthesized from the reaction of 2-hydroxy-3-methoxy-1-benzaldehyde( o-vanillin) with 2-chlorobenzylamine. The title compound has been characterized by using elemental analysis, FT-IR, 1H NMR, 13C NMR and UV-vis spectroscopic techniques. The crystal structure of the title compound has also been examined cyrstallographically. It crystallizes in the orthorhombic space group Pbca with unit cell parameters: a = 7.208(1) Å, b = 13.726(2) Å, c = 27.858(4) Å, V = 2756.0(1) Å 3, Dc = 1.18 g cm -3 and Z = 8. The crystal structure was solved by direct methods and refined by full-matrix least squares to a find R = 0.046 for 2773 observed reflections.

  5. Spectroscopic studies and crystal structure of (E)-N Prime -(2-hydroxy-3-methoxybenzylidene)isonicotinohydrazide

    SciTech Connect

    Ozay, H., E-mail: havaozay@hotmail.com; Yildiz, M. [Canakkaale Onsekiz Mart University, Department of Chemistry, Faculty of Science and Arts (Turkey)] [Canakkaale Onsekiz Mart University, Department of Chemistry, Faculty of Science and Arts (Turkey); Unver, H. [Ankara University, Department of Physics, Faculty of Science (Turkey)] [Ankara University, Department of Physics, Faculty of Science (Turkey); Kiraz, A. [Near East University, Ataturk Faculty of Education (Turkey)] [Near East University, Ataturk Faculty of Education (Turkey)

    2013-01-15

    The structure of compound has also been examined cyrstallographically. It crystallizes in the monoclinic space group P2{sub 1}/c with a = 7.673(1), b = 16.251(2), c = 10.874(1) A, {beta} = 110.42(1) Degree-Sign , V = 1270.7(3) A{sup 3}, D{sub x} = 1.418 g cm{sup -3}, R{sub 1} = 0.0349 and wR{sub 2} = 0.0935 [I > 2{sigma}(I)], respectively. The title compound has been synthesized from the reaction of isonicotinohydrazide with 2-hydroxy-3-methoxybenzaldehyde. It has been characterized by using elemental analysis, MS, IR, {sup 1}H NMR, {sup 13}C NMR and UV-Visible spectroscopic techniques.

  6. Spectroscopic Studies on Eu{sup 3+} Doped Boro-Tellurite Glasses

    SciTech Connect

    Selvaraju, K.; Marimuthu, K. [Department of Physics, Gandhigram Rural Institute - Deemed University, Gandhigram - 624 302 (India)

    2011-07-15

    Eu{sup 3+} doped boro-tellurite glasses have been synthesized and its optical behavior have been studied and reported. The presence of varying tellurium dioxide content results changes in spectroscopic behavoir were explored through UV-VIS, and Luminescence spectra. The bonding parameters have been calculated based on the observed band positions of the absorption spectra. The Judd-Ofelt intensity parameters {Omega}{sub {lambda}} ({lambda} = 2, 4 and 6) have been determined through the luminescence spectra without applying any constraints and the results are presented. The Judd-Ofelt parameters have been used to determine various optical properties corresponding to {sup 5}D{sub 0}{yields}{sup 7}F{sub J}(J = 1,2,3 and 4) transitions of Eu{sup 3+} ions. The varying optical properties of the prepared glasses with the change in tellurium dioxide have been studied and compared with similar studies.

  7. An in situ study of protein adsorption on combinatorial Cu-Al films using spectroscopic ellipsometry.

    PubMed

    McArthur, M A; Byrne, T M; Sanderson, R J; Rockwell, G P; Lohstreter, L B; Bai, Zhijun; Filiaggi, M J; Dahn, J R

    2010-11-01

    An approach to quantifying adsorbed protein layers at the protein/metal interface through spectroscopic ellipsometry using an in situ technique is described. A combinatorial binary Cu(1-x)Al(x) (0Studies on composition spread libraries of samples allow the screening of multiple compositions at once, resulting in less measurement time, less preparation time, better systematic experiments, increased reliability of data, and the opportunity for better understanding of the impact of composition on protein adsorption. Using a custom-designed tubular flow cell, the metallic thin films were exposed to protein solutions of fibrinogen and albumin at two concentrations. The thickness of adsorbed protein layers was monitored dynamically by spectroscopic ellipsometry. It was found that both fibrinogen and albumin preferentially adsorbed onto Cu-rich surfaces, and for an Al content above approximately 21 at.%, a significantly lower protein thickness was observed for both fibrinogen and albumin. These amounts depended greatly on the Al(2)O(3) content of the film surface, with a higher oxide content leading to a decreased protein thickness. Vastly different amounts of fibrinogen were found to adsorb on pure copper when measured using in situ or ex situ techniques due to a copper corrosion effect that occurs during ex situ measurements. PMID:20650615

  8. Application of spectroscopic techniques to the study of illuminated manuscripts: A survey

    NASA Astrophysics Data System (ADS)

    Pessanha, S.; Manso, M.; Carvalho, M. L.

    2012-05-01

    This work focused on the application of the most relevant spectroscopic techniques used for the characterization of illuminated manuscripts. The historical value of these unique and invaluable artworks, together with the increased awareness concerning the conservation of cultural heritage, prompted the application of analytical techniques to the study of these illuminations. This is essential for the understanding of the artist's working methods, which aids conservation-restoration. The characterization of the pigments may also help assign a probable date to the manuscript. For these purposes, the spectroscopic techniques used so far include those that provide information on the elemental content: X-ray fluorescence, total reflection X-ray fluorescence and scanning electron microscopy coupled with energy-dispersive spectroscopy and laser-induced breakdown spectroscopy. Complementary techniques, such as X-ray diffraction, Fourier transform infrared and Raman spectroscopy, reveal information regarding the compounds present in the samples. The techniques, suitability, technological evolution and development of high-performance detectors, as well as the possibility of microanalysis and the higher sensitivity of the equipment, will also be discussed. Furthermore, issues such as the necessity of sampling, the portability of the equipment and the overall advantages and disadvantages of different techniques will be analyzed.

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

    NASA Astrophysics Data System (ADS)

    Brown, Logan Ryan; Gibb, Erika

    2014-06-01

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

  10. A Near-infrared Spectroscopic Study of Young Field Ultracool Dwarfs

    NASA Astrophysics Data System (ADS)

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

    2013-08-01

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

  11. A Near-Infrared Spectroscopic Study of Young Field Ultracool Dwarfs

    E-print Network

    Allers, K N

    2013-01-01

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

  12. Studying the dwarf galaxies in nearby groups of galaxies: Spectroscopic and photometric data

    NASA Astrophysics Data System (ADS)

    Hopp, U.; Vennik, J.

    2014-11-01

    Galaxy evolution by interaction-driven transformation is probably highly efficient in groups of galaxies. Dwarf galaxies with their shallow potential are expected to reflect the interaction most prominently in their observable structure. The major aim of this series of papers is to establish a data base which allows to study the impact of group interaction onto the morphology and star-forming properties of dwarf galaxies. Firstly, we present our selection rules for target groups and the morphological selection method of target dwarf member candidates. Secondly, the spectroscopic follow-up observations with the HET are presented. Thirdly, we applied own reduction methods based on adaptive filtering to derive surface photometry of the candidates. The spectroscopic follow-up indicate a dwarf identification success rate of roughly 55 %, and a group member success rate of about 33 %. A total of 17 new low surface-brightness members is presented. For all candidates, total magnitudes, colours, and light distribution parameters are derived and discussed in the context of scaling relations. We point out short comings of the SDSS standard pipeline for surface photometry for these dim objects. We conclude that our selection strategy is rather efficient to obtain a sample of dim, low surface brightness members of groups of galaxies within the Virgo super-cluster. The photometric scaling relation in these X-ray dim, rather isolated groups does not significantly differ from those of the galaxies within the local volume.

  13. [Study on the spectroscopic data and vibrational levels of the ground SiH+ molecular ion].

    PubMed

    Zhao, Jun; Zeng, Hui

    2014-12-01

    The ground electronic state and the reasonable dissociation limit of SiH+ molecular ion have been correctly determined based on group theory and atomic and molecular reaction statics. The energy, equilibrium geometry and harmonic frequency of the ground electronic state of SiH+ molecular ion have been calculated using the method QCISD(T)/cc-pVQZ. The whole potential curves for the ground electronic state is further scanned using the above method, the potential energy functions and relevant spectroscopic constants of this state are then first obtained by least square fitting to the Murrell-Sorbie function (n=9) and the modified Murrell-Sorbie+c6 function, respectively. The present results showed that the calculated results based on the Murrell-Sorbie function (n=9) are in better agreement with the experimental values, with the relative errors between spectroscopic constants and the experimental values being 0.13%, 3.07%, 0.38%, 5.25% and 0.52% respectively. With the potential obtained at the QCISD(T)/cc-pVQZ level of theory, the total of 27 vibrational states are predicted when J=0 by numerically solving the radial Schrodinger equation of nuclear motion. The complete vibrational levels, inertial rotation and six centrifugal distortion constants are obtained for the ground electronic state of SiH+ molecular ion for the first time. Calculation results in the present work may provide theoretical supports for the further study of SiH+ molecular ion. PMID:25881406

  14. Ab initio study of the O4H(+) novel species: spectroscopic fingerprints to aid its observation.

    PubMed

    Xavier, F George D; Hernández-Lamoneda, Rámon

    2015-06-28

    A detailed ab initio characterization of the structural, energetic and spectroscopic properties of the novel O4H(+) species is presented. The equilibrium structures and relative energies of all multiplet states have been determined systematically by analyzing static and dynamical correlation effects. The two and three body dissociation processes have been studied and indicate the presence of conical intersections in various states including the ground state. Comparison with available thermochemical data is very good, supporting the applied methodology. The reaction, H3(+) + O4? O4H(+) + H2, was found to be exothermic ?H = -19.4 kcal mol(-1) and therefore, it is proposed that the product in the singlet state could be formed in the interstellar medium (ISM) via collision processes. To aid in its laboratory or radioastronomy detection in the interstellar medium we determined spectroscopic fingerprints. It is estimated for the most stable geometry of O4H(+) dipole allowed electronic transitions in the visible region at 429 nm and 666 nm, an intense band at 1745 cm(-1) in the infrared and signals at 40.6, 81.2 and 139.2 GHz in the microwave region at 10, 50 and 150 K respectively, relevant for detection in the ISM. PMID:26028209

  15. A single-photon fluorescence and multi-photon spectroscopic study of atherosclerotic lesions

    NASA Astrophysics Data System (ADS)

    Smith, Michael S. D.; Ko, Alex C. T.; Ridsdale, Andrew; Schattka, Bernie; Pegoraro, Adrian; Hewko, Mark D.; Shiomi, Masashi; Stolow, Albert; Sowa, Michael G.

    2009-06-01

    In this study we compare the single-photon autofluorescence and multi-photon emission spectra obtained from the luminal surface of healthy segments of artery with segments where there are early atherosclerotic lesions. Arterial tissue was harvested from atherosclerosis-prone WHHL-MI rabbits (Watanabe heritable hyperlipidemic rabbit-myocardial infarction), an animal model which mimics spontaneous myocardial infarction in humans. Single photon fluorescence emission spectra of samples were acquired using a simple spectrofluorometer set-up with 400 nm excitation. Samples were also investigated using a home built multi-photon microscope based on a Ti:sapphire femto-second oscillator. The excitation wavelength was set at 800 nm with a ~100 femto-second pulse width. Epi-multi-photon spectroscopic signals were collected through a fibre-optics coupled spectrometer. While the single-photon fluorescence spectra of atherosclerotic lesions show minimal spectroscopic difference from those of healthy arterial tissue, the multi-photon spectra collected from atherosclerotic lesions show marked changes in the relative intensity of two-photon excited fluorescence (TPEF) and second-harmonic generation (SHG) signals when compared with those from healthy arterial tissue. The observed sharp increase of the relative SHG signal intensity in a plaque is in agreement with the known pathology of early lesions which have increased collagen content.

  16. Quantum mechanical study of the structure and spectroscopic (FT-IR, FT-Raman, 13C, 1H and UV), NBO and HOMO-LUMO analysis of 2-quinoxaline carboxylic acid.

    PubMed

    Prabavathi, N; Nilufer, A; Krishnakumar, V

    2012-06-15

    The FTIR and FT-Raman spectra of 2-quinoxaline carboxylic acid (2-QCA) has been recorded in the region 4000-450 and 4000-100 cm(-1), respectively. The conformational analysis, optimized geometry, frequency and intensity of the vibrational bands of 2-QCA were obtained by the density functional theory (DFT) with complete relaxation in the potential energy surface using 6-31G(d) basis set. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FTIR and FT-Raman spectra. The observed and the calculated frequencies are found to be in good agreement. The (1)H and(13)C NMR spectra have been recorded and (1)H and (13)C nuclear magnetic resonance chemical shifts of the molecule were also calculated using the gauge independent atomic orbital (GIAO) method and their respective linear correlations were obtained. The theoretical UV-visible spectrum of the compound using CIS method and the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The calculated HOMO and LUMO energies show that charge transfer occurs within molecule. The Mulliken charges, the values of electric dipole moment (?) of the molecule were computed using DFT calculations. The change in electron density (ED) in the ?* antibonding orbitals and stabilization energies E(2) have been calculated by natural bond (NBO) analysis to give clear evidence of stabilization originating in the hyper conjugation of hydrogen-bonded interactions. PMID:22446782

  17. Development of Laser Spectroscopic Techniques and Their Application to the Study of Self-Organizing Molecular Assemblies.

    NASA Astrophysics Data System (ADS)

    Reed, Wayne Frederick

    Laser spectroscopic techniques have been developed and adapted to computer based data gathering, reduction and analysis. The systems implemented are a laser flash photolysis and transient dichroism spectrometer, a single photon counting spectrometer for determination of fluorescence lifetimes and time-resolved fluorescence polarization anisotropy, and a light scattering system for both static and dynamic measurements. These techniques have been concerted to study self-organizing molecular assemblies, particularly surfactant vesicles. Quaternary ammonium surfactant monomers with polymerizable styrene moieties on the headgroup have been sonicated into unilamellar vesicles and these in turn have been photopolymerized by both steady state and pulsed laser irradiation. The detailed kinetics of photopolymerization have been determined and a model developed which permits, in conjunction with the laser spectroscopic data, the characterization of the process in terms of average polymer chain length, quantum efficiency of free radical formation, free radical lifetime, and a characteristic rate parameter. Subsequent to characterizing and modelling the photopolymerization process the consequences of it on vesicle surface properties have been investigated with molecular probes. Strong evidence has been obtained that indicates that photopolymerization leads to the formation of clefts or pockets on the vesicle surface and to extensive surface inhomogeneity. Based on the experimental data, a computer simulation has been developed to help graphically visualize the photopolymerization process and to semi-quantitatively characterize the resulting surface inhomogeneity. As a first step in exploring the possibilities opened up by the discovery of clefts in the vesicle surface, the interaction between a photoexcitable proton transfer agent, 8-hydroxy-1,3,6 - pyrenetrisulfonate (POH), and vesicles has been studied. In unpolymerized vesicles POH loses its proton ejection capacity after several hours, whereas it remains active virtually indefinitely in polymerized vesicles. Polymerized vesicles thus allow selective accomodation of molecules into their surface clefts and permit communication of such molecules with the aqueous medium surrounding the vesicle. Possibilities for utilization of polymeric surfactant vesicles, and different synthetic strategies, are discussed in the light of these findings.

  18. Behind the reactivity of lactones: a computational and spectroscopic study of phenol·?-butyrolactone.

    PubMed

    León, Iker; González, Jorge; Millán, Judith; Castaño, Fernando; Fernández, José A

    2014-04-10

    In this work, the intermolecular interaction between phenol and ?-butyrolactone (GBL) has been studied by a combination of spectroscopic and computational techniques. The electronic and vibrational transitions of phenol · GBL were measured in a supersonic jet expansion by resonant two-photon ionization (R2PI) and ion dip IR (IDIR) spectroscopy. The results obtained were compared with calculations carried out with both M06-2X and MP2 molecular orbital methods in order to characterize the intermolecular interactions. The singly detected conformer is stabilized by a relatively strong hydrogen bond in which phenol acts as a proton donor to the carbonyl group of GBL. The phenol · GBL2 cluster has also been studied, finding up to three populated conformers. Nevertheless, in the three species, the main interaction between the phenolic hydroxyl group and the GBL's carbonyl group remains similar to that of phenol · GBL. Furthermore, the C ? O · · · H interaction is reinforced. PMID:24678986

  19. Spectroscopic study of antileishmanial drug incubated in the promastigotes of Leishmania mexicana

    NASA Astrophysics Data System (ADS)

    Hung, J.; Castillo, J.; Jiménez, G.; Hasegawa, M.; Rodriguez, M.

    2003-11-01

    In this work we present spectroscopic study of Boldine (aporphine alkaloid) that possesses important biological activities, in particular, in interaction with the promastigotes of Leishmania mexicana. The results show the applicability of autofluorescence of this drug to determinate the possible mechanism of its biological action. The blue shift and hyperchromic effect in the emission spectrum of the drug in interaction with the parasite cells indicate an energy transference process between them. The morphological change of cell shape of the promastigotes treated with the drug is observed using confocal microscopy. This morphological cell-shape transformation evidences an important interaction between the drug studied and some protein of the parasite cell. Here we describe for the first time the fluorescence properties of the Boldine in the promastigotes of L. mexicana.

  20. Spectroscopic, reactivity and NLO analysis of new hydrazone-containing dipyrromethane using experimental and theoretical approaches

    NASA Astrophysics Data System (ADS)

    Singh, R. N.; Rawat, Poonat; Kumar, Amit

    2014-06-01

    The molecular structure and detailed spectroscopic analysis of a novel synthesized dipyrromethane: 1,9-bis[(2-hydroxybenzoyl)-hydrazonomethyl]-5-(2-nitrophenyl)-dipyrromethane (3) have been performed using both experimental techniques and theoretical calculations. Thermodynamic parameters (H, G, S) of reactants and products have been used to investigate the nature of synthesis. The singlet chemical shift at 5.343 ppm of meso-proton designates formation of product molecule (3). TD-DFT has been used to calculate oscillatory strength (f) and wavelength absorption maxima (?max) of various electronic excitations and their nature within molecule. The molecular orbital coefficients and molecular plots analysis assign nature of electronic excitations as ? ? ?*. Natural bond orbital (NBO) analysis has been carried out to investigate the intramolecular H-bonding, conjugative and hyperconjugative interactions within molecule. The result of intramolecular hydrogen bonding (O68sbnd H69⋯O22/O66sbnd H67⋯O45) is obvious in 1H NMR, FT-IR and NBO due to down field chemical shift, vibrational red shift, and n2(O22) ? ?*(O68sbnd H69)/n2(O45) ? ?*(O66sbnd H67) interactions energies 105.12/104.91 (kJ/mol), respectively. To investigate the strength and nature of H-bonding, topological parameters at bond critical points (BCP) have been analyzed by ‘Quantum theory of Atoms in molecules’ (QTAIM). Local reactivity descriptors- Fukui functions(fk+,fk-), local softnesses (sk+,sk-) and electrophilicity indices (?k+,?k-) analyses have been performed to find out the reactive sites of the molecule. The computed first hyperpolarizability (?0 = 14.30 × 10-30 esu) evaluates the molecule to be suitable for non-linear optical (NLO) response.

  1. Prosthetic implant associated sarcomas: a case report emphasizing surface evaluation and spectroscopic trace metal analysis.

    PubMed

    Adams, Julie E; Jaffe, Kenneth A; Lemons, Jack E; Siegal, Gene P

    2003-02-01

    Advances with implantation of synthetic biomaterials in the setting of orthopedic surgery have clearly resulted in improvements in patient outcomes. However, all implants have been shown to have associated risks. For example, ionic and particulate debris from implants have been shown to engage in biological interactions with the native tissue, and have been associated with a wide range of metabolic, bacteriologic, immunologic, and oncogenic effects. The propensity of synthetic biomaterials to undergo degradation, producing an inflammatory reaction or other sequelae, has been well recognized. The use of porous implants, which allow for a greater interface area between native tissue and the prosthesis, may magnify the interaction between biologically active tissue and synthetic devices in some situations, giving rise to new and intriguing issues concerning biocorrosion and biocompatibility. In this article, we report the case of a high-grade conventional osteosarcoma occurring at the site of a modular porous-surfaced titanium and cobalt alloy total hip prosthesis 3 years after device implantation. Detailed spectroscopic trace metal analysis was performed and elevated levels of both vanadium and chromium, but not aluminum, nickel, or titanium were identified in the tumor. PMID:12616473

  2. Spectroscopic Observations and Analysis of the Unusual Type Ia SN1999ac

    SciTech Connect

    Garavini, G.; Aldering, G.; Amadon, A.; Amanullah, R.; Astier,P.; Balland, C.; Blanc, G.; Conley, A.; Dahlen, T.; Deustua, S.E.; Ellis,R.; Fabbro, S.; Fadeyev, V.; Fan, X.; Folatelli, G.; Frye, B.; Gates,E.L.; Gibbons, R.; Goldhaber, G.; Goldman, B.; Goobar, A.; Groom, D.E.; Haissinski, J.; Hardin, D.; Hook, I.; Howell, D.A.; Kent, S.; Kim, A.G.; Knop, R.A.; Kowalski, M.; Kuznetsova, N.; Lee, B.C.; Lidman, C.; Mendez,J.; Miller, G.J.; Moniez, M.; Mouchet, M.; Mourao, A.; Newberg, H.; Nobili, S.; Nugent, P.E.; Pain, R.; Perdereau, O.; Perlmutter, S.; Quimby, R.; Regnault, N.; Rich, J.; Richards, G.T.; Ruiz-Lapuente, P.; Schaefer, B.E.; Schahmaneche, K.; Smith, E.; Spadafora, A.L.; Stanishev,V.; Thomas, R.C.; Walton, N.A.; Wang, L.; Wood-Vasey, W.M.

    2005-07-12

    The authors present optical spectra of the peculiar Type Ia supernova (SN Ia) 1999ac. The data extend from -15 to +42 days with respect to B-band maximum and reveal an event that is unusual in several respects. prior to B-band maximum, the spectra resemble those of SN 1999aa, a slowly declining event, but possess stronger Si II and Ca II signatures (more characteristic of a spectroscopically normal SN). Spectra after B-band maximum appear more normal. The expansion velocities inferred from the Iron lines appear to be lower than average; whereas, the expansion velocity inferred from Calcium H and K are higher than average. The expansion velocities inferred from the Iron lines appear to be lower than average; whereas, the expansion velocity inferred from Calcium H and K are higher than average. The expansion velocities inferred from Si II are among the slowest ever observed, though SN 1999ac is not particularly dim. The analysis of the parameters v{sub 10}(Si II), R(Si II), v, and {Delta}m{sub 15} further underlines the unique characteristics of SN 1999ac. They find convincing evidence of C II {lambda}6580 in the day -15 spectrum with ejection velocity v > 16,000 km s{sup -1}, but this signature disappears by day -9. This rapid evolution at early times highlights the importance of extremely early-time spectroscopy.

  3. Spectroscopic Observations and Analysis of the Unusual Type Ia SN 1999ac

    E-print Network

    The Supernova Cosmology Project; :; G. Garavini; G. Aldering; A. Amadon; R. Amanullah; P. Astier; C. Balland; G. Blanc; A. Conley; T. Dahlen; S. E. Deustua; R. Ellis S. Fabbro; V. Fadeyev; X. Fan; G. Folatelli; B. Frye; E. L. Gates; R. Gibbons; G. Goldhaber; B. Goldman; A. Goobar; D. E. Groom; J. Haissinski; D. Hardin; I. Hook; D. A. Howell; S. Kent; A. G. Kim; R. A. Knop; M. Kowalski; N. Kuznetsova; B. C. Lee C. Lidman; J. Mendez; G. J. Miller; M. Moniez; M. Mouchet; A. Mourao; H. Newberg; S. Nobili; P. E. Nugent; R. Pain; O. Perdereau; S. Perlmutter; R. Quimby; N. Regnault; J. Rich; G. T. Richards; P. Ruiz-Lapuente; B. E. Schaefer; K. Schahmaneche; E. Smith; A. L. Spadafora; V. Stanishev; R. C. Thomas; N. A. Walton; L. Wang; W. M. Wood-Vasey

    2005-07-12

    We present optical spectra of the peculiar Type Ia supernova (SN Ia) 1999ac. The data extend from -15 to +42 days with respect to B-band maximum and reveal an event that is unusual in several respects. Prior to B-band maximum, the spectra resemble those of SN 1999aa, a slowly declining event, but possess stronger SiII and CaII signatures (more characteristic of a spectroscopically normal SN). Spectra after B-band maximum appear more normal. The expansion velocities inferred from the Iron lines appear to be lower than average; whereas, the expansion velocity inferred from Calcium H and K are higher than average. The expansion velocities inferred from SiII are among the slowest ever observed, though SN 1999ac is not particularly dim. The analysis of the parameters v_10, R(SiII), dv(SiII)/dt, and d_m15 further underlines the unique characteristics of SN 1999ac. We find convincing evidence of CII 6580 in the day -15 spectrum with ejection velocity v > 16,000 km/s, but this signature disappears by day -9. This rapid evolution at early times highlights the importance of extremely early-time spectroscopy.

  4. Central Stars of Planetary Nebulae in the Large Magellanic Cloud: A Far-UV Spectroscopic Analysis

    E-print Network

    J. E. Herald; L. Bianchi

    2004-04-19

    We observed seven central stars of planetary nebulae (CSPN) in the Large Magellanic Cloud (LMC) with the Far Ultraviolet Spectroscopic Explorer (FUSE), and performed a model-based analysis of these spectra in conjunction with Hubble Space Telescope (HST) spectra in the UV and optical range to determine the stellar and nebular parameters. Most of the objects show wind features, and they have effective temperatures ranging from 38 to 60 kK with mass-loss rates of ~= 5x10^-8 Msun/yr. Five of the objects have typical LMC abundances. One object (SMP LMC 61) is a [WC4] star, and we fit its spectra with He/C/O-rich abundances typical of the [WC] class, and find its atmosphere to be iron-deficient. Most objects have very hot (T ~> 2000 K) molecular hydrogen in their nebulae, which may indicate a shocked environment. One of these (SMP LMC 62) also displays OVI 1032-38 nebular emission lines, rarely observed in PN.

  5. Spectral analysis of tissues from patients with cancer using a portable spectroscopic diagnostic ratiometer unit

    NASA Astrophysics Data System (ADS)

    Sordillo, Laura A.; Pu, Yang; Sordillo, Peter P.; Budansky, Yury; Alfano, R. R.

    2014-05-01

    Spectral profiles of tissues from patients with breast carcinoma, malignant carcinoid and non-small cell lung carcinoma were acquired using native fluorescence spectroscopy. A novel spectroscopic ratiometer device (S3-LED) with selective excitation wavelengths at 280 nm and 335 nm was used to produce the emission spectra of the key biomolecules, tryptophan and NADH, in the tissue samples. In each of the samples, analysis of emission intensity peaks from biomolecules showed increased 340 nm/440 nm and 340 nm/460 nm ratios in the malignant samples compared to their paired normal samples. This most likely represented increased tryptophan to NADH ratios in the malignant tissue samples compared to their paired normal samples. Among the non-small cell lung carcinoma and breast carcinomas, it appeared that tumors of very large size or poor differentiation had an even greater increase in the 340 nm/440 nm and 340 nm/460 nm ratios. In the samples of malignant carcinoid, which is known to be a highly metabolically active tumor, a marked increase in these ratios was also seen.

  6. Near infrared spectroscopic reflectance imaging: supervised vs. unsupervised analysis using an art conservation application

    Microsoft Academic Search

    James R Mansfield; Michael G Sowa; Claudine Majzels; Cathy Collins; Edward Cloutis; Henry H Mantsch

    1999-01-01

    Near-IR spectroscopic imaging was used to analyze the remnants of a work of art, a 16th century drawing, attributed to the School of Pieter Bruegel the Elder, which had been significantly altered during a cleaning attempt. Using a combination of a CCD camera and a liquid crystal tunable filter (LCTF), near-IR spectroscopic images (650–1050 nm) were collected from the drawing

  7. 14986 Biochemistry 1994,33, 14986-14992 Spectroscopic Study of Ser92 Mutants of Human Myoglobin: Hydrogen Bonding

    E-print Network

    Boxer, Steven G.

    14986 Biochemistry 1994,33, 14986- 14992 Spectroscopic Study of Ser92 Mutants of Human Myoglobin, Ser92 was replaced with Ala and Asp in human Mb. By comparing the optical, 'H-NMR, resonance Raman and stabilization of higher oxidation states of the heme iron. Recently, X-ray crystallographic studies of sperm

  8. Spectroscopic monitoring of the Herbig Ae star HD 104237. II. Non-radial pulsations, mode analysis, and fundamental stellar parameters

    NASA Astrophysics Data System (ADS)

    Fumel, A.; Böhm, T.

    2012-04-01

    Context. Herbig Ae/Be stars are intermediate-mass pre-main sequence (PMS) stars showing signs of intense activity and strong stellar winds, whose origin is not yet understood in the frame of current theoretical models of stellar evolution for young stars. In addition, the evolutionary tracks of the earlier Herbig Ae stars cross the theoretical PMS instability strip located roughly in the same area of the HR diagram as the ? Scuti variables. Many of these stars exhibit pulsations of ? Scuti type. Aims: Understanding the internal structure of pulsating Herbig Ae stars based on asteroseismic studies will help constraining the origin of their tremendous activity, winds, and variability. It is therefore necessary to investigate the location of the PMS instability strip and of its boundaries, and to extend the sample of observed and studied pulsating Herbig Ae stars. The aim of this work was to carry out a thorough analysis of the line profile variations of the prototype Herbig Ae star HD 104237 based on high-resolution spectroscopy and to redetermine precisely its fundamental parameters, which are the basic ingredients of a forthcoming asteroseismic modeling. Methods: HD 104237 is a pulsating Herbig Ae star with eight detected frequencies based on the analysis of radial velocity variations. In this article, we reinvestigated an extensive high-resolution quasi-continuous spectroscopic data set in order to search for very faint indications of non-radial pulsations in the line profile by working on dynamical spectra of equivalent photospheric (LSD) profiles of HD 104237. A 2D Fourier analysis (F2D) was performed of the entire profile and the temporal variation of the central depth of the line was studied with the time-series analysis tools Period04 and SigSpec. We present the results of these analysis including the mode identification corresponding to the detected dominant frequency, as well as a new determination of its fundamental stellar parameters. Results: The analysis of spectroscopic data set of April 22-25 obtained at SAAO in 1999 has confirmed the presence of multiple oscillation modes of low-degree ? in HD 104237 and led to the first direct detection of a non-radial pulsation mode in this star: the dominant mode F1 was identified by the Fourier 2D method having a degree ? value comprised between 1 and 2, the symmetry of the pattern variation indicating an azimuthal order of ± 1. The detailed study of the fundamental stellar parameters has provided a Teff, log g, and iron abundance of 8550 ± 150 K, 3.9 ± 0.3, and -4.38 ± 0.19 (i.e. [Fe/H] = +0.16 ± 0.19 ), respectively. Based on observations collected at the 1.9 m SAAO telescope.

  9. Raman spectroscopic analysis of geological and biogeological specimens of relevance to the ExoMars mission.

    PubMed

    Edwards, Howell G M; Hutchinson, Ian B; Ingley, Richard; Parnell, John; Vítek, Petr; Jehli?ka, Jan

    2013-06-01

    A novel miniaturized Raman spectrometer is scheduled to fly as part of the analytical instrumentation package on an ESA remote robotic lander in the ESA/Roscosmos ExoMars mission to search for evidence for extant or extinct life on Mars in 2018. The Raman spectrometer will be part of the first-pass analytical stage of the sampling procedure, following detailed surface examination by the PanCam scanning camera unit on the ExoMars rover vehicle. The requirements of the analytical protocol are stringent and critical; this study represents a laboratory blind interrogation of specimens that form a list of materials that are of relevance to martian exploration and at this stage simulates a test of current laboratory instrumentation to highlight the Raman technique strengths and possible weaknesses that may be encountered in practice on the martian surface and from which future studies could be formulated. In this preliminary exercise, some 10 samples that are considered terrestrial representatives of the mineralogy and possible biogeologically modified structures that may be identified on Mars have been examined with Raman spectroscopy, and conclusions have been drawn about the viability of the unambiguous spectral identification of biomolecular life signatures. It is concluded that the Raman spectroscopic technique does indeed demonstrate the capability to identify biomolecular signatures and the mineralogy in real-world terrestrial samples with a very high degree of success without any preconception being made about their origin and classification. PMID:23758166

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

    PubMed

    Kurhekar, Anil Sudhakar; Apte, Prakash R

    2013-02-22

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

  11. Spectroscopic analyses of Fe and water in clays: A Martian surface weathering study

    NASA Technical Reports Server (NTRS)

    Bishop, J. L.; Pieters, Carle M.; Edwards, J. O.; Coyne, L. M.; Chang, S.

    1991-01-01

    Martian surface morphology suggests the presence of liquid H2O on Mars in the past. Reflectance spectra of the Martian surface include features which correspond to the crystal field transitions of iron, as well as features supporting the presence of ice and minerals containing structural OH and surface water. Researchers initiated further spectroscopic studies of surface iron and water and structural OH in clays in order to determine what remotely obtained spectra can indicate about the presence of clays on Mars based on a clearer understanding of the factors influencing the spectral features. Current technology allows researchers to better correlate the low frequency fundamental stretching and bending vibrations of O-H bonds with the diagnostic near infrared overtone and combination bands used in mineral characterization and identification.

  12. Spectroscopic and simulation studies of adsorption and removal of hydrocarbons using novel materials

    SciTech Connect

    Koh, C.A.; Nooney, R.I. [Univ. of London (United Kingdom); Maddox, M.; Gubbins, K.E. [Cornell Univ., Ithaca, NY (United States). School of Chemical Engineering

    1995-12-01

    The authors report adsorption and spectroscopic measurements for mixtures involving low molecular weight hydrocarbons (methane, propane, isobutane) and carbon dioxide and also for pure methane; where possible, comparisons with molecular simulation are made. AlPO{sub 4}-5 and VPI-5 were found to selectively adsorb isobutane in isobutane/CO{sub 2} gas mixtures and propane in propane/methane gas mixtures, while little or no selectivity was observed for isobutane in isobutane/propane on AlPO{sub 4}-5. In-situ diffuse reflectance infrared spectroscopy has been used to study the adsorbate-adsorbent and adsorbate-adsorbate interactions of trace gases on VPI-5. This provided an insight into the extents of adsorption and strengths of the intermolecular adsorbate-adsorbent interactions.

  13. Vibrational spectroscopic studies of triethoxy(4-(trifluoromethyl)-phenyl) silane and its sol-gel coating

    NASA Astrophysics Data System (ADS)

    Li, Ying-Sing

    2012-10-01

    We have prepared a silica sol-gel using triethoxy (4-(trifluoromethyl)-phenyl) silane (TETFMPS) as a precursor in ethanol solution under acidic condition. The prepared sol-gel was applied to the surface treatment of aluminum for corrosion prevention. Infrared and Raman spectra of the silane coupling agent, sol-gel and sol-gel films on metal have been collected. Infrared spectroscopy has been used to study the thermal effect on the chemical composition of xerogel. Results suggested that TETFMPS molecule has a Cs point group symmetry with the plane of reflection orthogonal to the phenyl ring and the organic part of the sol-gel film remains essentially unchanged at or below 450 °C but decomposes at or above 550 °C. After the decomposition of the organic branch, the remaining film is composed of silica. Vibrational assignments were suggested by using the collected spectroscopic data in different states along with the group vibrational frequencies and other related references.

  14. Phosphorus-31 nuclear magnetic resonance spectroscopic study of the canine pancreas: applications to acute alcoholic pancreatitis

    SciTech Connect

    Janes, N.; Clemens, J.A.; Glickson, J.D.; Cameron, J.L.

    1988-01-01

    The first nuclear magnetic resonance spectroscopic study of the canine pancreas is described. Both in-vivo, ex-vivo protocols and NMR observables are discussed. The stability of the ex-vivo preparation based on the NMR observables is established for at least four hours. The spectra obtained from the in-vivo and ex-vivo preparations exhibited similar metabolite ratios, further validating the model. Metabolite levels were unchanged by a 50% increase in perfusion rate. Only trace amounts of phosphocreatine were observed either in the intact gland or in extracts. Acute alcoholic pancreatitis was mimicked by free fatty acid infusion. Injury resulted in hyperamylasemia, edema (weight gain), increased hematocrit and perfusion pressure, and depressed levels of high energy phosphates.

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

    PubMed Central

    Kurhekar, Anil Sudhakar; Apte, Prakash R

    2014-01-01

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

  16. Spectroscopic study of major components of dissolved organic matter naturally occurring in water

    SciTech Connect

    Patsayeva, S. [Moscow State Univ. (Russian Federation). Physics Dept.; Reuter, R. [Univ. of Oldenburg (Germany). Physics Dept.

    1995-12-31

    Natural organic compounds are present in significant concentration in all types of water. Many organic chemicals found in natural waters can be regarded as products of both biosynthesis and biodegradation. Until now not more than 30% of the dissolved organic matter (DOM) have been chemically characterized. The characterized fraction includes compound classes as carbohydrates, amino acids, hydrocarbons, fatty acids, phenolic compounds and others. The spectroscopic study of dissolved organic matter and its major components is important for applications of lidar remote sensing techniques for water quality measurements. In this paper, fluorescence emission and excitation spectra, as well as absorption spectra for commercially available analogues of major components of gelbstoff are analyzed and compared with spectra of natural water samples of different origin.

  17. SPECTROSCOPIC STUDY OF THE N159/N160 COMPLEX IN THE LARGE MAGELLANIC CLOUD

    SciTech Connect

    Farina, Cecilia; Bosch, Guillermo L. [Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, 1900 La Plata (Argentina); Morrell, Nidia I. [Las Campanas Observatory, Observatories of the Carnegie Institution of Washington, La Serena (Chile); Barba, Rodolfo H. [Complejo Astronomico El Leoncito, Avda. Espana 1412 Sur, San Juan (Argentina); Walborn, Nolan R. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)], E-mail: ceciliaf@fcaglp.unlp.edu.ar

    2009-08-15

    We present a spectroscopic study of the N159/N160 massive star-forming region south of 30 Doradus in the Large Magellanic Cloud, classifying a total of 189 stars in the field of the complex. Most of them belong to O and early B spectral classes; we have also found some uncommon and very interesting spectra, including members of the Onfp class, a Be P Cygni star, and some possible multiple systems. Using spectral types as broad indicators of evolutionary stages, we considered the evolutionary status of the region as a whole. We infer that massive stars at different evolutionary stages are present throughout the region, favoring the idea of a common time for the origin of recent star formation in the N159/N160 complex as a whole, while sequential star formation at different rates is probably present in several subregions.

  18. Spectroscopic and structural studies of L-arginine doped Potassium Dihydrogen Phosphate crystals

    NASA Astrophysics Data System (ADS)

    Govani, Jayesh; Botez, Cristian; Durrer, William; Manciu, Felicia

    2009-03-01

    We report in this study the spectroscopic and structural characterization of standard and L-arginine doped potassium dihydrogen phosphate crystals synthesized by a solution growth technique. The infrared absorption and Raman results demonstrate chemical functionalization between the amino (NH3^+) groups of the organic material and the phosphate units of the inorganic crystals. This affirmation, which also implies the achievement of successful doping, is supported by the existence of extra vibrational lines in the IR and Raman spectra of L-arginine doped potassium dihydrogen phosphate crystals; these vibrational lines exhibit shifting towards lower frequencies as compared with the characteristic bands of L-arginine. Incorporation of the amino acid into the structure of the inorganic material is revealed by X-ray diffraction results also, where the shifting of diffraction lines and the appearance of a new one are observed.

  19. Spectroscopic studies on Fe 3+ and Mn 2+ doped SrB 4O 7 glasses

    NASA Astrophysics Data System (ADS)

    Prakash, I. N.; Babu, B.; Venkata Reddy, Ch.; Narayana Murty, P.; Reddy, Y. P.; Sambasiva Rao, P.; Ravikumar, R. V. S. S. N.

    2011-09-01

    EPR and optical absorption studies on Fe 3+ and Mn 2+ doped strontium tetraborate (SrB 4O 7) glasses are carried out at room temperature. The EPR spectrum of the Fe 3+ doped glass consists of signals with g-values 9.04, 4.22 and 2.04, whereas the EPR spectrum of Mn 2+ doped glass exhibits a characteristic hyperfine sextet around g=2.0. The spectroscopic analyses of the obtained results confirmed distorted octahedral site symmetry for the Fe 3+ and Mn 2+ impurity ions. Crystal field and Racah parameters evaluated from optical absorption spectra are: Dq=790, B=700 and C=3000 cm -1 for Fe 3+doped glass and Dq=880, B=700 and C=2975 cm -1 for Mn 2+ doped glass.

  20. Fourier-transform Raman spectroscopic study of a Neolithic waterlogged wood assemblage.

    PubMed

    Petrou, M; Edwards, H G M; Janaway, R C; Thompson, G B; Wilson, A S

    2009-12-01

    The use of Fourier-transform Raman spectroscopy for characterising lignocellulosics has increased significantly over the last twenty years. Here, an FT-Raman spectroscopic study of changes in the chemistry of waterlogged archaeological wood of Pinus sp. and Quercus sp. from a prehistoric assemblage recovered from northern Greece is presented. FT-Raman spectral features of biodeteriorated wood were associated with the depletion of lignin and/or carbohydrate polymers at various stages of deterioration. Spectra from the archaeological wood are presented alongside spectra of sound wood of the same taxa. A comparison of the relative changes in intensities of spectral bands associated with lignin and carbohydrates resulting from decay clearly indicated extensive deterioration of both the softwood and hardwood samples and the carbohydrates appear to be more deteriorated than the lignin. The biodeterioration of the archaeological timbers followed a pattern of initial preferential loss of carbohydrates causing significant loss of cellulose and hemicellulose, followed by the degradation of lignin. PMID:19834692

  1. Hafnium(IV) chloride complexes with chelating ?-ketiminate ligands: Synthesis, spectroscopic characterization and volatility study.

    PubMed

    Patil, Siddappa A; Medina, Phillip A; Antic, Aleks; Ziller, Joseph W; Vohs, Jason K; Fahlman, Bradley D

    2015-09-01

    The synthesis and characterization of four new ?-ketiminate hafnium(IV) chloride complexes dichloro-bis[4-(phenylamido)pent-3-en-2-one]-hafnium (4a), dichloro-bis[4-(4-methylphenylamido)pent-3-en-2-one]-hafnium (4b), dichloro-bis[4-(4-methoxyphenylamido)pent-3-en-2-one]-hafnium (4c), and dichloro-bis[4-(4-chlorophenylamido)pent-3-en-2-one]-hafnium (4d) are reported. All the complexes (4a-d) were characterized by spectroscopic methods ((1)H NMR, (13)C NMR, IR), and elemental analysis while the compound 4c was further examined by single-crystal X-ray diffraction, revealing that the complex is monomer with the hafnium center in octahedral coordination environment and oxygens of the chelating N-O ligands are trans to each other and the chloride ligands are in a cis arrangement. Volatile trends are established for four new ?-ketiminate hafnium(IV) chloride complexes (4a-d). Sublimation enthalpies (?Hsub) were calculated from thermogravimetric analysis (TGA) data, which show that, the dependence of ?Hsub on the molecular weight (4a-c) and inductive effects from chlorine (4d). PMID:25897715

  2. Spectroscopic study on the interaction of resveratrol and pterostilbene with human serum albumin.

    PubMed

    Nair, Maya S

    2015-08-01

    The interaction of human serum albumin (HSA) with two stilbene compounds, resveratrol and pterostilbene was investigated using fluorescence, UV-visible absorption, Fourier transform infrared spectroscopic methods and molecular modeling technique. The intrinsic fluorescence of HSA was quenched significantly by resveratrol and pterostilbene. Analysis of fluorescence quenching data of HSA by the two compounds using Stern-Volmer and modified Stern-Volmer methods showed the formation of ground state complexes of HSA with resveratrol and pterostilbene. The binding analysis showed that the binding constant for resveratrol as 4.47×10(6) and 0.299×10(2)M(-1)s(-1) for pterostilbene revealing the high binding affinity of resveratrol to HSA. The conformational changes of HSA were investigated using synchronous fluorescence and Fourier transform infrared spectroscopy. The efficiency of energy transfer and the distance between HSA and resveratrol/pterostilbene were calculated. The binding of resveratrol/pterostilbene was modeled by molecular docking, which is in accordance with the experimental data. PMID:26048525

  3. Spectroscopic studies on the binding interaction of phenothiazinium dyes toluidine blue O, azure A and azure B to DNA

    NASA Astrophysics Data System (ADS)

    Paul, Puja; Suresh Kumar, Gopinatha

    2013-04-01

    In this study a detailed characterization of the binding aspects of three phenothiazinium dyes, toluidine blue O (TBO), azure A and azure B with herring testes DNA is presented employing spectroscopic techniques. The absorbance and fluorescence properties of these dyes have been remarkably modified upon binding with DNA and the interaction is manifested through noncooperative binding as revealed form non-linear Scatchard plots with negative slopes at all binding ratios. The binding clearly revealed the high preference of TBO to DNA followed by the other two dyes azure A and azure B. The affinity of TBO was higher by about two times than that of the azures. From the series of studies using absorption, steady-state emission, the effect of ferrocyanide ion-induced steady-state fluorescence quenching, fluorescence polarization anisotropy, circular dichroism, the mode of binding of these dyes to the DNA double helix has been substantiated to be principally intercalative in nature. The stoichiometry of the association of these dyes to DNA was determined by the continuous variation analysis of Job from fluorescence data. The conformational aspects of the interaction was delineated from circular dichroism studies wherein higher perturbation was observed with TBO. Hydrodynamic study using viscosity measurements of linear rod like DNA confirmed that the binding was intercalative and strongest for TBO and weaker for azure A and azure B. The utility of the present work lies in exploring the potential binding applicability of these dyes to DNA for their development as effective therapeutic agents.

  4. Ex-vivo holographic microscopy and spectroscopic analysis of head and neck cancer

    NASA Astrophysics Data System (ADS)

    Holler, Stephen; Wurtz, Robert; Auyeung, Kelsey; Auyeung, Kris; Paspaley-Grbavac, Milan; Mulroe, Brigid; Sobrero, Maximiliano; Miles, Brett

    2015-03-01

    Optical probes to identify tumor margins in vivo would greatly reduce the time, effort and complexity in the surgical removal of malignant tissue in head and neck cancers. Current approaches involve visual microscopy of stained tissue samples to determine cancer margins, which results in the excision of excess of tissue to assure complete removal of the cancer. Such surgical procedures and follow-on chemotherapy can adversely affect the patient's recovery and subsequent quality of life. In order to reduce the complexity of the process and minimize adverse effects on the patient, we investigate ex vivo tissue samples (stained and unstained) using digital holographic microscopy in conjunction with spectroscopic analyses (reflectance and transmission spectroscopy) in order to determine label-free, optically identifiable characteristic features that may ultimately be used for in vivo processing of cancerous tissues. The tissue samples studied were squamous cell carcinomas and associated controls from patients of varying age, gender and race. Holographic microscopic imaging scans across both cancerous and non-cancerous tissue samples yielded amplitude and phase reconstructions that were correlated with spectral signatures. Though the holographic reconstructions and measured spectra indicate variations even among the same class of tissue, preliminary results indicate the existence of some discriminating features. Further analyses are presently underway to further this work and extract additional information from the imaging and spectral data that may prove useful for in vivo surgical identification.

  5. Studies of multiple stellar systems - IV. The triple-lined spectroscopic system Gliese 644

    NASA Astrophysics Data System (ADS)

    Mazeh, Tsevi; Latham, David W.; Goldberg, Elad; Torres, Guillermo; Stefanik, Robert P.; Henry, Todd J.; Zucker, Shay; Gnat, Orly; Ofek, Eran O.

    2001-07-01

    We present a radial velocity study of the triple-lined system Gliese 644 and derive spectroscopic elements for the inner and outer orbits with periods of 2.9655 and 627d. We also utilize old visual data, as well as modern speckle and adaptive optics observations, to derive a new astrometric solution for the outer orbit. These two orbits together allow us to derive masses for each of the three components in the system: MA=0.410+/-0.028 (6.9 per cent), MBa=0.336+/-0.016 (4.7 per cent), and MBb=0.304+/-0.014 (4.7 per cent)Msolar. We suggest that the relative inclination of the two orbits is very small. Our individual masses and spectroscopic light ratios for the three M stars in the Gliese 644 system provide three points for the mass-luminosity relation near the bottom of the main sequence, where the relation is poorly determined. These three points agree well with theoretical models for solar metallicity and an age of 5Gyr. Our radial velocities for Gliese 643 and vB 8, two common proper motion companions of Gliese 644, support the interpretation that all five M stars are moving together in a physically bound group. We discuss possible scenarios for the formation and evolution of this configuration, such as the formation of all five stars in a sequence of fragmentation events leading directly to the hierarchical configuration now observed, versus formation in a small N cluster with subsequent dynamical evolution into the present hierarchical configuration.

  6. Crystallographic, Kinetic, and Spectroscopic Study of the First Ligninolytic Peroxidase Presenting a Catalytic Tyrosine*

    PubMed Central

    Miki, Yuta; Calviño, Fabiola R.; Pogni, Rebecca; Giansanti, Stefania; Ruiz-Dueñas, Francisco J.; Martínez, María Jesús; Basosi, Riccardo; Romero, Antonio; Martínez, Angel T.

    2011-01-01

    Trametes cervina lignin peroxidase (LiP) is a unique enzyme lacking the catalytic tryptophan strictly conserved in all other LiPs and versatile peroxidases (more than 30 sequences available). Recombinant T. cervina LiP and site-directed variants were investigated by crystallographic, kinetic, and spectroscopic techniques. The crystal structure shows three substrate oxidation site candidates involving His-170, Asp-146, and Tyr-181. Steady-state kinetics for oxidation of veratryl alcohol (the typical LiP substrate) by variants at the above three residues reveals a crucial role of Tyr-181 in LiP activity. Moreover, assays with ferrocytochrome c show that its ability to oxidize large molecules (a requisite property for oxidation of the lignin polymer) originates in Tyr-181. This residue is also involved in the oxidation of 1,4-dimethoxybenzene, a reaction initiated by the one-electron abstraction with formation of substrate cation radical, as described for the well known Phanerochaete chrysosporium LiP. Detailed spectroscopic and kinetic investigations, including low temperature EPR, show that the porphyrin radical in the two-electron activated T. cervina LiP is unstable and rapidly receives one electron from Tyr-181, forming a catalytic protein radical, which is identified as an H-bonded neutral tyrosyl radical. The crystal structure reveals a partially exposed location of Tyr-181, compatible with its catalytic role, and several neighbor residues probably contributing to catalysis: (i) by enabling substrate recognition by aromatic interactions; (ii) by acting as proton acceptor/donor from Tyr-181 or H-bonding the radical form; and (iii) by providing the acidic environment that would facilitate oxidation. This is the first structure-function study of the only ligninolytic peroxidase described to date that has a catalytic tyrosine. PMID:21367853

  7. Crystallographic, kinetic, and spectroscopic study of the first ligninolytic peroxidase presenting a catalytic tyrosine.

    PubMed

    Miki, Yuta; Calviño, Fabiola R; Pogni, Rebecca; Giansanti, Stefania; Ruiz-Dueñas, Francisco J; Martínez, María Jesús; Basosi, Riccardo; Romero, Antonio; Martínez, Angel T

    2011-04-29

    Trametes cervina lignin peroxidase (LiP) is a unique enzyme lacking the catalytic tryptophan strictly conserved in all other LiPs and versatile peroxidases (more than 30 sequences available). Recombinant T. cervina LiP and site-directed variants were investigated by crystallographic, kinetic, and spectroscopic techniques. The crystal structure shows three substrate oxidation site candidates involving His-170, Asp-146, and Tyr-181. Steady-state kinetics for oxidation of veratryl alcohol (the typical LiP substrate) by variants at the above three residues reveals a crucial role of Tyr-181 in LiP activity. Moreover, assays with ferrocytochrome c show that its ability to oxidize large molecules (a requisite property for oxidation of the lignin polymer) originates in Tyr-181. This residue is also involved in the oxidation of 1,4-dimethoxybenzene, a reaction initiated by the one-electron abstraction with formation of substrate cation radical, as described for the well known Phanerochaete chrysosporium LiP. Detailed spectroscopic and kinetic investigations, including low temperature EPR, show that the porphyrin radical in the two-electron activated T. cervina LiP is unstable and rapidly receives one electron from Tyr-181, forming a catalytic protein radical, which is identified as an H-bonded neutral tyrosyl radical. The crystal structure reveals a partially exposed location of Tyr-181, compatible with its catalytic role, and several neighbor residues probably contributing to catalysis: (i) by enabling substrate recognition by aromatic interactions; (ii) by acting as proton acceptor/donor from Tyr-181 or H-bonding the radical form; and (iii) by providing the acidic environment that would facilitate oxidation. This is the first structure-function study of the only ligninolytic peroxidase described to date that has a catalytic tyrosine. PMID:21367853

  8. Comparative two- and three-dimensional analysis of nanoparticle localization in different cell types by Raman spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Bräutigam, Katharina; Bocklitz, Thomas; Silge, Anja; Dierker, Christian; Ossig, Rainer; Schnekenburger, Jürgen; Cialla, Dana; Rösch, Petra; Popp, Jürgen

    2014-09-01

    The increasing production and application of engineered nanomaterials requires a detailed understanding of the potential toxicity of nanoparticles and their uptake in living cells and tissue. For that purpose, a highly sensitive and selective method for detecting single nonlabeled nanoparticles and nanoparticle agglomerations in cells and animal tissue is required. Here, we show that Raman microspectroscopy allows for the specific detection of TiO2 nanoparticles inside cultured NIH/3T3 fibroblasts and RAW 264.7 macrophages. The spatial position of TiO2 nanoparticles and in parallel the relative intracellular concentration and distribution of cellular constituents such as proteins or DNA residues were identified and displayed by construction of two- and three-dimensional Raman maps. The resulting Raman images reflected the significant differences in nanoparticle uptake and intracellular storage of fibroblasts and macrophages. Furthermore, TiO2 nanomaterials could be characterized and the presence of rutile- and anatase-phase TiO2 were determined inside cells. Together, the data shown here prove that Raman spectroscopic imaging is a promising technique for studying the interaction of nanomaterials with living cells and for differentiating intracellular nanoparticles from those localized on the cell membrane. The technology provides a label-free, non-destructive, material-specific analysis of whole cells with high spatial resolution, along with additional information on the current status of the material properties.

  9. Application of merged spectroscopic data combined with chemometric analysis for resolution of hemoglobin intermediates during chemical unfolding

    NASA Astrophysics Data System (ADS)

    Fotouhi, L.; Yousefinejad, S.; Salehi, N.; Saboury, A. A.; Sheibani, N.; Moosavi-Movahedi, A. A.

    2015-02-01

    Using tetradecyltrimethylammonium bromide (TTAB) as a surfactant denaturant, and augmentation of different spectroscopic data, helped to detect the intermediates of hemoglobin (Hb) during unfolding process. UV-vis, fluorescence, and circular dichroism spectroscopy were used simultaneously to monitor different aspects of hemoglobin species from the tertiary or secondary structure points of view. Application of the multivariate curve resolution-alternating least square (MCR-ALS), using the initial estimates of spectral profiles and appropriate constraints on different parts of augmented spectroscopic data, showed good efficiency for characterization of intermediates during Hb unfolding. These results indicated the existence of five protein species, including three intermediate-like compounds in this process. The unfolding pathway in the presence of TTAB included conversion of oxyhemoglobin into deoxyhemoglobin, and then ferrylhemoglobin, ferrihemoglobin or aquamethemoglobin, which finally transformed into hemichrome. This is the first application of chemometric analysis on the merged spectroscopic data related to chemical denaturation of a protein. These types of analysis in multisubunit proteins not only increase the domain of information, but also can reduce the ambiguities of the obtained results.

  10. Model-based spectroscopic analysis of the oral cavity: impact of anatomy

    PubMed Central

    McGee, Sasha; Mirkovic, Jelena; Mardirossian, Vartan; Elackattu, Alphi; Yu, Chung-Chieh; Kabani, Sadru; Gallagher, George; Pistey, Robert; Galindo, Luis; Badizadegan, Kamran; Wang, Zimmern; Dasari, Ramachandra; Feld, Michael S.; Grillone, Gregory

    2008-01-01

    In order to evaluate the impact of anatomy on the spectral properties of oral tissue, we used reflectance and fluorescence spectroscopy to characterize nine different anatomic sites. All spectra were collected in vivo from healthy oral mucosa. We analyzed 710 spectra collected from the oral cavity of 79 healthy volunteers. From the spectra, we extracted spectral parameters related to the morphological and biochemical properties of the tissue. The parameter distributions for the nine sites were compared, and we also related the parameters to the physical properties of the tissue site. k-Means cluster analysis was performed to identify sites or groups of sites that showed similar or distinct spectral properties. For the majority of the spectral parameters, certain sites or groups of sites exhibited distinct parameter distributions. Sites that are normally keratinized, most notably the hard palate and gingiva, were distinct from nonkeratinized sites for a number of parameters and frequently clustered together. The considerable degree of spectral contrast (differences in the spectral properties) between anatomic sites was also demonstrated by successfully discriminating between several pairs of sites using only two spectral parameters. We tested whether the 95% confidence interval for the distribution for each parameter, extracted from a subset of the tissue data could correctly characterize a second set of validation data. Excellent classification accuracy was demonstrated. Our results reveal that intrinsic differences in the anatomy of the oral cavity produce significant spectral contrasts between various sites, as reflected in the extracted spectral parameters. This work provides an important foundation for guiding the development of spectroscopic-based diagnostic algorithms for oral cancer. PMID:19123680

  11. Molecular and spectroscopic analysis of non-hydrolyzable sedimentary organic matter from the St. Lawrence Estuary

    NASA Astrophysics Data System (ADS)

    Ibrahim, M.; Simpson, A. J.; Gelinas, Y.

    2011-12-01

    Sediments are the ultimate long-term sink for organic carbon (OC) on Earth, thus playing an important role in the global cycles of O2 and CO2. Estuaries and river deltas are major conduits for terrestrial organic matter (OM) into marine systems, where it is mixed with locally produced OM and is eventually deposited and buried in the sediment bed. About 45% of global OC burial occurs along these river deltas and estuaries (Hedges and Keil, 1995), therefore it is of interest to follow OM deposition and preservation in these terrestrial to marine transition zones. We chemically fractionated bulk OM from a series of sediments from the St. Lawrence Estuary and Gulf into distinct reactivity classes. We define three such OM fractions based on pioneering work by Hedges and Keil (1995) who classified OM based on chemical reactivities: labile (degradable at similar rate under oxic and anoxic conditions), non-hydrolyzable (degraded primarily under oxic conditions), and refractory (preserved on long time scales independently of redox conditions). Here we present data on the elemental (C and N), isotopic (?13C and ?15N) and spectroscopic (FTIR, HR-MAS 1H/13C NMR) characterization of the different fractions, focusing primarily on the non-hydrolyzable fraction because of its importance in the long-term burial of OC below the seafloor. We used mild oxidation methods (cupric oxide and ruthenium tetroxide oxidation) followed by chromatographic analysis of the oxidation products. Combining results from the bulk and molecular analytical techniques provides insights into the composition and cycling of non-hydrolyzable OM in transitional system, from which OM preservation can be better understood. Hedges, J. I., Keil, Richard G. (1995). "Sedimentary organic matter preservation: an assessment and speculative synthesis." Marine Chemistry 49(2-3): 81-115.

  12. Instrumental analysis of bacterial cells using vibrational and emission Mössbauer spectroscopic techniques.

    PubMed

    Kamnev, Alexander A; Tugarova, Anna V; Antonyuk, Lyudmila P; Tarantilis, Petros A; Kulikov, Leonid A; Perfiliev, Yurii D; Polissiou, Moschos G; Gardiner, Philip H E

    2006-07-28

    In biosciences and biotechnology, the expanding application of physicochemical approaches using modern instrumental techniques is an efficient strategy to obtain valuable and often unique information at the molecular level. In this work, we applied a combination of vibrational (Fourier transform infrared (FTIR), FT-Raman) spectroscopic techniques, useful in overall structural and compositional analysis of bacterial cells of the rhizobacterium Azospirillum brasilense, with 57Co emission Mössbauer spectroscopy (EMS) used for sensitive monitoring of metal binding and further transformations in live bacterial cells. The information obtained, together with ICP-MS analyses for metals taken up by the bacteria, is useful in analysing the impact of the environmental conditions (heavy metal stress) on the bacterial metabolism and some differences in the heavy metal stress-induced behaviour of non-endophytic (Sp7) and facultatively endophytic (Sp245) strains. The results show that, while both strains Sp7 and Sp245 take up noticeable and comparable amounts of heavy metals from the medium (0.12 and 0.13 mg Co, 0.48 and 0.44 mg Cu or 4.2 and 2.1 mg Zn per gram of dry biomass, respectively, at a metal concentration of 0.2 mM in the medium), their metabolic responses differ essentially. Whereas for strain Sp7 the FTIR measurements showed significant accumulation of polyhydroxyalkanoates as storage materials involved in stress endurance, strain Sp245 did not show any major changes in cellular composition. Nevertheless, EMS measurements showed rapid binding of cobalt(II) by live bacterial cells (chemically similar to metal binding by dead bacteria) and its further transformation in the live cells within an hour. PMID:17723559

  13. Surface spectroscopic studies of the deposition of TiN thin films from tetrakis-(dimethylamido)-titanium and ammonia

    E-print Network

    Goodman, Wayne

    Surface spectroscopic studies of the deposition of TiN thin films from tetrakis-(dimethylamido)-titanium 1995 The adsorption and pyrolysis of tetrakis- dimethylamido -titanium TDMAT , Ti NMe2 4, on several , the growth of low-carbon-content 8 at. % titanium nitride films proceeds readily, via surface mediated

  14. Structure-function relationship of viral coat proteins. A site directed spectroscopic study of M13 coat protein

    Microsoft Academic Search

    D. Stopar

    1997-01-01

    This thesis describes the results of a spectroscopic study of the major coat protein of bacteriophage M13. During the infection process this protein is incorporated into the cytoplasmic membrane of Escherichia coli host cells. To specifically monitor the local structural changes and changes in the environment of the protein upon membrane insertion, a set of cysteine site-specific mutants of protein

  15. Long path ftir spectroscopic study of the reactions of CF3O radicals with ethane and propane

    Microsoft Academic Search

    J. Chen; T. Zhu; H. Niki; G. J. Mains

    1992-01-01

    A long path FTIR-based product study was carried out by the visible (? > 400 nm) photolysis of mixtures containing CF3NO, NO and ethane or propane (in mtorr range) in 700 torr of synthetic air at 297 ± 2 K. Kinetic and spectroscopic evidence has been obtained for the reaction (1), CF3O + RH ? CF3OH + R (RH =

  16. Spectroscopic and Electronic Structure Studies of the 4-Sulfide Bridged Tetranuclear CuZ Cluster in N2O

    E-print Network

    Chen, Peng

    Spectroscopic and Electronic Structure Studies of the µ4-Sulfide Bridged Tetranuclear CuZ Cluster description of the µ4-sulfide bridged tetranuclear CuZ cluster in N2O reductase. The ground state of CuZ has

  17. Adding water to sugar: A spectroscopic and computational study of a-and b-phenylxyloside in the gas phase

    E-print Network

    Davis, Ben G.

    Adding water to sugar: A spectroscopic and computational study of a- and b of Chemistry, Physical and Theoretical Chemistry Laboratory, South Parks Road, Oxford, UK OX1 3QZ. E-mail: john.simons@chem.ox.ac.uk b Department of Chemistry, Grinnell College, Grinnell, IA, USA c Department of Chemistry, Chemistry

  18. Spectroscopic ellipsometry studies of the optical properties of doped poly(3,4-ethylenedioxythiophene): an anisotropic metal

    Microsoft Academic Search

    Leif A. A. Pettersson; Fredrik Carlsson; Olle Inganäs; Hans Arwin

    1998-01-01

    Poly(3,4-ethylenedioxythiophene) (PEDOT) is a conjugated polymer with high electrical conductivity in the doped state, good thermal and chemical stability and fast electrochemical switching. The material is used as an antistatic layer, and has potential for use as a (transparent) electrode material and for electrochromic applications. Thin films (<1 ?m) of doped PEDOT have been studied with variable angle spectroscopic ellipsometry.

  19. Depth Profiling Photoelectron-Spectroscopic Study of an Organic Spin Valve with a Plasma-Modified Pentacene Spacer

    E-print Network

    Lin, Minn-Tsong

    Depth Profiling Photoelectron-Spectroscopic Study of an Organic Spin Valve with a Plasma) in an organic spin valve with an oxygen plasma-treated pentacene (PC) spacer. The spin valve containing PC ratios up to 1.64% at room temperature. X-ray photoelectron spectroscopy with depth profiling is utilized

  20. Nonlinear Vibrational Spectroscopic Studies of the Adsorption and Speciation of Nitric Acid at the Vapor/Acid Solution Interface

    E-print Network

    Richmond, Geraldine L.

    Nonlinear Vibrational Spectroscopic Studies of the Adsorption and Speciation of Nitric AcidVed: December 18, 2006; In Final Form: February 15, 2007 Nitric acid plays an important role and troposphere depend on the state of nitric acid at these surfaces. The vapor/liquid interface of HNO3-H2O

  1. Growth, spectroscopic investigation, optical, mechanical, chemical etching and nonlinear optical studies of semi-organic crystal: Bis (thiourea) zinc formate.

    PubMed

    Hanumantharao, Redrothu; Kalainathan, S

    2013-04-01

    Single crystals of Bis (thiourea) zinc formate (BTZF) were grown by slow evaporation method at room temperature. The grown crystal was confirmed by single crystal XRD, (1)H NMR and Mass spectroscopic techniques. Single crystal XRD technique revealed that material crystallized in monoclinic system with cell parameters a=8.693Å, b=7.151Å and c=9.311Å. The presence of hydrogen atoms in the grown sample was confirmed by proton NMR analysis. The mass spectral analysis was carried out to measure the accurate molecular mass of the compound. The recorded UV-Vis-NIR transmittance spectrum show excellent transmission in the range of 200-1100nm. Measuring transmittance of BTZF permitted the calculation of the extinction coefficient K, Reflectance R, as functions of photon energy. The etching study indicates the occurrence of different types of etch pit patterns on the growth surface. The Vickers (Hv) microhardness were carried out in the load range of 10-50g. Optical nonlinearities of BTZF have been investigated by Z-scan technique with He-Ne laser radiation of wavelength 638nm. PMID:23376259

  2. Binding of Phenazinium Dye Safranin T to Polyriboadenylic Acid: Spectroscopic and Thermodynamic Study

    PubMed Central

    Roy, Snigdha; Das, Suman

    2014-01-01

    Here, we report results from experiments designed to explore the association of the phenazinium dye safranin T (ST, 3,7-diamino-2,8-dimethyl-5-phenylphenazinium chloride) with single and double stranded form of polyriboadenylic acid (hereafter poly-A) using several spectroscopic techniques. We demonstrate that the dye binds to single stranded polyriboadenylic acid (hereafter ss poly-A) with high affinity while it does not interact at all with the double stranded (ds) form of the polynucleotide. Fluorescence and absorption spectral studies reveal the molecular aspects of binding of ST to single stranded form of the polynucleotide. This observation is also supported by the circular dichroism study. Thermodynamic data obtained from temperature dependence of binding constant reveals that association is driven by negative enthalpy change and opposed by negative entropy change. Ferrocyanide quenching studies have shown intercalative binding of ST to ss poly-A. Experiments on viscosity measurements confirm the binding mode of the dye to be intercalative. The effect of [Na+] ion concentration on the binding process suggests the role of electrostatic forces in the complexation. Present studies reveal the utility of the dye in probing nucleic acid structure. PMID:24498422

  3. Raman Spectroscopic Analysis of Geological and Biogeological Specimens of Relevance to the ExoMars Mission

    PubMed Central

    Edwards, Howell G.M.; Ingley, Richard; Parnell, John; Vítek, Petr; Jehli?ka, Jan

    2013-01-01

    Abstract A novel miniaturized Raman spectrometer is scheduled to fly as part of the analytical instrumentation package on an ESA remote robotic lander in the ESA/Roscosmos ExoMars mission to search for evidence for extant or extinct life on Mars in 2018. The Raman spectrometer will be part of the first-pass analytical stage of the sampling procedure, following detailed surface examination by the PanCam scanning camera unit on the ExoMars rover vehicle. The requirements of the analytical protocol are stringent and critical; this study represents a laboratory blind interrogation of specimens that form a list of materials that are of relevance to martian exploration and at this stage simulates a test of current laboratory instrumentation to highlight the Raman technique strengths and possible weaknesses that may be encountered in practice on the martian surface and from which future studies could be formulated. In this preliminary exercise, some 10 samples that are considered terrestrial representatives of the mineralogy and possible biogeologically modified structures that may be identified on Mars have been examined with Raman spectroscopy, and conclusions have been drawn about the viability of the unambiguous spectral identification of biomolecular life signatures. It is concluded that the Raman spectroscopic technique does indeed demonstrate the capability to identify biomolecular signatures and the mineralogy in real-world terrestrial samples with a very high degree of success without any preconception being made about their origin and classification. Key Words: Biosignatures—Mars Exploration Rovers—Raman spectroscopy—Search for life (biosignatures)—Planetary instrumentation. Astrobiology 13, 543–549. PMID:23758166

  4. Vibrational spectroscopic study of the contents of a chest excavated from the wreck of the HMS Pandora

    Microsoft Academic Search

    H. G. M. Edwards; D. W. Farwell; J. S. Lee; P. M. Fredericks

    2003-01-01

    The FT-IR and Raman spectroscopic analysis of a red powder found in a chest from an officer's cabin during the excavation of the wreck of the 18th Century frigate HMS Pandora have confirmed that the pigment is cinnabar, mercury(II) sulphide. Weaker signals in the Raman spectrum are assignable to a proteinaceous material, such as collagen, typical of a degraded vellum

  5. A Photometric and Spectroscopic Study of Dwarf and Giant Galaxies in the Coma Cluster. III. Spectral Ages and Metallicities

    Microsoft Academic Search

    Bianca M. Poggianti; Terry J. Bridges; Bahram Mobasher; Dave Carter; M. Doi; M. Iye; N. Kashikawa; Y. Komiyama; S. Okamura; M. Sekiguchi; K. Shimasaku; M. Yagi; N. Yasuda

    2001-01-01

    We present a detailed analysis of the spectroscopic catalog of galaxies in the Coma Cluster from Mobasher et al. (Paper II of the series). This catalog comprises ~300 spectra of cluster members with absolute magnitudes in the range MB=-20.5 to -14 in two areas of ~1×1.5 Mpc toward the center and the southwest region of the cluster. In order to

  6. Structural studies of E. coli ribosomes by spectroscopic techniques: A specialized review

    NASA Astrophysics Data System (ADS)

    Bonicontro, Adalberto; Risuleo, Gianfranco

    2005-12-01

    We present a review on our interdisciplinary line of research based on strategies of molecular biology and biophysics. These have been applied to the study of the prokaryotic ribosome of the bacterium Escherichia coli. Our investigations on this organelle have continued for more than a decade and we have adopted different spectroscopic biophysical techniques such as: dielectric and fluorescence spectroscopy as well as light scattering (photon correlation spectroscopy). Here we report studies on the whole 70S ribosomes and on the separated subunits 30S and 50S. Our results evidence intrinsic structural features of the subunits: the small shows a more "floppy" structure, while the large one appears to be more rigid. Also, an inner "kernel" formed by the RNA/protein association is found within the ribosome. This kernel is surrounded by a ribonucleoprotein complex more exposed to the solvent. Initial analyses were done on the so called Kaldtschmit-Wittmann ribosome: more recently we have extended the studies to the "tight couple" ribosome known for its better functional performance in vitro. Data evidence a phenomenological correlation between the differential biological activity and the intrinsic structural properties of the two-ribosome species. Finally, investigations were also conducted on particles treated at sub-denaturing temperatures and on ribosomes partially deproteinized by salt treatment (ribosomal cores). Results suggest that the thermal treatment and the selective removal of proteins cause analogous structural alterations.

  7. Spectroscopic studies on the spontaneous assembly of phenosafranin on glycosaminoglycans templates

    NASA Astrophysics Data System (ADS)

    Zhang, Shuzhen; Zhao, Fenglin; Li, Na; Li, Ke'an; Tong, Shenyang

    2002-10-01

    Spectroscopic studies showed that binding of phenosafranin (PSF) molecules to glycosaminoglycans (GAGs) resulted in the following observations: (i) appearance of a 52.6 nm hypsochromic shift of the visible absorption band; (ii) static quenching of fluorescence from PSF; (iii) induction of strong circular dichroism (CD) signal of PSF. Stoichiometry of the PSF-GAGs complex was determined by spectrophotometric titration, spectrofluorimetric titration and MacIntosh extraction method. These studies demonstrated the formation of the extended helical PSF array aligned on the helical backbone of GAGs templates by electrostatic force, and the dimeric binding mode of PSF to each anionic site was proposed. The comparative studies between PSF-heparin (Hep) and PSF-chondroitin 4-sulfate (CS) complexes revealed that: (i) stoichiometry of PSF-Hep complex was 1.8 times of PSF-CS complex; (ii) Hep was more effective than CS (1.8 times) in decreasing the absorbance of PSF; and (iii) Stern-Volmer constants of the Hep-PSF system were greater than that of the CS-PSF system. These differences were attributed to the different charge density on the Hep and CS molecules, which in turn suggested that the electrostatic force was dominant in the interaction between PSF and GAGs.

  8. Raman spectroscopic study of keratin 8 knockdown oral squamous cell carcinoma derived cells

    NASA Astrophysics Data System (ADS)

    Singh, S. P.; Alam, Hunain; Dmello, Crismita; Vaidya, Milind M.; Krishna, C. Murali

    2012-03-01

    Keratins are one of most widely used markers for oral cancers. Keratin 8 and 18 are expressed in simple epithelia and perform both mechanical and regulatory functions. Their expression are not seen in normal oral tissues but are often expressed in oral squamous cell carcinoma. Aberrant expression of keratins 8 and 18 is most common change in human oral cancer. Optical-spectroscopic methods are sensitive to biochemical changes and being projected as novel diagnostic tools for cancer diagnosis. Aim of this study was to evaluate potentials of Raman spectroscopy in detecting minor changes associated with differential level of keratin expression in tongue-cancer-derived AW13516 cells. Knockdown clones for K8 were generated and synchronized by growing under serum-free conditions. Cell pellets of three independent experiments in duplicate were used for recording Raman spectra with fiberoptic-probe coupled HE-785 Raman-instrument. A total of 123 and 96 spectra from knockdown clones and vector controls respectively in 1200-1800 cm-1 region were successfully utilized for classification using LDA. Two separate clusters with classification-efficiency of ~95% were obtained. Leave-one-out cross-validation yielded ~63% efficiency. Findings of the study demonstrate the potentials of Raman spectroscopy in detecting even subtle changes such as variations in keratin expression levels. Future studies towards identifying Raman signals from keratin in oral cells can help in precise cancer diagnosis.

  9. Applications of Synchrotron Radiation and Optical Spectroscopic Techniques to the Study of Electrochemical Interfaces

    NASA Astrophysics Data System (ADS)

    Kim, Sunghyun

    Electrochemical interfaces, especially structural changes and spectroscopic properties of adsorbed species on electrode surfaces induced by electrode potential have been examined by means of X-ray absorption fine structure and optical spectroscopic techniques. Potential modulation reflectance spectroscopy and wavelength modulation reflectance technique have been used to monitor the spectral properties of cobalt tetrasulfonated phthalocyanine (CoTsPc) and methylene (MB) blue irreversibly adsorbed on electrode surfaces. With a combination of cyclic voltammetry, linear relationship has been found between the relative reflectivity and the coverage of oxidized species of CoTsPc on the basal plane of highly oriented pyrolytic graphite (HOPG(bp)). Wavelength modulation study has shown that CoTsPc and MB on electrode surfaces exhibit almost the same spectral properties with those when they are in solution phase. Spectral changes accompanying the one-electron reduction of mu-oxo(bis) (iron meso -tetrakis(methoxyphenyl)porphyrin) (FeTMPP)_2 O irreversibly adsorbed on Black Pearl (BP) in aqueous electrolyte have been examined in situ through X-ray absorption fine structure. In the pH range 5-10.8, the average iron -to-porphinato nitrogen distance, d(Fe-N_ {rm p}) (2.08 +/- 0.01 A) for the ferric species was found to be very similar to that for crystalline (FeTMPP)_2O. At extreme pHs, d(Fe-N_{rm p} ) values smaller than those observed in the intermediate pH range, which strongly suggest an axially coordinated dihydroxy (at very high pH) and diaquo (at very low pH) complexes as the predominant species. In contrast, the corresponding ferrous counterpart displayed values for d(Fe-N_{rm p}) (2.04 +/- 0.01 A) consistent with the iron center placed in the plane of the ring over the whole pH region examined. The XAFS studies of Ni and 9:1 Ni/Fe and 9:1 Ni/Co composite hydroxide have shown that (i) Ni-O and Ni-Ni distances in Ni(OH)_2 system are larger than those in NiOOH produced by oxidation; (ii) iron and cobalt ions replace nickel ions in hydrous oxide lattice forming single phase; (iii) iron and cobalt do not undergo oxidation state changes upon oxidizing Ni(OH) _2 to NiOOH, but remain as 3+ state. The XAFS studies of FeS_2 and its Li ion intercalated species have shown that electrochemical insertion of Li ion brings about a marked decrease in the amplitude of the EXAFS and makes Fe-S distance longer. (Abstract shortened by UMI.).

  10. Molecular modeling and spectroscopic studies on the interaction of the chiral drug venlafaxine hydrochloride with bovine serum albumin.

    PubMed

    Shahabadi, Nahid; Hadidi, Saba

    2014-03-25

    This study was designed to examine the interaction of racemic antidepressant drug "S,R-venlafaxine hydrochloride (VEN)" with bovine serum albumin (BSA) under physiological conditions. The mechanism of interaction was studied by spectroscopic techniques combination with molecular modeling. Stern-Volmer analysis of fluorescence quenching data shows the presence of the static quenching mechanism. The thermodynamic parameters indicated that the hydrogen bonding and weak van der Waals interactions are the predominant intermolecular forces stabilizing the complex. The number of binding sites (n) was calculated. Through the site marker competitive experiment, VEN was confirmed to be located in subdomain IIIA of BSA. The binding distance (r=4.93 nm) between the donor BSA and acceptor VEN was obtained according to Förster's non-radiative energy transfer theory. According to UV-vis spectra and CD data binding of VEN leaded to conformational changes of BSA. Molecular docking simulations of S and R-VEN revealed that both isomers have similar interaction and the same binding sites, from this point of view S and R isomers are equal. PMID:24299981

  11. Synthesis, spectroscopic, thermal and quantum chemical studies on trivalent erbium NO chelating sulfamonomethoxine-cyclophosph(V)azane complex

    NASA Astrophysics Data System (ADS)

    Al-Mogren, Muneerah M.; Alaghaz, Abdel-Nasser M. A.; El-Gogary, Tarek M.; Albohy, Salwa A. H.

    2013-09-01

    Novel hexachlorocyclophosph(V)azane of sulfamonomethoxine (L), was prepared and their coordinating behavior toward the lanthanide ion erbium (III) was studied. The structures of the isolated products were proposed based on elemental analyses, IR, UV-VIS, 1H NMR, 31P NMR, SEM, TEM, XRD, mass spectra, effective magnetic susceptibility measurements and thermogravimetric analysis (TGA). The coordination polyhedra of the eight donor atoms around the two erbium (III) ions are best described as distorted dodecahedral. Computational studies were carried out at the DFT-B3LYP/6-31G(d) level of theory on the structural and spectroscopic properties of L and its binuclear erbium (III) complex. Different tautomers of the ligand were optimized at the ab initio DFT level. Keto-form structure is about 30.5 kcal/mol more stable than the enol form (taking zpe correction into account). Simulated IR frequencies were scaled and compared with that experimentally measured. TD-DFT method was used to compute the UV-VIS spectra in gas phase and DMF.

  12. AN IMPROVED SPECTROSCOPIC ANALYSIS OF DA WHITE DWARFS FROM THE SLOAN DIGITAL SKY SURVEY DATA RELEASE 4

    SciTech Connect

    Tremblay, P.-E.; Bergeron, P.; Gianninas, A., E-mail: tremblay@astro.umontreal.ca, E-mail: bergeron@astro.umontreal.ca, E-mail: gianninas@astro.umontreal.ca [Departement de Physique, Universite de Montreal, C.P. 6128, Succ. Centre-Ville, Montreal, Quebec H3C 3J7 (Canada)

    2011-04-01

    We present an improved spectroscopic and photometric analysis of hydrogen-line DA white dwarfs from the Sloan Digital Sky Survey Data Release 4 (SDSS DR4) based on model atmospheres that include improved Stark broadening profiles with non-ideal gas effects. We also perform a careful visual inspection of all spectroscopic fits with high signal-to-noise ratios (S/Ns > 12) and present improved atmospheric parameters (T{sub eff} and log g) for each white dwarf. Through a comparison of spectroscopic and photometric temperatures, we report the discovery of 35 DA+DB/DC double degenerate candidates and two helium-rich DA stars. We also determine that a cutoff at S/N = 15 optimizes the size and quality of the sample for computing the mean mass of DA white dwarfs, for which we report a value of 0.613 M{sub sun}. We compare our results to previous analyses of the SDSS DR4 and find a good agreement if we account for the shift produced by the improved Stark profiles. Finally, the properties of DA white dwarfs in the SDSS are weighed against those of the Villanova White Dwarf Catalog sample of Gianninas et al. We find systematically lower masses (by about 3% on average), a difference that we trace back to the data reduction procedure of the SDSS. We conclude that a better understanding of these differences will be important to determine the absolute temperature scale and mean mass of DA white dwarfs.

  13. Explanatory analysis of spectroscopic data using machine learning of simple, interpretable rules

    E-print Network

    Fernandez, Thomas

    only in combination with modern supervised machine learning techniques, such as artificial neural. Introduction Fourier transform infrared (FT-IR) and Raman are vibrational spectroscopic techniques which Abstract Whole organism or tissue profiling by vibrational spectroscopy produces vast amounts of seemingly

  14. High-Resolution Spectroscopic Studies of Reaction Intermediates Relevant to Atmospheric Chemistry

    NASA Astrophysics Data System (ADS)

    Endo, Yasuki

    2014-06-01

    We have been studying short lived reaction intermediates and complexes containing short lived species by high-resolution spectroscopic means. Laser induced fluorescence spectrosocpy with resolutions up to 0.02 wn is used for observations of electronic transitions, and Fourier-transform microwave (FTMW) spectroscopy and FTMW-mm-wave double resonance spectroscopy are used for observations of pure rotational spectra. Both of the methods are combined with supersonic jet sytems equipped with pulse discharge nozzles to produce short lived species. Last several years, we are concentrating on observations of short lived oxygen bearing species and their complexes especially with water. Such species are considred to be important in atmospheric chemistry, since chemistry in the earth's atmosphere mainly proceeds as oxidation reactions of trace species existing in the atmosphere, where various oxygen bearing reaction intermediates are playing important roles. Detections by high-resolution spectroscopy are expected to provide valuable information on these species. Furthermore, importance of molecular complexes containing reaction intermediates with water in atmospheric chemistry has been discussed recently, where detections of such species are highly required since quite limited experimental information has been obtained so far. In the talk, results of a number of such species, either monomers or complexes, studied recently in our laboratory will be reviewed.

  15. Spectroscopic study of humic acids fractionated by means of tangential ultrafiltration

    NASA Astrophysics Data System (ADS)

    Francioso, O.; Sánchez-Cortés, S.; Casarini, D.; Garcia-Ramos, J. V.; Ciavatta, C.; Gessa, C.

    2002-05-01

    Different chemical and spectroscopic techniques—diffuse reflectance infrared Fourier transform (DRIFT), surface-enhanced Raman spectroscopy (SERS), and 1H, 13C nuclear magnetic resonance (NMR) have been applied to investigate a peat humic acid (HA) separated by tangential ultrafiltration into different nominal molecular weight (NMW) fractions. Each fraction analyzed showed a characteristic DRIFT and NMR pattern. High nominal molecular weight fractions were mainly characterized by long chains of methyl and methylene groups and poorly substituted aromatic rings, while in low nominal molecular weight fractions (L-NMW), phenolic and oxygen-containing groups were predominant. A comparative study on fractions before and after treatment with 0.5 M HCl was carried out. Purified fractions showed either an increase in the carboxylate and phenolic OH groups or an improvement in signal-to-noise ratio of their NMR spectra. The SERS study of NMW fractions allowed significative information on structure and conformation of these fractions. In particular, L-NMW fractions showed a great structural modification, when different alkaline extractants or treatment with HCl were used. Humic-like substances obtained by catechol and gallic acid polymerization on metal surface were investigated using SERS. The SERS spectra of these polymers were compared and discussed with those of NMW HA fractions.

  16. MHD Spectroscopic Study of the Stabilizing Effect of Plasma Flow on the Resistive Wall Mode

    NASA Astrophysics Data System (ADS)

    Reimerdes, H.; Garofalo, A. M.; Navratil, G. A.; Chu, M. S.; Jackson, G. L.; Jensen, T. H.; La Haye, R. J.; Scoville, J. T.; Strait, E. J.; Edgell, D. H.; Jayakumar, R. J.; Okabayashi, M.

    2003-10-01

    MHD Spectroscopic Study of the Stabilizing Effect of Plasma Flow on the Resistive Wall Mode,* H. Reimerdes, A.M. Garofalo, G.A. Navratil, Columbia U, M.S. Chu, G.L. Jackson, T.H. Jensen, R.J. La Haye, J.T. Scoville, E.J. Strait, GA, D.H. Edgell, FAR-TECH, Inc., R.J. Jayakumar, LLNL, M. Okabayashi, PPPL - Resistive wall mode (RWM) stabilization by plasma rotation has been under study for the last decade. Dissipation caused by an interaction between the quasi-static magnetic perturbation and a near-sonic plasma flow alters the RWM stability [Bondeson, Phys. Rev. Lett. 72, 2709 (1994)]. To probe the RWM stability in DIII-D, we extend the technique of MHD spectroscopy, which was previously applied at frequencies above 10 kHz [Fasoli, et al., Phys. Rev. Lett. 75, 645 (1995)], to frequencies of a few Hz. Internal coils generate a rotating magnetic field, whose spatial structure largely overlaps with the RWM structure. The plasma response, measured as the perturbed field at the wall, is rigid and peaks when the external field rotates at a fraction of the inverse wall time in the direction of the plasma rotation, which is in good agreement with a single mode model [Garofalo, et al., Phys. Plasmas 9, 4573 (2002)]. This measurement is used to determine the contribution of the proposed dissipation mechanisms to the stabilization of the RWM.

  17. Scanning Tunnelling Spectroscopic Studies of Dirac Fermions in Graphene and Topological Insulators

    NASA Astrophysics Data System (ADS)

    Yeh, N.-C.; Teague, M. L.; Wu, R. T.-P.; Chu, H.; Boyd, D. A.; Bockrath, M. W.; He, L.; Xiu, F.-X.; Wang, K.-L.

    2012-03-01

    We report novel properties derived from scanning tunnelling spectroscopic (STS) studies of Dirac fermions in graphene and the surface state (SS) of a strong topological insulator (STI), Bi2Se3. For mono-layer graphene grown on Cu by chemical vapour deposition (CVD), strain-induced scalar and gauge potentials are manifested by the charging effects and the tunnelling conductance peaks at quantized energies, respectively. Additionally, spontaneous time-reversal symmetry breaking is evidenced by the alternating anti-localization and localization spectra associated with the zero-mode of two sublattices while global time-reversal symmetry is preserved under the presence of pseudo-magnetic fields. For Bi2Se3 epitaxial films grown on Si(111) by molecular beam epitaxy (MBE), spatially localized unitary impurity resonances with sensitive dependence on the energy difference between the Fermi level and the Dirac point are observed for samples thicker than 6 quintuple layers (QL). These findings are characteristic of the SS of a STI and are direct manifestation of strong topological protection against impurities. For samples thinner than 6-QL, STS studies reveal the openup of an energy gap in the SS due to overlaps of wave functions between the surface and interface layers. Additionally, spin-preserving quasiparticle interference wave-vectors are observed, which are consistent with the Rashba-like spin-orbit splitting.

  18. A spectroscopic and thermodynamic study of porphyrin/DNA supramolecular assemblies.

    PubMed Central

    Pasternack, R F; Goldsmith, J I; Szép, S; Gibbs, E J

    1998-01-01

    Assemblies of trans-bis(N-methylpyridinium-4-yl)diphenylporphine ions on the surface of calf thymus DNA have been studied using several spectroscopic techniques: absorbance, circular dichroism, and resonance light scattering. The aggregation equilibrium can be treated as a two-state system-monomer and assembly-each bound to the nucleic acid template. The aggregate absorption spectrum in the Soret region is resolved into two bands of Lorentzian line shape, while the DNA-bound monomer spectrum in this region is composed of two Gaussian bands. The Beer-Lambert law is obeyed by both porphyrin forms. The assembly is also characterized by an extremely large, bisignate induced circular dichroism (CD) profile and by enhanced resonance light scattering (RLS). Both the CD and RLS intensities depend linearly on aggregate concentration. The RLS result is consistent with a model for the aggregates as being either of a characteristic size or of a fixed distribution of sizes, independent of total porphyrin concentration or ionic strength. Above threshold values of concentration and ionic strength, the mass action expression for the equilibrium has a particularly simple form: K' = cac-1; where cac is defined as the "critical assembly concentration."offe dependence of the cac upon temperature and ionic strength (NaCl) has been investigated at a fixed DNA concentration. The value of the cac scales as the inverse square of the sodium chloride concentration and, from temperature dependence studies, the aggregation process is shown to be exothermic. PMID:9675203

  19. Characterizing the structure of lipodisq nanoparticles for membrane protein spectroscopic studies.

    PubMed

    Zhang, Rongfu; Sahu, Indra D; Liu, Lishan; Osatuke, Anna; Comer, Raven G; Dabney-Smith, Carole; Lorigan, Gary A

    2015-01-01

    Membrane protein spectroscopic studies are challenging due to the difficulty introduced in preparing homogenous and functional hydrophobic proteins incorporated into a lipid bilayer system. Traditional membrane mimics such as micelles or liposomes have proved to be powerful in solubilizing membrane proteins for biophysical studies, however, several drawbacks have limited their applications. Recently, a nanosized complex termed lipodisq nanoparticles was utilized as an alternative membrane mimic to overcome these caveats by providing a homogeneous lipid bilayer environment. Despite all the benefits that lipodisq nanoparticles could provide to enhance the biophysical studies of membrane proteins, structural characterization in different lipid compositions that closely mimic the native membrane environment is still lacking. In this study, the formation of lipodisq nanoparticles using different weight ratios of POPC/POPG lipids to SMA polymers was characterized via solid-state nuclear magnetic resonance (SSNMR) spectroscopy and dynamic light scattering (DLS). A critical weight ratio of (1/1.25) for the complete solubilization of POPC/POPG vesicles has been observed and POPC/POPG vesicles turned clear instantaneously upon the addition of the SMA polymer. The size of lipodisq nanoparticles formed from POPC/POPG lipids at this weight ratio of (1/1.25) was found to be about 30 nm in radius. We also showed that upon the complete solubilization of POPC/POPG vesicles by SMA polymers, the average size of the lipodisq nanoparticles is weight ratio dependent, when more SMA polymers were introduced, smaller lipodisq nanoparticles were obtained. The results of this study will be helpful for a variety of biophysical experiments when specific size of lipid disc is required. Further, this study will provide a proper path for researchers working on membrane proteins to obtain pertinent structure and dynamic information in a physiologically relevant membrane mimetic environment. PMID:24853657

  20. AN IMAGING AND SPECTROSCOPIC STUDY OF FOUR STRONG Mg II ABSORBERS REVEALED BY GRB 060418

    SciTech Connect

    Pollack, L. K.; Prochaska, J. X. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Chen, H.-W. [Department of Astronomy and Astrophysics and Kavli Institute for Cosmological Physics, University of Chicago, Chicago, IL 60637 (United States); Bloom, J. S. [Department of Astronomy, University of California, Berkeley, CA 94720-3411 (United States)], E-mail: hchen@oddjob.uchicago.edu

    2009-08-20

    We present results from an imaging and spectroscopic study of four strong Mg II absorbers of W(2796) {approx}> 1 A revealed by the afterglow of GRB 060418 at z{sub GRB} = 1.491. These absorbers, at z = 0.603, 0.656, 1.107, and z {sub GRB}, exhibit large ion abundances that suggest neutral gas columns characteristic of damped Ly{alpha} systems. The imaging data include optical images obtained using Low-Resolution Imaging Spectrometer (LRIS) on the Keck I telescope and using Advanced Camera for Surveys on board Hubble Space Telescope, and near-infrared H-band images obtained using Persson's Auxiliary Nasmyth Infrared Camera on the Magellan Baade Telescope and K'-band images obtained using NIRC2 with laser guide star adaptive optics on the Keck II telescope. These images reveal six distinct objects at {delta} {theta} {approx}< 3.''5 of the afterglow's position, two of which exhibit well-resolved mature disk morphology, one shows red colors, and three are blue compact sources. Follow-up spectroscopic observations using LRIS confirm that one of the disk galaxies coincides with the Mg II absorber at z = 0.656. The observed broadband spectral energy distributions of the second disk galaxy and the red source indicate that they are associated with the absorbers at z = 0.603 and z = 1.107, respectively. These results show that strong Mg II absorbers identified in gamma-ray burst (GRB) afterglow spectra are associated with typical galaxies of luminosity {approx}0.1 - 1 L{sub *} at impact parameter of {rho} {approx}< 10 h {sup -1} kpc. The close angular separation would preclude easy detections toward a bright quasar. Finally, we associate the remaining three blue compact sources with the GRB host galaxy, noting that they are likely star-forming knots located at projected distances of {rho} = 2 - 12 h {sup -1} kpc from the afterglow. At the afterglow's position, we derive a 2{sigma} upper limit to the underlying star-formation rate intensity of 0.0074 M{sub sun} yr{sup -1} kpc{sup -2}.

  1. Understanding ion sensing in Zn(II) porphyrins: spectroscopic and computational studies of nitrite/nitrate binding.

    PubMed

    Whittington, Christi L; Maza, William A; Woodcock, H Lee; Larsen, Randy W

    2012-04-16

    The development of effective sensor elements relies on the ability of a chromophore to bind an analyte selectively and then study the binding through changes in spectroscopic signals. In this report the ability of Zn(II) Tetraphenyl Porphyrin (ZnTPP) to selectively bind nitrite over nitrate ions is examined. The results of Benesi-Hildebrand analysis reveals that ZnTPP binds NO(2)(-) and NO(3)(-) ions with association constants of 739 ± 70 M(-1) and 134 ± 15 M(-1), respectively. Interestingly, addition of a pyridine ligand to the fifth coordination site of the Zn(II) center enhances ion binding with the association constants increasing to 71,300 ± 8,000 M(-1) and 18,900 ± 3,000 M(-1) for nitrite and nitrate, respectively. Density functional theory calculations suggest a binding mechanism through which Zn(II)-porphyrin interactions are disrupted by ligand and base coordination to Zn(II), with Zn(II) having more favorable overlap with nitrite orbitals, which are less delocalized than nitrate orbitals. Overall, these provide new insights into the ability to tune the affinity and selectivity of porphyrin based sensors utilizing electronic factors associated with the central Zn(II) ion. PMID:22480312

  2. Infrared Spectroscopic and Kinetic Studies of Molecular Ions and Hydrogen in Glow Discharges with a Difference Frequency Laser System

    Microsoft Academic Search

    Dairene Uy

    1996-01-01

    A difference frequency laser system has been used to study the fundamental molecular ions rm H_3^+, CH_3^+, C_2H_3^+, NH_2^+, O_2H^+, CH_5^+, and rm H_3O^+, and the H_2 molecule in positive column and hollow cathode glow discharges. The studies have been both infrared spectroscopic (2200-3600 cm ^{-1}) and kinetic in nature. It has been observed that using 100% parahydrogen instead of

  3. Hen egg white lysozyme fibrillation: a deep-UV resonance Raman spectroscopic study.

    PubMed

    Xu, Ming; Ermolenkov, Vladimir V; Uversky, Vladimir N; Lednev, Igor K

    2008-08-01

    Amyloid fibrils are associated with numerous degenerative diseases. The molecular mechanism of the structural transformation of native protein to the highly ordered cross-beta structure, the key feature of amyloid fibrils, is under active investigation. Conventional biophysical methods have limited application in addressing the problem because of the heterogeneous nature of the system. In this study, we demonstrated that deep-UV resonance Raman (DUVRR) spectroscopy in combination with circular dichroism (CD) and intrinsic tryptophan fluorescence allowed for quantitative characterization of protein structural evolution at all stages of hen egg white lysozyme fibrillation in vitro. DUVRR spectroscopy was found to be complimentary to the far-UV CD because it is (i) more sensitive to beta -sheet than to alpha -helix, and (ii) capable of characterizing quantitatively inhomogeneous and highly light-scattering samples. In addition, phenylalanine, a natural DUVRR spectroscopic biomarker of protein structural rearrangements, exhibited substantial changes in the Raman cross section of the 1000-cm(-1) band at various stages of fibrillation. PMID:19412971

  4. Atomically resolved spectroscopic study of Sr2IrO4: Experiment and theory

    PubMed Central

    Li, Qing; Cao, Guixin; Okamoto, Satoshi; Yi, Jieyu; Lin, Wenzhi; Sales, Brian C.; Yan, Jiaqiang; Arita, Ryotaro; Kuneš, Jan; Kozhevnikov, Anton V.; Eguiluz, Adolfo G.; Imada, Masatoshi; Gai, Zheng; Pan, Minghu; Mandrus, David G.

    2013-01-01

    Particularly in Sr2IrO4, the interplay between spin-orbit coupling, bandwidth and on-site Coulomb repulsion stabilizes a Jeff = 1/2 spin-orbital entangled insulating state at low temperatures. Whether this insulating phase is Mott- or Slater-type, has been under intense debate. We address this issue via spatially resolved imaging and spectroscopic studies of the Sr2IrO4 surface using scanning tunneling microscopy/spectroscopy (STM/S). STS results clearly illustrate the opening of an insulating gap (150 ~ 250?meV) below the Néel temperature (TN), in qualitative agreement with our density-functional theory (DFT) calculations. More importantly, the temperature dependence of the gap is qualitatively consistent with our DFT + dynamical mean field theory (DMFT) results, both showing a continuous transition from a gapped insulating ground state to a non-gap phase as temperatures approach TN. These results indicate a significant Slater character of gap formation, thus suggesting that Sr2IrO4 is a uniquely correlated system, where Slater and Mott-Hubbard-type behaviors coexist. PMID:24166292

  5. Spectroscopic Studies of Carotenoid-to-Bacteriochlorophyll Energy Transfer in LHRC Photosynthetic Complex from Roseiflexus castenholzii

    SciTech Connect

    Niedzwiedzki, Dariusz; Collins, Aaron M.; LaFountain, Amy M; Enriquez, Miriam M; Frank, Harry A; Blankenship, R. E.

    2010-01-01

    Carotenoids present in the photosynthetic light-harvesting reaction center (LHRC) complex from chlorosome lacking filamentous anoxygenic phototroph, Roseiflexus castenholzii were purified and characterized for their photochemical properties. The LHRC from anaerobically grown cells contains five different carotenoids, methoxy-keto-myxocoxanthin, ?-carotene, and its three derivatives, whereas the LHRC from aerobically grown cells contains only three carotenoid pigments with methoxy-keto-myxocoxanthin being the dominant one. The spectroscopic properties and dynamics of excited singlet states of the carotenoids were studied by steady-state absorption, fluorescence and ultrafast time-resolved optical spectroscopy in organic solvent and in the intact LHRC complex. Time-resolved transient absorption spectroscopy performed in the near-infrared (NIR) on purified carotenoids combined with steady-state absorption spectroscopy led to the precise determination of values of the energies of the S{sub 1}(2{sup 1}A{sub g}{sup ?}) excited state. Global and single wavelength fitting of the ultrafast spectral and temporal data sets of the carotenoids in solvents and in the LHRC revealed the pathways of de-excitation of the carotenoid excited states.

  6. (18O,>16O) Two-neutron transfer reactions for spectroscopic studies

    NASA Astrophysics Data System (ADS)

    Cavallaro, M.; Agodi, C.; Bond?, M.; Cappuzzello, F.; Carbone, D.; Cunsolo, A.; Foti, A.; De Napoli, M.; Nicolosi, D.; Tropea, S.; Lubian, J.; Garcia, V. N.; Paes, B.; Linares, R.; Borello-Lewin, T.; Rodrigues, M. R. D.

    2013-05-01

    A systematic study of the response of different nuclei to the (18O,16O) two-neutron transfer reaction at 84 MeV incident energy was pursued at the INFN-LNS in Catania (Italy).The experiments were performed using several solid targets from light (9Be, 11B, 12,13C, 16O, 28Si) to heavier ones (58,64Ni, 120Sn, 208Pb). The 16O ejectiles were detected at forward angles by the MAGNEX magnetic spectrometer and identified without the need of time of flight measurements. Exploiting the large momentum (? 25%) and angular (50 msr) acceptance of the spectrometer, energy spectra were obtained with a relevant yield up to about 20 MeV excitation energy.A common feature of the light nuclei spectra is the strong population of states with well known configuration of two-particle over a core and the appearance of unknown resonant structures in the continuum. These latter can reveal the excitation of a collective mode connected with the transfer of a pair.For the heavier nuclei as 66Ni a completely different behaviour is observed indicating the presence of more dissipative processes in the reaction mechanisms that hide the spectroscopic information.

  7. Chelerythrine-lysozyme interaction: spectroscopic studies, thermodynamics and molecular modeling exploration.

    PubMed

    Jash, Chandrima; Basu, Pritha; Payghan, Pavan V; Ghoshal, Nanda; Kumar, Gopinatha Suresh

    2015-07-01

    The binding of the iminium and alkanolamine forms of chelerythrine to lysozyme (Lyz) was investigated by spectroscopy and docking studies. The thermodynamics of the binding was studied by calorimetry. Spectroscopic evidence suggested that Trp-62 and Trp-63 in the ?-domain of the protein are closer to the binding site; moreover, the binding site was at a distance of 2.27 and 2.00 nm from the iminium and alkanolamine forms, respectively, according to the Forster theory of non-radiation energy transfer. The equilibrium binding constants for the iminium and alkanolamine forms at 298 K were evaluated to be 1.29 × 10(5) and 7.79 × 10(5) M(-1), respectively. The binding resulted in an alteration of the secondary structure of the protein with a distinct reduction of the helical organization. The binding of iminium was endothermic, involving electrostatic and hydrophobic interactions, while that of alkanolamine form was exothermic and dominated by hydrogen bonding interactions. Docking studies provided the atomistic details pertaining to the binding of both forms of chelerythrine and supported the higher binding in favour of the alkanolamine over the iminium. Furthermore, molecular dynamics study provided accurate insights regarding the binding of both chelerythrine forms in accordance with the experimental results obtained. Chelerythrine binding pocket involves the catalytic region and aggregation prone K-peptide region, which are sandwiched between one another. Overall, these results suggest that both the forms of the alkaloid bind to the protein but the neutral form has higher affinity than the cationic form. PMID:26041372

  8. Combined Mössbauer spectroscopic, multi-edge X-ray absorption spectroscopic, and density functional theoretical study of the radical SAM enzyme spore photoproduct lyase.

    PubMed

    Silver, Sunshine C; Gardenghi, David J; Naik, Sunil G; Shepard, Eric M; Huynh, Boi Hanh; Szilagyi, Robert K; Broderick, Joan B

    2014-03-01

    Spore photoproduct lyase (SPL), a member of the radical S-adenosyl-L-methionine (SAM) superfamily, catalyzes the direct reversal of the spore photoproduct, a thymine dimer specific to bacterial spores, to two thymines. SPL requires SAM and a redox-active [4Fe-4S] cluster for catalysis. Mössbauer analysis of anaerobically purified SPL indicates the presence of a mixture of cluster states with the majority (40 %) as [2Fe-2S](2+) clusters and a smaller amount (15 %) as [4Fe-4S](2+) clusters. On reduction, the cluster content changes to primarily (60 %) [4Fe-4S](+). The speciation information from Mössbauer data allowed us to deconvolute iron and sulfur K-edge X-ray absorption spectra to uncover electronic (X-ray absorption near-edge structure, XANES) and geometric (extended X-ray absorption fine structure, EXAFS) structural features of the Fe-S clusters, and their interactions with SAM. The iron K-edge EXAFS data provide evidence for elongation of a [2Fe-2S] rhomb of the [4Fe-4S] cluster on binding SAM on the basis of an Fe···Fe scatterer at 3.0 Å. The XANES spectra of reduced SPL in the absence and presence of SAM overlay one another, indicating that SAM is not undergoing reductive cleavage. The X-ray absorption spectroscopy data for SPL samples and data for model complexes from the literature allowed the deconvolution of contributions from [2Fe-2S] and [4Fe-4S] clusters to the sulfur K-edge XANES spectra. The analysis of pre-edge features revealed electronic changes in the Fe-S clusters as a function of the presence of SAM. The spectroscopic findings were further corroborated by density functional theory calculations that provided insights into structural and electronic perturbations that can be correlated by considering the role of SAM as a catalyst or substrate. PMID:24532333

  9. Spectroscopic analysis of pharmaceutical formulations through the use of chemometric tools

    NASA Astrophysics Data System (ADS)

    Ornelas-Soto, N.; Barbosa-García, O.; Meneses-Nava, M.; Ramos-Ortíz, G.; Pichardo-Molina, J.; Maldonado, J. L.; Contreras, U.; López-Martínez, L.; López-de-Alba, P.; López-Barajas, F.

    2009-09-01

    In this work, fast and reliable spectroscopic methods in combination with chemometric tools were developed for simultaneous determination of Acetylsalicylic Acid, Acetaminophen and Caffeine in commercial formulations. For the first-order multivariate calibration method (PLS-1), calibration and validation sets were constructed with 23 and 10 samples respectively according to a central composite design. The Micro-Raman, FTIR-HATR and UV absorption spectra in the region of 100-2000 cm-1, 400-4400 cm-1 and 200-350 nm, respectively, were recorded. The % REP's (Percentage of relative error of prediction) was less than 18 for all used spectroscopic techniques. Subsequently, commercial pharmaceutical samples were analyzed with percentage of recovery between 90 and 117% for the three compounds.

  10. Synthesis and spectroscopic characterization studies of low molecular weight light emitting PPV segmented copolymers

    NASA Astrophysics Data System (ADS)

    Ali, Basil; Jabar, Sattar; Salih, Whidad; Al Tamimi, Raed K.; Al Attar, Hameed; Monkman, Andy P.

    2009-12-01

    New tuneable segmented alternating copoly( p-phenylene vinylene) (PPV) derivatives were chemically synthesised via the Wittig polycondensation reaction. The chemical and optical properties in solution and in solid state were evaluated. The absorption and photoemission spectra show that incorporating an ethane dioxy spacer limits the conjugation length and produces a blue emitting copolymer, poly[1,2-ethane dioxy 2-methoxy-1,4-phenylene-vinyl 1,4-phenylene-vinyl 3-methoxy 1,4-phenylene] (EDO-PPV- 1) 1. A red shift in the copolymer emission was achieved by adding an electron-donating group, a hexoloxy-substituted PPV segment, poly[1,2-ethane dioxy 2-methoxy-1,4-phenylene-vinyl 2,5-dihexoloxy 1,4-phenylene-vinyl 3-methoxy 1,4-phenylene] (EDO-PPV- 2) 2. The photophysical properties of these block copolymers was compared with the fully conjugated copolymer poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) 3. The absorption band of the ? deloc- ?deloc? transition at 400-500 nm is limited in 1 and 2 indicating that the conjugation is effectively interrupted. The effect of torsional motions on the Stokes shift in these segmented copolymers is discussed. The photoluminescence (PL) efficiency and lifetime of 1 and 2 is different, indicating that the contribution from additional non-radiative decay channels due to interchain interactions is significant. The steady state and time-resolved photophysical characteristics of the thin film form of the copolymers indicates a high order of stacking in copolymer 1 and strong interchain interaction leading to strong excimer emission which may be ascribed to the low folding degree and planarity of the copolymers chemical structure. The spectroscopic time-resolved analysis confirms the interchain interaction.

  11. Analysis and optimization of thin film photovoltaic materials and device fabrication by real time spectroscopic ellipsometry

    Microsoft Academic Search

    Jian Li; Jason A. Stoke; Nikolas J. Podraza; Deepak Sainju; Anuja Parikh; Xinmin Cao; Himal Khatri; Nicolas Barreau; Sylvain Marsillac; Xunming Deng; Robert W. Collins

    2007-01-01

    Methods of spectroscopic ellipsometry (SE) have been applied to investigate the growth and properties of the material components used in the three major thin film photovoltaics technologies: (1) hydrogenated silicon (Si:H); (2) cadmium telluride (CdTe); and (3) copper indium-gallium diselenide (CuIn1-xGaxSe2 or CIGS). In Si:H technology, real time SE (RTSE) has been applied to establish deposition phase diagrams that describe

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

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

  13. Spectroscopic measurement and analysis of water and oil in transformer insulating paper

    Microsoft Academic Search

    Patrick J. Baird; Henryk Herman; Gary C. Stevens; Paul N. Jarman

    2006-01-01

    A portable fiber-optic spectroscopic system (TRANSPEC) has been developed for nondestructive measurement of aged transformer insulating paper. Following successful measurement of degree of polymerization (DP) of a range of transformer-aged paper samples, the system has now been shown to separate the oil and paper information for measurement of DP in oil-wetted paper samples. In addition, the system has been shown

  14. Line narrowing spectroscopic studies of DNA-carcinogen adducts and DNA-dye complexes

    SciTech Connect

    Suh, Myungkoo

    1995-12-06

    Laser-induced fluorescence line narrowing and non-line narrowing spectroscopic methods were applied to conformational studies of stable DNA adducts of the 7{beta}, 8{alpha}-dihydoxy-9{alpha}, l0{alpha}-epoxy-7,8,9, 10-tetrahydrobenzo[{alpha}]pyrene (anti-BPDE). Stereochemically distinct (+)-trans-, ({minus})-trans-, (+)-cis- and ({minus})-cis adducts of anti-BPDE bound to exocyclic amino group of the central guanine in an 11-mer oligonucleotide, exist in a mixture of conformations in frozen aqueous buffer matrices. The (+)-trans adduct adopts primarily an external conformation with a smaller fraction ( {approximately} 25 %) exists in a partially base-stacked conformation. Both cis adducts were found to be intercalated with significant {pi}-{pi} stacking interactions between the pyrenyl residues and the bases. Conformations of the trans-adduct of (+)-anti -BPDE in 11-mer oligonucleotides were studied as a function of flanking bases. In single stranded form the adduct at G{sub 2} or G{sub 3} (5 ft-flanking, base guanine) adopts a conformation with strong, interaction with the bases. In contrast, the adduct with a 5ft-flanking, thymine exists in a primarily helixexternal conformation. Similar differences were observed in the double stranded oligonucleotides. The nature of the 3ft-flanking base has little influence on the conformational equilibrium of the (+)-trans-anti BPDE-dG adduct. The formation and repair of BPDE-N{sup 2}-dG in DNA isolated from the skin of mice treated topically with benzo[{alpha}]pyrene (BP) was studied. Low-temperature fluorescence spectroscopy of the intact DNA identified the major adduct as (+)-trans-anti-BPDE-N-dG, and the minor adduct fraction consisted mainly of (+)-cis-anti-BPDE-N{sup 2}-dG.

  15. Synthetic, Spectroscopic and DFT Studies of Iron Complexes with Iminobenzo(semi)quinone Ligands: Implications for o-Aminophenol Dioxygenases

    PubMed Central

    Bittner, Michael M.; Kraus, David; Lindeman, Sergey V.; Popescu, Codrina V.; Fiedler, Adam T.

    2014-01-01

    The oxidative C-C bond cleavage of o-aminophenols by nonheme Fe dioxygenases is a critical step in both human metabolism (the kynurenine pathway) and the microbial degradation of nitroaromatic pollutants. The catalytic cycle of o-aminophenol dioxygenases (APDOs) has been proposed to involve formation of an Fe(II)/O2/iminobenzosemiquinone complex, although the presence of a substrate radical has been called into question by studies of related ring-cleaving dioxygenases. Recently, we reported the first synthesis of an iron(II) complex coordinated to an iminobenzosemiquinone (ISQ) ligand, namely, [Fe(Ph2Tp)(ISQtBu)] (2a; where Ph2Tp = hydrotris(3,5-diphenylpyrazol-1-yl)borate and ISQtBu is the radical anion derived from 2-amino-4,6-di-tert-butylphenol). In the current manuscript, density functional theory (DFT) calculations and a wide variety of spectroscopic methods (electronic absorption, Mössbauer, magnetic circular dichroism, and resonance Raman) were employed to obtain detailed electronic-structure descriptions of 2a and its one-electron oxidized derivative [3a]+. In addition, we describe the synthesis and characterization of a parallel series of complexes featuring the neutral supporting ligand tris(4,5-diphenyl-1-methylimidazol-2-yl)phosphine (Ph2TIP). The isomer shifts of ~0.97 mm/s obtained via Mössbauer experiments confirm that 2a (and its Ph2TIP-based analogue [2b]+) contain Fe(II) centers, and the presence of an ISQ radical was verified by analysis of the absorption spectra in light of time-dependent DFT calculations. The collective spectroscopic data indicate that one-electron oxidation of the Fe2+–ISQ complexes yields complexes ([3a]+ and [3b]2+) with electronic configurations between the Fe3+–ISQ and Fe2+–IBQ limits (IBQ = iminobenzoquinone), highlighting the ability of o-amidophenolates to access multiple oxidation states. The implications of these results for the mechanism of APDOs and other ring-cleaving dioxygenases are discussed. PMID:23744733

  16. Two-Pronged Approach to Overcome Spectroscopically Interfering Organic Compounds with Isotopic Water Analysis

    NASA Astrophysics Data System (ADS)

    Saad, Nabil; Hsiao, Gregor; Chapellet-Volpini, London; Vu, Danthu

    2013-04-01

    The ability to measure the stable isotopes of hydrogen (dD) and oxygen (d18O) has become much more accessible with the advent of Cavity Ring-Down Spectroscopy (CRDS) laser optical devices. These small and inexpensive analyzers have led to a significant increase in the acquisition of data from a variety of studies in the fields of groundwater, watershed, and other water source applications. However for some samples, such as those linked to fracking, mining, and other activities where higher than normal concentrations of organic materials are to be found, optical spectroscopy may require an adaptation from current methodologies in order to ensure data confidence. That is because CRDS is able to measure all the components within a spectral region - which will include the spectral characteristics of the isotopologues of water as well as the available features from interfering organic molecules. Although, at the first level, the information from the organic material provides spectral overlaps that can perturb the isotopic ratios, a more thorough review shows that these features are a source of information that will be inherently useful. This presentation will examine the approaches developed within the past year to allow for more accurate analyses of such samples by optical methods. The first approach uses an advanced spectroscopic model to flag the presence of organic material in the sample. Signals from known interfering compounds (i.e., alcohols, ketones, aldehydes, short-chain hydrocarbons, etc.) are incorporated into the overall fit of the measured spectra used to calculate the concentration of the individual isotopes. The second approach uses physical treatment of the sample to break down the organic molecules into non-interfering species. The vaporized liquid or solid sample travels through a cartridge packed with an oxidation catalyst. The interfering organic molecules will undergo high temperature oxidation using O2 present in the air carrier gas stream prior to isotopic measurement with CRDS. This approach is highly effective for organics at lower (< 5% v/v) concentrations and is promising to be extended to some higher concentration contamination as it was recently shown in our preliminary experiments.

  17. Simulation studies and spectroscopic measurements of a position sensitive detector based on pixelated CdTe crystals

    E-print Network

    Karafasoulis, K; Seferlis, S; Kaissas, I; Lambropoulos, C; Loukas, D; Potiriadis, C

    2010-01-01

    Simulation studies and spectroscopic measurements are presented regarding the development of a pixel multilayer CdTe detector under development in the context of the COCAE project. The instrument will be used for the localization and identification of radioactive sources and radioactively contaminated spots. For the localization task the Compton effect is exploited. The detector response under different radiation fields as well as the overall efficiency of the detector has been evaluated. Spectroscopic measurements have been performed to evaluate the energy resolution of the detector. The efficiency of the event reconstruction has been studied in a wide range of initial photon energies by exploiting the detector's angular resolution measure distribution. Furthermore, the ability of the COCAE detector to localize radioactive sources has been investigated.

  18. Simulation studies and spectroscopic measurements of a position sensitive detector based on pixelated CdTe crystals

    E-print Network

    K. Karafasoulis; K. Zachariadou; S. Seferlis; I. Kaissas; C. Lambropoulos; D. Loukas; C. Potiriadis

    2010-11-15

    Simulation studies and spectroscopic measurements are presented regarding the development of a pixel multilayer CdTe detector under development in the context of the COCAE project. The instrument will be used for the localization and identification of radioactive sources and radioactively contaminated spots. For the localization task the Compton effect is exploited. The detector response under different radiation fields as well as the overall efficiency of the detector has been evaluated. Spectroscopic measurements have been performed to evaluate the energy resolution of the detector. The efficiency of the event reconstruction has been studied in a wide range of initial photon energies by exploiting the detector's angular resolution measure distribution. Furthermore, the ability of the COCAE detector to localize radioactive sources has been investigated.

  19. Equilibrium, Kinetics, and Spectroscopic Studies of SF6 Hydrate in NaCl Electrolyte Solution.

    PubMed

    Seo, Youngrok; Moon, Donghyun; Lee, Changho; Park, Jeong-Woo; Kim, Byeong-Soo; Lee, Gang-Woo; Dotel, Pratik; Lee, Jong-Won; Cha, Minjun; Yoon, Ji-Ho

    2015-05-19

    Many studies have focused on desalination via hydrate formation; however, for their potential application, knowledge pertaining to thermodynamic stability, formation kinetics, and guest occupation behavior in clathrate hydrates needs to be determined. Herein, the phase equilibria of SF6 hydrates in the presence of NaCl solutions (0, 2, 4, and 10 wt %) were monitored in the temperature range of 277-286 K and under pressures of up to 1.4 MPa. The formation kinetics of SF6 hydrates in the presence of NaCl solutions (0, 2, and 4 wt %) was also investigated. Gas consumption curves of SF6 hydrates showed that a pure SF6 hydrate system allowed fast hydrate growth as well as high conversion yield, whereas SF6 hydrate in the presence of NaCl solutions showed retarded hydrate growth rate as well as low conversion yield. In addition, structural identification of SF6 hydrates with and without NaCl solutions was performed using spectroscopic tools such as Raman spectroscopy and X-ray diffraction. The Raman spectrometer was also used to evaluate the temperature-dependent release behavior of guest molecules in SF6 and SF6 + 4 wt % NaCl hydrates. The results indicate that whereas SF6 hydrate starts to decompose at around 240 K, the escape of SF6 molecules in SF6 + 4 wt % NaCl hydrate is initiated rapidly at around 205 K. The results of this study can provide a better understanding of guest-host interaction in electrolyte-containing systems. PMID:25893445

  20. FTIR Spectroscopic Analysis of Surface Oxidation Reactions During Ozonation of Fossil Resin and Coal

    Microsoft Academic Search

    Q. YU; K. BUKKA; Y. YE; J. D. MILLER

    1992-01-01

    Diffuse and specular reflectance FTIR analysis both fossil resin (resinite) and coal has been carried out to study surface oxidation reactions which occur during the selective flotation of fossil resin from coal by ozone conditioning. It was found from the FTIR spectra that ozonation of both fossil resin and coal causes an increase in the peak intensity associated with stretching

  1. Are matrix isolated species really “isolated”? Infrared spectroscopic and theoretical studies of noble gas-transition metal oxide complexes

    Microsoft Academic Search

    YanYing Zhao; MingFei Zhou

    2010-01-01

    In this review, we summarize our recent results on matrix isolation infrared spectroscopic studies and theoretical investigations\\u000a of noble gas-transition metal oxide complexes. The results show that some transition metal oxide species trapped in solid\\u000a noble gas matrices are chemically coordinated by one or multiple noble gas atoms forming noble gas complexes and, hence, cannot\\u000a be regarded as isolated species.

  2. Long path FTIR spectroscopic study of the reactions of CF3O radicals with ethane and propane

    Microsoft Academic Search

    J. Chen; T. Zhu; H. Niki; G. J. Mains

    1992-01-01

    A long path FTIR-based product study was carried out by the visible photolysis of mixtures containing CF3NO, NO and ethane or propane (in mtorr range) in 700 torr of synthetic air at 297 +\\/- 2 K. Kinetic and spectroscopic evidence has been obtained for the reaction (1), CF3O + RH yields CF3OH + R (RH = C2H6 or C3H8). Using

  3. Surface termination of BaTiO 3 (001) single crystals: A combined electron spectroscopic and theoretical study

    Microsoft Academic Search

    Andrea Berlich; Heiko Strauss; Christian Langheinrich; Angelika Chassé; Harald Morgner

    2011-01-01

    The surface termination of oxide surfaces is of crucial importance for the growth of a second material like metals or other oxides. In this study we have investigated the surface of a BaTiO3 (001) single crystal during sample preparation by various electron spectroscopic methods. It is shown by X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS) and metastable induced electron

  4. Spectroscopic and calorimetric studies on the interaction of human serum albumin with DPPC\\/PEG:2000-DPPE membranes

    Microsoft Academic Search

    Manuela Pantusa; Luigi Sportelli; Rosa Bartucci

    2008-01-01

    Site specific spectroscopic techniques and differential scanning calorimetry were used to study human serum albumin (HSA)\\u000a in the absence and in the presence of membranes composed of dipalmitoylphosphatidylcholine (DPPC) and poly(ethylene glycol:2000)-dipalmitoylphosphatidylethanolamine\\u000a (PEG:2000-DPPE). Electron spin resonance (ESR) of a maleimide spin-label (5-MSL) covalently bound to the free sulfhydryl group\\u000a at the unique cystein Cys-34 in domain I, intrinsic fluorescence of

  5. Reversible phase transformation of LaNiO3-x thin films studied in situ by spectroscopic ellipsometry

    Microsoft Academic Search

    Bruno Berini; Niels Keller; Yves Dumont; Elena Popova; Wafaa Noun; Marcel Guyot; Jacky Vigneron; Arnaud Etcheberry; Nuno Franco; Rui M. C. da Silva

    2007-01-01

    An in situ spectroscopic ellipsometry study has been performed to investigate LaNiO3-x phase transition associated with oxygenation and\\/or reduction reversible treatments. Epitaxial thin films of LaNiO3 were deposited onto SrTiO3 (001) substrates by pulsed laser deposition. Reduction of oxygen stoichiometry of these films under high vacuum, which leads to compound with the formula LaNiO3-x , is realized in the deposition

  6. Mössbauer and X-ray photoelectron spectroscopic studies of heat-treated calcium borate glasses containing iron

    Microsoft Academic Search

    M. J. Tricker; J. M. Thomas; M. H. Omar; A. Osman; A. Bishay

    1974-01-01

    57Fe Mössbauer and X-ray photoelectron spectroscopic studies have been carried out on a number of iron-containing calcium borate glasses which show large changes in d.c. conductivity upon annealing. The Mössbauer spectra of the unannealed glass samples are compatible with the presence of predominantly ferric iron in a six-co-ordinate oxygen environment. Upon annealing a partial ordering of the glassy phase is

  7. Spectroscopic study of transparent self-standing films of (3-glycidoxypropyl) trimethosysilane and (3-trimethoxysilylpropyl) ethylenediamine doped with europium complexes

    Microsoft Academic Search

    Robson F. de Farias; Severino Alves; Mônica F. Belian; Magda R. S. Vieira; Jucimar M. de Souza; Gilmara G. Pedrosa; Gilberto F. de Sá

    2003-01-01

    By using (3-glycidoxypropyl) trimethosysilane (GPTMS) and (3-trimethoxysilylpropyl) ethylenediamine (TSPED) as precursors, transparent self-standing films doped with the luminescent complexes Eu(hfc)3·bipy and Eu(hfc)3·terpy were prepared. The doped films were so studied from a spectroscopic point of view. It is verified that the film composition exerts effects on both, the intensity and lifetime of the emission process. For the GPTMS and TSPED

  8. Spectroscopic and quantum chemical study of the structure of a new paramagnetic dimeric palladium(II,III) complex with creatine

    NASA Astrophysics Data System (ADS)

    Mitewa, Mariana; Enchev, Venelin; Bakalova, Tatyana

    2002-05-01

    The structure and coordination mode of the newly synthesized dimeric paramagnetic Pd(II,III) complex are studied using magneto-chemical, EPR and IR spectroscopic methods. In order to perform reliable assignment of the IR bands, the structure and IR spectrum of the free creatine were calculated using ab initio method. For calculation of the configuration of its deprotonated and doubly deprotonated forms the semiempirical AM1 method was used.

  9. Native Corrinoids from Clostridium cochlearium Are Adeninylcobamides: Spectroscopic Analysis and Identification of Pseudovitamin B12 and Factor A

    PubMed Central

    Hoffmann, Bernd; Oberhuber, Michael; Stupperich, Erhard; Bothe, Harald; Buckel, Wolfgang; Konrat, Robert; Kräutler, Bernhard

    2000-01-01

    The corrinoids from the obligate anaerobe Clostridium cochlearium were extracted as a mixture of Co?-cyano derivatives. From 50 g of frozen cells, approximately 2 mg (1.5 ?mol) of B12 derivatives was obtained as a crystalline sample. Analysis of the corrinoid sample of C. cochlearium by a combination of high-pressure liquid chromatography and UV-Vis absorbance spectroscopy revealed the presence of three cyano corrinoids in a ratio of about 3:1:1. The spectroscopic data acquired for the sample indicated the main components to be pseudovitamin B12 (Co?-cyano-7"-adeninylcobamide) (60%) and factor A (Co?-cyano-7"-[2-methyl]adeninylcobamide) (20%). Authentic pseudovitamin B12 was prepared by guided biosynthesis from cobinamide and adenine. Both pseudovitamin B12 and its homologue, factor A, were subjected to complete spectroscopic analysis by UV-Vis, circular dichroism, mass spectrometry, and by one- and two-dimensional 1H, 13C-, and 15N nuclear magnetic resonance (NMR) spectroscopy. The third component was indicated by the mass spectra to be an isomer of factor A and is likely (according to NMR) to be 7"-[N6-methyl]-adeninylcobamide, a previously unknown corrinoid. C. cochlearium thus biosynthesizes as its native “complete” B12 cofactors the 7"-adeninylcobamides and two homologous corrinoids, in which the nucleotide base is a methylated adenine. PMID:10940017

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

    NASA Astrophysics Data System (ADS)

    Kim, Young-Dong

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

  11. Infrared spectroscopic study of C(2)F(6) monolayers and bilayers on graphite.

    PubMed

    Hopkins, Todd A; Boyd, David A; Xia, Yu; Shifflett, G Michael; Hess, Frank M; Hess, George B

    2008-04-21

    We report an experimental study of adsorbed films of C(2)F(6) on graphite by using infrared reflection absorption spectroscopy supplemented by ellipsometry. The vibrational C-F stretch modes nu(5) (parallel to the molecular axis) and nu(7) (perpendicular) in the film are strongly blueshifted by dynamic dipole coupling, and these shifts are sensitive to lattice spacing and molecular tilt. The relative strength of the absorption peaks mainly depends on the tilt angle relative to the surface normal. We use the strength data to estimate the tilt angle across the known monolayer phases, information that is difficult to obtain by other techniques. Although only the surface-normal component of the induced dipole moment appreciably couples to the external infrared field, surface-parallel components contribute to the intralayer coupling and hence to the frequency shifts for tilted molecules. Comparison to model calculations for a range of herringbone tilt configurations allows us to draw conclusions regarding the pattern of tilt azimuths. On this basis, we offer a revised interpretation of the origin of the Ising-type ordering transition found by Arndt et al. [Phys. Rev. Lett. 80, 1686 (1998)] in heat capacity measurements. Our phase boundaries for monolayer phases above 80 K are in good agreement with earlier results of the Saarbrucken group. We identify three distinct bilayer phases near saturation in isothermal pressure scans from ellipsometric steps and spectroscopic signatures. In temperature scans, we find evidence for several monolayer phases more dense than the well-established 2 x 2 commensurate phase and for a stable trilayer phase below about 60 K. PMID:18433265

  12. Infrared spectroscopic study of C2F6 monolayers and bilayers on graphite

    NASA Astrophysics Data System (ADS)

    Hopkins, Todd A.; Boyd, David A.; Xia, Yu; Shifflett, G. Michael; Hess, Frank M.; Hess, George B.

    2008-04-01

    We report an experimental study of adsorbed films of C2F6 on graphite by using infrared reflection absorption spectroscopy supplemented by ellipsometry. The vibrational C-F stretch modes ?5 (parallel to the molecular axis) and ?7 (perpendicular) in the film are strongly blueshifted by dynamic dipole coupling, and these shifts are sensitive to lattice spacing and molecular tilt. The relative strength of the absorption peaks mainly depends on the tilt angle relative to the surface normal. We use the strength data to estimate the tilt angle across the known monolayer phases, information that is difficult to obtain by other techniques. Although only the surface-normal component of the induced dipole moment appreciably couples to the external infrared field, surface-parallel components contribute to the intralayer coupling and hence to the frequency shifts for tilted molecules. Comparison to model calculations for a range of herringbone tilt configurations allows us to draw conclusions regarding the pattern of tilt azimuths. On this basis, we offer a revised interpretation of the origin of the Ising-type ordering transition found by Arndt et al. [Phys. Rev. Lett. 80, 1686 (1998)] in heat capacity measurements. Our phase boundaries for monolayer phases above 80K are in good agreement with earlier results of the Saarbrücken group. We identify three distinct bilayer phases near saturation in isothermal pressure scans from ellipsometric steps and spectroscopic signatures. In temperature scans, we find evidence for several monolayer phases more dense than the well-established 2×2 commensurate phase and for a stable trilayer phase below about 60K.

  13. Spectroscopic studies of the corrinoid/iron-sulfur protein from Moorella thermoacetica.

    PubMed

    Stich, Troy A; Seravalli, Javier; Venkateshrao, Swarnalatha; Spiro, Thomas G; Ragsdale, Stephen W; Brunold, Thomas C

    2006-04-19

    Methyl transfer reactions are important in a number of biochemical pathways. An important class of methyltransferases uses the cobalt cofactor cobalamin, which receives a methyl group from an appropriate methyl donor protein to form an intermediate organometallic methyl-Co bond that subsequently is cleaved by a methyl acceptor. Control of the axial ligation state of cobalamin influences both the mode (i.e., homolytic vs heterolytic) and the rate of Co-C bond cleavage. Here we have studied the axial ligation of a corrinoid iron-sulfur protein (CFeSP) that plays a key role in energy generation and cell carbon synthesis by anaerobic microbes, such as methanogenic archaea and acetogenic bacteria. This protein accepts a methyl group from methyltetrahydrofolate forming Me-Co(3+)CFeSP that then donates a methyl cation (Me) from Me-Co(3+)CFeSP to a nickel site on acetyl-CoA synthase. To unambiguously establish the binding scheme of the corrinoid cofactor in the CFeSP, we have combined resonance Raman, magnetic circular dichroism, and EPR spectroscopic methods with computational chemistry. Our results clearly demonstrate that the Me-Co3+ and Co2+ states of the CFeSP have an axial water ligand like the free MeCbi+ and Co(2+)Cbi+ cofactors; however, the Co-OH2 bond length is lengthened by about 0.2 angstroms for the protein-bound cofactor. Elongation of the Co-OH2 bond of the CFeSP-bound cofactor is proposed to make the cobalt center more "Co1+-like", a requirement to facilitate heterolytic Co-C bond cleavage. PMID:16608335

  14. Raman Spectroscopic Study Of The Dehydration Of Sulfates Using An Acoustic Levitator

    NASA Astrophysics Data System (ADS)

    Brotton, Stephen; Kaiser, R.

    2012-10-01

    The martian orbiters, landers, and rovers identified water-bearing sulfates on the martian surface. Furthermore, the Galileo mission suggests that hydrated salts such as magnesium sulfate are present on the surface of Europa and Ganymede. To understand the hydrologic history of Mars and some of Jupiter’s and Saturn’s moons, future missions need to identify in situ the hydration states of sulfates including magnesium sulfate (MgSO4 • nH2O n = 7, 6, . . ., 0), gypsum (CaSO4 • 2H2O), bassanite (CaSO4 • 0.5H2O) and anhydrite (CaSO4). Raman spectroscopy is ideally suited for this purpose, since the Raman spectrum for each different degree of hydration is unique. To obtain laboratory Raman spectra for comparison with the in situ measurements, we have developed a novel apparatus combining an acoustic levitator and a pressure-compatible process chamber. Particles with diameters between 10 µm and a few mm can be levitated at the pressure nodes of the ultrasonic standing wave. The chamber is interfaced to complimentary FTIR and Raman spectroscopic probes to characterize any chemical and physical modifications of the levitated particles. The particles can be heated to well-defined temperatures between 300 K and 1000 K using a carbon dioxide laser; the temperature of the particle will be probed via its black-body spectrum. The present apparatus enables (i) the production of high particle temperatures, (ii) precise measurement of the temperature, and (iii) accurate control of the environmental conditions (gas pressure and composition) within the chamber. Using this apparatus, we have studied the dehydration of sulfates including gypsum and epsomite (MgSO4 • 7H2O) in an anhydrous nitrogen atmosphere. We will present spectra showing the variation of the Raman spectra as gypsum, for example, is dehydrated to form anhydrite.

  15. Spectroscopic studies of molecular iodine emitted into the gas phase by seaweed

    NASA Astrophysics Data System (ADS)

    Ball, S. M.; Hollingsworth, A. M.; Humbles, J.; Leblanc, C.; Potin, P.; McFiggans, G.

    2009-12-01

    Time profiles of molecular iodine emissions from seven species of seaweed have been measured at high time resolution (7.5 s) by direct spectroscopic quantification of the gas phase I2 using broadband cavity enhanced absorption spectroscopy. Substantial differences were found between species, both in the amounts of I2 emitted when the plants were exposed to air and in the shapes of their emission time profiles. Two species of kelp, Laminaria digitata and Laminaria hyperborea, were found to be the most potent emitters, producing an intense burst of I2 when first exposed to air. I2 was also observed from Saccharina latissima and Ascophyllum nodosum but in lower amounts and with broader time profiles. I2 mixing ratios from two Fucus species and Dictyopteris membranacea were at or below the detection limit of the present instrument (25 pptv). A further set of experiments investigated the time dependence of I2 emissions and aerosol particle formation when fragments of L. digitata were exposed to desiccation in air, to ozone and to oligoguluronate stress factors. Particle formation occurred in all L. digitata stress experiments where ozone and light were present, subject to the I2 mixing ratios being above certain threshold amounts. Moreover, the particle number concentrations closely tracked variations in the I2 mixing ratios, confirming the results of previous studies that the condensable particle-forming gases derive from the photochemical oxidation of the plant's I2 emissions. This work also supports the theory that particle nucleation in the coastal atmosphere occurs in "hot-spot" regions of locally elevated concentrations of condensable gases: the greatest atmospheric concentrations of I2 and hence of condensable iodine oxides are likely to be above plants of the most efficiently emitting kelp species and localised in time to shortly after these seaweeds are uncovered by a receding tide.

  16. Spectroscopic studies of molecular iodine emitted into the gas phase by seaweed

    NASA Astrophysics Data System (ADS)

    Ball, S. M.; Hollingsworth, A. M.; Humbles, J.; Leblanc, C.; Potin, P.; McFiggans, G.

    2010-07-01

    Time profiles of molecular iodine emissions from seven species of seaweed have been measured at high time resolution (7.5 s) by direct spectroscopic quantification of the gas phase I2 using broadband cavity enhanced absorption spectroscopy. Substantial differences were found between species, both in the amounts of I2 emitted when the plants were exposed to air and in the shapes of their emission time profiles. Two species of kelp, Laminaria digitata and Laminaria hyperborea, were found to be the most potent emitters, producing an intense burst of I2 when first exposed to air. I2 was also observed from Saccharina latissima and Ascophyllum nodosum but in lower amounts and with broader time profiles. I2 mixing ratios from two Fucus species and Dictyopteris membranacea were at or below the detection limit of the present instrument (25 pptv). A further set of experiments investigated the time dependence of I2 emissions and aerosol particle formation when fragments of L. digitata were exposed to desiccation in air, to ozone and to oligoguluronate stress factors. Particle formation occurred in all L. digitata stress experiments where ozone and light were present, subject to the I2 mixing ratios being above certain threshold amounts. Moreover, the particle number concentrations closely tracked variations in the I2 mixing ratios, confirming the results of previous studies that the condensable particle-forming gases derive from the photochemical oxidation of the plant's I2 emissions. This work also supports the theory that particle nucleation in the coastal atmosphere occurs in "hot-spot" regions of locally elevated concentrations of condensable gases: the greatest atmospheric concentrations of I2 and hence of condensable iodine oxides are likely to be above plants of the most efficiently emitting kelp species and localised in time to shortly after these seaweeds are uncovered by a receding tide.

  17. Speciation of Heptavalent Technetium in Sulfuric Acid: Structural and Spectroscopic Studies.

    SciTech Connect

    Poineau, Frederic; Weck, Philippe F.; German, Konstantin; Maruk, Alesya; Kirakosyan, Gayane; Lukens, Wayne; Rego, Daniel B.; Sattelberger, Alfred P.; Czerwinski, Kenneth R.

    2010-06-10

    The speciation of Tc(VII) in 12 M sulfuric acid was studied by NMR, UV-visible and XAFS spectroscopy, experimental results were supported by DFT calculation and were in agreement with the formation of TcO{sub 3}OH(H{sub 2}O){sub 2}. In summary, the speciation of heptvalent technetium has been investigated in sulfuric acid. In 12 M H{sub 2}SO{sub 4}, a yellow solution is observed, and its {sup 99}Tc NMR spectrum is consistent with a heptavalent complex. The yellow solution was further characterized by EXAFS spectroscopy, and results are consistent with the formation of TcO{sub 3}(OH)(H{sub 2}O){sub 2}. No technetium heptoxide or sulfato- complexes were detected in these conditions. The molecular structure of TcO{sub 3}(OH)(H{sub 2}O){sub 2} has been optimized by DFT techniques, and the structural parameters are well in accordance with those found by XAFS spectroscopy. The experimental electronic spectra exhibit ligand-to-metal charge transfer transitions that have been assigned using TDDFT methods. Calculations demonstrate the theoretical electronic spectrum of TcO{sub 3}(OH)(H{sub 2}O){sub 2} to be in very good agreement with the experimental one. Recent experiments in 12 M H{sub 2}SO{sub 4} show the yellow solution to be very reactive in presence of reducing agents presumably forming low valent Tc species. Current spectroscopic works focus on the speciation of these species.

  18. Thermodynamic and Spectroscopic Studies of Lanthanides(III) Complexation with Polyamines in Dimethyl Sulfoxide

    SciTech Connect

    Di Bernardo, Plinio; Zanonato, Pier Luigi; Melchior, Andrea; Portanova, Roberto; Tolazzi, Marilena; Choppin, Gregory R.; Wang, Zheming

    2008-02-04

    The thermodynamic parameters of complexation of Ln(III) cations with tris(2-aminoethyl)amine (tren) and tetraethylenepentamine (tetren) were determined in dimethyl sulfoxide (DMSO) by potentiometry and calorimetry. The excitation and emission spectra and luminescence decay constants of Eu3+ and Tb3+ complexed by tren and tetren, as well as those of the same lanthanides(III) complexed with diethylenetriamine (dien) and triethylenetetramine (trien), were also obtained in the same solvent. The combination of thermodynamic and spectroscopic data showed that, in the 1:1 complexes, all nitrogens of the ligands bound to the lanthanides except in the case of tren, in which only pendant N bound. For the larger ligands (trien, tren, tetren) in the higher complexes (ML2), there was less complete binding by available donors, presumably due to steric crowding. FT-IR studies were carried out in an acetonitrile/DMSO mixture, suitably chosen in order to follow the changes in the primary solvation sphere of lanthanide(III) due to complexation of amine ligands. Results show that the mean number of molecules of DMSO removed from the inner coordination sphere of lanthanides(III) is lower than ligand denticity and that the coordination number of the metal ions increases with amine complexation from ?8 to ?10. Independently of the number and structure of the amines, linear trends, similar for all lanthanides, were obtained by plotting the values of *Gj°, *Hj° and T*Sj° for the complexation of ethylenediamine (en), dien, trien, tren and tetren as a function of the number of amine metal-coordinated nitrogen atoms. The main factors on which the thermodynamic functions of lanthanide(III) complexation reactions in DMSO depend are discussed.

  19. Thermodynamic and spectroscopic studies of lanthanides(III) complexation with polyamines in dimethyl sulfoxide.

    PubMed

    Di Bernardo, P; Zanonato, P L; Melchior, A; Portanova, R; Tolazzi, M; Choppin, G R; Wang, Z

    2008-02-01

    The thermodynamic parameters of complexation of Ln(III) cations with tris(2-aminoethyl)amine (tren) and tetraethylenepentamine (tetren) were determined in dimethyl sulfoxide (DMSO) by potentiometry and calorimetry. The excitation and emission spectra and luminescence decay constants of Eu3+ and Tb3+ complexed by tren and tetren, as well as those of the same lanthanides(III) complexed with diethylenetriamine (dien) and triethylenetetramine (trien), were also obtained in the same solvent. The combination of thermodynamic and spectroscopic data showed that, in the 1:1 complexes, all nitrogens of the ligands are bound to the lanthanides except in the case of tren, in which the pendant N is bound. For the larger ligands (trien, tren, tetren) in the higher complexes (ML2), there was less complete binding by available donors, presumably due to steric crowding. FT-IR studies were carried out in an acetonitrile/DMSO mixture, suitably chosen to follow the changes in the primary solvation sphere of lanthanide(III) due to complexation of amine groups. Results show that the mean number of molecules of DMSO removed from the inner coordination sphere of lanthanides(III) is lower than ligand denticity and that the coordination number of the metal ions increases with amine complexation from approximately 8 to approximately 10. Independently of the number and structure of the amines, linear trends, similar for all lanthanides, were obtained by plotting the values of DeltaGj degrees, DeltaHj degrees, and TDeltaSj degrees for the complexation of ethylenediamine (en), dien, trien, tren, and tetren as a function of the number of amine metal-coordinated nitrogen atoms. The main factors on which the thermodynamic functions of lanthanide(III) complexation reactions in DMSO depend are discussed. PMID:18166040

  20. Spectroscopic studies of Cu (II) complexes with an insect kinin analog

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potentiometric and spectroscopic data, including CD and EPR results, as well as theoretical calculations have shown that the insertion of (2R,4R)-4-aminopyroglutamate (apy), a novel cis-peptide bond mimic, in the insect kinin peptide, Ac-Arg-Phe-apy-Trp-Gly-NH2 leads to a very effective chelating ag...

  1. Application and New Developments in Fluorescence Spectroscopic Techniques in Studying Individual Molecules

    Microsoft Academic Search

    Digambara Patra

    2008-01-01

    Techniques based on fluorescence have played a variety of roles in chemistry, physics, spectroscopy, medicine, nanotechnology, and biotechnology due to their high selectivity, sensitivity, simplicity, and fastness in spectroscopic and imaging measurements. While detecting fluorescence from individual molecules by fluorescence?based techniques, poor signal, limited lifespan of fluorophores, trade?off between time resolution, and the level of detail of information were few

  2. Molecular conformational stability and Spectroscopic analysis of Parared with experimental techniques and quantum chemical calculations

    NASA Astrophysics Data System (ADS)

    Srinivasaraghavan, R.; Thamaraikannan, S.; Seshadri, S.; Gnanasambandan, T.

    2015-02-01

    The complete vibrational assignment and analysis of the fundamental modes of Parared was carried out using the experimental FTIR and FT-Raman data and quantum chemical studies. The observed vibrational data were compared with the wavenumbers derived theoretically from the optimized geometry of the compound from the DFT-B3LYP gradient calculations employing 6-31G(d,p) and 6-311++G(d,p) basis sets. Thermodynamic properties like entropy, heat capacity and enthalpy have been calculated for the molecule. HOMO-LUMO energy gap has been calculated. The intramolecular contacts have been interpreted using natural bond orbital (NBO) and natural localized molecular orbital (NLMO) analysis. Important non-linear properties such as electric dipole moment and first hyperpolarizability of Parared have been computed using B3LYP quantum chemical calculations. Finally, the Mulliken population analysis on atomic charges of the title compound has been calculated.

  3. Spectroscopic Observations

    NSDL National Science Digital Library

    This is a series of three activities about light and spectra. First, learners will construct their own spectroscope, observe common light sources, record the observed spectra, and compare their findings. Next, learners will use their spectroscopes to observe the spectra from different gas tubes and compare each observed spectrum to known spectra. Finally, they will observe a solar spectrum created by a prism, view a solar spectrum on paper, and attempt to determine the elements present in the Sun. This activity requires spectroscope posters and gratings available from the Stanford Solar Center (http://solar-center.stanford.edu/posters/), fluorescent and incandescent light sources, and emission lamps and power sources. This activity is from the Stanford Solar Center's All About the Sun: Sun and Stars activity guide for Grades 5-8 and can also accompany the Stanford Solar Center's Build Your Own Spectroscope activity.

  4. Purged window apparatus. [On-line spectroscopic analysis of gas flow systems

    DOEpatents

    Ballard, E.O.

    1982-04-05

    A purged window apparatus is described which utilizes tangentially injected heated purge gases in the vicinity of electromagnetic radiation transmitting windows and a tapered external mounting tube to accelerate these gases to provide a vortex flow on the window surface and a turbulent flow throughout the mounting tube thereby preventing backstreaming of flowing gases under investigation in a chamber to which a plurality of similar purged apparatus is attached with the consequent result that spectroscopic analyses can be undertaken for lengthy periods without the necessity of interrupting the flow for cleaning or replacing the windows due to contamination.

  5. Electrochemical and spectroscopic studies of some less stable oxidation states of selected lanthanide and actinide elements

    SciTech Connect

    Hobart, D. E.

    1981-06-01

    Simultaneous observation of electrochemical and spectroscopic properties (spectroelectrochemistry) at optically transparent electrodes (OTE's) was used to study some less stable oxidation states of selected lanthanide and actinide elements. Cyclic voltammetry at microelectrodes was used in conjunction with spectroelectrochemistry for the study of redox couples. Additional analytical techniques were used. The formal reduction potential (E/sup 0/') values of the M(III)/M(II) redox couples in 1 M KCl at pH 6 were -0.34 +- 0.01 V for Eu, -1.18 +- 0.01 V for Yb, and -1.50 +- 0.01 V for Sm. Spectropotentiostatic determination of E/sup 0/' for the Eu(III)/Eu(II) redox couple yielded a value of -0.391 +- 0.005 V. Spectropotentiostatic measurement of the Ce(IV)/Ce(III) redox couple in concentrated carbonate solution gave E/sup 0/' equal to 0.051 +- 0.005 V, which is about 1.7 V less positive than the E/sup 0/' value in noncomplexing solution. This same difference in potential was observed for the E/sup 0/' values of the Pr(IV)/Pr(III) and Tb(IV)/Tb(III) redox couples in carbonate solution, and thus Pr(IV) and Tb(IV) were stabilized in this medium. The U(VI)/U(V)/U(IV) and U(IV)/U(III) redox couples were studied in 1 M KCl at OTE's. Spectropotentiostatic measurement of the Np(VI)/Np(V) redox couple in 1 M HClO/sub 4/ gave an E/sup 0/' value of 1.140 +- 0.005 V. An E/sup 0/' value of 0.46 +- 0.01 V for the Np(VII)/Np(VI) couple was found by voltammetry. Oxidation of Am(III) was studied in concentrated carbonate solution, and a reversible cyclic voltammogram for the Am(IV)/Am(III) couple yielded E/sup 0/' = 0.92 +- 0.01 V in this medium; this value was used to estimate the standard reduction potential (E/sup 0/) of the couple as 2.62 +- 0.01 V. Attempts to oxidize Cm(III) in concentrated carbonate solution were not successful which suggests that the predicted E/sup 0/ value for the Cm(IV)/Cm(III) redox couple may be in error.

  6. Oxasqualenoids from Laurencia viridis: Combined Spectroscopic-Computational Analysis and Antifouling Potential.

    PubMed

    Cen-Pacheco, Francisco; Santiago-Benítez, Adrián J; García, Celina; Álvarez-Méndez, Sergio J; Martín-Rodríguez, Alberto J; Norte, Manuel; Martín, Victor S; Gavín, José A; Fernández, José J; Daranas, Antonio Hernández

    2015-04-24

    The chemical study of the red alga Laurencia viridis has led to the isolation of four new polyether triterpenoids: 28-hydroxysaiyacenol B (2), saiyacenol C (3), 15,16-epoxythyrsiferol A (4), and 15,16-epoxythyrsiferol B (5). The structures of 2 and 3 were established mainly by NMR data analysis and comparison with the well-known metabolite dehydrothyrsiferol (1). However, due to the existence of a nonprotonated carbon within the epoxide functionality, stereochemical assignments in 4 and 5 required an in-depth structural study that included NOESY data, J-based configuration analysis, comparison with synthetic models, and DFT calculations. The biological activities of the new metabolites and other related oxasqualenoids were evaluated for the first time against a panel of relevant biofouling marine organisms, and structure-activity conclusions were obtained. PMID:25781558

  7. [Spectroscopic and dynamical studies of highly energized small polyatomic molecules]. Technical progress report, February 1, 1990--June 30, 1992

    SciTech Connect

    Not Available

    1992-12-31

    Stimulated emission pumping (SEP) spectroscopy was used on acetylene and on formyl radical. An attempt was made for pattern recognition based on statistics; a method was invented that combined CNPI (complete nuclear permutation-inversion) group theory and SCC (spectral cross-correlation). But the direction away from statistical pattern recognition back to traditional spectroscopic pattern recognition was taken. Vibrational states and quantum numbers are discussed. For the formyl radical, the fluorescence excitation spectrum was recorded and a rotational analysis of the 0{sup 0}{sub 0} band performed.

  8. Vibrational spectroscopic study of the contents of a chest excavated from the wreck of the HMS Pandora.

    PubMed

    Edwards, H G M; Farwell, D W; Lee, J S; Fredericks, P M

    2003-08-01

    The FT-IR and Raman spectroscopic analysis of a red powder found in a chest from an officer's cabin during the excavation of the wreck of the 18th Century frigate HMS Pandora have confirmed that the pigment is cinnabar, mercury(II) sulphide. Weaker signals in the Raman spectrum are assignable to a proteinaceous material, such as collagen, typical of a degraded vellum or parchment. Comparison of the Raman spectra with that of a pigmented seal from a 1786 Lieutenant's commission demonstrated that the beeswax component of the seal was not observable. PMID:12909144

  9. Vibrational spectroscopic study of the contents of a chest excavated from the wreck of the HMS Pandora

    NASA Astrophysics Data System (ADS)

    Edwards, H. G. M.; Farwell, D. W.; Lee, J. S.; Fredericks, P. M.

    2003-08-01

    The FT-IR and Raman spectroscopic analysis of a red powder found in a chest from an officer's cabin during the excavation of the wreck of the 18th Century frigate HMS Pandora have confirmed that the pigment is cinnabar, mercury(II) sulphide. Weaker signals in the Raman spectrum are assignable to a proteinaceous material, such as collagen, typical of a degraded vellum or parchment. Comparison of the Raman spectra with that of a pigmented seal from a 1786 Lieutenant's commission demonstrated that the beeswax component of the seal was not observable.

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

    SciTech Connect

    Sawyer, Karma Rae

    2008-12-12

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

  11. New 1,2,4-triazole-based azo-azomethine dyes. Part I: Synthesis, characterization and spectroscopic studies

    NASA Astrophysics Data System (ADS)

    Khanmohammadi, Hamid; Erfantalab, Malihe

    2012-02-01

    Four new 1,2,4-triazole-based azo-azomethine dyes were synthesized via condensation of 3,5-diamino-1,2,4-triazole with azo-coupled o-vanillin precursors. The prepared dyes were characterized by IR, UV-vis and 1H NMR spectroscopic methods as well as elemental analyses. Thermal properties of the prepared dyes were examined by thermogravimetric analysis. Results indicated that the framework of the dyes was stable up to 225 °C. Also, the influence of various factors including time and mixed DMSO/EtOH solution on UV-vis spectra of the dyes were investigated.

  12. Covalent dyads of porphyrin-fullerene and perylene-fullerene for organic photovoltaics: Spectroscopic and photocurrent studies

    NASA Astrophysics Data System (ADS)

    Wróbel, Danuta; Lewandowska, Kornelia

    2011-07-01

    Supermolecular complexes of zinc porphyrin or perylenediimide as covalent dyads with fullerene (C 60) in chloroform and as Langmuir-Blodgett layers on an Au substrate were studied. In our studies we have used following spectroscopic methods: electronic absorption, fluorescence and electron spin resonance in solution. Also infrared absorption spectra in a KBr pellet and reflectance-absorption in Langmuir-Blodgett layers were monitored. Photocurrent generation in a photoelectrochemical cell was also studied. The redistribution of charge both upon porphyrin linkage to C 60 and when the systems are deposited on the Au substrate was shown. Photocurrent examinations show a great influence of the fullerene presence on photoresponse of the systems.

  13. Raman spectroscopic study of the photoprotection of extremophilic microbes against ultraviolet radiation

    NASA Astrophysics Data System (ADS)

    Edwards, H. G. M.; Moeller, R.; Jorge Villar, S. E.; Horneck, G.; Stackebrandt, E.

    2006-12-01

    Extremophiles use a range of pigments for protection against low-wavelength radiation in exposed terrestrial habitats and photoaccessory materials are synthesized for the effective harnessing of photosynthetically active radiation. Raman spectroscopy has been demonstrated to be a useful probe for information on the survival strategies employed by extremophilic bacteria through the identification of key biomolecular signatures of the suite of protective chemicals synthesized by the organisms in stressed environments. Raman spectroscopic analyses of Bacillus spp. spores, Bacillus atrophaeus (DSM 675: deep red) and Bacillus subtilis (DSM 5611: light grey and DSM 7264: dark grey), Deinococcus radiodurans (pink) and Natronomonas pharaonis (red), of visually different pigmentation showed the presence of different carotenoids and other protectant biomolecules, which assist microorganisms against UVA radiation. The implications for the survival of extremophilic microbes in extraterrestrial habitats and for the detection of the protectant biomolecules by remote, robotic Raman spectroscopic instrumentation in an astrobiological search for life context are discussed.

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

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

  15. Highly aromatic character of biogeomacromolecules in Chitinozoa: A spectroscopic and pyrolytic study

    Microsoft Academic Search

    Suryendu Dutta; Rainer Brocke; Christoph Hartkopf-Fröder; Ralf Littke; Heinz Wilkes; Ulrich Mann

    2007-01-01

    Extraordinarily well-preserved chitinozoans from an Upper Silurian sedimentary sequence in south-east Turkey were recovered from different depth levels, hand-picked from the palynological residue, cleaned and analysed by micro-FTIR and Curie point pyrolysis-gas chromatography–mass spectrometry. Hand-picked chitinozoans were predominantly represented by the genera Bursachitina, Calpichitina, Cingulochitina, Ancyrochitina, Angochitina and Pterochitina. Both spectroscopic and pyrolytic investigations suggest that biogeomacromolecules of these Chitinozoa

  16. In situ Raman spectroscopic studies of the teeth of the chiton Acanthopleura hirtosa

    Microsoft Academic Search

    Alasdair P. Lee; John Webb; D. J. Macey; Wilhelm van Bronswijk; Angela R. Savarese; G. Charmaine de Witt

    1998-01-01

    In situ Raman spectroscopy, in combination with energy dispersive spectroscopy, has been used for the first time to determine\\u000a the identities and locations, at the micron level, of mineral phases present in single chiton teeth that have been extensively\\u000a mineralized. At the later stages of development the major lateral teeth of the chiton Acanthopleura hirtosa show characteristic spectroscopic evidence for

  17. Raman spectroscopic study on the behavior of boric acid in wood

    Microsoft Academic Search

    Shigeru Yamauchi; Shuichi Doi

    2003-01-01

    Raman spectra of Japanese cedar (Cryptomeria japonica D. Don) treated by vacuum impregnation with aqueous boric acid solutions (8.1 × 10?2 to 7.29 × 10?1?mol?dm?3) were recorded using a near-infrared laser as an excitation source. Raman spectroscopic measurements were carried out on\\u000a treated wood blocks of two sizes: 20(T) × 20(R) × 5(L) mm (A-type) and 15(T) × 15(R) ×

  18. IR spectroscopic study of the interaction of type Y zeolites with Fe(CO)/sub 5/

    SciTech Connect

    Lapidus, A.L.; Sominskii, S.D.; Savel'ev, M.M.; Muranova, L.M.; Borisovich, I.G.; Vasserberg, V.E.

    1987-08-01

    IR spectroscopic investigation has shown that polynuclear iron carbonyl complexes, which are formed upon adsorption of Fe(CO)/sub 5/ on type Y zeolites (Li/sup +/, Na/sup +/, K/sup +/, Rb/sup +/, Cs/sup +/), undergo reversible decarbonylation-carbonylation processes as a result of temperature changes, either in an atmosphere of CO and H/sub 2/, or under vacuum. The nature of these processes depends upon the nature of the exchanging cation.

  19. A Spectroscopic Database for MIPAS

    Microsoft Academic Search

    J.-M. Flaud; C. Piccolo; B. Carli

    2003-01-01

    The analysis and interpretation of atmospheric limb spectra such as those recorded by MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) require good knowledge of the molecular parameters of the atmospheric species. This is why a spectroscopic database dedicated to the MIPAS experiment has been generated. The new spectroscopic parameters were first validated through a comparison between atmospheric simulations and ATMOS

  20. Application of spectroscopic techniques for the study of paper documents: A survey

    NASA Astrophysics Data System (ADS)

    Manso, M.; Carvalho, M. L.

    2009-06-01

    For many centuries paper was the main material for recording cultural achievements all over the world. Paper is mostly made from cellulose with small amounts of organic and inorganic additives, which allow its identification and characterization and may also contribute to its degradation. Prior to 1850, paper was made entirely from rags, using hemp, flax and cotton fibres. After this period, due to the enormous increase in demand, wood pulp began to be commonly used as raw material, resulting in rapid degradation of paper. Spectroscopic techniques represent one of the most powerful tools to investigate the constituents of paper documents in order to establish its identification and its state of degradation. This review describes the application of selected spectroscopic techniques used for paper characterization and conservation. The spectroscopic techniques that have been used and will be reviewed include: Fourier-Transform Infrared spectroscopy, Raman spectroscopy, Nuclear Magnetic Resonance spectroscopy, X-Ray spectroscopy, Laser-based Spectroscopy, Inductively Coupled Mass Spectroscopy, Laser ablation, Atomic Absorption Spectroscopy and X-Ray Photoelectron Spectroscopy.

  1. Biotransformations of Antidiabetic Vanadium Prodrugs in Mammalian Cells and Cell Culture Media: A XANES Spectroscopic Study.

    PubMed

    Levina, Aviva; McLeod, Andrew I; Pulte, Anna; Aitken, Jade B; Lay, Peter A

    2015-07-20

    The antidiabetic activities of vanadium(V) and -(IV) prodrugs are determined by their ability to release active species upon interactions with components of biological media. The first X-ray absorption spectroscopic study of the reactivity of typical vanadium (V) antidiabetics, vanadate ([V(V)O4](3-), A) and a vanadium(IV) bis(maltolato) complex (B), with mammalian cell cultures has been performed using HepG2 (human hepatoma), A549 (human lung carcinoma), and 3T3-L1 (mouse adipocytes and preadipocytes) cell lines, as well as the corresponding cell culture media. X-ray absorption near-edge structure data were analyzed using empirical correlations with a library of model vanadium(V), -(IV), and -(III) complexes. Both A and B ([V] = 1.0 mM) gradually converged into similar mixtures of predominantly five- and six-coordinate V(V) species (?75% total V) in a cell culture medium within 24 h at 310 K. Speciation of V in intact HepG2 cells also changed with the incubation time (from ?20% to ?70% V(IV) of total V), but it was largely independent of the prodrug used (A or B) or of the predominant V oxidation state in the medium. Subcellular fractionation of A549 cells suggested that V(V) reduction to V(IV) occurred predominantly in the cytoplasm, while accumulation of V(V) in the nucleus was likely to have been facilitated by noncovalent bonding to histone proteins. The nuclear V(V) is likely to modulate the transcription process and to be ultimately related to cell death at high concentrations of V, which may be important in anticancer activities. Mature 3T3-L1 adipocytes (unlike for preadipocytes) showed a higher propensity to form V(IV) species, despite the prevalence of V(V) in the medium. The distinct V biochemistry in these cells is consistent with their crucial role in insulin-dependent glucose and fat metabolism and may also point to an endogenous role of V in adipocytes. PMID:25906315

  2. Spectroscopic Study of Extended Star Clusters in Dwarf Galaxy NGC 6822

    NASA Astrophysics Data System (ADS)

    Hwang, Narae; Park, Hong Soo; Lee, Myung Gyoon; Lim, Sungsoon; Hodge, Paul W.; Kim, Sang Chul; Miller, Bryan; Weisz, Daniel

    2014-03-01

    We present a spectroscopic study of the four extended star clusters (ESCs) in NGC 6822 based on the data obtained with the Gemini Multi-Object Spectrograph on the Gemini-South 8.1 m telescope. The radial velocities derived from the spectra range from -61.2 ± 20.4 km s-1 (for C1) to -115.34 ± 57.9 km s-1 (for C4) and, unlike the intermediate-age carbon stars, they do not display any sign of systematic rotation around NGC 6822. The ages and metallicities derived using the Lick indices show that the ESCs are old (>=8 Gyr) and metal poor ([Fe/H] <~ -1.5). NGC 6822 is found to have both metal poor ([Fe/H] ?-2.0) and metal rich ([Fe/H] ?-0.9) star clusters within 15' (2 kpc) from the center, whereas only metal poor clusters are observed in the outer halo with r >= 20'(2.6 kpc). The kinematics, old ages, and low metallicities of ESCs suggest that ESCs may have accreted into the halo of NGC 6822. Based on the velocity distribution of ESCs, we have determined the total mass and the mass-to-light ratio of NGC 6822: M_{N6822} = 7.5^{+4.5}_{-0.1} \\times 10^{9}\\ M_{\\odot } and (M/L)_{N6822} = 75^{+45}_{-1} (M/L)_{\\odot }. It shows that NGC 6822 is one of the most dark matter dominated dwarf galaxies in the Local Group. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência, Tecnologia e Inovação (Brazil), and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina).

  3. FTIR spectroscopic study of the mechanism for the gas-phase reaction between ozone and tetramethylethylene

    SciTech Connect

    Niki, H.; Maker, P.D.; Savage, C.M.; Breitenbach, L.P.; Hurley, M.D.

    1987-02-12

    Long-path FTIR spectroscopic product studies were made of mixtures containing part-per-million concentrations of O/sub 3/ and (CH/sub 3/)/sub 2/C double bonded C(CH/sub 3/)/sub 2/ (TME) in 700 Torr of O/sub 2/-N/sub 2/ to determine the formation and reactions of the dimethyl-substituted Criegee intermediate (CH/sub 3/)/sub 2/COO expected from O/sub 3/ + TME ..-->.. (CH/sub 3/)/sub 2/COO + (CH/sub 3/)/sub 2/C double bonded O. The observed stoichiometry, ..delta..-(TME)/..delta..(O/sub 3/), was typically 1.7, and among the products were CO, CO/sub 2/, HCHO, CH/sub 3/OH, CH/sub 3/OOH, CH/sub 3/C(double bonded O)OH, CH/sub 3/C(double bonded O)OOH, (CH/sub 3/)/sub 2/C double bonded O, CH/sub 3/C(double bonded O)CHO, CH/sub 3/C(double bonded O)OCH/sub 3/, CH/sub 3/C(double bonded O)CH/sub 2/(OH), and products tentatively identified as (CH/sub 2/)/sub 2/C(OH)-C(CH/sub 3/)/sub 2/OOH AND CH/sub 3/C(double bonded O)CH/sub 2/(OOH). In addition, /sup 16/O- and /sup 18/O-labeled products were identified in /sup 18/O/sub 3/-TME-air mixtures, and the effects of added HCHO, CH/sub 3/CHO, and NO/sub 2/ (or /sup 15/NO/sub 2/) on the product distribution were determined. The results indicate that ca. 25% of the (CH/sub 3/)/sub 2/COO moiety formed was thermally stable, and that the remainder largely dissociated to yield the following free radicals, i.e., (CH/sub 3/)/sub 2/COO ..-->.. CH/sub 3/C(OOH)double bonded CH/sub 2/ ..-->.. CH/sub 3/C(double bonded O)CH/sub 2/ + HO. The HO-initiated oxidation of TME was shown to account for the excess consumption of TME over O/sub 3/ as well as for some of the major products observed.

  4. Apparatus for and method of performing spectroscopic analysis on an article

    DOEpatents

    Powell, George Louis (Oak Ridge, TN); Hallman, Jr., Russell Louis (Knoxville, TN)

    1999-01-01

    An apparatus for and method of analyzing an article having an entrance and an exit in communication with the entrance. The apparatus comprises: a spectrometer having an emission source with a focal point; a plurality of mirrors; and a detector connected to the spectroscope. The emission source is positioned so that its focal point is substantially coextensive with the entrance of the article. The mirrors comprise: a first mirror positionable adjacent the exit of the article and a second mirror positioned relative to the other of said plurality of mirrors. The first mirror receives scattered emissions exiting the article and substantially collimates the scattered emissions. The second mirror substantially focuses the collimated emissions into a focused emission. The detector receives the focused emission from the mirrors.

  5. Apparatus for and method of performing spectroscopic analysis on an article

    DOEpatents

    Powell, G.L.; Hallman, R.L. Jr.

    1999-04-20

    An apparatus and method are disclosed for analyzing an article having an entrance and an exit in communication with the entrance. The apparatus comprises: a spectrometer having an emission source with a focal point; a plurality of mirrors; and a detector connected to the spectroscope. The emission source is positioned so that its focal point is substantially coextensive with the entrance of the article. The mirrors comprise: a first mirror positionable adjacent the exit of the article and a second mirror positioned relative to the other of said plurality of mirrors. The first mirror receives scattered emissions exiting the article and substantially collimates the scattered emissions. The second mirror substantially focuses the collimated emissions into a focused emission. The detector receives the focused emission from the mirrors. 6 figs.

  6. FTIR and FT-PL Spectroscopic Analysis of TPV Materials and Devices

    SciTech Connect

    Webb, J. D.; Gedvilas, L. M.; Olson, M. R.; Wu, X.; Duda, A.; Wanlass, M. W.; Jones, K. M.

    1998-10-28

    Impurities in cadmium sulfide (CdS) films are a concern in the fabrication of copper (indium, gallium) diselenide (CIGS) and cadmium telluride (CdTe) photovoltaic devices. Devices incorporating chemical-bath-deposited (CBD) CdS are comparable in quality to devices incorporating purer CdS films grown using vacuum deposition techniques, despite the higher impurity concentrations typically observed in the CBD CdS films. In this paper, we summarize and review the results of Fourier transform infrared (FTIR), Auger, electron microprobe, and X-ray photoelectron spectroscopic (XPS) analyses of the impurities in CBD CdS films. We show that these impurities differ as a function of substrate type and film deposition conditions. We also show that some of these impurities exist as 102 micron-scale precipitates.

  7. Vibrational spectroscopic studies and computational study of quinoline-2-carbaldehyde benzoyl hydrazone

    NASA Astrophysics Data System (ADS)

    Sheeja, S. R.; Mangalam, Neema Ani; Prathapachandra Kurup, M. R.; Sheena Mary, Y.; Raju, K.; Varghese, Hema Tresa; Panicker, C. Yohannan

    2010-06-01

    FT-IR spectrum of quinoline-2-carbaldehyde benzoyl hydrazone (HQb··H 2O) was recorded and analyzed. The synthesis and crystal structure data are also described. The vibrational wavenumbers were examined theoretically using the Gaussian03 package of programs using HF/6-31G(d) and B3LYP/6-31G(d) levels of theory. The data obtained from vibrational wavenumber calculations are used to assign vibrational bands obtained in infrared spectroscopy of the studied molecule. The first hyperpolarizability, infrared intensities and Raman activities are reported. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive object for future studies of non-linear optics. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated values. The changes in the C sbnd N bond lengths suggest an extended ?-electron delocalization over quinoline and hydrazone moieties which is responsible for the non-linearity of the molecule.

  8. Micro-Raman spectroscopic study of nanolaminated Ti{sub 5}Al{sub 2}C{sub 3}

    SciTech Connect

    Zhang, H.; Li, Z. J. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, X. H. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Xiang, H. M.; Zhou, Y. C, E-mail: yczhou714@gmail.com [Science and Technology of Advanced Functional Composite Laboratory, ARIMPT, No.1 South Dahongmen Road, Beijing 100076 (China)

    2014-03-31

    Micro-Raman spectroscopic study and lattice dynamics calculations were conducted to study a recently identified layered ternary carbide, Ti{sub 5}Al{sub 2}C{sub 3}. The experimental Raman shifts were remarkably consistent with the calculated values. Polarized Raman spectrum was collected in the polycrystalline sample, which confirmed the theoretical symmetry assignment of the Raman modes. In addition, the atomic vibrations of the peaks at 192?cm{sup ?1}, 311?cm{sup ?1}, and 660?cm{sup ?1} were identified to be the combination of the counterparts in Ti{sub 2}AlC and Ti{sub 3}AlC{sub 2}.

  9. Multivariate statistical analysis of heavy metal concentration in soils of Yelagiri Hills, Tamilnadu, India - Spectroscopical approach

    NASA Astrophysics Data System (ADS)

    Chandrasekaran, A.; Ravisankar, R.; Harikrishnan, N.; Satapathy, K. K.; Prasad, M. V. R.; Kanagasabapathy, K. V.

    2015-02-01

    Anthropogenic activities increase the accumulation of heavy metals in the soil environment. Soil pollution significantly reduces environmental quality and affects the human health. In the present study soil samples were collected at different locations of Yelagiri Hills, Tamilnadu, India for heavy metal analysis. The samples were analyzed for twelve selected heavy metals (Mg, Al, K, Ca, Ti, Fe, V, Cr, Mn, Co, Ni and Zn) using energy dispersive X-ray fluorescence (EDXRF) spectroscopy. Heavy metals concentration in soil were investigated using enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF) and pollution load index (PLI) to determine metal accumulation, distribution and its pollution status. Heavy metal toxicity risk was assessed using soil quality guidelines (SQGs) given by target and intervention values of Dutch soil standards. The concentration of Ni, Co, Zn, Cr, Mn, Fe, Ti, K, Al, Mg were mainly controlled by natural sources. Multivariate statistical methods such as correlation matrix, principal component analysis and cluster analysis were applied for the identification of heavy metal sources (anthropogenic/natural origin). Geo-statistical methods such as kirging identified hot spots of metal contamination in road areas influenced mainly by presence of natural rocks.

  10. A photometric and spectroscopic study of NSVS 14256825: the second sdOB+dM eclipsing binary

    NASA Astrophysics Data System (ADS)

    Almeida, L. A.; Jablonski, F.; Tello, J.; Rodrigues, C. V.

    2012-06-01

    We present an analysis of UBVRCICJH photometry and phase-resolved optical spectroscopy of NSVS 14256825, an HW Vir type binary. The members of this class consist of a hot subdwarf and a main-sequence low-mass star in a close orbit (Porb˜ 0.1 d). Using the primary-eclipse timings, we refine the ephemeris for the system, which has an orbital period of 0.110 37 d. From the spectroscopic data analysis, we derive the effective temperature, T1= 40 000 ± 500 K, the surface gravity, log g1= 5.50 ± 0.05, and the helium abundance, ?, for the hot component. Simultaneously modelling the photometric and spectroscopic data using the Wilson-Devinney code, we obtain the geometrical and physical parameters of NSVS 14256825. Using the fitted orbital inclination and mass ratio (i= 82°.5 ± 0°.3 and q=M2/M1= 0.260 ± 0.012, respectively), the components of the system have M1= 0.419 ± 0.070 M?, R1= 0.188 ± 0.010 R?, M2= 0.109 ± 0.023 M? and R2= 0.162 ± 0.008 R?. From its spectral characteristics, the hot star is classified as a subdwarf OB (sdOB) star. Based on observations carried out at the Observatório do Pico dos Dias/Laboratório Nacional de Astrofísica (OPD/LNA) in Brazil.

  11. FTIR spectroscopic analysis of sputum: preliminary findings on a potential novel diagnostic marker for COPD.

    PubMed

    Whiteman, S C; Yang, Y; Jones, J M; Spiteri, M A

    2008-02-01

    COPD is a common, progressively disabling disease and a major health burden worldwide. Fourier transform infrared (FTIR) spectroscopy provides for sensitive analysis of complex biological samples. COPD pathogenesis involves quantitative and qualitative changes in sputum biosynthesis. This first study explores whether FTIR can produce distinct spectral profiles of human sputum, and capture differences between COPD and health. Sputum obtained from 15 COPD patients and 15 healthy volunteers was analysed using FTIR spectroscopy; differences in peak positions, height and configuration were identified and measured. All samples gave reproducible characteristic IR absorption spectra. The most relevant regions identified were the amide and glycogen rich regions, showing crucial spectral differences between health and COPD relating to peak position shifts or intensity alteration. These novel preliminary findings support further exploration of FTIR sputum profiling in a clinical study to determine its potential as a practical method for monitoring COPD. PMID:19124356

  12. Vibrational spectroscopic studies and computational study of ethyl methyl ketone thiosemicarbazone

    NASA Astrophysics Data System (ADS)

    Anoop, M. R.; Binil, P. S.; Suma, S.; Sudarsanakumar, M. R.; Y, Sheena Mary.; Varghese, Hema Tresa; Panicker, C. Yohannan

    2010-04-01

    FT-IR and FT-Raman spectra of ethyl methyl ketone thiosemicarbazone were recorded and analyzed. The crystal structure is also described. The vibrational wavenumbers were computed using HF/6-31G(d) and B3LYP/6-31G(d) basis sets and are assigned with the aid of MOLEKEL program. The first hyperpolarizability, infrared intensities and Raman activities are also reported. The calculated first hyperpolarizability is comparable with the reported values of similar derivatives and is an attractive molecule for future applications in non-linear optics. The geometrical parameters of the title compound obtained from XRD studies are in agreement with the calculated values. The red shift of the NH stretching wavenumber in the infrared spectrum compared to the computed wavenumber indicates the weakening of the N-H bond resulting in proton transfer to the neighbouring sulfur atom.

  13. Isotope fractionation and spectroscopic analysis as an evidence of Cr(VI) reduction during biosorption.

    PubMed

    Šillerová, Hana; Chrastný, Vladislav; ?adková, Eva; Komárek, Michael

    2014-01-01

    This work investigates the mechanisms behind Cr(VI) biosorption/reduction on three biomaterials (brewers draff, grape waste and synthetic humic acid). Coupled Cr isotope analysis with ICP-OES, XPS and SEM was tested as a novel approach to study the reduction of Cr(VI) by the biomaterials. The Cr(VI) biosorption process was accompanied with heavier Cr isotopes enrichment in the remaining Cr(VI) fraction. A significant fractionation of Cr stable isotopes was observed with no significant pH effect; ?(53)Cr of the remaining fraction ranged from 0.2‰ to 1.9‰ while ?(53)Cr of the product (sorbed Cr) ranged from -1.2‰ to -2.8‰. The Rayleigh fractionation model fitted well the measured data and Cr isotope analysis provides thus an efficient tool to quantify Cr(VI) reduction by different biomaterials. In general, the sorption/reduction potential of the three studied biomaterials decreased in the following order: grape waste>humic acids>brewers draff. PMID:24139156

  14. Insights on Hydrogen Liberation from Water Using Anionic Transition Metal Oxide Clusters: a Combined Computational and Spectroscopic Study

    NASA Astrophysics Data System (ADS)

    Ramabhadran, Raghunath O.; Mann, Jenniffer E.; Waller, Sarah. E.; Rothgeb, David W.; Jarrold, Caroline C.; Raghavachari, Krishnan

    2013-06-01

    Transition Metal Oxides (TMOs) offer widespread applications in catalysis and the generation of alternate sources of energy. Cluster models are useful to model the defect sites in these TMO surfaces which are responsible for their catalytic activities. In this combined computational (DFT) and spectroscopic (PES/MS) study, we present the interesting features in the chemical reactions of molybdenum oxide and tungsten oxide clusters with water. The results obtained provide valuable insights on the roles played by differing metal-oxygen bond strengths, the initial electrostatic complex formed and the geometric factors involved in the liberation of hydrogen gas from water.

  15. Spectroscopic study of a long high-electron-density argon plasma column generated at atmospheric pressure

    SciTech Connect

    Li Shouzhe; Huang Wentong; Wang Dezhen [Key Laboratory of Materials Modification by Laser, Ion and Electron Beams (Dalian University of Technology), Ministry of Education, and School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China)

    2010-02-15

    A stable plasma column is generated in a quartz tube using a pair of hollow electrodes driven by a sinusoidal power supply of 45 kHz at atmospheric pressure in argon. Two distinct operating modes (low-current and high-current modes) are identified through observing its discharge phenomena, measuring its electrical characteristics, and determining the gas temperatures by spectroscopic diagnosis of Q branch of UV OH spectrum. The electron density in the high-current mode is diagnosed by Stark broadening and is found to be two orders higher than that in low-current mode.

  16. Theoretical study on the spectroscopic properties and electronic structures of heteroleptic phosphorescent Ir(III) complexes

    Microsoft Academic Search

    Min Zhang; Ze-Sheng Li; Yan Li; Jia Liu; Jia-Zhong Sun

    2009-01-01

    The geometries, spectroscopic and electronic structures properties of a series of heteroleptic phosphorescent Ir(III) complexes including N981, N982, N983, N984 have been characterized by density functional theory calculations. The excited-state properties of the Ir(III) complexes have been characterized by CIS method. The ground- and excited-state geometries were optimized at the B3LYP\\/LANL2DZ and CIS\\/LANL2DZ levels, respectively. By using the time-dependent density

  17. Analysis of satellite data to deduce stratospheric constituents and UV spectroscopic properties of the atmosphere

    NASA Technical Reports Server (NTRS)

    Mcpeters, Richard D.

    1990-01-01

    The objective is to better understand the stratosphere, its constituents, and its ultraviolet optical properties, through detailed analysis of data from the SBUV instrument on Nimbus 7 and comparison with data from other instruments, including the NOAA 9 SBUV 2, SAGE, SME, and SMM. One conclusion to be drawn from the Ozone Trends Panel report is that there are unresolved differences in the ozone profiles measured by different instruments. While the purpose of the work is more to understand the details of the UV radiation field in the stratosphere than it is to assess the accuracy of the SBUV ozone measurement itself, improved understanding of specific problems in the UV will lead to more accurate ozone retrievals. Areas of study include the effect of aerosols on the backscattered albedo, the shape of the ozone profile near the stratopause, the effect of possible polar mesospheric clouds, and the measureability of nitric oxide and sulfur dioxide.

  18. Spectroscopic analysis of the equilibrium and kinetic DNA binding properties of several actinomycin analogs.

    PubMed Central

    Shafer, R H; Burnette, R R; Mirau, P A

    1980-01-01

    Experiments are described that measure DNA dissociation kinetics and thermal denaturation temperatures for a series of actinomycin analogs containing, in the 3' amino acid position, pipecolic acid, proline or azetidine-2-carboxylic acid. Also included are studies on actinomycin C3. Analysis of the temperature dependence of the slowest rate constant for DNA dissociation shows that both the enthalpy and entropy of ativation increase as the ring size of the 3' amino acid decreases from six to five to four. All compounds increase the DNA melting temperature to the same extent except for the analog containing pipecolic acid, which shows a smaller effect. These results are discussed in terms of a possible role for conformational changes in the actinomycin pentapeptide lactone rings in determining the slow DNA dissociations rates for this class of intercalators. It is suggested that cis-trans isomerization of proline may be important in this regard. PMID:7443543

  19. Spectroscopic and Thermooxidative Analysis of Organic Okra Oil and Seeds from Abelmoschus esculentus

    PubMed Central

    de Sousa Ferreira Soares, Geórgia; Gomes, Vinicius de Morais; dos Reis Albuquerque, Anderson; Barbosa Dantas, Manoel; Rosenhain, Raul; de Souza, Antônio Gouveia; Persunh, Darlene Camati; Gadelha, Carlos Alberto de Almeida; Costa, Maria José de Carvalho; Gadelha, Tatiane Santi

    2012-01-01

    With changes in human consumption from animal fats to vegetable oils, the search for seed types, often from unconventional vegetable sources has grown. Research on the chemical composition of both seed and oil for Brazilian Okra in South America is still incipient. In this study, flour and oil from organic Okra seeds (Abelmoschus esculentus L Moench), grown in northeastern Brazil were analyzed. Similar to Okra varieties from the Middle East and Central America, Brazilian Okra has significant amounts of protein (22.14%), lipids (14.01%), and high amounts of unsaturated lipids (66.32%), especially the oleic (20.38%) and linoleic acids (44.48%). Oil analysis through PDSC revealed an oxidation temperature of 175.2°C, which in combination with low amounts of peroxide, demonstrates its resistance to oxidation and favors its use for human consumption. PMID:22645459

  20. Spectroscopic and thermooxidative analysis of organic okra oil and seeds from Abelmoschus esculentus.

    PubMed

    de Sousa Ferreira Soares, Geórgia; Gomes, Vinicius de Morais; Dos Reis Albuquerque, Anderson; Barbosa Dantas, Manoel; Rosenhain, Raul; de Souza, Antônio Gouveia; Persunh, Darlene Camati; Gadelha, Carlos Alberto de Almeida; Costa, Maria José de Carvalho; Gadelha, Tatiane Santi

    2012-01-01

    With changes in human consumption from animal fats to vegetable oils, the search for seed types, often from unconventional vegetable sources has grown. Research on the chemical composition of both seed and oil for Brazilian Okra in South America is still incipient. In this study, flour and oil from organic Okra seeds (Abelmoschus esculentus L Moench), grown in northeastern Brazil were analyzed. Similar to Okra varieties from the Middle East and Central America, Brazilian Okra has significant amounts of protein (22.14%), lipids (14.01%), and high amounts of unsaturated lipids (66.32%), especially the oleic (20.38%) and linoleic acids (44.48%). Oil analysis through PDSC revealed an oxidation temperature of 175.2 °C, which in combination with low amounts of peroxide, demonstrates its resistance to oxidation and favors its use for human consumption. PMID:22645459

  1. Spectroscopic analysis of sdB stars from the ESO Supernova Ia Progenitor Survey

    E-print Network

    T. Lisker; U. Heber; R. Napiwotzki; N. Christlieb; D. Reimers; D. Homeier

    2003-10-28

    We report on the analysis of high-resolution optical spectra for 77 subdwarf B (sdB) stars from the ESO Supernova Ia Progenitor Survey. Effective temperature, surface gravity, and photospheric helium abundance are determined simultaneously by spectral line profile fitting of hydrogen and helium lines, and are found to be in agreement with previous studies of sdB stars. 24 objects show spectral signs of a cool companion, being either companion absorption lines or a flux contribution at Halpha. Five stars with relatively high luminosity show peculiar Halpha profiles, possibly indicating stellar winds. Our results are compared to recent theoretical simulations by Han et al. (2003) for the distribution in effective temperature and surface gravity, and are found to agree very well with these calculations. Finally we present a binary system consisting of two helium-rich hot subdwarfs.

  2. Local structural studies of the cubic Cd1–xCaxO system through Cd K-edge extended X-ray absorption spectroscopic studies

    PubMed Central

    Srihari, Velaga; Sridharan, V.; Nomura, Masaharu; Sastry, V. Sankara; Sundar, C. S

    2012-01-01

    Cd K-edge extended X-ray absorption fine-structure spectroscopic studies were carried out on Cd1–xCaxO (0 ? x ?0.9) solid solutions and the first and second nearest neighbour (NN) distances and their mean square relative displacement ?2 were estimated. The first NN distance, d Cd–O(x), was found to be smaller than its expected value, a(x)/2, obtained from the X-ray diffraction measurements. It increases monotonically and non-linearly with a negative curvature, comparable with that of the a(x) value variation. The variation ?2 of the 1NN with x is consistent with a disordered solid solution model. The 2NN distances d Cd–Cd(x) and d Cd–Ca(x) are found to follow the average values obtained by X-ray diffraction with d Cd–Ca(x) > d Cd–Cd(x). From detailed analysis it is argued that the solid solution exhibits a bimodal distribution of the 1NN distances, d Cd–O(x) and d Ca–O(x), and that the system belongs to a persistent type. PMID:22713887

  3. XANES Spectroscopic Analysis of Phosphorus Speciation in Alum-Amended Poultry Litter

    SciTech Connect

    Seiter,J.; Staats-Borda, K.; Ginder-Vogel, M.; Sparks, D.

    2008-01-01

    Aluminum sulfate (alum; Al2(SO4)3{center_dot}14H2O) is used as a chemical treatment of poultry litter to reduce the solubility and release of phosphate, thereby minimizing the impacts on adjacent aquatic ecosystems when poultry litter is land applied as a crop fertilizer. The objective of this study was to determine, through the use of X-ray absorption near edge structure (XANES) spectroscopy and sequential extraction, how alum amendments alter P distribution and solid-state speciation within the poultry litter system. Our results indicate that traditional sequential fractionation procedures may not account for variability in P speciation in heterogeneous animal manures. Analysis shows that NaOH-extracted P in alum amended litters is predominantly organic ({approx}80%), whereas in the control samples, >60% of NaOH-extracted P was inorganic P. Linear least squares fitting (LLSF) analysis of spectra collected of sequentially extracted litters showed that the P is present in inorganic (P sorbed on Al oxides, calcium phosphates) and organic forms (phytic acid, polyphosphates, and monoesters) in alum- and non-alum-amended poultry litter. When determining land application rates of poultry litter, all of these compounds must be considered, especially organic P. Results of the sequential extractions in conjunction with LLSF suggest that no P species is completely removed by a single extractant. Rather, there is a continuum of removal as extractant strength increases. Overall, alum-amended litters exhibited higher proportions of Al-bound P species and phytic acid, whereas untreated samples contained Ca-P minerals and organic P compounds. This study provides in situ information about P speciation in the poultry litter solid and about P availability in alum- and non-alum-treated poultry litter that will dictate P losses to ground and surface water systems.

  4. Spectroscopic analysis of myoglobin and cytochrome c dynamics in isolated cardiomyocytes during hypoxia and reoxygenation.

    PubMed

    Almohammedi, A; Kapetanaki, S M; Wood, B R; Raven, E L; Storey, N M; Hudson, A J

    2015-04-01

    Raman microspectroscopy was applied to monitor the intracellular redox state of myoglobin and cytochrome c from isolated adult rat cardiomyocytes during hypoxia and reoxygenation. The nitrite reductase activity of myoglobin leads to the production of nitric oxide in cells under hypoxic conditions, which is linked to the inhibition of mitochondrial respiration. In this work, the subsequent reoxygenation of cells after hypoxia is shown to lead to increased levels of oxygen-bound myoglobin relative to the initial levels observed under normoxic conditions. Increased levels of reduced cytochrome c in ex vivo cells are also observed during hypoxia and reoxygenation by Raman microspectroscopy. The cellular response to reoxygenation differed dramatically depending on the method used in the preceding step to create hypoxic conditions in the cell suspension, where a chemical agent, sodium dithionite, leads to reduction of cytochromes in addition to removal of dissolved oxygen, and bubbling-N2 gas leads to displacement of dissolved oxygen only. These results have an impact on the assessment of experimental simulations of hypoxia in cells. The spectroscopic technique employed in this work will be used in the future as an analytical method to monitor the effects of varying levels of oxygen and nutrients supplied to cardiomyocytes during either the preconditioning of cells or the reperfusion of ischaemic tissue. PMID:25694541

  5. Solid-state spectroscopic analysis of lignins from several Austral hardwoods.

    PubMed

    Martínez, A T; Almendros, G; González-Vila, F J; Fründ, R

    1999-10-01

    In order to gain information about lignin molecular characteristics with a direct bearing on the remarkable susceptibility of some Austral hardwoods to biological delignification, milled-wood lignins were isolated and analyzed by spectroscopic techniques in the solid state. Cross polarization and magic-angle spinning 13C nuclear magnetic resonance (13C CPMAS NMR) and Fourier-transform infrared (FTIR) spectra of the lignin preparations were obtained. The most diagnostic peaks were assigned and quantified as percentages of the total spectral area, and the differences observed discussed in terms of lignin composition. The spectral patterns obtained revealed that the woods from Gevuina avellana, Eucryphia cordifolia and Nothofagus dombeyii have lignin with high syringyl/guaiacyl ratio, as evidenced by relative areas of 13C NMR signals at 153 and 148 ppm, and FTIR bands at 1,335 and 1,275 cm-1. The presence of syringyl-rich lignins, characterized by lower redox potential and condensation degree than guaiacyl-rich lignins, could be a structural factor contributing to the ease of extensive delignification of these woods by white-rot fungi. PMID:10903083

  6. Spectroscopic analysis of moss (Ceratodon purpureus and Physcomitrella patens) recombinant non-symbiotic hemoglobins

    PubMed Central

    Vázquez-Limón, Consuelo; Castro-Bustos, Saraí; Arredondo-Peter, Raúl

    2012-01-01

    Non-symbiotic hemoglobins (nsHbs) are O2-binding proteins widely distributed in land plants, including primitive bryophytes. Little is known about the properties of bryophyte nsHbs. Here, we report the spectroscopic characterization of two moss recombinant nsHbs, CerpurnsHb of Ceratodon purpureus and PhypatnsHb of Physcomitrella patens. Spectra showed that the absorption maxima of the ferrous and ferric forms of recombinant CerpurnsHb are located at 418, 531 and 557 nm and 407, 537, 569 (shoulder) and 632 (shoulder) nm, respectively, and of PhypatnsHb are located at 422, 529 and 557 nm and 407, 531, 571 (shoulder) and 647 (shoulder) nm, respectively. These absorption maxima are similar to those of rice Hb1. Also, the absorption maxima of the oxygenated ferrous form of recombinant CerpurnsHb and PhypatnsHb are located at 412, 541 and 575 nm and 414, 541 and 574 nm, respectively, similar to those of oxygenated rice Hb1 and cowpea leghemoglobin II. This evidence indicates that CerpurnsHb and PhypatnsHb are mostly hexacoordinate and that they bind O2. PMID:23336017

  7. Spectroscopic analysis of moss (Ceratodon purpureus and Physcomitrella patens) recombinant non-symbiotic hemoglobins.

    PubMed

    Vázquez-Limón, Consuelo; Castro-Bustos, Saraí; Arredondo-Peter, Raúl

    2012-11-01

    Non-symbiotic hemoglobins (nsHbs) are O(2)-binding proteins widely distributed in land plants, including primitive bryophytes. Little is known about the properties of bryophyte nsHbs. Here, we report the spectroscopic characterization of two moss recombinant nsHbs, CerpurnsHb of Ceratodon purpureus and PhypatnsHb of Physcomitrella patens. Spectra showed that the absorption maxima of the ferrous and ferric forms of recombinant CerpurnsHb are located at 418, 531 and 557 nm and 407, 537, 569 (shoulder) and 632 (shoulder) nm, respectively, and of PhypatnsHb are located at 422, 529 and 557 nm and 407, 531, 571 (shoulder) and 647 (shoulder) nm, respectively. These absorption maxima are similar to those of rice Hb1. Also, the absorption maxima of the oxygenated ferrous form of recombinant CerpurnsHb and PhypatnsHb are located at 412, 541 and 575 nm and 414, 541 and 574 nm, respectively, similar to those of oxygenated rice Hb1 and cowpea leghemoglobin II. This evidence indicates that CerpurnsHb and PhypatnsHb are mostly hexacoordinate and that they bind O(2). PMID:23336017

  8. Photometric and Spectroscopic Analysis of Young, Nearby Open Cluster Collinder 70

    NASA Astrophysics Data System (ADS)

    Thomann, Clara; James, D. J.; Boberg, O. M.; Cargile, P.; Aarnio, A.

    2013-01-01

    We present the results of a wide-field (80' x 80') photometric and spectroscopic survey of the young open cluster Collinder 70, which is also known as the ORI OB 1b association, centered on the central star of Orion's belt, ? Ori (Alnilam). Seventy Coll 70 spectroscopy targets were selected from BVRIc color magnitude diagrams for observation using the CTIO HYDRA multi-object spectrograph; we aimed to identify targets exhibiting H? in emission and a strong lithium 6708-A line in absorption. About a third of our targets (23/70 stars) are consistent with being youthful members of Coll 70. Intermediate resolution ( 20000) HYDRA Li 6708A equivalent widths and Baraffe et al. (2002) evolutionary models strongly suggest that this association is << 30 Myr. Observational evidence showing that that some stars exhibit primordial levels of lithium, giant-like features in low-resolution spectra and the presence of infra-red excesses indicate that the association is considerably younger than 30 Myr and is a potentially valuable target for age determination using the Lithium Depletion Boundary method.

  9. 3D stereoscopic analysis of a Coronal Mass Ejection and comparison with UV spectroscopic data

    E-print Network

    Susino, Roberto; Dolei, Sergio

    2014-01-01

    A three-dimensional (3D) reconstruction of the 2007, May 20 partial-halo Coronal Mass Ejection (CME) has been made using STEREO/EUVI and STEREO/COR1 coronagraphic images. The trajectory and kinematics of the erupting filament have been derived from EUVI image pairs with the "tie-pointing" triangulation technique, while the polarization ratio technique has been applied to COR1 data to determine the average position and depth of the CME front along the line of sight. These 3D geometrical information have been combined for the first time with spectroscopic measurements of the OVI $\\lambda\\lambda$1031.91, 1037.61 \\AA\\ line profiles made with the Ultraviolet Coronagraph Spectrometer (UVCS) on board SOHO. Comparison between the prominence trajectory extrapolated at the altitude of UVCS observations and the core transit time measured from UVCS data made possible a firm identification of the CME core observed in white light and UV with the prominence plasma expelled during the CME. Results on the 3D structure of the ...

  10. Spectroscopic and thermal studies of 8 MeV electron beam irradiated HPMC films

    NASA Astrophysics Data System (ADS)

    Sangappa; Asha, S.; Demappa, T.; Sanjeev, Ganesh; Parameswara, P.; Somashekar, R.

    2009-07-01

    Radiation-induced changes in hydroxypropyl methylcellulose (HPMC) films under electron irradiation were investigated and correlated with dose. Polymer samples were irradiated in air at room temperature by an electron beam accelerator in the range of 0-100 kGy. Various properties of the irradiated films were studied using a Ultraviolet-Visible spectrophotometer and Fourier transform infrared spectroscopy and thermogravimetric analysis. Electron irradiation was found to induce changes in the physical, chemical and thermal properties, depending on the irradiation dose.

  11. Inclusion complexation of 2-aminopyrimidines with ?-cyclodextrin, physico-chemical and nuclear magnetic spectroscopic studies

    NASA Astrophysics Data System (ADS)

    Sumitha Celin, T.; Nagarajan, S.

    2014-01-01

    Inclusion complexation of 2-aminopyrimidines with ?-cyclodextrin was studied in the solid state by infrared spectroscopy (IR), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The aminopyrimidine- ?-CD complexes were also investigated in a solution by nuclear magnetic resonance spectral techniques (1H-NMR and 13C-NMR). Qualitative modifications in the position and number of peaks or bands obtained from spectral methods as well as thermal analysis indicated the inclusion.

  12. Analysis of 2D periodic nanostructures with an oxide overlayer via spectroscopic ellipsometry.

    PubMed

    Ghong, T H; Byun, J S; Han, S-H; Chung, J-M; Kim, Y D

    2011-07-01

    The accurate nondestructive determination of the shapes or critical dimensions of periodic nanostructures is essential to the current integrated-circuits technology. Optical critical dimension (OCD) metrology is fast, nondestructive, and can be used in air, allows higher sampling rates compared to the non-optical methods such as scanning electron microscopy (SEM) or atomic-force microscopy (AFM), and does not damage the sample. The data are typically analyzed via rigorous coupled-wave analysis (RCWA), where the sample is modeled as a series of layers whose dimensional parameters are determined by a least-squares fit. The layers are typically approximated as a combination of core material and ambient. Oxide overlayers and surface roughness are common, however, and call into question two-phase approximation. In this study, a structure that is periodic in two dimensions and that is coated with a thin (3 nm) oxide was studied, and an extension of the RCWA method that allows structural information to be extracted from optical data even in the presence of oxide overlayers or surface roughness was developed. PMID:22121747

  13. Synthesis, crystal structure, spectroscopic and density functional theory (DFT) study of N-[3-anthracen-9-yl-1-(4-bromo-phenyl)-allylidene]-N-benzenesulfonohydrazine

    NASA Astrophysics Data System (ADS)

    Arshad, Muhammad Nadeem; Asiri, Abdullah M.; Alamry, Khalid A.; Mahmood, Tariq; Gilani, Mazhar Amjad; Ayub, Khurshid; Birinji, Abdulhadi Salih

    2015-05-01

    N-[3-anthracen-9-yl-1-(4-bromo-phenyl)-allylidene]-N-benzenesulfonohydrazine has been synthesized and characterized by various spectroscopic techniques including FT-IR, UV-vis, 1H-NMR, 13C-NMR spectroscopy, and the structure was unequivocally confirmed by single crystal X-ray diffraction studies. The compound crystallized in monoclinic system with P21/n space group, and adopted cis-geometry around the azomethine Cdbnd N double bond. The X-ray crystal structure revealed that the intermolecular packing was stabilized by C-H⋯O type hydrogen bonding interaction, whereas NH was not involved in hydrogen bonding due to steric hindrance. Absorption wavelength was studied by scanning UV-vis. absorption spectrum in different solvents to explore excited state stability of the molecule in polar solvent. Density functional theory calculations were performed at B3LYP/6-31G (d, p) level in order to compare the experimental results with the theoretical results. The simulated molecular electrostatic potential (MEP), Mulliken charges and NPA (natural population analysis) also confirmed the presence of specific intermolecular hydrogen bonding (C-H⋯O). In addition natural bond orbital (NBO) analysis (intra and inter molecular bonding and interaction among bonds), frontier molecular orbital analysis (electronic properties) and first hyperpolarizability analysis (nonlinear optical response) were simulated at B3LYP/6-31G (d, p) level of theory.

  14. Synthesis, crystal structure, spectroscopic and density functional theory (DFT) study of N-[3-anthracen-9-yl-1-(4-bromo-phenyl)-allylidene]-N-benzenesulfonohydrazine.

    PubMed

    Arshad, Muhammad Nadeem; Asiri, Abdullah M; Alamry, Khalid A; Mahmood, Tariq; Gilani, Mazhar Amjad; Ayub, Khurshid; Birinji, Abdulhadi Salih

    2015-05-01

    N-[3-anthracen-9-yl-1-(4-bromo-phenyl)-allylidene]-N-benzenesulfonohydrazine has been synthesized and characterized by various spectroscopic techniques including FT-IR, UV-vis, (1)H-NMR, (13)C-NMR spectroscopy, and the structure was unequivocally confirmed by single crystal X-ray diffraction studies. The compound crystallized in monoclinic system with P21/n space group, and adopted cis-geometry around the azomethine CN double bond. The X-ray crystal structure revealed that the intermolecular packing was stabilized by C-H?O type hydrogen bonding interaction, whereas NH was not involved in hydrogen bonding due to steric hindrance. Absorption wavelength was studied by scanning UV-vis. absorption spectrum in different solvents to explore excited state stability of the molecule in polar solvent. Density functional theory calculations were performed at B3LYP/6-31G (d, p) level in order to compare the experimental results with the theoretical results. The simulated molecular electrostatic potential (MEP), Mulliken charges and NPA (natural population analysis) also confirmed the presence of specific intermolecular hydrogen bonding (C-H?O). In addition natural bond orbital (NBO) analysis (intra and inter molecular bonding and interaction among bonds), frontier molecular orbital analysis (electronic properties) and first hyperpolarizability analysis (nonlinear optical response) were simulated at B3LYP/6-31G (d, p) level of theory. PMID:25721652

  15. Surface analysis of all elements with isotopic resolution at high ambient pressures using ion spectroscopic techniques

    SciTech Connect

    Smentkowski, V.S.; Krauss, A.R.; Gruen, D.M. [Argonne National Lab., IL (United States). Materials Science and Chemistry Div.; Holecek, J.C.; Schultz, J.A. [Ionweks, Houston, TX (United States)

    1997-09-01

    The authors have developed a mass spectrometer capable of surface analysis using the techniques of secondary ion mass spectroscopy (SIMS) and mass spectroscopy of recoiled ions (MSRI). For SIMS, an energetic ion beam creates a collision cascade which results in the ejection of low kinetic energy secondary ions from the surface being analyzed. The low kinetic energy SIMS ions are very susceptible to charge neutralization with the surface, and as a result, the SIMS ion yield varies by orders of magnitude depending on the chemical state of the surface. SIM spectra contain elemental ions, and molecular ions. For MSRI, a pulsed ion beam induces a binary collision with the surface being analyzed and the surface species are recoiled into the forward scattering direction with a large kinetic energy. The violence of the binary collision results in complete molecular decomposition, and only elemental ions are detected. The high kinetic energy MSRI ions are much less susceptible to charge neutralization with the surface than the low kinetic energy SIMS ions. In MSRI, the ion yield typically varies by less than a factor of ten as the chemical state of the surface changes--simplifying quantitative analysis vs. SIMS. In this paper, they authors will demonstrate that the high kinetic energy MSRI ions are able to transverse high pressure paths with only a reduction in peak intensity--making MSRI an ideal tool for real-time, in-situ film growth studies. The use of a single analyzer for both MSRI and SIMS is unique and provides complimentary information.

  16. Analysis of eupatilin-human serum albumin interactions by means of spectroscopic and computational modelling.

    PubMed

    Tang, Jianghong; Lian, Ning; Bi, Chenglu; Li, Weihua

    2007-05-01

    The interaction of eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone) with human serum albumin (HSA) was studied at simulative physiological pH, with a HSA concentration of 3.0 x 10(-6)mol L(-1) and eupatilin concentrations over the range of 6.0 x 10(-6) to 1.9 x 10(-5) mol L(-1). Fluorescence spectroscopy in combination with UV absorption spectroscopy and Fourier transform infrared (FTIR) spectroscopy were used to study the binding properties (including binding mechanism, the binding constants, the number of binding sites and the binding mode) of the interaction of eupatilin with HSA and the effect of this drug on HSA conformation changes. According to the Scatchard equation there was only one class of binding site that could bind to HAS; the binding constants were 1.53 x 10(5), 1.20 x 10(5), 1.05 x 10(5), 0.87 x 10(5) L mol(-1) at temperatures of 287, 298, 310 and 318 K, respectively. The FTIR spectra revealed that the protein secondary structure changed, with reductions in alpha-helices of about 3.65% at a drug to protein molar ratio of 3. The thermodynamic analysis (enthalpy and entropy change: DeltaH(0) and DeltaS(0)) and the computational modelling study indicated that hydrophobic force played an important role in eupatilin-HSA complex stabilization, and eupatilin could bind within the subdomain IIA of HSA. PMID:17524228

  17. Build Your Own Spectroscope

    NSDL National Science Digital Library

    Students build a working spectroscope to study the nature of light. (Younger students use a prism to learn about the rainbow.) The curriculum includes study guides for various grade groups, PowerPoints to explain concepts, age-appropriate hands-on activities, and 3 videos.

  18. Planetary Surface Analysis Using Fast Laser Spectroscopic Techniques: Combined Microscopic Raman, LIBS, and Fluorescence Spectroscopy

    NASA Astrophysics Data System (ADS)

    Blacksberg, J.; Rossman, G. R.; Maruyama, Y.; Charbon, E.

    2011-12-01

    In situ exploration of planetary surfaces has to date required multiple techniques that, when used together, yield important information about their formation histories and evolution. We present a time-resolved laser spectroscopic technique that could potentially collect complementary sets of data providing information on mineral structure, composition, and hydration state. Using a picosecond-scale pulsed laser and a fast time-resolved detector we can simultaneously collect spectra from Raman, Laser Induced Breakdown Spectroscopy (LIBS), and fluorescence emissions that are separated in time due to the unique decay times of each process. The use of a laser with high rep rate (40 KHz) and low pulse energy (1 ?J/pulse) allows us to rapidly collect high signal to noise Raman spectra while minimizing sample damage. Increasing the pulse energy by about an order of magnitude creates a microscopic plasma near the surface and enables the collection of LIBS spectra at an unusually high rep rate and low pulse energy. Simultaneously, broader fluorescence peaks can be detected with lifetimes varying from nanosecond to microsecond. We will present Raman, LIBS, and fluorescence spectra obtained on natural mineral samples such as sulfates, clays, pyroxenes and carbonates that are of interest for Mars mineralogy. We demonstrate this technique using a photocathode-based streak camera detector as well as a newly-developed solid state Single Photon Avalanche Diode (SPAD) sensor array based on Complementary Metal-Oxide Semiconductor (CMOS) technology. We will discuss the impact of system design and detector choice on science return of a potential planetary surface mission, with a specific focus on size, weight, power, and complexity. The research described here was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA).

  19. A vibrational spectroscopic study of the silicate mineral lomonosovite Na?Ti?(Si?O?)(PO?)O?.

    PubMed

    Frost, Ray L; López, Andrés; Theiss, Frederick L; Graça, Leonardo M; Scholz, Ricardo

    2015-01-01

    The mineral lomonosovite has been studied using a combination of scanning electron microscopy with energy dispersive X-ray analysis and vibrational spectroscopy. Qualitative chemical analysis gave Si, P, Na and Ti as the as major elements with small amounts of Mn, Ca, Fe and Al. The mineral lomonosovite has a formula Na?Ti?(Si?O?)(PO?)O?. Raman bands observed at 909, 925 and 939 cm(-1) are associated with phosphate units. Raman bands found at 975, 999, 1070, 1080 and 1084 cm(-1) are attributed to siloxane stretching vibrations. The observation of multiple bands in both the phosphate stretching and bending regions supports the concept that the symmetry of the phosphate anion in the structure of lomonosovite is significantly reduced. Infrared spectroscopy identifies bands in the water stretching and bending regions, thus suggesting that water is involved with the structure of lomonosovite either through adsorption on the surface or by bonding to the phosphate units. PMID:25004895

  20. Development and analysis of spectroscopic learning tools and the light and spectroscopy concept inventory for introductory college astronomy

    NASA Astrophysics Data System (ADS)

    Bardar, Erin M.

    Electromagnetic radiation is the fundamental carrier of astronomical information. Spectral features serve as the fingerprints of the universe, revealing many important properties of objects in the cosmos such as temperature, elemental compositions, and relative motion. Because of its importance to astronomical research, the nature of light and the electromagnetic spectrum is by far the most universally covered topic in astronomy education. Yet, to the surprise and disappointment of instructors, many students struggle to understand underlying fundamental concepts related to light and spectroscopic phenomena. This dissertation describes research into introductory college astronomy students' understanding of light and spectroscopy concepts, through the development and analysis of both instructional materials and an assessment instrument. The purpose of this research was two-fold: (1) to develop a novel suite of spectroscopic learning tools that enhance student understanding of light and spectroscopy and (2) to design and validate a Light and Spectroscopy Concept Inventory (LSCI) with the sensitivity to distinguish the relative effectiveness of various teaching interventions within the context of introductory college astronomy. Through a systematic investigation that included multiple rounds of clinical interviews, open-ended written surveys, and multiple-choice testing, introductory college astronomy students' commonly held misconceptions and reasoning difficulties were explored for concepts relating to: (1) The nature of the electromagnetic spectrum, including the interrelationships of wavelength, frequency, energy, and speed; (2) interpretation of Doppler shift; (3) properties of blackbody radiation; and (4) the connection between spectral features and underlying physical processes. These difficulties guided the development of instructional materials including six unique "homelab" exercises, a binocular spectrometer, a spectral analysis software tool, and the 26-question Light and Spectroscopy Concept Inventory (LSCI). In the fall of 2005, a multi-institution field-test of the LSCI was conducted with student examinees from 14 course sections at 11 colleges and universities employing various instructional techniques. Through statistical analysis, the inventory was proven to be a reliable (Cronbach's alpha = 0.77) and valid assessment instrument that was able to illustrate statistically significant learning gains (p < 0.05) for most course sections, with students utilizing our suite of instructional materials exhibiting among the highest performance gains (Effect Size = 1.31).