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Sample records for alpha-al2o3 spectroscopic evidence

  1. Fractionation of Suwannee River fulvic acid and aldrich humic acid on alpha-Al2O3: spectroscopic evidence.

    PubMed

    Claret, Francis; Schäfer, Thorsten; Brevet, Julien; Reiller, Pascal E

    2008-12-01

    Sorptive fractionation of Suwannee River Fulvic Acid (SRFA) and Purified Aldrich Humic Acid (PAHA) on alpha-Al2O3 at pH 6 was probed in the supernatant using different spectroscopic techniques. Comparison of dissolved organic carbon (DOC) analysis with UV/vis spectrophotometric measurements at 254 nm, including specific UV absorbance (SUVA) calculation, revealed a decrease in chromophoric compounds for the nonsorbed extracts after a 24 h contact time. This fractionation, only observable below a certain ratio between initial number of sites of humic substances and of alpha-Al2O3, seems to indicate a higher fractionation for PAHA. C(1s) near-edge X-ray absorption fine structure spectroscopy (NEXAFS) confirmed this trend and points to a decrease in phenolic moieties in the supernatant and to an eventual increase in phenolic moieties on the surface. Time-resolved luminescence spectroscopy (TRLS) of Eu(III) as luminescent probe showed a decrease in the ratio between the (5)D0-->(7)F2 and (5)D0-->(7)F1 transitions for the fractionated organic matter (OM) that is thought to be associated with a lower energy transfer from the OM to Eu(III) due to the loss of polar aromatics. These modifications in the supernatant are a hint for the modification of sorbed humic extracts on the surface. PMID:19192802

  2. The structure of the alpha-Al2O3(0001) surface from low-energyelectron diffraction: Al termination and evidence for large thermalvibrations

    SciTech Connect

    Soares, E.A.; Van Hove, M.A.; Walters, C.F.; McCarty, K.F.

    2000-05-05

    We have determined the surface structure of alpha-Al2O3(0001) using dynamical low-energy electron diffraction (LEED). Sapphire surfaces were prepared in three different ways, and the diffraction results were analyzed using an exhaustive search of possible models. For all sample processing conditions, the clearly favored structure has a single Al layer termination and a large first interlayer contraction. In addition, we find that the surface atoms have unusually large vibrational amplitudes at room temperature, suggestive of an anharmonic vibrational mode.

  3. Oxygen diffusion in alpha-Al2O3. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Cawley, J. D.; Halloran, J. W.; Cooper, A. R.

    1984-01-01

    Oxygen self diffusion coefficients were determined in single crystal alpha-Al2O3 using the gas exchange technique. The samples were semi-infinite slabs cut from five different boules with varying background impurities. The diffusion direction was parallel to the c-axis. The tracer profiles were determined by two techniques, single spectrum proton activation and secondary ion mass spectrometry. The SIMS proved to be a more useful tool. The determined diffusion coefficients, which were insensitive to impurity levels and oxygen partial pressure, could be described by D = .00151 exp (-572kJ/RT) sq m/s. The insensitivities are discussed in terms of point defect clustering. Two independent models are consistent with the findings, the first considers the clusters as immobile point defect traps which buffer changes in the defect chemistry. The second considers clusters to be mobile and oxygen diffusion to be intrinsic behavior, the mechanism for oxygen transport involving neutral clusters of Schottky quintuplets.

  4. Catalytic oxidation of elemental mercury over the modified catalyst Mn/alpha-Al2O3 at lower temperatures.

    PubMed

    Li, Jianfeng; Yan, Naiqiang; Qu, Zan; Qiao, Shaohua; Yang, Shijian; Guo, Yongfu; Liu, Ping; Jia, Jinping

    2010-01-01

    In order to facilitate the removal of elemental mercury (Hg(0)) from coal-fired flue gas, catalytic oxidation of Hg(0) with manganese oxides supported on inert alumina (alpha-Al2O3) was investigated at lower temperatures (373-473 K). To improve the catalytic activity and the sulfur-tolerance of the catalysts at lower temperatures, several metal elements were employed as dopants to modify the catalyst of Mn/alpha-Al2O3. The best performance among the tested elements was achieved with molybdenum (Mo) as the dopant in the catalysts. It can work even better than the noble metal catalyst Pd/alpha-Al2O3. Additionally, the Mo doped catalyst displayed excellent sulfur-tolerance performance at lower temperatures, and the catalytic oxidation efficiency for Mo(0.03)-Mn/alpha-Al2O3 was over 95% in the presence of 500 ppm SO2 versus only about 48% for the unmodified catalyst. The apparent catalytic reaction rate constant increased by approximately 5.5 times at 423 K. In addition, the possible mechanisms involved in Hg(0) oxidation and the reaction with the Mo modified catalyst have been discussed. PMID:19950921

  5. The Characteristics of Interface Misfit Dislocations for Epitaxial alpha-Fe2O3 on alpha-Al2O3(0001)

    SciTech Connect

    Wang, Chong M.; Thevuthasan, Suntharampillai; Gao, Fei; McCready, David E.; Chambers, Scott A.

    2002-07-01

    Alpha-Fe2O3(0001) films of thickness equal to {approx}7 nm and {approx}70 nm were epitaxially grown on alpha-Al2O3(0001) by oxygen plasma assisted molecular beam epitaxy (OPA-MBE). The interfaces were characterized using high resolution transmission electron microscopy (HRTEM), electron energy-loss spectroscopy (EELS), and x-ray diffraction (XRD). The interface exhibited coherent regions separated by equally-spaced misfit dislocations. When imaged from the[2110] direction, the dislocation spacing is 7.0 +- 1.1 nm for the 70 nm thick specimen, and 7.2 +- 0.1 nm for the 7 nm thick specimen. When imaged from the[0110] direction, the dislocation spacing is 4.5 +- 0.1 nm for the 7 nm thick specimen. The experimentally observed dislocation spacings are approximately consistent with those calculated from the lattice mismatch between alpha-Al2O3 and alpha-Fe2O3, implying that the lattice mismatch is accommodated mainly be interface misfit dislocations above the critical thickness, which is less than 7 nm. This conclusion is also corroborated by the measured residual strain of {approx}0.5% determined from x-ray diffraction for the 70 nm film . EELS analysis reveals that the Fe L2,3-edge shows no measurable chemical shift relative to the L2,3-edge of structural Fe3?, indicating complete oxidation of Fe in the as-grown film.

  6. Influence of thermal quenching on the thermostimulated processes in alpha-Al2O3. Role of F and F+ centres.

    PubMed

    Vincellér, S; Molnár, G; Berkane-Krachai, A; Iacconi, P

    2002-01-01

    Anion deficient alpha-Al2O3 is highly sensitive to ionising radiations and is widely used as a thermoluminescence and optically stimulated luminescence dosemeter in environmental monitoring. Two types of alpha alumina were studied and it was observed that both were affected by thermal quenching of luminescence. This effect, which manifests itself by the decay of the TL response when the heating rate increases, can be described by the Mott-Seitz theory. It was observed that thermostimulated exoemission response increased when the heating rate increased, whereas thermostimulated conductivity remained constant. However, none of the available theories could explain the dependence of the F- centre emission on the heating rate. A model is proposed to describe simultaneously the various thermally stimulated processes. PMID:12382832

  7. Vanadium oxides on aluminum oxide supports. 1. Surface termination and reducibility of vanadia films on alpha-Al2O3(0001).

    PubMed

    Todorova, Tanya K; Ganduglia-Pirovano, M Veronica; Sauer, Joachim

    2005-12-15

    Using density functional theory and statistical thermodynamics, we obtained the phase diagram of thin VnOm films of varying thickness (approximately 2-6 A, 1-6 vanadium layers) supported on alpha-Al2O3(0001). Depending on the temperature, oxygen pressure, and vanadium concentration, films with different thickness and termination may form. In ultrahigh vacuum (UHV), at room temperature and for low vanadium concentrations, an ultrathin (1 x 1) O=V-terminated film is most stable. As more vanadium is supplied, the thickest possible films form. Their structures and terminations correspond to previous findings for the (0001) surface of bulk V2O3 [Kresse et al., Surf. Sci. 2004, 555, 118]. The presence of surface vanadyl (O=V) groups is a prevalent feature. They are stable up to at least 800 K in UHV. Vanadyl oxygen atoms induce a V(2p) core-level shift of about 2 eV on the surface V atoms. The reducibility of the supported films is characterized by the energy of oxygen defect formation. For the stable structures, the results vary between 4.11 and 3.59 eV per 1/2O2. In contrast, oxygen removal from the V2O5(001) surface is much easier (1.93 eV). This provides a possible explanation for the lower catalytic activity of vanadium oxides supported on alumina compared to that of crystalline vanadia particles. PMID:16375327

  8. Comparative assessment of structural and biological properties of biomimetically coated hydroxyapatite on alumina (alpha-Al2O3) and titanium (Ti-6Al-4V) alloy substrates.

    PubMed

    Kapoor, Renu; Sistla, Pavana Goury; Kumar, Jerald Mahesh; Raj, T Avinash; Srinivas, G; Chakraborty, Jui; Sinha, Mithlesh K; Basu, Debabrata; Pande, Gopal

    2010-09-01

    Previous reports have shown the use of hydroxyapatite (HAp) and related calcium phosphate coatings on metal and nonmetal substrates for preparing tissue-engineering scaffolds, especially for osteogenic differentiation. These studies have revealed that the structural properties of coated substrates are dependent significantly on the method and conditions used for coating and also whether the substrates had been modified prior to the coating. In this article, we have done a comparative evaluation of the structural features of the HAp coatings, prepared by using simulated body fluid (SBF) at 25 degrees C for various time periods, on a nonporous metal substrate titanium-aluminium-vanadium (Ti-6Al-4V) alloy and a bioinert ceramic substrate alpha-alumina (alpha-Al(2)O(3)), with and without their prior treatment with the globular protein bovine serum albumin (BSA). Our analysis of these substrates by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared (FTIR) spectrometry showed significant and consistent differences in the quantitative and qualitative properties of the coatings. Interestingly, the bioactivity of these substrates in terms of supporting in vitro cell adhesion and spreading, and in vivo effects of implanted substrates, showed a predictable pattern, thus indicating that some coated substrates prepared under our conditions could be more suitable for biological/biomedical applications. PMID:20730928

  9. Oxygen-Permeable, Hydrophobic Membranes of Silanized alpha-Al2O3

    NASA Technical Reports Server (NTRS)

    Atwater, James E.; Akse, James R.

    2006-01-01

    Membranes made of silanized alumina have been prepared and tested as prototypes of derivatized ceramic membranes that are both highly permeable to oxygen and hydrophobic. Improved oxygen-permeable, hydrophobic membranes would be attractive for use in several technological disciplines, including supporting high-temperature aqueousphase oxidation in industrial production of chemicals, oxygenation of aqueous streams for bioreactors, and oxygenation of blood during open-heart surgery and in cases of extreme pulmonary dysfunction. In comparison with organic polymeric oxygen-permeable membranes now commercially available, the derivatized ceramic membranes are more chemically robust, are capable of withstanding higher temperatures, and exhibit higher oxygen-diffusion coefficients.

  10. Boundary migration and disappearance of voids in Alpha-Al2O3 at 2000 deg C

    NASA Technical Reports Server (NTRS)

    Komatsu, M.; Fujita, H.

    1984-01-01

    A series of photographs taken with Osaka University's high temperature 3MV electron microscope of alpha-A1(z)O(3) at 2000 C is presented. The dynamic study shows grain boundary migration in progress and demonstrates that disappearance of voids is controlled by boundary migration.

  11. Spectroscopic Evidence for Nonuniform Starspot Properties on II Pegasi

    NASA Technical Reports Server (NTRS)

    ONeal, Douglas; Saar, Steven H.; Neff, James E.

    1998-01-01

    We present spectroscopic evidence for Multiple Spot temperatures on the RS CVn star II Pegasi (HD 224085). We model the strengths of the 7055 and 8860 A TiO absorption bands in the spectrum of II Peg using weighted sums of inactive comparison spectra: a K star to represent the nonspotted photosphere and an M star to represent the spots. The best fit yields independent measurements of the starspot filling factor (f(sub s) and mean spot temperature (T(sub s)) averaged over the visible hemisphere of the star. During three-fourths of a rotation of II Peg in late 1996, we measure a constant f(sub s) approximately equals 55% +/- 5%. However, (T(sub s) varies from 3350 +/- 60 to 3550 +/- 70 K. We compute (T(sub s) for two simple models: (1) a star with two distinct spot temperatures, and (2) a star with different umbral/penumbral area ratios. The changing (T(sub s) correlates with emission strengths of H(alpha) and the Ca II infrared triplet in the sense that cooler (T(sub s) accompanies weaker emission. We explore possible implications of these results for the physical properties of the spots on II Peg and for stellar surface structure in general.

  12. II Peg: Spectroscopic Evidence for Multiple Starspot Temperatures

    NASA Astrophysics Data System (ADS)

    O'Neal, Douglas; Saar, Steven H.; Neff, James E. Neff

    We present spectroscopic evidence for multiple spot temperatures on the RS CVn star II Pegasi (HD 224085). We fit the strengths of the 7055 AAg and 8860 AAg TiO absorption bands in the spectrum of an active star using weighted sums of comparison spectra: the spectrum of an inactive K star to represent the non-spotted photosphere and the spectrum of an M star to represent the spots. We can thus independently measure starspot filling factor (fspot) and temperature (tspot). During 3/4 of a rotation of II Peg in Sept.-Oct. 1996, we measure fspot approximately constant at 55+/-5%. However, tspot varies from 3350 K to 3500 K. Since our method yields one derived tspot integrated over the visible hemisphere of the star, we present the results of simple models of a star with two distinct spot temperatures and compute the tspot we would derive in those cases. The changing tspot correlates with emission strengths of Hα and the Ca 2 infrared triplet, in the sense that cooler \\tspot accompanies weaker emission. We explore the consequences of these results for the physical properties of the spots on II Peg and for stellar surface structure in general.

  13. Spectroscopic Evidence for Nonuniform Starspot Properties on II Pegasi

    NASA Astrophysics Data System (ADS)

    O'Neal, Douglas; Saar, Steven H.; Neff, James E.

    1998-07-01

    We present spectroscopic evidence for multiple spot temperatures on the RS CVn star II Pegasi (HD 224085). We model the strengths of the 7055 and 8860 Å TiO absorption bands in the spectrum of II Peg using weighted sums of inactive comparison spectra: a K star to represent the nonspotted photosphere and an M star to represent the spots. The best fit yields independent measurements of the starspot filling factor (fS) and mean spot temperature () averaged over the visible hemisphere of the star. During three-fourths of a rotation of II Peg in late 1996, we measure a constant fS~55%+/-5%. However, varies from 3350+/-60 to 3550+/-70 K. We compute for two simple models: (1) a star with two distinct spot temperatures, and (2) a star with different umbral/penumbral area ratios. The changing correlates with emission strengths of Hα and the Ca II infrared triplet in the sense that cooler accompanies weaker emission. We explore possible implications of these results for the physical properties of the spots on II Peg and for stellar surface structure in general.

  14. Spectroscopic Evidence for Gas Infall in GF 9-2

    NASA Astrophysics Data System (ADS)

    Furuya, Ray S.; Kitamura, Yoshimi; Shinnaga, Hiroko

    2009-02-01

    We present spectroscopic evidence for the infall motion of gas in the natal cloud core harboring an extremely young low-mass protostar GF 9-2. We previously discussed that the ongoing collapse of the GF 9-2 core has agreement with the Larson-Penston-Hunter (LPH) theoretical solution for the gravitational collapse of a core. To discuss the gas infall on firmer ground, we have carried out on-the-fly mapping observations of the HCO+ (1-0) line using the Nobeyama 45 m telescope equipped with the 25 Beam Array Receiver System. Furthermore, we observed the HCN (1-0) line with the 45 m telescope, and the HCO+ (3-2) line with the Caltech Submillimeter Observatory 10.4 m telescope. The optically thick HCO+ and HCN lines show blueskewed profiles whose deepest absorptions are seen at the peak velocity of optically thin lines, i.e., the systemic velocity of the cloud, indicating the presence of gas infall toward the central protostar. We compared the observed HCO+ line profiles with model ones by solving the radiative transfer in the core under LTE assumption. We found that the core gas has a constant infall velocity of ~0.5 km s-1 in the central region, leading to a mass accretion rate of 2.5 × 10-5 M sun yr-1. Consequently, we confirm that the gas infall in the GF 9-2 core is consistent with the LPH solution.

  15. Spectroscopic evidence for Davydov-like solitons in acetanilide

    NASA Astrophysics Data System (ADS)

    Careri, G.; Buontempo, U.; Galluzzi, F.; Scott, A. C.; Gratton, E.; Shyamsunder, E.

    1984-10-01

    Detailed measurements of infrared absorption and Raman scattering on crystalline acetanilide [(CH3CONHC6H5)x] at low temperature show a new band close to the conventional amide I band. Equilibrium properties and spectroscopic data rule out explanations based on a conventional assignment, crystal defects, Fermi resonance, and upon frozen kinetics between two different subsystems. Thus we cannot account for this band using the concepts of conventional molecular spectroscopy, but a soliton model, similar to that proposed by Davydov for α-helix in protein, is in satisfactory agreement with the experimental data.

  16. Vibrational spectroscopic evidence for (NO)3 formation on Cu(111).

    PubMed

    Koshida, H; Okuyama, H; Hatta, S; Aruga, T

    2016-08-01

    The formation of (NO)3 on Cu(111) was recently reported based on scanning tunneling microscopy observations [A. Shiotari et al., J. Chem. Phys. 141, 134705 (2014)]. We herein report studies into this system using electron energy loss spectroscopy and verify the above findings through vibrational analysis. For the surface covered with mixed isotopes of N(16)O and N(18)O, we observed four peaks corresponding to N-O stretching vibrations, which were ascribed to the four isotopic combinations of the trimer. Dynamic coupling within the trimer was evaluated from model calculations of the coupled oscillators. Furthermore, we observed hindered rotation and translation modes in the dipole scattering regime, suggesting that the molecular axis is tilted from the surface normal. These results provide spectroscopic support for the formation of (NO)3 on Cu(111). PMID:27497570

  17. Vibrational spectroscopic evidence for (NO)3 formation on Cu(111)

    NASA Astrophysics Data System (ADS)

    Koshida, H.; Okuyama, H.; Hatta, S.; Aruga, T.

    2016-08-01

    The formation of (NO)3 on Cu(111) was recently reported based on scanning tunneling microscopy observations [A. Shiotari et al., J. Chem. Phys. 141, 134705 (2014)]. We herein report studies into this system using electron energy loss spectroscopy and verify the above findings through vibrational analysis. For the surface covered with mixed isotopes of N16O and N18O, we observed four peaks corresponding to N-O stretching vibrations, which were ascribed to the four isotopic combinations of the trimer. Dynamic coupling within the trimer was evaluated from model calculations of the coupled oscillators. Furthermore, we observed hindered rotation and translation modes in the dipole scattering regime, suggesting that the molecular axis is tilted from the surface normal. These results provide spectroscopic support for the formation of (NO)3 on Cu(111).

  18. Even-odd staggering of the spectroscopic factor as new evidence for α clustering

    NASA Astrophysics Data System (ADS)

    Delion, D. S.; Dumitrescu, A.; Baran, V. V.

    2016-04-01

    We evidence a staggering effect of the experimental spectroscopic factors corresponding to even-even and odd-mass (odd-mass and odd-odd) α emitters. The comparison to the theoretical estimate within the standard Bardeen-Cooper-Schrieffer (BCS) approach reveals a similar staggering, but with a different behavior. It turns out that the ratio between corresponding experimental and theoretical spectroscopic factors is proportional to the experimental reduced decay width. A similar dependence was found in a previous work between the strength of the quadrupole-quadrupole α -core interaction, describing the α -decay fine structure and the reduced width. Thus, the even-odd staggering effect in the spectroscopic factor is a new evidence of the α -clustering phenomenon in medium and heavy nuclei.

  19. Spectroscopic Characterization of Mineralogy Across Vesta: Evidence of Different Lithologies

    NASA Technical Reports Server (NTRS)

    De Sanotis, M. C.; Ammannito, E.; Filacchione, G.; Capria, M. T.; Tosi, F.; Capaccioni, F.; Zambon, F.; Carraro, F.; Fonte, S.; Frigeri, A.; Jaumann, R.; Magni, G.; Marchi, S.; McCord, T. B.; McFadden, L. A.; McSween, H. Y.; Mittlefehldt, D. W.; Nathues, A.; Palomba, E.; Pieters, C. M.; Raymond, C. A.; Russell, C. T.; Turrini, D.

    2012-01-01

    The average spectrum of Vesta, obtained by VIR in the range 0.25-5.1 microns, shows clear evidence of absorption bands due to pyroxenes and thermal emissions beyond 3.5 11m. Vesta shows considerable variability across its surface in terms of spectral reflectance and emission, band depths, bands widths and bands centers, reflecting a complex geological history. Vesta's average spectrum and inferred mineralogy resemble those of howardite meteorites. On a regional scale, significant deviations are seen: the south polar 500km Rheasilvia impact crater has a higher diogenitic component, and equatorial regions show a higher eucritic component. This lithologic distribution, with a concentration of Mg-pyroxenes in the Rheasilvia area, reinforces the hypothesis of a deeper diogenitic crust excavated by the impact that formed the Rheasilvia crater, and an upper eucritic crust, whose remnants are seen in the equatorial region. This scenario has implications for Vesta differentiation, consistent with magma ocean models. However, serial magmatism models could also have concentrated pyroxene cumulates in plutons emplaced within the lower crust,

  20. Soil examination for a forensic trace evidence laboratory--Part 1: Spectroscopic techniques.

    PubMed

    Woods, Brenda; Lennard, Chris; Kirkbride, K Paul; Robertson, James

    2014-12-01

    In the past, forensic soil examination was a routine aspect of trace evidence examination in forensic science. However, in Australia, the apparent need for soil examinations has diminished and with it the capability of forensic science laboratories to carry out soil examination has been eroded. In recent years, due to soil examinations contributing to some high profile investigations, interest in soil examinations has been renewed. Routine soil examinations conducted in a forensic science laboratory by trace evidence scientists can be facilitated if the examinations are conducted using the instrumentation routinely used by these examiners. Spectroscopic techniques such as visible microspectrophotometry (MSP) and Attenuated Total Reflectance (ATR) Fourier Transform Infrared spectroscopy (FTIR) are routinely used by trace evidence analysts for the colour and compositional analysis, respectively, of forensic items, including paints, fibres, inks and toners, tapes, adhesives and other miscellaneous examinations. This article presents an examination of the feasibility of using MSP and ATR-FTIR as a first step in the forensic comparison of soils with particular reference to Australian soil samples. This initial study demonstrates MSP and ATR-FTIR can effectively be used as a screening test for the discrimination of "forensic-sized" soil samples prior to submission for more detailed analyses by a soil expert. PMID:25205526

  1. Oligomerization in As (III) sulfide solutions: Theoretical constraints and spectroscopic evidence

    NASA Astrophysics Data System (ADS)

    Helz, George R.; Tossell, John A.; Charnock, John M.; Pattrick, Richard A. D.; Vaughan, David J.; David Garner, C.

    1995-11-01

    Bond distances, vibrational frequencies, gas-phase energetics, and proton affinities for various thioarsenite molecules and ions are predicted from molecular orbital theory and used to interpret EXAFS and Raman spectra of dissolved thioarsenites in undersaturated, alkaline 1 M NaHS solutions. From MO predictions, Raman peaks at 325 and 412 cm - are assigned to AsS(SH) 2- and a peak at 382 cm - to AsS 2(SH) 2- At alkaline pH, As-S distances in dissolved thioarsenites are 2.21-2.23 Å and no statistically significant As-As interactions are recorded, consistent with predominance of the monomers, AsS(SH) 2- and AsS 2(SH ) 2-. Estimated proton affinities suggest that thioarsenites with a negative charge greater than 2 are unstable in water. In seeming contradiction to this spectroscopic evidence, a new analysis of published solubility studies reinforces previous inferences that the trimer, As 3S 4(SH) 2-, is the predominant thioarsenite in systems saturated with As 2S 3. Previously proposed dimeric species of the form, H xAs2S 4x- , are rejected based on predicted thermodynamic properties. Dimer plus tetramer combinations also are rejected. Estimated free energies for AsS (OH)(SH) - and AsS(SH) 2- are presented. We reconcile the spectroscopic and solubility evidence by showing that in undersaturated solutions monomers can become thermodynamically favored over oligomers. This pattern should be looked for in other sulfide systems as well. Sulfidic natural waters are in many cases undersaturated with respect to AS 2S 3 phases, so monomeric thioarsenites could be more important in nature than the trimers that have been characterized in saturated solutions. EXAFS spectra show that amorphous AS 2S 3 resembles orpiment in the first shell around As, but that higher shells are disordered. Disorder may be caused by occasional realgar-like, As-As bonds, consistent with the observation that amorphous AS 2S 3 is slightly S deficient.

  2. Visible-NIR Spectroscopic Evidence for the Composition of Low-Albedo Altered Soils on Mars

    NASA Astrophysics Data System (ADS)

    Murchie, S.; Merenyi, E.; Singer, R.; Kirkland, L.

    1996-03-01

    Spectroscopic studies of altered Martian soils at visible and at NIR wavelengths have generally supported the canonical model of the surface layer as consisting mostly of 2 components, bright red hematite-containing dust and dark gray pyroxene-containing sand. However several of the studies have also provided tantalizing evidence for distinct 1 micrometer Fe absorptions in discrete areas, particularly dark red soils which are hypothesized to consist of duricrust. These distinct absorptions have been proposed to originate from one or more non-hematitic ferric phases. We have tested this hypothesis by merging high spatial resolution visible- and NIR-wavelength data to synthesize composite 0.44-3.14 1lm spectra for regions of western Arabia and Margaritifer Terra. The extended wavelength coverage allows more complete assessment of ferric, ferrous, and H2O absorptions in both wavelength ranges. The composite data show that, compared to nearby bright red soil in Arabia, dark red soil in Oxia has a lower albedo, a more negative continuum slope, and a stronger 3 micrometer H2O absorption . However Fe absorptions are closely similar in position and depth. These results suggest that at least some dark red soils may differ from "normal" dust and mafic sand more in texture than in Fe mineralogy, although there appears to be enrichment in a water-containing phase and/or a dark, spectrally neutral phase. In contrast, there is clear evidence for enrichment of a low-albedo ferric mineral in dark gray soils composing Sinus Meridiani. These have visible- and NIR-wavelength absorptions consistent with crystalline hematite with relatively little pyroxene, plus a very weak 3 micrometer H2O absorption. These properties suggest a Ethology richer in crystalline hematite and less hydrated than both dust and mafic-rich sand.

  3. An Optical Spectroscopic Survey of the Serpens Main Cluster: Evidence for Two Populations?

    NASA Astrophysics Data System (ADS)

    Erickson, Kristen L.; Wilking, Bruce A.; Meyer, Michael R.; Kim, Jinyoung Serena; Sherry, William; Freeman, Matthew

    2015-03-01

    We have completed an optical spectroscopic survey of a sample of candidate young stars in the Serpens Main star-forming region selected from deep B, V, and R band images. While infrared, X-ray, and optical surveys of the cloud have identified many young stellar objects (YSOs), these surveys have been biased toward particular stages of pre-main sequence evolution. We have obtained over 700 moderate resolution optical spectra that, when combined with published data, have led to the identification of 63 association members based on the presence of Hα in emission, lithium absorption, X-ray emission, a mid-infrared excess, and/or reflection nebulosity. Twelve YSOs are identified based on the presence of lithium absorption alone. An additional 16 objects are classified as possible association members and their pre-main sequence nature is in need of confirmation. Spectral types along with V and R band photometry were used to derive effective temperatures and bolometric luminosities for association members to compare with theoretical tracks and isochrones for pre-main sequence stars. An average age of 2 Myr is derived for this population. When compared to simulations, there is no obvious evidence for an age spread when considering the major sources of uncertainties in the derived luminosities. However when compared to the young cluster in Ophiuchus, the association members in Serpens appear to have a larger spread in luminosities and hence ages which could be intrinsic to the region or the result of a foreground population of YSOs associated with the Aquila Rift. Modeling of the spectral energy distributions from optical through mid-infrared wavelengths has revealed three new transition disk objects, making a total of six in the cluster. Echelle spectra for a subset of these sources enabled estimates of v sin i for seven association members. Analysis of gravity-sensitive lines in the echelle and moderate resolution spectra of the association members indicate surface

  4. Ground-Based Evidence of Spectroscopic Features in the Atmosphere of HAT-P-26b

    NASA Astrophysics Data System (ADS)

    Stevenson, Kevin B.; Bean, Jacob; Gilbert, Greg; Line, Michael R.; Fortney, Jonathan J.; Desert, Jean-Michel

    2016-01-01

    HAT-P-26b is a low-density, Neptune-mass exoplanet that transits its K1 host star every 4.2 days. With an equilibrium temperature of ~990 K, its atmosphere is expected to contain appreciable amounts of water and methane. However, due to obscuring clouds, the detection of spectroscopic features in other planetary atmospheres of comparable temperature has been elusive. Using Magellan's recently-upgraded LDSS-3C detector, we performed transmission spectroscopy observations of HAT-P-26b in the red optical (0.7 - 1.0 μm) and acquired broadband Spitzer measurements at 3.6 and 4.5 μm. We will present the first constraints on the transmission spectrum of HAT-P-26b, which favor the detection of spectroscopic features and argue against the presence of thick, high-level clouds. We will also compare our findings to those of other characterized exoplanets and examine potential trends in the data.

  5. Evidences of long lived cages in functionalized polymers: Effects on chromophore dynamic and spectroscopic properties

    NASA Astrophysics Data System (ADS)

    Prampolini, Giacomo; Monti, Susanna; De Mitri, Nicola; Barone, Vincenzo

    2014-05-01

    molecules between the two zones and a significant modulation of the flexibility and mobility of the dye. Very similar trends were found for the same g (r) computed in the GS. For this latter state, the impact on the distribution of the values adopted by the δ1 dihedral angle, which defines the orientation of the naphthalene ring in relation to the carboxyl group (Figure 4), is evident in the right panel of Figure 1: in toluene solution there are two distinct peaks centered around 0° and ±180°, meaning that two planar conformations are equally probable. Instead, inside the polymer only the δ1≈0° conformer is populated, confirming that the initial orientation of this portion of the probe is preserved by the hindering action of the close polymer chains which prevent a complete rotation of the naphthoyloxy group. The same constraining was also found in the EES, though less evident because of a decreased flexibility of the δ1 torsion.In order to support this view, the effect on dye’s flexibility of the intermolecular interactions of the latter with the polymer bundle was checked and compared with the one due to the dye-solvent interactions established in toluene solution. This was accomplished through a mean field descriptor which was connected to the torsional degrees of freedom, as detailed in the Supporting Information. In this particular case it was interesting to examine the specific behavior of the δ1 dihedral angle. The resulting mean field W (δ1) in the polymer and in toluene solution, displayed in Figure 2, presents a marked difference between the two surrounding media with toluene leading to a nearly vanishing and flatter W(δ1). It is also worth noticing that the entanglement of the polymer around the dye creates a supplementary well, centered at about δ1 = 0, that constrains this angle to librate within a limited interval rather than exploring the complete range of values.Further proofs of the existence of a tight and stable cleft and its constraining

  6. Spectroscopic evidence for spin-polarized silicon atoms on Si(553)-Au

    SciTech Connect

    Snijders, Paul C; Johnson, P.S.; Guisinger, Nathan; Erwin, S. C.; Himpsel, F.J.

    2012-01-01

    The stepped Si(553)-Au surface undergoes a $1\\times3$ reconstruction at low temperature which has recently been interpreted theoretically as the $\\times3$ ordering of spin-polarized silicon atoms along a step edge in each surface unit cell. This predicted magnetic ground state has a clear spectroscopic signature---a silicon step-edge state at $0.5$ eV above the Fermi level---that arises from strong exchange splitting and hence would not occur without spin polarization. Here we report spatially resolved scanning tunneling spectroscopy data for Si(553)-Au that reveal key differences in the unoccupied step-edge density of states between room temperature and $40$ K. At low temperature we find an unoccupied state at 0.55 eV above every third step-edge silicon atom, in excellent agreement with the spin-polarized ground state predicted theoretically.

  7. Search for evidence of Allene on Titan with new spectroscopic data

    NASA Astrophysics Data System (ADS)

    Jolly, A.; Benilan, Y.; Manceron, L.; Kwabia-Tchana, F.; Nixon, C.

    2015-10-01

    The Composite Infrared Spectrometer (CIRS) on board Cassini has recorded spectra in the far and mid-infrared since 2004 with a spectral resolution of up to0.5 cm-1. Mismatch between observed and model spectra obtained from the available line lists has led us to study the spectroscopic parameters of HC3N, C4H 2 and C2 N2, the longest gas phase carbon chains observed so far on Titan. Fundamental and hot band intensities, as well as line lists were systematically verified by comparison with new laboratory spectra. Erroneous band intensities,as well as an absence or shortage of hot band transitions in the available line lists leading to model-data mismatches and inaccurate quantifications have been found.

  8. Spectroscopic Evidence for SN 2010ma Associated with GRB 101219B

    NASA Astrophysics Data System (ADS)

    Sparre, M.; Sollerman, J.; Fynbo, J. P. U.; Malesani, D.; Goldoni, P.; de Ugarte Postigo, A.; Covino, S.; D'Elia, V.; Flores, H.; Hammer, F.; Hjorth, J.; Jakobsson, P.; Kaper, L.; Leloudas, G.; Levan, A. J.; Milvang-Jensen, B.; Schulze, S.; Tagliaferri, G.; Tanvir, N. R.; Watson, D. J.; Wiersema, K.; Wijers, R. A. M. J.

    2011-07-01

    We report on the spectroscopic detection of supernova SN 2010ma associated with the long gamma-ray burst GRB 101219B. We observed the optical counterpart of the GRB on three nights with the X-shooter spectrograph at the Very Large Telescope. From weak absorption lines, we measure a redshift of z = 0.55. The first-epoch UV-near-infrared afterglow spectrum, taken 11.6 hr after the burst, is well fit by a power law consistent with the slope of the X-ray spectrum. The second- and third-epoch spectra (obtained 16.4 and 36.7 days after the burst), however, display clear bumps closely resembling those of the broad-lined type-Ic SN 1998bw if placed at z = 0.55. Apart from demonstrating that spectroscopic SN signatures can be observed for GRBs at these large distances, our discovery makes a step forward in establishing a general connection between GRBs and SNe. In fact, unlike most previous unambiguous GRB-associated SNe, GRB 101219B has a large gamma-ray energy (E iso = 4.2 × 1051 erg), a bright afterglow, and obeys the "Amati" relation, thus being fully consistent with the cosmological population of GRBs. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile, under program 086.A-0073(B). Also 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 e Tecnologia (Brazil), and Ministerio de Ciencia, Tecnología e Innovacón Productiva (Argentina).

  9. Spectroscopic Evidence for Clusters of Like-Charged Ions in Ionic Liquids Stabilized by Cooperative Hydrogen Bonding.

    PubMed

    Knorr, Anne; Stange, Peter; Fumino, Koichi; Weinhold, Frank; Ludwig, Ralf

    2016-02-01

    Direct spectroscopic evidence for hydrogen-bonded clusters of like-charged ions is reported for ionic liquids. The measured infrared O-H vibrational bands of the hydroxyethyl groups in the cations can be assigned to the dispersion-corrected DFT calculated frequencies of linear and cyclic clusters. Compensating the like-charge Coulomb repulsion, these cationic clusters can range up to cyclic tetramers resembling molecular clusters of water and alcohols. These ionic clusters are mainly present at low temperature and show strong cooperative effects in hydrogen bonding. DFT-D3 calculations of the pure multiply charged clusters suggest that the attractive hydrogen bonds can compete with repulsive Coulomb forces. PMID:26670942

  10. Studies on the inclusion behavior of 9-Aminoacridine into cyclodextrins: Spectroscopic and theoretical evidences

    NASA Astrophysics Data System (ADS)

    Manivannan, C.; Vijay Solomon, R.; Venuvanalingam, P.; Renganathan, R.

    2013-02-01

    9-Aminoacridine (9-AA) is an important attractive pharmaceutical drug employed as chemotheraptic agent for wound dressings. However, 9-AA possesses limited solubility and rapid metabolic decomposition renders this potential drug to limit its applications. Here we propose cyclodextrins (CDs) as a drug carrier to improve the bioavailability, solubility of 9-AA. The interaction between 9-AA and CDs (α-CD and β-CD) has been studied using UV-Vis absorption, steady state time resolved fluorescence, 1H NMR and FT-IR spectroscopy techniques. The spectroscopic measurements show that 9-AA does not form stable complex with α-CD and also confirmed by DFT calculations. On the other hand, 9-AA forms inclusion complex with β-CD in a 1:1 stoichiometry ratio. Our DFT results suggest that 9-AA stabilizes inside the CD environment through hydrogen bonding that has unambiguously confirmed by AIM analysis. Thus our studies provide a useful insights in the development of Aminoacridine based drugs & its delivery through a suitable carrier like CDs.

  11. Spectroscopic evidence for biochar amendment promoting humic acid synthesis and intensifying humification during composting.

    PubMed

    Wang, Cheng; Tu, Qiaoping; Dong, Da; Strong, P J; Wang, Hailong; Sun, Bin; Wu, Weixiang

    2014-09-15

    Despite the many benefits of biochar amendment in composting, little information is available about its effects on organic matter humification during the process. In this study the analytical results for two in-vessel composting piles were compared, one amended with biochar (VPSB, pig manure+sawdust+biochar) and the other serving as a control (VPS, pig manure+sawdust). During the 74 days of humification, the increased content of humic acid carbon in VPSB is 16.9% more than that of the control. Spectroscopic analyses show a higher O-alkyl C/alkyl C ratio and aromaticity in VPSB at the thermophilic phase, and peak intensities of fulvic-like and humic-like substances were achieved faster in VPSB than VPS. These data inferred that biochar amendment promoted the neo-synthesis of humic acids and intensified the humification of pig manure. Increase in carboxylic groups of biochar as a result of oxidation reactions and sorption of humic substances may correspond to the faster formation of aromatic polymers in biochar-supplemented composting pile. The results suggest that biochar amendment might be a potential method to enhance humification during pig manure composting. PMID:25194558

  12. Spectroscopic Evidence for the Two C-H-Cleaving Intermediates of Aspergillus nidulans Isopenicillin N Synthase.

    PubMed

    Tamanaha, Esta; Zhang, Bo; Guo, Yisong; Chang, Wei-Chen; Barr, Eric W; Xing, Gang; St Clair, Jennifer; Ye, Shengfa; Neese, Frank; Bollinger, J Martin; Krebs, Carsten

    2016-07-20

    The enzyme isopenicillin N synthase (IPNS) installs the β-lactam and thiazolidine rings of the penicillin core into the linear tripeptide l-δ-aminoadipoyl-l-Cys-d-Val (ACV) on the pathways to a number of important antibacterial drugs. A classic set of enzymological and crystallographic studies by Baldwin and co-workers established that this overall four-electron oxidation occurs by a sequence of two oxidative cyclizations, with the β-lactam ring being installed first and the thiazolidine ring second. Each phase requires cleavage of an aliphatic C-H bond of the substrate: the pro-S-CCys,β-H bond for closure of the β-lactam ring, and the CVal,β-H bond for installation of the thiazolidine ring. IPNS uses a mononuclear non-heme-iron(II) cofactor and dioxygen as cosubstrate to cleave these C-H bonds and direct the ring closures. Despite the intense scrutiny to which the enzyme has been subjected, the identities of the oxidized iron intermediates that cleave the C-H bonds have been addressed only computationally; no experimental insight into their geometric or electronic structures has been reported. In this work, we have employed a combination of transient-state-kinetic and spectroscopic methods, together with the specifically deuterium-labeled substrates, A[d2-C]V and AC[d8-V], to identify both C-H-cleaving intermediates. The results show that they are high-spin Fe(III)-superoxo and high-spin Fe(IV)-oxo complexes, respectively, in agreement with published mechanistic proposals derived computationally from Baldwin's founding work. PMID:27193226

  13. Interaction between aqueous uranium (VI) and sulfide minerals: Spectroscopic evidence for sorption and reduction

    SciTech Connect

    Wersin, P.; Hochella, M.F. Jr.; Persson, P.; Redden, G.; Leckie, J.O. ); Harris, D.W. )

    1994-07-01

    The interaction of aqueous U(VI) with galena and pyrite surfaces under anoxic conditions has been studied by solution analysis and by spectroscopic methods. The solution data indicate that uranyl uptake is strongly dependent on pH; maximum uptake (>98%) occurs above a pH range of between 4.8 and 5.5, depending on experimental conditions. Increasing the sorbate/sorbent ratio results in a relative decrease in uptake of uranyl and in slower sorption kinetics. Auger electron spectroscopy analysis indicates an inhomogeneous distribution of sorbed uranium at the surface. In the case of galena, formation of small precipitates ([approximately] 40 nm wide needles) of a uranium oxide compound are found. Pyrite shows a patchy distribution of uranium, mainly associated with oxidized surface species of sulfur and iron. X-ray photoelectron spectroscopy yields insight into possible redox processes indicating, for both sulfides, the concomitant formation of polysulfides and a uranium oxide compound with a mixed oxidation state at a U(VI)/U(IV) ratio of [approximately] 2. Furthermore, in the case of pyrite, at pH above 6 increased oxidation of sulfur and iron and higher relative amounts of unreduced surface-uranyl are observed. Fourier Transformed Infrared analysis of surface-bound uranyl shows a significant shift of the asymmetric stretching frequency to lower wavenumbers which is consistent with the formation of a U[sub 3]O[sub 8]-type compound and thus, independently, confirms the partial reduction of uranyl at the sulfide surface. The combination of AES, XPS, and FTIR provides a powerful approach for identifying mechanisms that govern the interaction of redox sensitive compounds in aqueous systems. The overall results indicate that sulfide minerals are efficient scavengers of soluble uranyl. Comparing the results with recent field observations, the authors suggest that thermodynamically metastable U[sub 3]O[sub 8] controls uranium concentrations in many anoxic groundwaters.

  14. Evidence for CO in Jupiter's atmosphere from airborne spectroscopic observations at 5 microns

    NASA Technical Reports Server (NTRS)

    Larson, H. P.; Fink, U.; Treffers, R. R.

    1978-01-01

    High-altitude (12.4 km) spectra of Jupiter recorded at the Kuiper Airborne Observatory are analyzed for the presence of CO absorption lines. A line-by-line comparison of Jupiter's spectrum with that of carbon monoxide is presented, as well as a correlation analysis that includes the influence of other gases present in Jupiter's atmosphere (CH4, NH3, H2O, PH3, and GeH4). The resulting evidence points strongly to the presence of carbon monoxide in Jupiter's atmosphere, thus strengthening Beer's evidence for it. Possible explanations for the existence and observability of Jovian CO, including convection from hotter, deeper layers or decomposition of organic molecules, are explored. A recent suggestion that the Jovian CO is restricted to stratospheric levels is not supported by the observations.

  15. First Spectroscopic Evidence for High Ionization State and Low Oxygen Abundance in Lyα Emitters

    NASA Astrophysics Data System (ADS)

    Nakajima, Kimihiko; Ouchi, Masami; Shimasaku, Kazuhiro; Hashimoto, Takuya; Ono, Yoshiaki; Lee, Janice C.

    2013-05-01

    We present results from Keck/NIRSPEC and Magellan/MMIRS follow-up spectroscopy of Lyα emitters (LAEs) at z = 2.2 identified in our Subaru narrowband survey. We successfully detect Hα emission from seven LAEs, and perform a detailed analysis of six LAEs free from active galactic nucleus activity, two out of which, CDFS-3865 and COSMOS-30679, have [O II] and [O III] line detections. They are the first [O II]-detected LAEs at high-z, and their [O III]/[O II] ratios and R23-indices provide the first simultaneous determinations of ionization parameter and oxygen abundance for LAEs. CDFS-3865 has a very high ionization parameter (q_{ion}=2.5^{+1.7}_{-0.8} \\times 10^8 cm s-1) and a low oxygen abundance (12+log (O/H)=7.84^{+0.24}_{-0.25}) in contrast with moderate values of other high-z galaxies such as Lyman break galaxies (LBGs). COSMOS-30679 also possesses a relatively high ionization parameter (q_{ion}=8^{+10}_{-4} \\times 10^7 cm s-1) and a low oxygen abundance (12+log (O/H)=8.18^{+0.28}_{-0.28}). Both LAEs appear to fall below the mass-metallicity relation of z ~ 2 LBGs. Similarly, a low metallicity of 12 + log (O/H) < 8.4 is independently indicated for typical LAEs from a composite spectrum and the [N II]/Hα index. Such high ionization parameters and low oxygen abundances can be found in local star-forming galaxies, but this extreme local population occupies only ~0.06% of the Sloan Digital Sky Survey spectroscopic galaxy sample with a number density ~100 times smaller than that of LAEs. With their high ionization parameters and low oxygen abundances, LAEs would represent an early stage of galaxy formation dominated by massive stars in compact star-forming regions. High-q ion galaxies like LAEs would produce ionizing photons efficiently with a high escape fraction achieved by density-bounded H II regions, which would significantly contribute to cosmic reionization at z > 6. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is

  16. FIRST SPECTROSCOPIC EVIDENCE FOR HIGH IONIZATION STATE AND LOW OXYGEN ABUNDANCE IN Ly{alpha} EMITTERS ,

    SciTech Connect

    Nakajima, Kimihiko; Shimasaku, Kazuhiro; Hashimoto, Takuya; Ono, Yoshiaki; Ouchi, Masami; Lee, Janice C.

    2013-05-20

    We present results from Keck/NIRSPEC and Magellan/MMIRS follow-up spectroscopy of Ly{alpha} emitters (LAEs) at z = 2.2 identified in our Subaru narrowband survey. We successfully detect H{alpha} emission from seven LAEs, and perform a detailed analysis of six LAEs free from active galactic nucleus activity, two out of which, CDFS-3865 and COSMOS-30679, have [O II] and [O III] line detections. They are the first [O II]-detected LAEs at high-z, and their [O III]/[O II] ratios and R23-indices provide the first simultaneous determinations of ionization parameter and oxygen abundance for LAEs. CDFS-3865 has a very high ionization parameter (q{sub ion}=2.5{sup +1.7}{sub -0.8} Multiplication-Sign 10{sup 8} cm s{sup -1}) and a low oxygen abundance (12+ log (O/H)=7.84{sup +0.24}{sub -0.25}) in contrast with moderate values of other high-z galaxies such as Lyman break galaxies (LBGs). COSMOS-30679 also possesses a relatively high ionization parameter (q{sub ion}=8{sup +10}{sub -4} Multiplication-Sign 10{sup 7} cm s{sup -1}) and a low oxygen abundance (12+ log (O/H)=8.18{sup +0.28}{sub -0.28}). Both LAEs appear to fall below the mass-metallicity relation of z {approx} 2 LBGs. Similarly, a low metallicity of 12 + log (O/H) < 8.4 is independently indicated for typical LAEs from a composite spectrum and the [N II]/H{alpha} index. Such high ionization parameters and low oxygen abundances can be found in local star-forming galaxies, but this extreme local population occupies only {approx}0.06% of the Sloan Digital Sky Survey spectroscopic galaxy sample with a number density {approx}100 times smaller than that of LAEs. With their high ionization parameters and low oxygen abundances, LAEs would represent an early stage of galaxy formation dominated by massive stars in compact star-forming regions. High-q{sub ion} galaxies like LAEs would produce ionizing photons efficiently with a high escape fraction achieved by density-bounded H II regions, which would significantly contribute to

  17. X-ray photoelectron spectroscopic evidence for bacteria-enhanced dissolution of hornblende

    NASA Astrophysics Data System (ADS)

    Kalinowski, B. E.; Liermann, L. J.; Brantley, S. L.; Barnes, A.; Pantano, C. G.

    2000-04-01

    hornblende surface. Surface complexation is favored because of the extremely high association constants for siderophore + Fe(III). X-ray photoelectron spectroscopic data is therefore consistent with a model wherein enhanced Fe release by these bacteria or desferrioxamine B is caused by Fe-siderophore complexation at the silicate surface. Such complexation presumably weakens bonds between the Fe and the oxide lattice, causing enhanced Fe leaching and an Fe-depleted surface. Some leaching may also be due to LMWOA, although this is interpreted to be of secondary importance.

  18. Spectroscopic evidence for new denser structure of silica glass under ultrahigh pressure (Invited)

    NASA Astrophysics Data System (ADS)

    Murakami, M.

    2013-12-01

    Silica glass is a prototype network-forming glass serving as the basic framework of a variety of glasses, which widely used as a technologically useful material. Polyamorphism in silica glass is thus one of the most fascinating and puzzling topics in condensed matter physics. Silica glass can be also considered as the major and simplest analogue for all geophysically relevant silicate melts/magmas. Therefore, knowledge of the structural changes and the densification mechanisms of the silica glass under high-pressure is particularly important to provide the fundamental constraints on the thermal, chemical, and dynamical states of the Earth's interior. Previous experimental investigations of the highpressure structure of silicate glasses up to a pressure of ~40 GPa strongly suggest that changes in the Si-O coordination number are a key component of the densification mechanism. However, little is known about further densification above ~40 GPa due to experimental challenges and the lack of suitable in-situ structural probes. Acoustic wave velocity measurement is one of the most promising approaches for detecting structural changes of glasses and melts, inasmuch as the sound velocity directly reflects the density and elasticity, regardless of whether a sample is crystalline or amorphous. Our newly developed in-situ high-pressure Brillouin scattering spectroscopic system has recently proven to be highly suitable for exploring the acoustic velocities under ultrahigh-pressure conditions approaching to 200 GPa. Our recent in-situ high-pressure Brillouin scattering results for several silicate glasses at pressures above 200 GPa have revealed an anomalous increase in the effect of pressure on velocity at ~130-140 GPa. We infer this to be a new transition to a denser structure that is likely associated with the onset of a change in Si-O coordination number to higher than sixfold. However, the change in acoustic wave velocity profile as a function of pressure only indicates

  19. Spectroscopic Evidence for Strong Quantum Spin Fluctuations with Itinerant Character in YFe2Ge2

    DOE PAGESBeta

    Sirica, N.; Bondino, F.; Nappini, S.; Piz, I.; Poudel, L.; Christianson, Andrew D.; Mandrus, D.; Singh, David J; Mannella, Norman

    2015-03-04

    We report x-ray absorption and photoemission spectroscopy of the electronic structure in the normal state of metallic YFe2Ge2. The data reveal evidence for large fluctuating spin moments on the Fe sites, as indicated by exchange multiplets appearing in the Fe 3s core-level photoemission spectra, even though the compound does not show magnetic order. The magnitude of the multiplet splitting is comparable to that observed in the normal state of the Fe-pnictide superconductors. This shows a connection between YFe2Ge2 and the Fe-based superconductors even though it contains neither pnictogens nor chalcogens. Finally, the implication is that the chemical range of compoundsmore » showing at least one of the characteristic magnetic signatures of the Fe-based superconductors is broader than previously thought.« less

  20. In Situ Molecular Spectroscopic Evidence for CO2 Intercalation into Montmorillonite in Supercritical Carbon Dioxide

    SciTech Connect

    Loring, John S.; Schaef, Herbert T.; Turcu, Romulus VF; Thompson, Christopher J.; Miller, Quin RS; Martin, Paul F.; Hu, Jian Z.; Hoyt, David W.; Qafoku, Odeta; Ilton, Eugene S.; Felmy, Andrew R.; Rosso, Kevin M.

    2012-04-25

    The interaction of anhydrous supercritical CO2 (scCO2) with both kaolinite and ~1W (i.e. close to but less than one layer of hydration) calcium-saturated montmorillonite was investigated under conditions relevant to geologic carbon sequestration (50 °C and 90 bar). The CO2 molecular environment was probed in situ using a combination of three novel high-pressure techniques: X-ray diffraction, magic angle spinning nuclear magnetic resonance spectroscopy and attenuated total reflection infrared spectroscopy. We report the first direct evidence that the expansion of montmorillonite under scCO2 conditions is due to CO2 migration into the interlayer. Intercalated CO2 molecules are rotationally constrained and do not appear to react with waters to form bicarbonate or carbonic acid. In contrast, CO2 does not intercalate into kaolinite. The findings show that predicting the seal integrity of caprock will have complex dependence on clay mineralogy and hydration state.

  1. In situ molecular spectroscopic evidence for CO2 intercalation into montmorillonite in supercritical carbon dioxide.

    PubMed

    Loring, John S; Schaef, Herbert T; Turcu, Romulus V F; Thompson, Christopher J; Miller, Quin R S; Martin, Paul F; Hu, Jianzhi; Hoyt, David W; Qafoku, Odeta; Ilton, Eugene S; Felmy, Andrew R; Rosso, Kevin M

    2012-05-01

    The interaction of anhydrous supercritical CO(2) (scCO(2)) with both kaolinite and ~1W (i.e., close to but less than one layer of hydration) calcium-saturated montmorillonite was investigated under conditions relevant to geologic carbon sequestration (50 °C and 90 bar). The CO(2) molecular environment was probed in situ using a combination of three novel high-pressure techniques: X-ray diffraction, magic angle spinning nuclear magnetic resonance spectroscopy, and attenuated total reflection infrared spectroscopy. We report the first direct evidence that the expansion of montmorillonite under scCO(2) conditions is due to CO(2) migration into the interlayer. Intercalated CO(2) molecules are rotationally constrained and do not appear to react with waters to form bicarbonate or carbonic acid. In contrast, CO(2) does not intercalate into kaolinite. The findings show that predicting the seal integrity of caprock will have complex dependence on clay mineralogy and hydration state. PMID:22533894

  2. Reigniting the Debate: First Spectroscopic Evidence for Stratospheres In Hot Jupiters

    NASA Astrophysics Data System (ADS)

    Mandell, Avi M.; Haynes, Korey; Madhusudhan, Nikku; Deming, Drake; Knutson, Heather

    2015-12-01

    Hot Jupiters represent an extreme end of the exoplanet distribution: they orbit very close to their host stars, which subjects them to an intense heating from stellar radiation. An inverted temperature structure (i.e. a stratosphere) was an early observable prediction from atmospheric models of these planets, which demonstrated that high-temperature absorbers such as TiO and VO could reprocess incident UV/visible irradiation to heat the upper layers of the atmosphere.Evidence for such thermal inversions began with the first secondary eclipse measurements of transiting hot Jupiters taken with the IRAC camera on Spitzer, offering the chance to physical processe at work in the atmospheres of hot exoplanets. However, these efforts have been stymied by recent revelations of significant systematic biases and uncertainties buried within older Spitzer results, calling into question whether or not temperature inversions are actually present in hot Jupiters.We have recently published spectroscopy of secondary eclipses of the extrasolar planet WASP-33b using the Wide Field Camera 3 (WFC3) on the Hubble Space Telescope, which allow us to constrain the temperature structure and composition of its dayside atmosphere. WASP-33b is one of the most highly irradiated hot Jupiters discovered to date and orbits a relatively inactive A star, making it an excellent candidate for eclipse spectroscopy at NIR wavelengths (1.1 - 1.7 µm). We find that a fit to combined data from HST, Spitzer and ground-based photometry can rule out models without a temperature inversion; additionally, we find that our measured spectrum displays excess in the measured flux toward short wavelengths that is best explained as emission from TiO.This discovery re-opens the debate on the presence and origin of stratospheres in hot Jupiters, but it also confirms that the combination of HST spectroscopy and a robust analysis of Spitzer and ground-based photometry can conclusively detect thermally inverted atmospheres

  3. Spectroscopic evidence of 'jumping and pecking' of cholinium and H-bond enhanced cation-cation interaction in ionic liquids.

    PubMed

    Knorr, Anne; Fumino, Koichi; Bonsa, Anne-Marie; Ludwig, Ralf

    2015-12-14

    The subtle energy-balance between Coulomb-interaction, hydrogen bonding and dispersion forces governs the unique properties of ionic liquids. To measure weak interactions is still a challenge. This is in particular true in the condensed phase wherein a melange of different strong and directional types of interactions is present and cannot be detected separately. For the ionic liquids (2-hydroxyethyl)-trimethylammonium (cholinium) bis(trifluoro-methylsulfonyl)amide and N,N,N-trimethyl-N-propylammonium bis(trifluoromethylsulfonyl)amide which differ only in the 2-hydroxyethyl and the propyl groups of the cations, we could directly observe distinct vibrational signatures of hydrogen bonding between the cation and the anion indicated by 'jumping and pecking' motions of cholinium. The assignment could be confirmed by isotopic substitution H/D at the hydroxyl group of cholinium. For the first time we could also find direct spectroscopic evidence for H-bonding between like-charged ions. The repulsive Coulomb interaction between the cations is overcome by cooperative hydrogen bonding between the 2-hydroxyethyl functional groups of cholinium. This H-bond network is reflected in the properties of protic ionic liquids (PILs) such as viscosities and conductivities. PMID:26292169

  4. Spectroscopic Evidence for the Localization of Skyrmions near ν=1 as Tarrow 0

    NASA Astrophysics Data System (ADS)

    Barrett, S. E.

    2002-03-01

    Optically pumped nuclear magnetic resonance (OPNMR) measurements of ^71Ga spectra were carried out in an n-doped GaAs/Al_0.1Ga_0.9As multiple quantum well (MQW) sample near Landau level filling factor ν=1. Novel spin textures called skyrmions are predicted(S. L. Sondhi, A. Karlhede, S. A. Kivelson, and E. H. Rezayi, Phys. Rev. B) 47, 16419 (1993); H. A. Fertig, L. Brey, R. Cote, and A. H. MacDonald, Phys. Rev. B 50, 11018 (1994). to be the charged quasiparticles introduced by small deviations (|δν |) from this ferromagnetic quantum Hall ground state. At ``high'' temperatures, the spectra provide evidence for delocalized skyrmions. As the temperature is lowered (down to T ≈ 0.3 K), a ``tilted plateau'' emerges in the Knight shift data, which is a novel experimental signature of quasiparticle localization.(P. Khandelwal, A. E. Dementyev, N. N. Kuzma, S. E. Barrett, L. N. Pfeiffer, and K. W. West, Phys. Rev. Lett.) 86, 5353 (2001). The dependence of the spectra on both T and ν suggests that the localization is a collective process. The frozen limit spectra appear to rule out a 2D lattice of conventional skyrmions.

  5. Surface complexation modeling and spectroscopic evidence of antimony adsorption on iron-oxide-rich red earth soils.

    PubMed

    Vithanage, Meththika; Rajapaksha, Anushka Upamali; Dou, Xiaomin; Bolan, Nanthi S; Yang, Jae E; Ok, Yong Sik

    2013-09-15

    Few studies have investigated surface complexation of antimony (Sb) on natural sorbents. In addition, intrinsic acidic constants, speciation, and spectroscopic data are scarce for Sb sorption in soil. Only simple sorption models have been proposed to describe the sorption of Sb(V) on specific mineral surfaces. This study therefore assessed the mechanisms of Sb(III) and Sb(V) adsorption on natural red earth (NRE), a naturally occurring iron coated sand, at various pHs and Sb loadings. The Sb(V) adsorption followed typical anion adsorption curve with adsorption reaching maximum around pH 4-5, while no pH dependence was observed for Sb(III) sorption. The FT-IR spectra revealed that shifts in absorbance of the hydroxyl groups in iron-oxide were related to the Fe-O-Sb bonds and provided evidence for inner sphere bond formation. Direct evidence on the strong interaction of Sb(III) and Sb(V) with ≡Fe-O and ≡Al-O was observed from the decrease in Fe-2p, Al-2p, and Si-2p peaks of the X-ray photoelectron spectroscopy (XPS) data before and after Sb(V) and Sb(III) adsorption on NRE. Successful data modeling using the 2-pK diffuse double layer model (DDLM) with the FITEQL revealed that sorption occurs through the formation of bidentate mononuclear and binuclear complexes. Model simulations showed a high affinity to the ≡FeOH sites at high Sb loadings, whereas at low loadings, both≡ FeOH and ≡AlOH sites showed similar affinities to Sb. In the case of Sb(V), multilayer formation was also revealed in addition to surface complexation by the isotherm data fitted with the Freundlich model and two sites Langmuir equations, which indicated heterogeneous multilayer adsorption of Sb(V) on NRE. PMID:23791229

  6. Evidences of long lived cages in functionalized polymers: Effects on chromophore dynamic and spectroscopic properties

    NASA Astrophysics Data System (ADS)

    Prampolini, Giacomo; Monti, Susanna; De Mitri, Nicola; Barone, Vincenzo

    2014-05-01

    molecules between the two zones and a significant modulation of the flexibility and mobility of the dye. Very similar trends were found for the same g (r) computed in the GS. For this latter state, the impact on the distribution of the values adopted by the δ1 dihedral angle, which defines the orientation of the naphthalene ring in relation to the carboxyl group (Figure 4), is evident in the right panel of Figure 1: in toluene solution there are two distinct peaks centered around 0° and ±180°, meaning that two planar conformations are equally probable. Instead, inside the polymer only the δ1≈0° conformer is populated, confirming that the initial orientation of this portion of the probe is preserved by the hindering action of the close polymer chains which prevent a complete rotation of the naphthoyloxy group. The same constraining was also found in the EES, though less evident because of a decreased flexibility of the δ1 torsion.In order to support this view, the effect on dye’s flexibility of the intermolecular interactions of the latter with the polymer bundle was checked and compared with the one due to the dye-solvent interactions established in toluene solution. This was accomplished through a mean field descriptor which was connected to the torsional degrees of freedom, as detailed in the Supporting Information. In this particular case it was interesting to examine the specific behavior of the δ1 dihedral angle. The resulting mean field W (δ1) in the polymer and in toluene solution, displayed in Figure 2, presents a marked difference between the two surrounding media with toluene leading to a nearly vanishing and flatter W(δ1). It is also worth noticing that the entanglement of the polymer around the dye creates a supplementary well, centered at about δ1 = 0, that constrains this angle to librate within a limited interval rather than exploring the complete range of values.Further proofs of the existence of a tight and stable cleft and its constraining

  7. Evidence for a spectroscopic direct detection of reflected light from 51 Pegasi b

    NASA Astrophysics Data System (ADS)

    Martins, J. H. C.; Santos, N. C.; Figueira, P.; Faria, J. P.; Montalto, M.; Boisse, I.; Ehrenreich, D.; Lovis, C.; Mayor, M.; Melo, C.; Pepe, F.; Sousa, S. G.; Udry, S.; Cunha, D.

    2015-04-01

    Context. The detection of reflected light from an exoplanet is a difficult technical challenge at optical wavelengths. Even though this signal is expected to replicate the stellar signal, not only is it several orders of magnitude fainter, but it is also hidden among the stellar noise. Aims: We apply a variant of the cross-correlation technique to HARPS observations of 51 Peg to detect the reflected signal from planet 51 Peg b. Methods: Our method makes use of the cross-correlation function (CCF) of a binary mask with high-resolution spectra to amplify the minute planetary signal that is present in the spectra by a factor proportional to the number of spectral lines when performing the cross correlation. The resulting cross-correlation functions are then normalized by a stellar template to remove the stellar signal. Carefully selected sections of the resulting normalized CCFs are stacked to increase the planetary signal further. The recovered signal allows probing several of the planetary properties, including its real mass and albedo. Results: We detect evidence for the reflected signal from planet 51 Peg b at a significance of 3σnoise. The detection of the signal permits us to infer a real mass of 0.46+0.06-0.01 MJup (assuming a stellar mass of 1.04 MSun) for the planet and an orbital inclination of 80+10-19 degrees. The analysis of the data also allows us to infer a tentative value for the (radius-dependent) geometric albedo of the planet. The results suggest that 51Peg b may be an inflated hot Jupiter with a high albedo (e.g., an albedo of 0.5 yields a radius of 1.9 ± 0.3 RJup for a signal amplitude of 6.0 ± 0.4 × 10-5). Conclusions: We confirm that the method we perfected can be used to retrieve an exoplanet's reflected signal, even with current observing facilities. The advent of next generation of instruments (e.g. VLT-ESO/ESPRESSO) and observing facilities (e.g. a new generation of ELT telescopes) will yield new opportunities for this type of technique

  8. Mechanism of myo-inositol hexakisphosphate sorption on amorphous aluminum hydroxide: spectroscopic evidence for rapid surface precipitation.

    PubMed

    Yan, Yupeng; Li, Wei; Yang, Jun; Zheng, Anmin; Liu, Fan; Feng, Xionghan; Sparks, Donald L

    2014-06-17

    Inositol hexakisphosphates are the most abundant organic phosphates (OPs) in most soils and sediments. Adsorption, desorption, and precipitation reactions at environmental interfaces govern the reactivity, speciation, mobility, and bioavailability of inositol hexakisphosphates in terrestrial and aquatic environments. However, surface complexation and precipitation reactions of inositol hexakisphosphates on soil minerals have not been well understood. Here we investigate the surface complexation-precipitation process and mechanism of myo-inositol hexakisphosphate (IHP, phytate) on amorphous aluminum hydroxide (AAH) using macroscopic sorption experiments and multiple spectroscopic tools. The AAH (16.01 μmol m(-2)) exhibits much higher sorption density than boehmite (0.73 μmol m(-2)) and α-Al2O3 (1.13 μmol m(-2)). Kinetics of IHP sorption and accompanying OH(-) release, as well as zeta potential measurements, indicate that IHP is initially adsorbed on AAH through inner-sphere complexation via ligand exchange, followed by AAH dissolution and ternary complex formation; last, the ternary complexes rapidly transform to surface precipitates and bulk phase analogous to aluminum phytate (Al-IHP). The pH level, reaction time, and initial IHP loading evidently affect the interaction of IHP on AAH. In situ ATR-FTIR and solid-state NMR spectra further demonstrate that IHP sorbs on AAH and transforms to surface precipitates analogous to Al-IHP, consistent with the results of XRD analysis. This study indicates that active metal oxides such as AAH strongly mediate the speciation and behavior of IHP via rapid surface complexation-precipitation reactions, thus controlling the mobility and bioavailability of inositol phosphates in the environment. PMID:24871399

  9. Spectroscopic Quadrupole Moments in Sr,9896 : Evidence for Shape Coexistence in Neutron-Rich Strontium Isotopes at N =60

    NASA Astrophysics Data System (ADS)

    Clément, E.; Zielińska, M.; Görgen, A.; Korten, W.; Péru, S.; Libert, J.; Goutte, H.; Hilaire, S.; Bastin, B.; Bauer, C.; Blazhev, A.; Bree, N.; Bruyneel, B.; Butler, P. A.; Butterworth, J.; Delahaye, P.; Dijon, A.; Doherty, D. T.; Ekström, A.; Fitzpatrick, C.; Fransen, C.; Georgiev, G.; Gernhäuser, R.; Hess, H.; Iwanicki, J.; Jenkins, D. G.; Larsen, A. C.; Ljungvall, J.; Lutter, R.; Marley, P.; Moschner, K.; Napiorkowski, P. J.; Pakarinen, J.; Petts, A.; Reiter, P.; Renstrøm, T.; Seidlitz, M.; Siebeck, B.; Siem, S.; Sotty, C.; Srebrny, J.; Stefanescu, I.; Tveten, G. M.; Van de Walle, J.; Vermeulen, M.; Voulot, D.; Warr, N.; Wenander, F.; Wiens, A.; De Witte, H.; Wrzosek-Lipska, K.

    2016-01-01

    Neutron-rich Sr,9896 isotopes have been investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross sections. These results allow, for the first time, the drawing of definite conclusions about the shape coexistence of highly deformed prolate and spherical configurations. In particular, a very small mixing between the coexisting states is observed, contrary to other mass regions where strong mixing is present. Experimental results have been compared to beyond-mean-field calculations using the Gogny D1S interaction in a five-dimensional collective Hamiltonian formalism, which reproduce the shape change at N =60 .

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

    PubMed Central

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

    2016-01-01

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

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

    PubMed

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

    2016-01-01

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

  12. Measurement of the sign of the spectroscopic quadrupole moment for the 2(1)+ state in 70Se: no evidence for oblate shape.

    PubMed

    Hurst, A M; Butler, P A; Jenkins, D G; Delahaye, P; Wenander, F; Ames, F; Barton, C J; Behrens, T; Bürger, A; Cederkäll, J; Clément, E; Czosnyka, T; Davinson, T; de Angelis, G; Eberth, J; Ekström, A; Franchoo, S; Georgiev, G; Görgen, A; Herzberg, R-D; Huyse, M; Ivanov, O; Iwanicki, J; Jones, G D; Kent, P; Köster, U; Kröll, T; Krücken, R; Larsen, A C; Nespolo, M; Pantea, M; Paul, E S; Petri, M; Scheit, H; Sieber, T; Siem, S; Smith, J F; Steer, A; Stefanescu, I; Syed, N U H; Van de Walle, J; Van Duppen, P; Wadsworth, R; Warr, N; Weisshaar, D; Zielińska, M

    2007-02-16

    Using a method whereby molecular and atomic ions are independently selected, an isobarically pure beam of 70Se ions was postaccelerated to an energy of 206 MeV using REX-ISOLDE. Coulomb-excitation yields for states in the beam and target nuclei were deduced by recording deexcitation gamma rays in the highly segmented MINIBALL gamma-ray spectrometer in coincidence with scattered particles in a silicon detector. At these energies, the Coulomb-excitation yield for the first 2+ state is expected to be strongly sensitive to the sign of the spectroscopic quadrupole moment through the nuclear reorientation effect. Experimental evidence is presented here for a prolate shape for the first 2+ state in 70Se, reopening the question over whether there are, as reported earlier, deformed oblate shapes near to the ground state in the light selenium isotopes. PMID:17359019

  13. Fractionation of Suwannee River Fulvic Acid and Aldrich Humic Acid on α-Al2O3: Spectroscopic Evidence

    SciTech Connect

    Claret, F.; Schäfer, T; Brevet, J; Reiller, P

    2008-01-01

    Sorptive fractionation of Suwannee River Fulvic Acid (SRFA) and Purified Aldrich Humic Acid (PAHA) on a-Al2O3 at pH 6 was probed in the supernatant using different spectroscopic techniques. Comparison of dissolved organic carbon (DOC) analysis with UV/vis spectrophotometric measurements at 254 nm, including specific UV absorbance (SUVA) calculation, revealed a decrease in chromophoric compounds for the nonsorbed extracts after a 24 h contact time. This fractionation, only observable below a certain ratio between initial number of sites of humic substances and of a-Al2O3, seems to indicate a higher fractionation for PAHA. C(1s) near-edge X-ray absorption fine structure spectroscopy (NEXAFS) confirmed this trend and points to a decrease in phenolic moieties in the supernatant and to an eventual increase in phenolic moieties on the surface. Time-resolved luminescence spectroscopy (TRLS) of Eu(III) as luminescent probe showed a decrease in the ratio between the 5D0?7F2 and 5D0?7F1 transitions for the fractionated organic matter (OM) that is thought to be associated with a lower energy transfer from the OM to Eu(III) due to the loss of polar aromatics. These modifications in the supernatant are a hint for the modification of sorbed humic extracts on the surface.

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

    SciTech Connect

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

    2015-02-02

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

  15. Spectroscopic observations of propagating disturbances in a polar coronal hole: evidence of slow magneto-acoustic waves

    NASA Astrophysics Data System (ADS)

    Gupta, G. R.; Teriaca, L.; Marsch, E.; Solanki, S. K.; Banerjee, D.

    2012-10-01

    Aims: We focus on detecting and studying quasi-periodic propagating features that have been interpreted in terms of both slow magneto-acoustic waves and of high-speed upflows. Methods: We analyzed long-duration spectroscopic observations of the on-disk part of the south polar coronal hole taken on 1997 February 25 by the SUMER spectrometer onboard SOHO. We calibrated the velocity with respect to the off-limb region and obtained time-distance maps in intensity, Doppler velocity, and line width. We also performed a cross-correlation analysis on different time series curves at different latitudes. We studied average spectral line profiles at the roots of propagating disturbances and along the propagating ridges, and performed a red-blue asymmetry analysis. Results: We clearly find propagating disturbances in intensity and Doppler velocity with a projected propagation speed of about 60 ± 4.8 km s-1 and a periodicity of ≈14.5 min. To our knowledge, this is the first simultaneous detection of propagating disturbances in intensity as well as in Doppler velocity in a coronal hole. During the propagation, an intensity enhancement is associated with a blueshifted Doppler velocity. These disturbances are clearly seen in intensity also at higher latitudes (i.e., closer to the limb), while disturbances in Doppler velocity become faint there. The spectral line profiles averaged along the propagating ridges are found to be symmetric, to be well fitted by a single Gaussian, and have no noticeable red-blue asymmetry. Conclusions: Based on our analysis, we interpret these disturbances in terms of propagating slow magneto-acoustic waves.

  16. Direct spectroscopic evidence for phase competition between the pseudogap and superconductivity in Bi2Sr2CaCu2O(8+δ).

    PubMed

    Hashimoto, Makoto; Nowadnick, Elizabeth A; He, Rui-Hua; Vishik, Inna M; Moritz, Brian; He, Yu; Tanaka, Kiyohisa; Moore, Robert G; Lu, Donghui; Yoshida, Yoshiyuki; Ishikado, Motoyuki; Sasagawa, Takao; Fujita, Kazuhiro; Ishida, Shigeyuki; Uchida, Shinichi; Eisaki, Hiroshi; Hussain, Zahid; Devereaux, Thomas P; Shen, Zhi-Xun

    2015-01-01

    In the high-temperature (T(c)) cuprate superconductors, a growing body of evidence suggests that the pseudogap phase, existing below the pseudogap temperature T*, is characterized by some broken electronic symmetries distinct from those associated with superconductivity. In particular, recent scattering experiments have suggested that charge ordering competes with superconductivity. However, no direct link of an interplay between the two phases has been identified from the important low-energy excitations. Here, we report an antagonistic singularity at T(c) in the spectral weight of Bi2Sr2CaCu2O(8+δ) as compelling evidence for phase competition, which persists up to a high hole concentration p ~ 0.22. Comparison with theoretical calculations confirms that the singularity is a signature of competition between the order parameters for the pseudogap and superconductivity. The observation of the spectroscopic singularity at finite temperatures over a wide doping range provides new insights into the nature of the competitive interplay between the two orders and the complex phase diagram near the pseudogap critical point. PMID:25362356

  17. Spectroscopic and theoretical study of the "azo"-dye E124 in condensate phase: evidence of a dominant hydrazo form.

    PubMed

    Almeida, Mariana R; Stephani, Rodrigo; Dos Santos, Hélio F; de Oliveira, Luiz Fernando C

    2010-01-14

    Spectroscopic techniques, including Raman, IR, UV/vis, and NMR were used to characterize the samples of the azo dye Ponceau 4R (also known as E124, New Coccine; Cochineal Red; C.I. no. 16255; Food Red No. 102), which is 1,3-naphthalenedisulfonic acid, 7-hydroxy-8-[(4-sulfo-1-naphthalenyl) azo] trisodium salt in aqueous solution and solid state. In addition, first principle calculations were carried out for the azo (OH) and hydrazo (NH) tautomers in order to assist in the assignment of the experimental data. The two intense bands observed in the UV/vis spectrum, centered at 332 and 507 nm, can be compared to the calculated values at 296 and 474 nm for azo and 315 and 500 nm for hydrazo isomer, with the latter in closer agreement to the experiment. The Raman spectrum is quite sensitive to tautomeric equilibrium; in solid state and aqueous solution, three bands were observed around 1574, 1515, and 1364 cm(-1), assigned to mixed modes including deltaNH + betaCH + nuCC, deltaNH + nuC horizontal lineO + nuC horizontal lineN + betaCH and nuCC vibrations, respectively. These assignments are predicted only for the NH species centered at 1606, 1554, and 1375 cm(-1). The calculated Raman spectrum for the azo (OH) tautomer showed two strong bands at 1468 (nuN = N + deltaOH) and 1324 cm(-1) (nuCC + nuC-N), which were not obtained experimentally. The (13)C NMR spectrum showed a very characteristic peak at 192 ppm assigned to the carbon bound to oxygen in the naphthol ring; the predicted values were 165 ppm for OH and 187 for NH isomer, supporting once again the predominance of NH species in solution. Therefore, all of the experimental and theoretical results strongly suggest the food dye Ponceau 4R or E124 has a major contribution of the hydrazo structure instead of the azo form as the most abundant in condensate phase. PMID:19852449

  18. Spectroscopic mapping of the white horse alunite deposit, Marysvale volcanic field, Utah: Evidence of a magmatic component

    USGS Publications Warehouse

    Rockwell, B.W.; Cunningham, C.G.; Breit, G.N.; Rye, R.O.

    2006-01-01

    Previous studies have demonstrated that the replacement alunite deposits just north of the town of Marysvale, Utah, USA, were formed primarily by low-temperature (100??-170?? C), steam-heated processes near the early Miocene paleoground surface, immediately above convecting hydrothermal plumes. Pyrite-bearing propylitically altered rocks occur mainly beneath the steam-heated alunite and represent the sulfidized feeder zone of the H2S-dominated hydrothermal fluids, the oxidation of which at higher levels led to the formation of the alunite. Maps of surface mineralogy at the White Horse deposit generated from Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data were used in conjunction with X-ray diffraction studies of field samples to test the accuracy and precision of AVIRIS-based mineral mapping of altered rocks and demonstrate the utility of spectroscopic mapping for ore deposit characterization. The mineral maps identified multiple core zones of alunite that grade laterally outward to kaolinite. Surrounding the core zones are dominantly propylitically altered rocks containing illite, montmorillonite, and chlorite, with minor pyrite, kaolinite, gypsum, and remnant potassium feldspar from the parent rhyodacitic ash-flow tuff. The AVIRIS mapping also identified fracture zones expressed by ridge-forming selvages of quartz + dickite + kaolinite that form a crude ring around the advanced argillic core zones. Laboratory analyses identified the aluminum phosphate-sulfate (APS) minerals woodhouseite and svanbergite in one sample from these dickite-bearing argillic selvages. Reflectance spectroscopy determined that the outer edges of the selvages contain more dickite than do the medial regions. The quartz + dickite ?? kaolinite ?? APS-mineral selvages demonstrate that fracture control of replacement processes is more prevalent away from the advanced argillic core zones. Although not exposed at the White Horse deposit, pyrophyllite ?? ordered illite was identified

  19. Emitting species in chemiluminescence reactions with acidic potassium permanganate: a re-evaluation based on new spectroscopic evidence.

    PubMed

    Adcock, Jacqui L; Francis, Paul S; Barnett, Neil W

    2009-09-01

    The reaction of acidic potassium permanganate with a wide range of compounds is known to produce a broad red emission, and there is strong evidence for an excited manganese(II) emitting species. Nevertheless, numerous researchers have proposed other emitters for reactions with acidic potassium permanganate, particularly for systems where fluorescent compounds were present, either as enhancers or reaction products. We have examined many reactions of this type and found that, in most cases, the same red emission was produced. There were, however, some exceptions, including the oxidation of dihydralazine, certain thiols and sulphite (each in the presence of an enhancer). PMID:19353245

  20. Electrochemical and spectroscopic evidence on the one-electron reduction of U(VI) to U(V) on magnetite

    SciTech Connect

    Yuan, Ke; Ilton, Eugene S.; Antonio, Mark R.; Li, Zhongrui; Cook, Peter J.; Becker, Udo

    2015-05-19

    Reduction of U(VI) to U(IV) on mineral surfaces has been considered as a one-step two electron process. However, stabilized U(V), with no evidence of U(IV), found in recent studies indicates U(VI) can undergo a one electron reduction to U(V) without further progression to U(IV). We investigated the mechanisms of uranium reduction by reducing U(VI) electrochemically on a magnetite electrode at pH 3.4 . The one electron reduction of U(VI) was first confirmed using the cyclic voltammetry method. Formation of nano-size uranium precipitates on the surface of magnetite at reducing potentials and dissolution of the solids at oxidizing potentials were observed by in situ electrochemical AFM. XPS analysis of the magnetite electrodes polarized in uranium solutions at voltages from 0.1 ~ 0.9 V (vs. Ag/AgCl) showed the presence of only U(V) and U(VI). The highest amount of U(V) relative to U(VI) was prepared at 0.7 V, where the longest average U–Oaxial distance of 2.05 ± 0.01 Å was evident in the same sample revealed by EXAFS analysis. The results demonstrate that the electrochemical reduction of U(VI) on magnetite only yields U(V), even at a potential of 0.9 V, which favors the one-electron reduction mechanism. U(V) did not disproportionate but stabilized on magnetite through precipitation of mixed-valence state U(VI)/U(V) solids.

  1. Electrochemical and Spectroscopic Evidence on the One-Electron Reduction of U(VI) to U(V) on Magnetite.

    PubMed

    Yuan, Ke; Ilton, Eugene S; Antonio, Mark R; Li, Zhongrui; Cook, Peter J; Becker, Udo

    2015-05-19

    Reduction of U(VI) to U(IV) on mineral surfaces is often considered a one-step two-electron process. However, stabilized U(V), with no evidence of U(IV), found in recent studies indicates U(VI) can undergo a one-electron reduction to U(V) without further progression to U(IV). We investigated reduction pathways of uranium by reducing U(VI) electrochemically on a magnetite electrode at pH 3.4. Cyclic voltammetry confirms the one-electron reduction of U(VI) to U(V). Formation of nanosize uranium precipitates on the magnetite surface at reducing potentials and dissolution of the solids at oxidizing potentials are observed by in situ electrochemical atomic force microscopy. XPS analysis of the magnetite electrodes polarized in uranium solutions at voltages from -0.1 to -0.9 V (E(0)(U(VI)/U(V))= -0.135 V vs Ag/AgCl) show the presence of only U(V) and U(VI). The sample with the highest U(V)/U(VI) ratio was prepared at -0.7 V, where the longest average U-O(axial) distance of 2.05 ± 0.01 Å was evident in the same sample revealed by extended X-ray absorption fine structure analysis. The results demonstrate that the electrochemical reduction of U(VI) on magnetite only yields U(V), even at a potential of -0.9 V, which favors the one-electron reduction mechanism. U(V) does not disproportionate but stabilizes on magnetite through precipitation of mixed-valence state U(V)/U(VI) solids. PMID:25893535

  2. Gas-Phase Folding of a Prototypical Protonated Pentapeptide: Spectroscopic Evidence for Formation of a Charge-Stabilized β-Hairpin.

    PubMed

    Burke, Nicole L; DeBlase, Andrew F; Redwine, James G; Hopkins, John R; McLuckey, Scott A; Zwier, Timothy S

    2016-03-01

    Ultraviolet and infrared-ultraviolet (IR-UV) double-resonance photofragment spectroscopy has been carried out in a tandem mass spectrometer to determine the three-dimensional structure of cryogenically cooled protonated C-terminally methyl esterified leucine enkephalin [YGGFL-OMe+H](+). By comparing the experimental IR spectrum of the dominant conformer with the predictions of DFT M05-2X/6-31+G(d) calculations, a backbone structure was assigned that is analogous to that previously assigned by our group for the unmodified peptide [ Burke, N.L.; et al. Int. J. Mass Spectrom. 2015 , 378 , 196 ], despite the loss of a C-terminal OH binding site that was thought to play an important role in its stabilization. Both structures are characterized by a type II' β-turn around Gly(3)-Phe(4) and a γ-turn around Gly(2), providing spectroscopic evidence for the formation of a β-hairpin hydrogen bonding pattern. Rather than disrupting the peptide backbone structure, the protonated N-terminus serves to stabilize the β-hairpin by positioning itself in a pocket above the turn where it can form H-bonds to the Gly(3) and C-terminus C═O groups. This β-hairpin type structure has been previously proposed as the biologically active conformation of leucine enkephalin and its methyl ester in the nonpolar cell membrane environment [ Naito, A.; Nishimura, K. Curr. Top. Med. Chem. 2004 , 4 , 135 - 143 ]. PMID:26853832

  3. Spectroscopic and Crystallographic Evidence for the Role of a Water-Containing H-Bond Network in Oxidase Activity of an Engineered Myoglobin.

    PubMed

    Petrik, Igor D; Davydov, Roman; Ross, Matthew; Zhao, Xuan; Hoffman, Brian; Lu, Yi

    2016-02-01

    Heme-copper oxidases (HCOs) catalyze efficient reduction of oxygen to water in biological respiration. Despite progress in studying native enzymes and their models, the roles of non-covalent interactions in promoting this activity are still not well understood. Here we report EPR spectroscopic studies of cryoreduced oxy-F33Y-CuBMb, a functional model of HCOs engineered in myoglobin (Mb). We find that cryoreduction at 77 K of the O2-bound form, trapped in the conformation of the parent oxyferrous form, displays a ferric-hydroperoxo EPR signal, in contrast to the cryoreduced oxy-wild-type (WT) Mb, which is unable to deliver a proton and shows a signal from the peroxo-ferric state. Crystallography of oxy-F33Y-CuBMb reveals an extensive H-bond network involving H2O molecules, which is absent from oxy-WTMb. This H-bonding proton-delivery network is the key structural feature that transforms the reversible oxygen-binding protein, WTMb, into F33Y-CuBMb, an oxygen-activating enzyme that reduces O2 to H2O. These results provide direct evidence of the importance of H-bond networks involving H2O in conferring enzymatic activity to a designed protein. Incorporating such extended H-bond networks in designing other metalloenzymes may allow us to confer and fine-tune their enzymatic activities. PMID:26716352

  4. The purple Codex Rossanensis: spectroscopic characterisation and first evidence of the use of the elderberry lake in a sixth century manuscript.

    PubMed

    Bicchieri, Marina

    2014-12-01

    This paper presents the results obtained during the measurements campaign started in June 2012 and ended in November 2013 on the invaluable purple Codex Rossanensis, sixth century, one of the oldest surviving illuminated manuscripts of the New Testament. The tasks of the chemistry laboratory were to answer a variety of questions posed both by historians and restorers, concerning the materials used in a previous restoration, the composition of the pictorial palette and the different inks and to determine which colouring material had been applied to dye the parchment support. It was also requested to determine the state of preservation of the manuscript, as a result of its interactions with the environment in which the manuscript had been stored and the vicissitudes experienced during its life (fire, previous restoration, exhibition). The spectroscopic analyses performed by micro-Raman, micro-Fourier transform infrared and X-ray fluorescence allowed to fill a gap in the knowledge of the pictorial materials used in the Early Middle Ages. The pictorial palette, the inks, the dye applied to obtain the purple parchments, the support and the materials used in the previous restoration treatment executed in 1917-19 were fully characterised. Moreover, to the author's knowledge, the article shows the first experimental evidence of the use of the elderberry lake in a sixth century-illuminated manuscript. The lake was characterised by Raman spectroscopy. PMID:25056752

  5. Spectroscopic Evidence of the Improvement of Reactive Iron Mineral Content in Red Soil by Long-Term Application of Swine Manure.

    PubMed

    Huang, Chichao; Liu, Sha; Li, Ruizhi; Sun, Fusheng; Zhou, Ying; Yu, Guanghui

    2016-01-01

    Mineral elements in soil solutions are thought to be the precursor of the formation of reactive minerals, which play an important role in global carbon (C) cycling. However, information regarding the regulation of mineral elements release in soil is scarce. Here, we examined the long-term (i.e., 23 yrs) effects of fertilisation practices on Fe minerals in a red soil in Southern China. The results from chemical analysis and Fourier-transform infrared spectroscopy showed that long-term swine manure (M) treatment released greater amounts of minerals into soil solutions than chemical fertilisers (NPK) treatment, and Fe played a dominant role in the preservation of dissolved organic C. Furthermore, Fe K-edge X-ray absorption near-edge fine structure spectroscopy demonstrated that reactive Fe minerals were mainly composed of less crystalline ferrihydrite in the M-treated soil and more crystalline goethite in the NPK-treated soil. In conclusion, this study reported spectroscopic evidence of the improvement of reactive Femineral content in the M-treated soil colloids when compared to NPK-treated soil colloids. PMID:26752419

  6. Spectroscopic Evidence of the Improvement of Reactive Iron Mineral Content in Red Soil by Long-Term Application of Swine Manure

    PubMed Central

    Huang, Chichao; Liu, Sha; Li, Ruizhi; Sun, Fusheng; Zhou, Ying; Yu, Guanghui

    2016-01-01

    Mineral elements in soil solutions are thought to be the precursor of the formation of reactive minerals, which play an important role in global carbon (C) cycling. However, information regarding the regulation of mineral elements release in soil is scarce. Here, we examined the long-term (i.e., 23 yrs) effects of fertilisation practices on Fe minerals in a red soil in Southern China. The results from chemical analysis and Fourier-transform infrared spectroscopy showed that long-term swine manure (M) treatment released greater amounts of minerals into soil solutions than chemical fertilisers (NPK) treatment, and Fe played a dominant role in the preservation of dissolved organic C. Furthermore, Fe K-edge X-ray absorption near-edge fine structure spectroscopy demonstrated that reactive Fe minerals were mainly composed of less crystalline ferrihydrite in the M-treated soil and more crystalline goethite in the NPK-treated soil. In conclusion, this study reported spectroscopic evidence of the improvement of reactive Femineral content in the M-treated soil colloids when compared to NPK-treated soil colloids. PMID:26752419

  7. X-ray absorption spectroscopic evidence for the complexation of Hg(II) by reduced sulfur in soil humic substances

    SciTech Connect

    Xia, K.; Skyllberg, U.L.; Bleam, W.F.; Helmke, P.A.; Bloom, P.R.; Nater, E.A.

    1999-01-15

    Analysis of Hg(II) complexed by a soil humic acid (HA) using synchrotron-based X-ray absorption spectroscopy (XAS) revealed the importance of reduces sulfur functional groups (thiol (R-SH) and disulfide (R-SS-R)/disulfane (R-SSH)) in humic substances in the complexation of Hg(II). A two-coordinate binding environment with one oxygen atom and one sulfur atom at distances of 2.02 and 2.38 {angstrom}, respectively, was found in the first coordination shell of Hg(II) complexed by humic acid. Model calculations show that a second coordination sphere could contain one carbon atom and a second sulfur atom at 2.78 and 2.93 {angstrom}, respectively. This suggests that in addition to thiol S, disulfide/disulfane S may be involved with the complexation of Hg(II) in soil organic matter. The appearance of carbon atom in the second coordination shell suggests that one O-containing ligand such as carboxyl and phenol ligands rather than H{sub 2}O molecule is bound to the Hg(II). The involvement of oxygen ligand in addition to the reduced S ligands in the complexation of Hg(II) is due to the low density of reduced S ligands in humic substances. The XAS results from this experiment provided direct molecular level evidence for the preference of reduced S functional groups over oxygen ligands by Hg(II) in the complexation with humic substances.

  8. MR spectroscopic evidence for glial increase but not for neuro-axonal damage in MS normal-appearing white matter.

    PubMed

    Vrenken, H; Barkhof, F; Uitdehaag, B M J; Castelijns, J A; Polman, C H; Pouwels, P J W

    2005-02-01

    Quantitative single-voxel, short echo-time (TE) MR spectroscopy (MRS) was used to determine metabolite concentrations in the cerebral normal-appearing white matter (NAWM) of 76 patients with multiple sclerosis (MS), and the WM of 25 controls. In NAWM of all MS disease types (primary progressive, relapsing-remitting, and secondary progressive), the concentration ratio of total N-acetyl-aspartate (tNAA)/total creatine (tCr) was decreased compared to controls. Remarkably, this was entirely due to an increase of tCr in MS patients, whereas there was no difference in tNAA. Separate quantification of the two tNAA components yielded no significant difference in NAA (N-acetyl-aspartate), while the concentration of NAAG (N-acetyl-aspartyl-glutamate) was slightly-but significantly-elevated in MS patients. Myo-inositol (Ins) was strongly increased in MS patients, and choline-containing compounds (Cho) were mildly increased. There were no metabolite differences between disease types, and no correlations with disability scores. The results are supported by measures of spectral quality, which were identical for patients and controls. In conclusion, MS NAWM containing very little perilesional tissue is characterized by increased glial cell numbers (increase of Ins and tCr) without evidence of axonal dysfunction (normal NAA). Further studies should elucidate the mechanism underlying increased NAAG in MS NAWM. PMID:15678547

  9. Spectroscopic and Kinetic Evidence for the Crucial Role of Compound 0 in the P450cam -Catalyzed Hydroxylation of Camphor by Hydrogen Peroxide.

    PubMed

    Franke, Alicja; van Eldik, Rudi

    2015-10-19

    The hydroperoxo iron(III) intermediate P450cam Fe(III) -OOH, being the true Compound 0 (Cpd 0) involved in the natural catalytic cycle of P450cam , could be transiently observed in the peroxo-shunt oxidation of the substrate-free enzyme by hydrogen peroxide under mild basic conditions and low temperature. The prolonged lifetime of Cpd 0 enabled us to kinetically examine the formation and reactivity of P450cam Fe(III) -OOH species as a function of varying reaction conditions, such as pH, and concentration of H2 O2 , camphor, and potassium ions. The mechanism of hydrogen peroxide binding to the substrate-free form of P450cam differs completely from that observed for other heme proteins possessing the distal histidine as a general acid-base catalyst and is mainly governed by the ability of H2 O2 to undergo deprotonation at the hydroxo ligand coordinated to the iron(III) center under conditions of pH≥p${K{{{\\rm P450}\\hfill \\atop {\\rm a}\\hfill}}}$. Notably, no spectroscopic evidence for the formation of either Cpd I or Cpd II as products of heterolytic or homolytic OO bond cleavage, respectively, in Cpd 0 could be observed under the selected reaction conditions. The kinetic data obtained from the reactivity studies involving (1R)-camphor, provide, for the first time, experimental evidence for the catalytic activity of the P450Fe(III) -OOH intermediate in the oxidation of the natural substrate of P450cam . PMID:26353996

  10. Supergene destruction of a hydrothermal replacement alunite deposit at Big Rock Candy Mountain, Utah: Mineralogy, spectroscopic remote sensing, stable-isotope, and argon-age evidences

    USGS Publications Warehouse

    Cunningham, C.G.; Rye, R.O.; Rockwell, B.W.; Kunk, M.J.; Councell, T.B.

    2005-01-01

    Big Rock Candy Mountain is a prominent center of variegated altered volcanic rocks in west-central Utah. It consists of the eroded remnants of a hypogene alunite deposit that, at ???21 Ma, replaced intermediate-composition lava flows. The alunite formed in steam-heated conditions above the upwelling limb of a convection cell that was one of at least six spaced at 3- to 4-km intervals around the margin of a monzonite stock. Big Rock Candy Mountain is horizontally zoned outward from an alunite core to respective kaolinite, dickite, and propylite envelopes. The altered rocks are also vertically zoned from a lower pyrite-propylite assemblage upward through assemblages successively dominated by hypogene alunite, jarosite, and hematite, to a flooded silica cap. This hydrothermal assemblage is undergoing natural destruction in a steep canyon downcut by the Sevier River in Marysvale Canyon. Integrated geological, mineralogical, spectroscopic remote sensing using AVIRIS data, Ar radiometric, and stable isotopic studies trace the hypogene origin and supergene destruction of the deposit and permit distinction of primary (hydrothermal) and secondary (weathering) processes. This destruction has led to the formation of widespread supergene gypsum in cross-cutting fractures and as surficial crusts, and to natrojarosite, that gives the mountain its buff coloration along ridges facing the canyon. A small spring, Lemonade Spring, with a pH of 2.6 and containing Ca, Mg, Si, Al, Fe, Mn, Cl, and SO4, also occurs near the bottom of the canyon. The 40Ar/39 Ar age (21.32??0.07 Ma) of the alunite is similar to that for other replacement alunites at Marysvale. However, the age spectrum contains evidence of a 6.6-Ma thermal event that can be related to the tectonic activity responsible for the uplift that led to the downcutting of Big Rock Candy Mountain by the Sevier River. This ???6.6 Ma event also is present in the age spectrum of supergene natrojarosite forming today, and probably dates

  11. Non-covalent interactions of nitrous oxide with aromatic compounds: Spectroscopic and computational evidence for the formation of 1:1 complexes

    NASA Astrophysics Data System (ADS)

    Cao, Qian; Gor, Gennady Y.; Krogh-Jespersen, Karsten; Khriachtchev, Leonid

    2014-04-01

    We present the first study of intermolecular interactions between nitrous oxide (N2O) and three representative aromatic compounds (ACs): phenol, cresol, and toluene. The infrared spectroscopic experiments were performed in a Ne matrix and were supported by high-level quantum chemical calculations. Comparisons of the calculated and experimental vibrational spectra provide direct identification and characterization of the 1:1 N2O-AC complexes. Our results show that N2O is capable of forming non-covalently bonded complexes with ACs. Complex formation is dominated by dispersion forces, and the interaction energies are relatively low (about -3 kcal mol-1); however, the complexes are clearly detected by frequency shifts of the characteristic bands. These results suggest that N2O can be bound to the amino-acid residues tyrosine or phenylalanine in the form of π complexes.

  12. Non-covalent interactions of nitrous oxide with aromatic compounds: Spectroscopic and computational evidence for the formation of 1:1 complexes

    SciTech Connect

    Cao, Qian; Gor, Gennady Y.; Krogh-Jespersen, Karsten; Khriachtchev, Leonid

    2014-04-14

    We present the first study of intermolecular interactions between nitrous oxide (N{sub 2}O) and three representative aromatic compounds (ACs): phenol, cresol, and toluene. The infrared spectroscopic experiments were performed in a Ne matrix and were supported by high-level quantum chemical calculations. Comparisons of the calculated and experimental vibrational spectra provide direct identification and characterization of the 1:1 N{sub 2}O-AC complexes. Our results show that N{sub 2}O is capable of forming non-covalently bonded complexes with ACs. Complex formation is dominated by dispersion forces, and the interaction energies are relatively low (about −3 kcal mol{sup −1}); however, the complexes are clearly detected by frequency shifts of the characteristic bands. These results suggest that N{sub 2}O can be bound to the amino-acid residues tyrosine or phenylalanine in the form of π complexes.

  13. Spectroscopic Quadrupole Moments in {96,98}Sr: Evidence for Shape Coexistence in Neutron-Rich Strontium Isotopes at N=60.

    PubMed

    Clément, E; Zielińska, M; Görgen, A; Korten, W; Péru, S; Libert, J; Goutte, H; Hilaire, S; Bastin, B; Bauer, C; Blazhev, A; Bree, N; Bruyneel, B; Butler, P A; Butterworth, J; Delahaye, P; Dijon, A; Doherty, D T; Ekström, A; Fitzpatrick, C; Fransen, C; Georgiev, G; Gernhäuser, R; Hess, H; Iwanicki, J; Jenkins, D G; Larsen, A C; Ljungvall, J; Lutter, R; Marley, P; Moschner, K; Napiorkowski, P J; Pakarinen, J; Petts, A; Reiter, P; Renstrøm, T; Seidlitz, M; Siebeck, B; Siem, S; Sotty, C; Srebrny, J; Stefanescu, I; Tveten, G M; Van de Walle, J; Vermeulen, M; Voulot, D; Warr, N; Wenander, F; Wiens, A; De Witte, H; Wrzosek-Lipska, K

    2016-01-15

    Neutron-rich {96,98}Sr isotopes have been investigated by safe Coulomb excitation of radioactive beams at the REX-ISOLDE facility. Reduced transition probabilities and spectroscopic quadrupole moments have been extracted from the differential Coulomb excitation cross sections. These results allow, for the first time, the drawing of definite conclusions about the shape coexistence of highly deformed prolate and spherical configurations. In particular, a very small mixing between the coexisting states is observed, contrary to other mass regions where strong mixing is present. Experimental results have been compared to beyond-mean-field calculations using the Gogny D1S interaction in a five-dimensional collective Hamiltonian formalism, which reproduce the shape change at N=60. PMID:26824536

  14. Spectroscopic, Electrochemical and Computational Characterisation of Ru Species Involved in Catalytic Water Oxidation: Evidence for a [Ru(V) (O)(Py2 (Me) tacn)] Intermediate.

    PubMed

    Casadevall, Carla; Codolà, Zoel; Costas, Miquel; Lloret-Fillol, Julio

    2016-07-11

    A new family of ruthenium complexes based on the N-pentadentate ligand Py2 (Me) tacn (N-methyl-N',N''-bis(2-picolyl)-1,4,7-triazacyclononane) has been synthesised and its catalytic activity has been studied in the water-oxidation (WO) reaction. We have used chemical oxidants (ceric ammonium nitrate and NaIO4 ) to generate the WO intermediates [Ru(II) (OH2 )(Py2 (Me) tacn)](2+) , [Ru(III) (OH2 )(Py2 (Me) tacn)](3+) , [Ru(III) (OH)(Py2 (Me) tacn)](2+) and [Ru(IV) (O)(Py2 (Me) tacn)](2+) , which have been characterised spectroscopically. Their relative redox and pH stability in water has been studied by using UV/Vis and NMR spectroscopies, HRMS and spectroelectrochemistry. [Ru(IV) (O)(Py2 (Me) tacn)](2+) has a long half-life (>48 h) in water. The catalytic cycle of WO has been elucidated by using kinetic, spectroscopic, (18) O-labelling and theoretical studies, and the conclusion is that the rate-determining step is a single-site water nucleophilic attack on a metal-oxo species. Moreover, [Ru(IV) (O)(Py2 (Me) tacn)](2+) is proposed to be the resting state under catalytic conditions. By monitoring Ce(IV) consumption, we found that the O2 evolution rate is redox-controlled and independent of the initial concentration of Ce(IV) . Based on these facts, we propose herein that [Ru(IV) (O)(Py2 (Me) tacn)](2+) is oxidised to [Ru(V) (O)(Py2 (Me) tacn)](2+) prior to attack by a water molecule to give [Ru(III) (OOH)(Py2 (Me) tacn)](2+) . Finally, it is shown that the difference in WO reactivity between the homologous iron and ruthenium [M(OH2 )(Py2 (Me) tacn)](2+) (M=Ru, Fe) complexes is due to the difference in the redox stability of the key M(V) (O) intermediate. These results contribute to a better understanding of the WO mechanism and the differences between iron and ruthenium complexes in WO reactions. PMID:27324949

  15. Spectroscopic evidence on improvement in complex formation of O2N2 aza-crown macrocyclic ligands with Cu(II) acetate upon incorporation with [60]Fullerene.

    PubMed

    Ghanbari, Bahram; Gholamnezhad, Parisa

    2016-12-01

    The present paper reports the spectroscopic investigations on the complexation of Cu(II) with two macrocyclic ligands bonded to [60]Fullerene (L1 and L2) measured in N-methylpyrrolidone (NMP) as solvent. On the basis of UV-vis-NIR spectroscopy applying Jobs method of continuous variation, typical 1:1 stoichiometries were established for the complexes of Cu(II) with L1, and L2. DFT calculations suggested that superior HOMO distributions spread over the nitrogen-donor (as well as somehow oxygen- donor in L2) groups of L1 and L2 macrocycles were the key factor for the observed Kb value enhancement. Thermodynamic stabilities for these complexes have also been determined employing Benesi-Hildebrand equation and the results were compared in terms of their calculated binding constants (Kb). These measurements showed that L1 and L2 bound to these cations stronger than their parent free macrocyclic ligands 1 and 2, respectively. Furthermore, Kb values found for L2 complexes revealed that it could coordinate Cu(II) cation better than L1. Thermodynamic parameters (ΔG, ∆H, and -ΔS) derived from Van't Hoff equation showed that L1 and L2 coordination of Cu(II) cation were occurred due to both enthalpic and entropic factors while the coordination of Cu(II) with their parent macrocyclic ligands 1 and 2 only enjoyed from only enthalpic advantages. PMID:27380303

  16. Spectroscopic evidence on improvement in complex formation of O2N2 aza-crown macrocyclic ligands with Cu(II) acetate upon incorporation with [60]Fullerene

    NASA Astrophysics Data System (ADS)

    Ghanbari, Bahram; Gholamnezhad, Parisa

    2016-12-01

    The present paper reports the spectroscopic investigations on the complexation of Cu(II) with two macrocyclic ligands bonded to [60]Fullerene (L1 and L2) measured in N-methylpyrrolidone (NMP) as solvent. On the basis of UV-vis-NIR spectroscopy applying Jobs method of continuous variation, typical 1:1 stoichiometries were established for the complexes of Cu(II) with L1, and L2. DFT calculations suggested that superior HOMO distributions spread over the nitrogen-donor (as well as somehow oxygen- donor in L2) groups of L1 and L2 macrocycles were the key factor for the observed Kb value enhancement. Thermodynamic stabilities for these complexes have also been determined employing Benesi-Hildebrand equation and the results were compared in terms of their calculated binding constants (Kb). These measurements showed that L1 and L2 bound to these cations stronger than their parent free macrocyclic ligands 1 and 2, respectively. Furthermore, Kb values found for L2 complexes revealed that it could coordinate Cu(II) cation better than L1. Thermodynamic parameters (ΔG, ∆ H, and - ΔS) derived from Van't Hoff equation showed that L1 and L2 coordination of Cu(II) cation were occurred due to both enthalpic and entropic factors while the coordination of Cu(II) with their parent macrocyclic ligands 1 and 2 only enjoyed from only enthalpic advantages.

  17. PHOTOMETRIC AND SPECTROSCOPIC STUDIES OF MASSIVE BINARIES IN THE LARGE MAGELLANIC CLOUD. I. INTRODUCTION AND ORBITS FOR TWO DETACHED SYSTEMS: EVIDENCE FOR A MASS DISCREPANCY?

    SciTech Connect

    Massey, Philip; Neugent, Kathryn F.; Morrell, Nidia I.; Penny, Laura R.; DeGioia-Eastwood, Kathleen; Gies, Douglas R. E-mail: kneugent@lowell.edu E-mail: pennyl@cofc.edu E-mail: gies@chara.gsu.edu

    2012-04-01

    The stellar mass-luminosity relation is poorly constrained by observations for high-mass stars. We describe our program to find eclipsing massive binaries in the Magellanic Clouds using photometry of regions rich in massive stars, and our spectroscopic follow-up to obtain radial velocities and orbits. Our photometric campaign identified 48 early-type periodic variables, of which only 15 (31%) were found as part of the microlensing surveys. Spectroscopy is now complete for 17 of these systems, and in this paper we present analysis of the first two, LMC 172231 and ST2-28, simple detached systems of late-type O dwarfs of relatively modest masses. Our orbit analysis yields very precise masses ({approx}2%), and we use tomography to separate the components and determine effective temperatures by model fitting, necessary for determining accurate (0.05-0.07 dex) bolometric luminosities in combination with the light-curve analysis. Our approach allows more precise comparisons with evolutionary theory than previously possible. To our considerable surprise, we find a small, but significant, systematic discrepancy: all of the stars are slightly undermassive, by typically 11% (or overluminous by 0.2 dex) compared with that predicted by the evolutionary models. We examine our approach for systematic problems, but find no satisfactory explanation. The discrepancy is in the same sense as the long-discussed and elusive discrepancy between the masses measured from stellar atmosphere analysis with the stellar evolutionary models, and might suggest that either increased rotation or convective overshooting is needed in the models. Additional systems will be discussed in future papers of this series, and will hopefully confirm or refute this trend.

  18. Evidence for the kinematic Sunyaev-Zel'dovich effect with the Atacama Cosmology Telescope and velocity reconstruction from the Baryon Oscillation Spectroscopic Survey

    NASA Astrophysics Data System (ADS)

    Schaan, Emmanuel; Ferraro, Simone; Vargas-Magaña, Mariana; Smith, Kendrick M.; Ho, Shirley; Aiola, Simone; Battaglia, Nicholas; Bond, J. Richard; De Bernardis, Francesco; Calabrese, Erminia; Cho, Hsiao-Mei; Devlin, Mark J.; Dunkley, Joanna; Gallardo, Patricio A.; Hasselfield, Matthew; Henderson, Shawn; Hill, J. Colin; Hincks, Adam D.; Hlozek, Renée; Hubmayr, Johannes; Hughes, John P.; Irwin, Kent D.; Koopman, Brian; Kosowsky, Arthur; Li, Dale; Louis, Thibaut; Lungu, Marius; Madhavacheril, Mathew; Maurin, Loïc; McMahon, Jeffrey John; Moodley, Kavilan; Naess, Sigurd; Nati, Federico; Newburgh, Laura; Niemack, Michael D.; Page, Lyman A.; Pappas, Christine G.; Partridge, Bruce; Schmitt, Benjamin L.; Sehgal, Neelima; Sherwin, Blake D.; Sievers, Jonathan L.; Spergel, David N.; Staggs, Suzanne T.; van Engelen, Alexander; Wollack, Edward J.; ACTPol Collaboration

    2016-04-01

    We use microwave temperature maps from two seasons of data from the Atacama Cosmology Telescope at 146 GHz, together with the "Constant Mass" CMASS galaxy sample from the Baryon Oscillation Spectroscopic Survey to measure the kinematic Sunyaev-Zel'dovich (kSZ) effect over the redshift range z =0.4 - 0.7 . We use galaxy positions and the continuity equation to obtain a reconstruction of the line-of-sight velocity field. We stack the microwave temperature at the location of each halo, weighted by the corresponding reconstructed velocity. We vary the size of the aperture photometry filter used, thus probing the free electron profile of these halos from within the virial radius out to three virial radii, on the scales relevant for investigating the missing baryons problem. The resulting best fit kSZ model is preferred over the no-kSZ hypothesis at 3.3 and 2.9 σ for two independent velocity reconstruction methods, using 25,537 galaxies over 660 square degrees. The data suggest that the baryon profile is shallower than the dark matter in the inner regions of the halos probed here, potentially due to energy injection from active galactic nucleus or supernovae. Thus, by constraining the gas profile on a wide range of scales, this technique will be useful for understanding the role of feedback in galaxy groups and clusters. The effect of foregrounds that are uncorrelated with the galaxy velocities is expected to be well below our signal, and residual thermal Sunyaev-Zel'dovich contamination is controlled by masking the most massive clusters. Finally, we discuss the systematics involved in converting our measurement of the kSZ amplitude into the mean free electron fraction of the halos in our sample.

  19. Computational, electrochemical, and spectroscopic studies of two mononuclear cobaloximes: the influence of an axial pyridine and solvent on the redox behaviour and evidence for pyridine coordination to cobalt(i) and cobalt(ii) metal centres.

    PubMed

    Lawrence, Mark A W; Celestine, Michael J; Artis, Edward T; Joseph, Lorne S; Esquivel, Deisy L; Ledbetter, Abram J; Cropek, Donald M; Jarrett, William L; Bayse, Craig A; Brewer, Matthew I; Holder, Alvin A

    2016-06-21

    [Co(dmgBF2)2(H2O)2] (where dmgBF2 = difluoroboryldimethylglyoximato) was used to synthesize [Co(dmgBF2)2(H2O)(py)]·0.5(CH3)2CO (where py = pyridine) in acetone. The formulation of complex was confirmed by elemental analysis, high resolution MS, and various spectroscopic techniques. The complex [Co(dmgBF2)2(solv)(py)] (where solv = solvent) was readily formed in situ upon the addition of pyridine to complex . A spectrophotometric titration involving complex and pyridine proved the formation of such a species, with formation constants, log K = 5.5, 5.1, 5.0, 4.4, and 3.1 in 2-butanone, dichloromethane, acetone, 1,2-difluorobenzene/acetone (4 : 1, v/v), and acetonitrile, respectively, at 20 °C. In strongly coordinating solvents, such as acetonitrile, the lower magnitude of K along with cyclic voltammetry, NMR, and UV-visible spectroscopic measurements indicated extensive dissociation of the axial pyridine. In strongly coordinating solvents, [Co(dmgBF2)2(solv)(py)] can only be distinguished from [Co(dmgBF2)2(solv)2] upon addition of an excess of pyridine, however, in weakly coordinating solvents the distinctions were apparent without the need for excess pyridine. The coordination of pyridine to the cobalt(ii) centre diminished the peak current at the Epc value of the Co(I/0) redox couple, which was indicative of the relative position of the reaction equilibrium. Herein we report the first experimental and theoretical (59)Co NMR spectroscopic data for the formation of Co(i) species of reduced cobaloximes in the presence and absence of py (and its derivatives) in CD3CN. From spectroelectrochemical studies, it was found that pyridine coordination to a cobalt(i) metal centre is more favourable than coordination to a cobalt(ii) metal centre as evident by the larger formation constant, log K = 4.6 versus 3.1, respectively, in acetonitrile at 20 °C. The electrosynthesis of hydrogen by complexes and in various solvents demonstrated the dramatic effects of the axial

  20. Direct Spectroscopic Evidence for Phase Competition between the Pseudogap and Superconductivity in Bi2Sr2CaCu2O8+δ

    SciTech Connect

    Hashimoto, Makoto; Nowadnick, Elizabeth A.; He, Rui-Hua; Vishik, Inna M.; Moritz, Brian; He, Yu; Tanaka, Kiyohisa; Moore, Robert G.; Lu, Donghui; Yoshida, Yoshiyuki; Ishikado, Motoyuki; Sasagawa, Takao; Fujita, Kazuhiro; Ishida, Shigeyuku; Uchida, Shinichi; Eisaki, Hiroshi; Hussain, Zahid; Devereaux, Thomas P.; Shen, Zhi-Xun

    2014-11-02

    In the high-temperature (Tc) cuprate superconductors, increasing evidence suggests that the pseudogap, existing below the pseudogap temperature T*, has a distinct broken electronic symmetry from that of superconductivity. Particularly, recent scattering experiments on the underdoped cuprates have suggested that a charge ordering competes with superconductivity. However, no direct link of this physics and the important low-energy excitations has been identified. We report an antagonistic singularity at Tc in the spectral weight of Bi2Sr2CaCu2O8+δ as a compelling evidence for phase competition, which persists up to a high hole concentration p ~ 0.22. Comparison with a theoretical calculation confirms that the singularity is a signature of competition between the order parameters for the pseudogap and superconductivity. Our observation of the spectroscopic singularity at finite temperatures over a wide doping range provides new insights into the nature of the competitive interplay between the two intertwined phases and the complex phase diagram near the pseudogap critical point.

  1. Spectroscopic Evidence for Strong Quantum Spin Fluctuations with Itinerant Character in YFe2Ge2

    SciTech Connect

    Sirica, N.; Bondino, F.; Nappini, S.; Piz, I.; Poudel, L.; Christianson, Andrew D.; Mandrus, D.; Singh, David J; Mannella, Norman

    2015-03-04

    We report x-ray absorption and photoemission spectroscopy of the electronic structure in the normal state of metallic YFe2Ge2. The data reveal evidence for large fluctuating spin moments on the Fe sites, as indicated by exchange multiplets appearing in the Fe 3s core-level photoemission spectra, even though the compound does not show magnetic order. The magnitude of the multiplet splitting is comparable to that observed in the normal state of the Fe-pnictide superconductors. This shows a connection between YFe2Ge2 and the Fe-based superconductors even though it contains neither pnictogens nor chalcogens. Finally, the implication is that the chemical range of compounds showing at least one of the characteristic magnetic signatures of the Fe-based superconductors is broader than previously thought.

  2. Spectroscopic evidence for the coexistence of tetragonal and trigonal minima within the exited state adiabatic potential energy surfaces of hexachlorotellurate and -selenate complexes

    NASA Astrophysics Data System (ADS)

    Cremers, C.; Degen, J.

    1998-11-01

    Coexistence of Jahn-Teller minima resulting from the coupling to different accepting modes within the adiabatic potential energy surface (APES) is not possible within the framework of linear vibronic coupling theory. For the lowest exited triplet state 3T1u of inorganic complexes with s2 electronic ground-state configuration, such a coexistence, due to quadratic coupling effects, is discussed. As a direct experimental evidence two vibronic progressions with different accepting modes in the emission spectra resulting from a single electronic state are observed in the emission spectra of the title compounds. The observation of vibronic finestructure in the emission spectra of [TeCl6]2- is reported for the first time.

  3. Evidence of colour-modification induced charge and structural disorder in natural corundum: Spectroscopic studies of beryllium treated sapphires and rubies

    NASA Astrophysics Data System (ADS)

    Sastry, M. D.; Mane, Sandesh N.; Gaonkar, Mahesh P.; Bagla, H.; Panjikar, J.; Ramachandran, K. T.

    2009-07-01

    Corundum α - Al2O3 single crystals is an important gemstone known by different names depending on the colour it exhibits which in turn depends on the impurities that are present. The colour depends on the valence state of the impurity element present in corundum (Cr3+ in ruby, Fe3+ in yellow sapphire and Fe-Ti complex in blue sapphire). There have been a number of reports of diffusion controlled high temperature chemical reactions to influence the colouration in these materials. Present paper deals with the Raman and FT-IR results on Be treated rubies/sapphires and gives evidence of the disorder brought about by such treatments. This can be effectively used for diagnostic purposes for detecting the treated stones.

  4. Spectroscopic Evidence for a High-Spin Br-Fe(IV)-Oxo Intermediate in the -Ketoglutarate-Dependent Halogenase CyTc3 From Streptomyces

    SciTech Connect

    Fujimori, D.Galonic; Barr, E.W.; Matthews, M.L.; Koch, G.M.; Yonce, J.R.; Walsh, C.T.; Bollinger, J.M., Jr.; Krebs, C.; Riggs-Gelasco, P.J.

    2009-06-01

    The complex of the mononuclear non-heme halogenase CytC3 from Streptomyces, Fe(II), {alpha}-ketoglutarate, bromide, and the substrate l-2-aminobutyryl-S-CytC2 reacts with O{sub 2} to form a reaction intermediate. Variable-field, freeze-quench Moessbauer spectroscopy reveals this intermediate to be a mixture of two high-spin Fe(IV) complexes in an approximate 3.7/1 ratio. Freeze-quench Fe K-edge X-ray absorption spectroscopy provides further insight into the structure of this intermediate. A short 1.62-{angstrom} interaction between the Fe and one of its ligands is attributed to the Fe(IV)-oxo group, and a 2.43-{angstrom} interaction is assigned to the Fe-Br interaction. A significantly longer Fe-Br separation (2.53 {angstrom}) is observed in the reactant complex, consistent with lower valency of the Fe in the reactant complex. This intermediate is the first example for a Br-Fe(IV)-oxo complex in a protein and provides evidence for a unifying mechanism for Fe(II) and {alpha}-ketoglutarate-dependent dioxygenases and halogenases.

  5. Spectroscopic Evidence for a High-Spin Br-Fe(IV)-Oxo Intermediate in the alpha-Ketoglutarate-Dependent Halogenase CytC3 from Streptomyces

    SciTech Connect

    Galonic Fujimori,D.; Barr, E.; Matthews, M.; Koch, G.; Yonce, J.; Walsh, C.; Bollinger, J.; Krebs, C.; Riggs-Gelasco, P.

    2007-01-01

    The complex of the mononuclear non-heme halogenase CytC3 from Streptomyces, Fe(II), {alpha}-ketoglutarate, bromide, and the substrate l-2-aminobutyryl-S-CytC2 reacts with O2 to form a reaction intermediate. Variable-field, freeze-quench Mossbauer spectroscopy reveals this intermediate to be a mixture of two high-spin Fe(IV) complexes in an approximate 3.7/1 ratio. Freeze-quench Fe K-edge X-ray absorption spectroscopy provides further insight into the structure of this intermediate. A short 1.62-Angstroms interaction between the Fe and one of its ligands is attributed to the Fe(IV)-oxo group, and a 2.43-Angstroms interaction is assigned to the Fe-Br interaction. A significantly longer Fe-Br separation (2.53 Angstroms) is observed in the reactant complex, consistent with lower valency of the Fe in the reactant complex. This intermediate is the first example for a Br-Fe(IV)-oxo complex in a protein and provides evidence for a unifying mechanism for Fe(II) and {alpha}-ketoglutarate-dependent dioxygenases and halogenases.

  6. Arsenic(III, V) adsorption on a goethite-based adsorbent in the presence of major co-existing ions: Modeling competitive adsorption consistent with spectroscopic and molecular evidence

    NASA Astrophysics Data System (ADS)

    Kanematsu, Masakazu; Young, Thomas M.; Fukushi, Keisuke; Green, Peter G.; Darby, Jeannie L.

    2013-04-01

    Adsorption of the two oxyanions, arsenate (As(V)) and arsenite (As(III)), on a common goethite-based granular porous adsorbent is studied in the presence of major co-existing ions in groundwater (i.e., phosphate, silicic acid, sulfate, carbonate, magnesium, and calcium) and predicted using the extended triple layer model (ETLM), a dipole modified single-site triple layer surface complexation model consistent with spectroscopic and molecular evidence. Surface species of all ions were selected according to the previous ETLM studies and published experimental spectroscopic/theoretical molecular information. The adsorption equilibrium constants for all ions were determined using adsorption data obtained in single-solute systems. The adsorption equilibrium constants referenced to the site-occupancy standard state (indicated by Kθ) were compared with those for goethite in the literature if available. The values of these constants for the goethite-based adsorbent are found to be close to the values for goethite previously studied. These "constrained" adsorption equilibrium constants determined in single-solute systems were used in the ETLM to predict the competitive interactions of As(III, V) with the co-existing ions in binary-solute systems. The ETLM is capable of predicting As(III, V) adsorption in the presence of oxyanions (phosphate, silicic acid, sulfate, and carbonate). This study presents the first successful and systematic prediction of the competitive interactions of As(III, V) with these oxyanions using the ETLM. The ETLM prediction of surface (and aqueous) speciation also provides insights into the distinct adsorption behavior of As(III, V) in the presence of the oxyanions. Magnesium and calcium significantly enhanced As(V) adsorption at higher pH values, while they had little effect on As(III) adsorption. The enhanced adsorption of As(V), however, could not be predicted by the ETLM using the surface species proposed in previous ETLM studies. Further studies

  7. FT-IR Spectroscopic Evidence Of Phase Transition For NaA-ROH-Kerosine-H2O Microemulsion System Containing Nd3+ Ions

    NASA Astrophysics Data System (ADS)

    Liao, Hua; Xu, Zhen-Hua; Shi, Nai; Wu, Jin-Guang; Xu, Guang-Xian

    1989-12-01

    In the previous investigation, the saponification of naphthenic acid extractant system has been proved to be a process of the formation of a microemulsion of 14/0 type, and its full extraction of rare earths is a process of destruction of the W/O microemulsion[1]. When NdCl3 is partially extracted with NaA (sodium naphthenate) secoctylalcohol-- kerosine-- water microemulsion system (ME), both the NdA3 and the NaA co-exist in the same organic phase. However,the formation mechanism of microemulsion containing neodymium has not been much studied. In this paper, 10 aliquots of fully saponificated extractants were equilibrated with various amounts of NdC13 solutions respectively, then ten organic phases with different extraction efficiencies of neodymium from 094 to 9094 were obtained. After extraction,the volume of neodymium containing organic phase increased by 5 to 4594, because of the transfer of water molecules. The appearance of these organic phase still remained clear and transparent. The average hydrodynamic radius of the drops were found to be 100-300 Angstrom by using light scattering techniques. The results give a direct evidence of the microemulsion formation in the organic phase. Their FT-IR spectra were measured with CaFa liquid cells utilizing a Nicolet 7199B FT-IR spectrometer. The presence of various amounts of water in the organic phases was clearly detected from the relative intensity changes of 1644 cm-I, which is assigned to the bending mode of 1110 molecules. Fig.1 shows the change of water contents to the percent extraction of neodymium. Comparsion with the FT-IR spectra, it is seen that the 1560 cm-1 peak of the full saponificated extractant is attributed to the asym. stretching vibration of COO''' group, it shifted to 1536 for 100% extration of Nd ions, indicating the formation of neodymium naphthenate (NdA ) from ionic sodium naphthenate. The sym. strethching vibration of COO''' located at 1406 cm-1, it shifted to 1408 cm in 45% Nd extration

  8. Calibration method for spectroscopic systems

    DOEpatents

    Sandison, David R.

    1998-01-01

    Calibration spots of optically-characterized material placed in the field of view of a spectroscopic system allow calibration of the spectroscopic system. Response from the calibration spots is measured and used to calibrate for varying spectroscopic system operating parameters. The accurate calibration achieved allows quantitative spectroscopic analysis of responses taken at different times, different excitation conditions, and of different targets.

  9. Calibration method for spectroscopic systems

    DOEpatents

    Sandison, D.R.

    1998-11-17

    Calibration spots of optically-characterized material placed in the field of view of a spectroscopic system allow calibration of the spectroscopic system. Response from the calibration spots is measured and used to calibrate for varying spectroscopic system operating parameters. The accurate calibration achieved allows quantitative spectroscopic analysis of responses taken at different times, different excitation conditions, and of different targets. 3 figs.

  10. Spectroscopic evidence for the formation of singlet molecular oxygen (/sup 1/. delta. /sub g/O/sub 2/) upon irradiation of a solvent-oxygen (/sup 3/Sigma/sub g//sup -/O/sub 2/) cooperative absorption band

    SciTech Connect

    Scurlock, R.D.; Ogilby, P.R.

    1988-01-20

    It is well-known that the presence of molecular oxygen (/sup 3/..sigma../sub g//sup -/O/sub 2/) in a variety of organic solvents causes an often substantial red shift in the solvent absorption spectrum. This extra, broad absorption feature is reversibly removed by purging the solvent with nitrogen gas. Mulliken and Tsubomura assigned the oxygen-dependent absorption band to a transition from a ground state solvent-oxygen complex to a solvent-oxygen charge transfer (CT) state (sol/sup .+/O/sub 2//sup .-/). In addition to the broad Mulliken CT band, there are, often in the same spectral region, distinct singlet-triplet transitions (T/sub 1/ reverse arrow S/sub 0/) which are enhanced by molecular oxygen (/sup 3/..sigma../sub g//sup -/O/sub 2/). Since both of these solvent-oxygen cooperative transitions may result in the formation of reactive oxygenating species, singlet molecular oxygen (/sup 1/..delta../sub g/O/sub 2/) and/or the superoxide ion (O/sub 2//sup .-/), it follows that recent studies have focused on unsaturated hydrocarbon oxygenation subsequent to the irradiation of the oxygen-induced absorption bands in both the solution phase and cryogenic (10 K) glasses. In these particular experiments, oxygenated products characteristic of both /sup 1/..delta../sub g/O/sub 2/ and O/sub 2//sub .-/ were obtained, although the systems studied appeared to involve the participation of one intermediate at the exclusion of the other. In this communication, the authors provide, for the first time, direct spectroscopic evidence for the formation of /sup 1/..delta../sub g/O/sub 2/ following a solvent-oxygen (/sup 3/..sigma../sub g//sup -/O/sub 2/) cooperative absorption. They have observed, in a time-resolved experiment, a near-IR luminescence subsequent to laser excitation of the oxygen-induced absorption bands of mesitylene, p-xylene, o-xylene, toluene, and benzene at 355 nm and 1,4-dioxane at 266 nm. They suggest that this signal is due to /sup 1/..delta../sub g/O/sub 2

  11. Spectroscopic infrared ellipsometry

    NASA Astrophysics Data System (ADS)

    Roseler, A.

    1992-03-01

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

  12. Spectroscopic wear detector

    NASA Technical Reports Server (NTRS)

    Madzsar, George C. (Inventor)

    1993-01-01

    The elemental composition of a material exposed to hot gases and subjected to wear is determined. Atoms of an elemental species not appearing in this material are implanted in a surface at a depth based on the maximum allowable wear. The exhaust gases are spectroscopically monitored to determine the exposure of these atoms when the maximum allowable wear is reached.

  13. Spectroscopic Low Coherence Interferometry

    NASA Astrophysics Data System (ADS)

    Bosschaart, Nienke; van Leeuwen, T. G.; Aalders, Maurice C.; Hermann, Boris; Drexler, Wolfgang; Faber, Dirk J.

    Low-coherence interferometry (LCI) allows high-resolution volumetric imaging of tissue morphology and provides localized optical properties that can be related to the physiological status of tissue. This chapter discusses the combination of spatial and spectroscopic information by means of spectroscopic OCT (sOCT) and low-coherence spectroscopy (LCS). We describe the theory behind these modalities for the assessment of spatially resolved optical absorption and (back)scattering coefficient spectra. These spectra can be used for the highly localized quantification of chromophore concentrations and assessment of tissue organization on (sub)cellular scales. This leads to a wealth of potential clinical applications, ranging from neonatology for the determination of billibrubin concentrations, to oncology for the optical assessment of the aggressiveness of a cancerous lesion.

  14. Spectroscopic Binary Stars

    NASA Astrophysics Data System (ADS)

    Batten, A.; Murdin, P.

    2000-11-01

    Historically, spectroscopic binary stars were binary systems whose nature was discovered by the changing DOPPLER EFFECT or shift of the spectral lines of one or both of the component stars. The observed Doppler shift is a combination of that produced by the constant RADIAL VELOCITY (i.e. line-of-sight velocity) of the center of mass of the whole system, and the variable shift resulting from the o...

  15. Spectroscopically Unlocking Exoplanet Characteristics

    NASA Astrophysics Data System (ADS)

    Lewis, Nikole

    2016-05-01

    Spectroscopy plays a critical role in a number of areas of exoplanet research. The first exoplanets were detected by precisely measuring Doppler shifts in high resolution (R ~ 100,000) stellar spectra, a technique that has become known as the Radial Velocity (RV) method. The RV method provides critical constraints on exoplanet masses, but is currently limited to some degree by robust line shape predictions. Beyond the RV method, spectroscopy plays a critical role in the characterization of exoplanets beyond their mass and radius. The Hubble Space Telescope has spectroscopically observed the atmospheres of exoplanets that transit their host stars as seen from Earth giving us key insights into atmospheric abundances of key atomic and molecular species as well as cloud optical properties. Similar spectroscopic characterization of exoplanet atmospheres will be carried out at higher resolution (R ~ 100-3000) and with broader wavelength coverage with the James Webb Space Telescope. Future missions such as WFIRST that seek to the pave the way toward the detection and characterization of potentially habitable planets will have the capability of directly measuring the spectra of exoplanet atmospheres and potentially surfaces. Our ability to plan for and interpret spectra from exoplanets relies heavily on the fidelity of the spectroscopic databases available and would greatly benefit from further laboratory and theoretical work aimed at optical properties of atomic, molecular, and cloud/haze species in the pressure and temperature regimes relevant to exoplanet atmospheres.

  16. Spectroscopic survey of LAMOST

    NASA Astrophysics Data System (ADS)

    Zhao, Yongheng

    2014-07-01

    LAMOST is a special reflecting Schmidt telescope. LAMOST breaks through the bottleneck of the large scale spectroscopic survey observation with both large aperture (effective aperture of 3.6 - 4.9m) and wide field of view (5 degrees). It is an innovative active reflecting Schmidt configuration achieved by changing mirror surface continuously to achieve a series different reflecting Schmidt system in different moments. By using the parallel controllable fiber positioning technique, the focal surface of 1.75 meters in diameter accommodates 4000 optical fibers. Also, LAMOST has 16 spectrographs with 32 CCD cameras. LAMOST is the telescope of the highest spectrum acquiring rate. As a national large scientific project, LAMOST project was proposed formally in 1996. The construction was started in 2001 and completed in 2008. After commission period, LAMOST pilot survey was started in October 2011 and spectroscopic survey began in September 2012. From October 2011 to June 2013, LAMOST has obtained more than 2 million spectra of celestial objects. There are 1.7 million spectra of stars, in which the stellar parameters (effective temperature, surface gravity, metalicitiy and radial velocity) of more than 1 million stars was obtained. In the first period of spectroscopic survey of LAMOST, 5 million of stellar spectra will be obtained and will make substantial contribution to the study of the stellar astrophysics and the structure of the Galaxy, such as the spheroid substructure of the Galaxy, the galactic gravitational potential and the distribution of the dark matter in the Galaxy, the extremely metal poor stars and hypervelocity stars, the 3D extinction in the Galaxy, the structure of thin and thick disks of the Galaxy, and so on.

  17. Spectroscopic survey of LAMOST

    NASA Astrophysics Data System (ADS)

    Zhao, Yongheng

    2015-08-01

    LAMOST is a special reflecting Schmidt telescope. LAMOST breaks through the bottleneck of the large scale spectroscopic survey observation with both large aperture (effective aperture of 3.6 - 4.9m) and wide field of view (5 degrees). It is an innovative active reflecting Schmidt configuration achieved by changing mirror surface continuously to achieve a series different reflecting Schmidt system in different moments. By using the parallel controllable fiber positioning technique, the focal surface of 1.75 meters in diameter accommodates 4000 optical fibers. Also, LAMOST has 16 spectrographs with 32 CCD cameras. LAMOST is the telescope of the highest spectrum acquiring rate.In the spectroscopic survey of LAMOST from October 2011 to June 2014, LAMOST has obtained more than 4.13 million spectra of celestial objects. There are 3.27 million spectra of stars, in which the stellar parameters of 2.16 million stars were obtained.In the five-year regular survey upto 2017, LAMOST will obtaine 5 million stellar spectra, which would make substantial contribution to the study of the stellar astrophysics and the structure of the Galaxy, such as the spheroid substructure of the Galaxy, the galactic gravitational potential and the distribution of the dark matter in the Galaxy, the extremely metal poor stars and hypervelocity stars, the 3D extinction in the Galaxy, the structure of thin and thick disks of the Galaxy, and so on.

  18. Spectroscopic investigations of dithienyl polyenes

    NASA Astrophysics Data System (ADS)

    Cooper, Thomas M.; Sowards, Laura A.; Natarajan, Lalgudi V.; Kirkpatrick, Sean M.; Chandra, Suresh; McLean, Daniel G.; Spangler, Charles W.

    1999-10-01

    To understand the photophysics of nonlinear absorbers, we have investigated the photophysics of a series of di(2- thienyl-3,3',4,4'-butyl)polyenes. Spectroscopic measurements, including UV/Vis, fluorescence, fluorescence lifetimes, fluorescence quantum yields, triplet state lifetime, solvent effects and two-photon absorption coefficient were obtained as a function of the number of double bonds (n equals 1 - 5). Trends in the data reflected the ordering, energy gap between and mixing of 1Bu* and 1Ag* excited state configurations. We investigated the solvatochromism of a series of (alpha) ,(omega) -di(2- dithienyl 3,3',4,4'-butyl) polyenes. Absorption (n equals 1 - 5 double bonds) were collected in a series of aprotic solvents. The absorption energy dispersion effect sensitivity increased smoothly with n, reaching asymptotic behavior as n approached 5. The emission energy had less solvent sensitivity, giving evidence for a polar 1Bu* absorbing state and a nonpolar 1Ag* emitting state. We observed sensitivity of the absorbing and emitting states to solute-solvent dipole-dipole interactions, suggesting the dithienyl polyenes had a polar syn ground state conformation.

  19. Enhancing forensic science with spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Ricci, Camilla; Kazarian, Sergei G.

    2006-09-01

    This presentation outlines the research we are developing in the area of Fourier Transform Infrared (FTIR) spectroscopic imaging with the focus on materials of forensic interest. FTIR spectroscopic imaging has recently emerged as a powerful tool for characterisation of heterogeneous materials. FTIR imaging relies on the ability of the military-developed infrared array detector to simultaneously measure spectra from thousands of different locations in a sample. Recently developed application of FTIR imaging using an ATR (Attenuated Total Reflection) mode has demonstrated the ability of this method to achieve spatial resolution beyond the diffraction limit of infrared light in air. Chemical visualisation with enhanced spatial resolution in micro-ATR mode broadens the range of materials studied with FTIR imaging with applications to pharmaceutical formulations or biological samples. Macro-ATR imaging has also been developed for chemical imaging analysis of large surface area samples and was applied to analyse the surface of human skin (e.g. finger), counterfeit tablets, textile materials (clothing), etc. This approach demonstrated the ability of this imaging method to detect trace materials attached to the surface of the skin. This may also prove as a valuable tool in detection of traces of explosives left or trapped on the surfaces of different materials. This FTIR imaging method is substantially superior to many of the other imaging methods due to inherent chemical specificity of infrared spectroscopy and fast acquisition times of this technique. Our preliminary data demonstrated that this methodology will provide the means to non-destructive detection method that could relate evidence to its source. This will be important in a wider crime prevention programme. In summary, intrinsic chemical specificity and enhanced visualising capability of FTIR spectroscopic imaging open a window of opportunities for counter-terrorism and crime-fighting, with applications ranging

  20. Recombinant phytochrome A in yeast differs by its spectroscopic and photochemical properties from the major phyA' and is close to the minor phyA": evidence for posttranslational modification of the pigment in plants.

    PubMed

    Sineshchekov, V; Hennig, L; Lamparter, T; Hughes, J; Gärtner, W; Schäfer, E

    2001-06-01

    Previously, two pools of phytochrome A (phyA' and phyA") have been detected by in situ low-temperature fluorescence spectroscopy and photochemistry; it was suggested that they might differ in the nature of their posttranslational modification. In order to verify this possibility Arabidopsis and rice (Oryza) phyA were expressed in yeast and the pigments were assembled in vivo with phycocyanobilin (PCB) and phytochromobilin (P phi B). The resulting recombinant phytochromes in the red-light-absorbing form (Pr) were characterized in the yeast cell by (1) the fluorescence emission spectra; (2) the temperature dependence of Pr fluorescence intensity and activation energy of fluorescence decay; and (3) the extent of photoconversion of Pr into photoproduct lumi-R (gamma 1) or far-red-light absorbing form (Pfr) (gamma 2). Both Arabidopsis phyA/PCB and Oryza phyA/P phi B had low gamma 1 of ca 0.05, allowing their attribution to the Pr" phenomenological type of phytochrome comprising phyA", phyB and cryptogam phytochromes. The spectroscopic properties of Oryza phyA/P phi B were also very close to phyA". However, both investigated holoproteins differed from phyA", both with respect to the character of temperature dependence of the fluorescence yield and activation energy. Thus, recombinant Oryza phyA/P phi B is similar but not identical to phyA". The data demonstrate that the low-abundance-fraction plant phyA (phyA") comes from the same gene as the major (phyA') fraction. Because both endogenous phyA fractions differ from the phytochrome expressed in yeast, they appear to be posttranslationally modified and/or bound to partner proteins or cellular substructures. However, the character of the presumed chemical modification is different in phyA' and phyA" and its extent is more profound in the case of the former. PMID:11421077

  1. Infrared Solar Spectroscopic Measurements of Free Tropospheric CO, C2H6, and HCN above Mauna Loa, Hawaii: Seasonal Variations and Evidence for Enhanced Emissions from the Southeast Asian Tropical Fires of 1997-1998

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Goldman, A.; Murcray, F. J.; Stephen, T. M.; Pougatchev, N. S.; Fishman, J.; David, S. J.; Blatherwick, R. D.; Novelli, P. C.; Jones, N. B.

    1999-01-01

    High spectral resolution (0.003 per cm) infrared solar absorption measurements of CO, C2H6, and HCN have been recorded at the Network for the Detection of Stratospheric Change station on Mauna Loa, Hawaii, (19.5N, 155.6W, altitude 3.4 km). The observations were obtained on over 250 days between August 1995 and February 1998. Column measurements are reported for the 3.4-16 km altitude region, which corresponds approximately to the free troposphere above the station. Average CO mixing ratios computed for this layer have been compared with flask sampling CO measurements obtained in situ at the station during the same time period. Both show asymmetrical seasonal cycles superimposed on significant variability. The first 2 years of observations exhibit a broad January-April maximum and a sharper CO minimum during late summer. The C2H6 and CO 3.4-16 km columns were highly correlated throughout the observing period with the C2H6/CO slope intermediate between higher and lower values derived from similar infrared spectroscopic measurements at 32'N and 45'S latitude, respectively. Variable enhancements in CO, C2H6, and particularly HCN were observed beginning in about September 1997. The maximum HCN free tropospheric monthly mean column observed in November 1997 corresponds to an average 3.4-16 km mixing ratio of 0.7 ppbv (1 ppbv = 10(exp -9) per unit volume), more than a factor of 3 above the background level. The HCN enhancements continued through the end of the observational series. Back-trajectory calculations suggest that the emissions originated at low northern latitudes in southeast Asia. Surface CO mixing ratios and the C2H6 tropospheric columns measured during the same time also showed anomalous autumn 1997 maxima. The intense and widespread tropical wild fires that burned during the strong El Nino warm phase of 1997- 1998 are the likely source of the elevated emission products.

  2. Spectroscopic classification of supernova candidates

    NASA Astrophysics Data System (ADS)

    Hodgkin, S. T.; Hall, A.; Fraser, M.; Campbell, H.; Wyrzykowski, L.; Kostrzewa-Rutkowska, Z.; Pietro, N.

    2014-09-01

    We report the spectroscopic classification of four supernovae at the 2.5m Isaac Newton Telescope on La Palma, using the Intermediate Dispersion Spectrograph and the R300V grating (3500-8000 Ang; ~6 Ang resolution).

  3. Spectroscopic optical coherence elastography

    PubMed Central

    Adie, Steven G.; Liang, Xing; Kennedy, Brendan F.; John, Renu; Sampson, David D.; Boppart, Stephen A.

    2010-01-01

    We present an optical technique to image the frequency-dependent complex mechanical response of a viscoelastic sample. Three-dimensional hyperspectral data, comprising two-dimensional B-mode images and a third dimension corresponding to vibration frequency, were acquired from samples undergoing external mechanical excitation in the audio-frequency range. We describe the optical coherence tomography (OCT) signal when vibration is applied to a sample and detail the processing and acquisition techniques used to extract the local complex mechanical response from three-dimensional data that, due to a wide range of vibration frequencies, possess a wide range of sample velocities. We demonstrate frequency-dependent contrast of the displacement amplitude and phase of a silicone phantom containing inclusions of higher stiffness. Measurements of an ex vivo tumor margin demonstrate distinct spectra between adipose and tumor regions, and images of displacement amplitude and phase demonstrated spatially-resolved contrast. Contrast was also observed in displacement amplitude and phase images of a rat muscle sample. These results represent the first demonstration of mechanical spectroscopy based on B-mode OCT imaging. Spectroscopic optical coherence elastography (S-OCE) provides a high-resolution imaging capability for the detection of tissue pathologies that are characterized by a frequency-dependent viscoelastic response. PMID:21164898

  4. Spectroscopic optical coherence elastography.

    PubMed

    Adie, Steven G; Liang, Xing; Kennedy, Brendan F; John, Renu; Sampson, David D; Boppart, Stephen A

    2010-12-01

    We present an optical technique to image the frequency-dependent complex mechanical response of a viscoelastic sample. Three-dimensional hyperspectral data, comprising two-dimensional B-mode images and a third dimension corresponding to vibration frequency, were acquired from samples undergoing external mechanical excitation in the audio-frequency range. We describe the optical coherence tomography (OCT) signal when vibration is applied to a sample and detail the processing and acquisition techniques used to extract the local complex mechanical response from three-dimensional data that, due to a wide range of vibration frequencies, possess a wide range of sample velocities. We demonstrate frequency-dependent contrast of the displacement amplitude and phase of a silicone phantom containing inclusions of higher stiffness. Measurements of an ex vivo tumor margin demonstrate distinct spectra between adipose and tumor regions, and images of displacement amplitude and phase demonstrated spatially-resolved contrast. Contrast was also observed in displacement amplitude and phase images of a rat muscle sample. These results represent the first demonstration of mechanical spectroscopy based on B-mode OCT imaging. Spectroscopic optical coherence elastography (S-OCE) provides a high-resolution imaging capability for the detection of tissue pathologies that are characterized by a frequency-dependent viscoelastic response. PMID:21164898

  5. Infrared Solar Spectroscopic Measurements of Free Tropospheric CO, C2H6, and HCN above Mauna Loa, Hawaii: Seasonal Variations and Evidence for Enhanced Emissions from the Southeast Asian Fires of 1997-1998. Revised

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Goldman, A.; Murcray, F. J.; Stephen, T. M.; Pougatchev, N. S.; Fishman, J.; David, S. J.; Blatherwick, R. D.; Novelli, P. C.; Jones, N. B.; Connor, B. J.

    1999-01-01

    High spectral resolution (0.003/ cm) infrared solar absorption measurements of CO, C2H6, and HCN have been recorded at the Network for the Detection of Stratospheric Change station on Mauna Loa, Hawaii, (19.5 deg N, 155.6 deg W, altitude 3.4 km). The observations were obtained on over 250 days between August 1995 and February 1998. Column measurements are reported for the 3.4 - 16 km altitude region, which corresponds approximately to the free troposphere above the station. Average CO mixing ratios computed for this layer have been compared with flask sampling CO measurements obtained in situ at the station during the same time period. Both show asymmetrical seasonal cycles superimposed on significant variability. The first two years of observations exhibit a broad January-April maximum and a sharper CO minimum during late summer. The C2H6 and CO 3.4 - 16 km columns were highly correlated throughout the observing period with the C2H6/CO slope intermediate between higher and lower values derived from similar infrared spectroscopic measurements at 32 deg N and 45 deg S latitude, respectively. Variable enhancements in CO, C2H6, and particularly HCN were observed beginning in about September 1997. The maximum HCN free tropospheric monthly mean column observed in November 1997 corresponds to an average 3.4 - 16 km mixing ratio of 0.7 ppbv (1 ppbv = 10(exp -9) per unit volume), more than a factor of 3 above the background level. The HCN enhancements continued through the end of the observational series. Back-trajectory calculations suggest that the emissions originated at low northern latitudes in southeast Asia. Surface CO mixing ratios and the C2H6 tropospheric columns measured during the same time also showed anomalous autumn 1997 maxima. The intense and widespread tropical wild fires that burned during 3 the strong El Nino warm phase of 1997-1998 are the likely source of the elevated emission products.

  6. Spectroscopic characterization of the Stentor photoreceptor.

    PubMed

    Walker, E B; Lee, T Y; Song, P S

    1979-09-20

    1. On the basis of chromatographic and spectroscopic (absorption, fluorescence and its polarization, fluorescence lifetime, circular dichroism) characterization of the Stentor photoreceptor (stentorin) for photophobic response, the photoreceptor chromophore released from mild acid hydrolysis has been identified as hypericin. 2. The native chromophore is apparently linked to a protein (65 K) containing Lys and several hydrophobic residues, which is soluble in acetone and n-pentane. The peptide-linked stentorin (I) chromophore exhibits circular dichroism in the visible region due to the induced optical activity provided by the peptide. 3. The sodium dodecyl sulfate polyacrylamide gel electrophoresis of a 38% fraction of the sucrose density centrifugation has resolved stentorin II proteins having molecular weights of 13 000, 16 000, 65 000 and 130 000. These proteins, as well as the acetone-soluble peptide, have been spectroscopically characterized with particular emphasis on their primary photoreactivity as the photophobic receptor of Stentor coeruleus. 4. Irradiation of whole living Stentor in dilute buffer solutions induces a decrease in the pH of the medium. A strong dependence upon pH in the fluorescence spectra of both synthetic and native chromophores is also evident, showing a significant drop in the pKa of one or more hydroxyl groups in the excited state. A mechanism for the photophobic response, based on this lowering of the pKa as the primary photoprocess, has been discussed. PMID:39631

  7. Spectroscopic observations of cool degenerate star candidates

    NASA Technical Reports Server (NTRS)

    Hintzen, P.

    1986-01-01

    Spectroscopic observations are reported for 23 Luyten Half-Second degenerate star candidates and for 13 Luyten-Palomar common proper-motion pairs containing possible degenerate star components. Twenty-five degenerate stars are identified, 20 of which lack previous spectroscopy. Most of these stars are cool - Luyten color class g or later. One star, LP 77-57, shows broad continuum depressions similar to those in LHS 1126, which Liebert and Dahn attributed to pressure-shifted C2. A second degenerate star, LHS 290, exhibits apparent strong Swan bands which are blueshifted about 75 A. Further observations, including polarimetry and photometry, are required to appraise the spectroscopic peculiarities of these stars. Finally, five cool, sharp-lined DA white dwarfs have been observed to detect lines of metals and to determine line strengths. None of these DAs show signs of Mg b or the G band, and four show no evidence of Ca II K. The attempt to detect Ca MI in the fifth star, G199-71, was inconclusive.

  8. A DVD Spectroscope: A Simple, High-Resolution Classroom Spectroscope

    ERIC Educational Resources Information Center

    Wakabayashi, Fumitaka; Hamada, Kiyohito

    2006-01-01

    Digital versatile disks (DVDs) have successfully made up an inexpensive but high-resolution spectroscope suitable for classroom experiments that can easily be made with common material and gives clear and fine spectra of various light sources and colored material. The observed spectra can be photographed with a digital camera, and such images can…

  9. The α decay spectroscopic factor of heavy and superheavy nuclei

    NASA Astrophysics Data System (ADS)

    Seif, W. M.

    2013-10-01

    The spectroscopic factor which refers to the preformation probability of an α cluster inside parent radioactive nuclei is investigated. The study is based on the cluster model of α decay that is extended to account for the deformation degrees of freedom. The calculations are carried out for 179 even(Z)-even(N) parent nuclei in the mass region of A = 144-294. Taking into account the deformations of daughter nuclei, the semi-microscopic calculations of the α-daughter interaction potential are performed using the Hamiltonian energy density approach in terms of the SLy4 Skyrme-like effective interaction. The calculated potential is then implemented to find both the assault frequency and the penetration probability of the α particle by means of the Wentzel-Kramers-Brillouin approximation at different orientations of the deformed daughter. By averaging the obtained decay widths over different orientations, the half-lives of the mentioned α decays are then estimated. Taking into account the errors on both the released energy and the experimental half-life times, the extracted half-lives are employed in turn to deduce the α spectroscopic factor. The results show a periodic behaviour of the spectroscopic factor as a function of the charge and neutron numbers characterized by several local maxima and minima. The predicted minima are mainly related to the proton and neutron shell and subshell closures. In addition to the well-known closed shells of the nucleonic numbers 50, 82, and 126, the obtained values of the spectroscopic factor give some evidence for the presence of closed subshells of nucleonic numbers 70, 102 (104) and 152 (150). A simple formula is suggested to roughly estimate the spectroscopic factor in terms of the numbers of protons and neutrons of the parent nucleus outside its closed shells. The parameters of this formula are fitted to the deduced values of the spectroscopic factor.

  10. Spectroscopic study of sprites

    NASA Astrophysics Data System (ADS)

    Kanmae, Takeshi

    Optical emissions from sprites--large electric discharges in the mesosphere caused by intense lightning strokes--have been studied for decades. Studies have identified that sprite emissions are primarily composed of molecular band emissions of nitrogen and notably identified the near ultraviolet and blue emission from the N2+ First Negative system, which provided direct evidence of ionization in sprites. This implies that further evidence of the ionization may be provided by the visible and near infrared emission from the N2+ Meinel system, which is more accessible from ground-based platforms, though anticipated strong quenching in the mesosphere and below have made the presence of the emission somewhat controversial. To investigate the presence of the Meinel emission along the vertical extent of sprites, we made ground-based spectral observations in 2005. The observed spectra were mainly composed of the N2 First Positive system, and no or little indication of the Meinel bands were found. This study suggests that the quenching is indeed severe at sprite altitude, and it is difficult to study the ionization process in sprites via the Meinel emission. In addition, the data allowed us to investigate details of the First Positive emission from sprites. The observed First Positive spectra showed that the vibrational distribution of the upper state varies along the vertical extent of sprites, which is in agreement with previous reports, and furthermore this study indicates that the variation is associated with altitude, implying that collisional energy transfer processes play roles in exciting the First Positive emission, particularly at lower altitudes. Recent high-speed imaging observations have revealed the very dynamic nature of sprites: they develop within a few to 10 ms in forms of streamers and columnar glows. The underlying electron energies in these features have been inferred from their emissions in previous measurements, but they lacked either sufficient

  11. Spectroscopic characterization of polymers: report

    SciTech Connect

    Koenig, J.L.

    1987-10-01

    Polymer characterization has presented major difficulties to the analytical chemist, who has had to develop techniques to cope with the challenge. Even the elementary problem of measuring molecular weight is not easy. Yet such measurements are essential, because the physical, mechanical, and flow properties depend on the length of the polymer chain. Because of the limited solubility and high viscosity of polymers, many classical techniques have been of little use or have had to be extensively modified to measure the molecular weight of polymers. Size-exclusion chromatographic techniques such as gel permeation have been developed to measure these molecular weight distributions. Special chromatographic instruments with a range of spectroscopic detectors (including infrared and laser-light scattering) have emerged commercially to aid the analytical chemist in the fundamental endeavor to measure the length of the polymer chain and its distribution. The author describes the advantages and disadvantages and disadvantages of various spectroscopic techniques.

  12. Single nanoparticle tracking spectroscopic microscope

    DOEpatents

    Yang, Haw; Cang, Hu; Xu, Cangshan; Wong, Chung M.

    2011-07-19

    A system that can maintain and track the position of a single nanoparticle in three dimensions for a prolonged period has been disclosed. The system allows for continuously imaging the particle to observe any interactions it may have. The system also enables the acquisition of real-time sequential spectroscopic information from the particle. The apparatus holds great promise in performing single molecule spectroscopy and imaging on a non-stationary target.

  13. Spectroscopic Evidence of Formation of Small Polarons in Doped Manganites

    NASA Astrophysics Data System (ADS)

    Moritomo, Yutaka; Machida, Akihiko; Nakamura, Arao

    1998-03-01

    Temperature dependence of absorption spectra for thin films of doped manganites R_0.6Sr_0.4MnO_3, where R is rare-earth atom, has been investigated systematically changing averaged ionic radius < rA > of perovskite A-site. We have observed a specific absorption band at ~1.5eV due to optical excitations from small polarons (SP)(Machida et al.), submitted.. Spectral weight of the SP band increases with decreasing temperature and eventually disappears at the insulator-metal (IM) transition, indicating that SP in the paramagnetic state (T >= T_C) changes into bare electrons (or large polarons) in the ferromagnetic state due to the enhanced one-electron bandwidth W. We further derived important physical quantities, i.e., W, on-site exchange interaction J and binding energy Ep of SP, and discuss material dependence of stability of SP. This work was supported by a Grant-In-Aid for Scientific Research from the Ministry of Education, Science, Sport and Culture and from PRESTO, Japan Scienece and Technology Corporation (JST), Japan.

  14. Spectroscopic Evidence for Interstellar Ice in Comet Hyakutake

    NASA Technical Reports Server (NTRS)

    Irvine, W. M.; Bockelee-Morvan, D.; Lis, D. C.; Matthews, H. E.; Biver, N.; Crovisier, J.; Davies, J. K.; Dent, W. R. F.; Gautier, D.; Godfrey, P. D.; Keene, J.; Lovell, A. J.; Owen, T. C.; Phillips, T. G.; Rauer, H.; Schloerb, F. P.; Senay, M.; Young, K.

    1996-01-01

    Volatile compounds in comets are the most pristine materials surviving from the time of formation of the Solar System, and thus potentially provide information about conditions that prevailed in the primitive solar material. Moreover, comets may have supplied a substantial fraction of the volatiles on the terrestrial planets, perhaps including organic compounds that played a role in the origin of life on Earth. Here we report the detection of hydrogen isocyanide (HNC) in comet Hyakutake. The abundance of HNC relative to hydrogen cyanide (HCN) is very similar to that observed in quiescent interstellar molecular clouds, and quite different from the equilibrium ratio expected in the outermost solar nebula, where comets are thought to form. Such a departure from equilibrium has long been considered a hallmark of gas-phase chemical processing in the interstellar medium, suggesting that interstellar gases have been incorporated into the comet's nucleus, perhaps as ices frozen onto interstellar grains. If this interpretation is correct, our results should provide constraints on the temperature of the solar nebula, and the subsequent chemical processes that occurred in the region where comets formed.

  15. Spectroscopic and Visual Evidence of Perchlorate Deliquescence Under Martian Conditions

    NASA Astrophysics Data System (ADS)

    Nikolakakos, George; Whiteway, James

    2015-04-01

    One of the key findings during the Phoenix and Mars Science Laboratory landed Mars missions has been the detection of perchlorate, a highly deliquescent salt. Perchlorates are of great interest on Mars due to their high affinity for water vapour as well as their ability to greatly depress the freezing point of water when in solution. This has intriguing biological implications as resulting brines could potentially provide a habitable environment for living organisms. Additionally, it has been speculated that these salts may play a significant role in influencing the hydrological cycle on Mars. In order to experimentally study water exchange processes between the surface and atmosphere on Mars and assess the feasibility of a future landed detection tool, a stand-off Raman spectroscopy instrument and environmental simulation chamber have been developed at York University. A sample of magnesium perchlorate consistent with the size of patches found at the Phoenix site has been subjected to the low water vapour pressure and temperatures found at polar Martian latitudes. Results indicate that at a water vapour pressure of ~2 Pa (-54°C frost point temperature), Raman spectroscopy is able to detect the onset of brine formation and provide a relative estimate of the quantity of water taken up by the sample until complete deliquescence is reached. Significant uptake of water from the atmosphere is observed to occur prior to the frost point temperature being reached and on time scales relevant to the Martian diurnal cycle. This result suggests that perchlorates in the Martian regolith can contribute to the hydrological cycle, pre-emptively reducing the water vapour pressure before saturation is reached.

  16. Spectroscopic Evidence Against Nitric Acid Trihydrate in Polar Stratospheric Clouds

    NASA Technical Reports Server (NTRS)

    Toon, Owen B.; Tolbert, Margaret A.

    1995-01-01

    Heterogeneous reactions on polar stratospheric clouds (PSC's) play a key role in the photochemical mechanism thought to be responsible for ozone depletion in the Antarctic and Arctic. Reactions of PSC particles activate chlorine to forms that are capable of photochemical ozone destruction, and sequester nitrogen oxides (NOx) that would otherwise deactivate the chlorine. Although the heterogeneous chemistry is now well established, the composition of the clouds themselves is uncertain. It is commonly thought that they are composed of nitric acid trihydrate, although observations have left this question unresolved. Here we reanalyse infrared spectra of type 1 PSCs obtained in Antarctica in September 1987, using recently measured optical constants of the various compounds that might be present in PSCs. We find these PSCs were not composed of nitric acid trihydrate but instead had a more complex compositon, perhaps that of a ternary solution. Because cloud formation is sensitive to their composition, this finding will alter our understanding of the locations and conditions in which PSCs form. In addition, the extent of ozone loss depends on the ability of the PSCs to remove NOx permanently through sedimentation, The sedimentation rates depend on PSC particle size which in turn is controlled by the composition and formation mechanism.

  17. Spectroscopic evidence for interstellar ices in comet Hyakutake.

    PubMed

    Irvine, W M; Bockelee-Morvan, D; Lis, D C; Matthews, H E; Biver, N; Crovisier, J; Davies, J K; Dent, W R; Gautier, D; Godfrey, P D; Keene, J; Lovell, A J; Owen, T C; Phillips, T G; Rauer, H; Schloerb, F P; Senay, M; Young, K

    1996-10-01

    Volatile compounds in comets are the most pristine materials surviving from the time of formation of the Solar System, and thus potentially provide information about conditions that prevailed in the primitive solar nebula. Moreover, comets may have supplied a substantial fraction of the volatiles on the terrestrial planets, perhaps including organic compounds that played a role in the origin of life on Earth. Here we report the detection of hydrogen isocyanide (HNC) in comet Hyakutake. The abundance of HNC relative to hydrogen cyanide (HCN) is very similar to that observed in quiescent interstellar molecular clouds, and quite different from the equilibrium ratio expected in the outermost solar nebula, where comets are thought to form. Such a departure from equilibrium has long been considered a hallmark of gas-phase chemical processing in the interstellar medium, suggesting that interstellar gases have been incorporated into the comet's nucleus, perhaps as ices frozen onto interstellar grains. If this interpretation is correct, our results should provide constraints on the temperature of the solar nebula, and the subsequent chemical processes that occurred in the region where comets formed. PMID:8837771

  18. Chemical and Spectroscopic Evidence for an Fev-Oxo Complex

    SciTech Connect

    de Oliveira,F.; Chanda, A.; Banerjee, D.; Shan, X.; Mondal, S.; Que, Jr., L.; Bominaar, E.; Munck, E.; Collins, T.

    2007-01-01

    Iron(V)-oxo species have been proposed as key reactive intermediates in the catalysis of oxygen-activating enzymes and synthetic catalysts. Here, we report the synthesis of [Fe(TAML)(O)]{sup -} in nearly quantitative yield, where TAML is a macrocyclic tetraamide ligand. Mass spectrometry, Moessbauer, electron paramagnetic resonance, and x-ray absorption spectroscopies, as well as reactivity studies and density functional theory calculations show that this long-lived (hours at -60 C) intermediate is a spin S = 1/2 iron(V)-oxo complex. Iron-TAML systems have proven to be efficient catalysts in the decomposition of numerous pollutants by hydrogen peroxide, and the species we characterized is a likely reactive intermediate in these reactions.

  19. Spectroscopic signature for ferroelectric ice

    NASA Astrophysics Data System (ADS)

    Wójcik, Marek J.; Gług, Maciej; Boczar, Marek; Boda, Łukasz

    2014-09-01

    Various forms of ice exist within our galaxy. Particularly intriguing type of ice - ‘ferroelectric ice' was discovered experimentally and is stable in temperatures below 72 K. This form of ice can generate enormous electric fields and can play an important role in planetary formation. In this letter we present Car-Parrinello simulation of infrared spectra of ferroelectric ice and compare them with spectra of hexagonal ice. Librational region of the spectra can be treated as spectroscopic signature of ice XI and can be of help to identify ferroelectric ice in the Universe.

  20. The far ultraviolet spectroscopic explorer

    NASA Technical Reports Server (NTRS)

    Boggess, A.

    1982-01-01

    The scientific objectives and performance characteristics of a new astronomy mission referred to as the far ultraviolet spectroscopic explorer, or FUSE are being defined by a team involving people experienced instrumental requirements that best meet the scientific needs. The team is intended to have a lifetime of about one year, ending with the submission of a report to NASA which could be used as the basis for an engineering design study. The principal objective of FUSE is to obtain astronomical spectra at wavelengths shorter than is possible with the Space Telescope.

  1. High-energy spectroscopic astrophysics

    NASA Astrophysics Data System (ADS)

    Güdel, Manuel; Walter, Roland

    After three decades of intense research in X-ray and gamma-ray astronomy, the time was ripe to summarize basic knowledge on X-ray and gamma-ray spectroscopy for interested students and researchers ready to become involved in new high-energy missions. This volume exposes both the scientific basics and modern methods of high-energy spectroscopic astrophysics. The emphasis is on physical principles and observing methods rather than a discussion of particular classes of high-energy objects, but many examples and new results are included in the three chapters as well.

  2. Spectroscopic imaging in electron microscopy

    SciTech Connect

    Pennycook, Stephen J; Colliex, C.

    2012-01-01

    In the scanning transmission electron microscope, multiple signals can be simultaneously collected, including the transmitted and scattered electron signals (bright field and annular dark field or Z-contrast images), along with spectroscopic signals such as inelastically scattered electrons and emitted photons. In the last few years, the successful development of aberration correctors for the electron microscope has transformed the field of electron microscopy, opening up new possibilities for correlating structure to functionality. Aberration correction not only allows for enhanced structural resolution with incident probes into the sub-angstrom range, but can also provide greater probe currents to facilitate mapping of intrinsically weak spectroscopic signals at the nanoscale or even the atomic level. In this issue of MRS Bulletin, we illustrate the power of the new generation of electron microscopes with a combination of imaging and spectroscopy. We show the mapping of elemental distributions at atomic resolution and also the mapping of electronic and optical properties at unprecedented spatial resolution, with applications ranging from graphene to plasmonic nanostructures, and oxide interfaces to biology.

  3. Spectroscopic Observations of Nearby Low Mass Stars

    NASA Astrophysics Data System (ADS)

    Vican, Laura; Zuckerman, B. M.; Rodriguez, D.

    2014-01-01

    Young low-mass stars are known to be bright in X-ray and UV due to a high level of magnetic activity. By cross-correlating the GALEX Catalog with the WISE and 2MASS Point Source Catalogs, we have identified more than 2,000 stars whose UV excesses suggest ages in the 10-100 Myr range. We used the Shane 3-m telescope at Lick Observatory on Mount Hamilton, California to observe some of these 2,000 stars spectroscopically. We measured the equivalent width of lithium at 6708 A absorption and H-alpha emission lines. Out of a total of 122 stars observed with the Kast grating spectrometer, we find that roughly 10% have strong lithium absorption features. The high percentage of stars with lithium present is further evidence of the importance of UV emission as a youth indicator for low-mass stars. In addition, we used high-resolution spectra obtained with the Hamilton echelle spectrograph to determine radial velocities for several UV-bright stars. These radial velocities will be useful for the calculation of Galactic UVW space velocities for determination of possible moving group membership. This work is supported by NASA Astrophysics Data Analysis Program award NNX12AH37G to RIT and UCLA and Chilean FONDECYT grant 3130520 to Universidad de Chile. This submission presents work for the GALNYSS project and should be linked to abstracts submitted by David Rodriguez, Laura Vican, and Joel Kastner.

  4. Raman Spectroscopic Detection of Graphitic Carbon of Biogenic Parentage in an Ancient South African Chert

    NASA Technical Reports Server (NTRS)

    Wang, Alian; Haskin, Larry A.; Kuebler, Karla E.; Jolliff, Bradley L.; Walsh, Maud M.

    2001-01-01

    The detection of reduced carbon in martian rocks and soils is important in the search for evidence of life. A Raman spectroscopic study of South Africa chert reveals that 50 ppm carbon or less can be determined by this technique. Additional information is contained in the original extended abstract.

  5. The Hubble Spectroscopic Legacy Archive

    NASA Astrophysics Data System (ADS)

    Peeples, Molly S.; Tumlinson, Jason; Fox, Andrew; Aloisi, Alessandra; Ayres, Thomas R.; Danforth, Charles; Fleming, Scott W.; Jenkins, Edward B.; Jedrzejewski, Robert I.; Keeney, Brian A.; Oliveira, Cristina M.

    2016-01-01

    With no future space ultraviolet instruments currently planned, the data from the UV spectrographs aboard the Hubble Space Telescope have a legacy value beyond their initial science goals. The Hubble Spectroscopic Legacy Archive will provide to the community new science-grade combined spectra for all publicly available data obtained by the Cosmic Origins Spectrograph (COS) and the Space Telescope Imaging Spectrograph (STIS). These data will be packaged into "smart archives" according to target type and scientific themes to facilitate the construction of archival samples for common science uses. A new "quick look" capability will make the data easy for users to quickly access, assess the quality of, and download for archival science starting in Cycle 24, with the first generation of these products for the FUV modes of COS available online via MAST in early 2016.

  6. Multifunction Imaging and Spectroscopic Instrument

    NASA Technical Reports Server (NTRS)

    Mouroulis, Pantazis

    2004-01-01

    A proposed optoelectronic instrument would perform several different spectroscopic and imaging functions that, heretofore, have been performed by separate instruments. The functions would be reflectance, fluorescence, and Raman spectroscopies; variable-color confocal imaging at two different resolutions; and wide-field color imaging. The instrument was conceived for use in examination of minerals on remote planets. It could also be used on Earth to characterize material specimens. The conceptual design of the instrument emphasizes compactness and economy, to be achieved largely through sharing of components among subsystems that perform different imaging and spectrometric functions. The input optics for the various functions would be mounted in a single optical head. With the exception of a targeting lens, the input optics would all be aimed at the same spot on a specimen, thereby both (1) eliminating the need to reposition the specimen to perform different imaging and/or spectroscopic observations and (2) ensuring that data from such observations can be correlated with respect to known positions on the specimen. The figure schematically depicts the principal components and subsystems of the instrument. The targeting lens would collect light into a multimode optical fiber, which would guide the light through a fiber-selection switch to a reflection/ fluorescence spectrometer. The switch would have four positions, enabling selection of spectrometer input from the targeting lens, from either of one or two multimode optical fibers coming from a reflectance/fluorescence- microspectrometer optical head, or from a dark calibration position (no fiber). The switch would be the only moving part within the instrument.

  7. 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, Hα, (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.

  8. Spectroscopic Classifications of Optical Transients with SOAR

    NASA Astrophysics Data System (ADS)

    Hounsell, R. A.; Miller, J. A.; Pan, Y.-C.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.; Smith, K. W.; Wright, D.; Smartt, S. J.; Huber, M.; Chambers, K. C.; Flewelling, H.; Willman, M.; Primak, N.; Schultz, A.; Gibson, B.; Magnier, E.; Waters, C.; Tonry, J.; Wainscoat, R. J.

    2016-06-01

    We report the following classifications of optical transients from spectroscopic observations with the Goodman spectrograph on the SOAR 4-m telescope. Targets were supplied by the Pan-STARRS Survey for Transients (PSST).

  9. Monitoring spectroscopic binaries in anticipation of Gaia

    NASA Astrophysics Data System (ADS)

    Pourbaix, Dimitri; Halbwachs, Jean-Louis; Arenou, Frederic

    2015-08-01

    For several already known spectroscopic binaries, it is anticipated that Gaia will provide an exquisite astrometric orbit of the photocenter. In case of double-lined spectroscopic binaries, the orbital inclination supplied by Gaia will lead to the mass of both components.. For those masses to be useful, an accuracy of 2-3% is required. This can only be achieved if the spectroscopic orbit is very accurate too. A long term monitoring of good spectroscopic candidates in on going on Sophie at the Observatory of Haute Provence and on Hermes on the Mercator telescope in La Palma. For some of these systems, we have already derived a definitive SB2 orbital solution while, for others, the secondary remains unreachable. We present these new solutions in conjunction with the possible impact on the Hipparcos astrometric solution.

  10. Asiago spectroscopic classification of AT2016bry

    NASA Astrophysics Data System (ADS)

    Ochner, P.; Tinella, V.; Righetti, G. L.; Belligoli, R.; Castellani, F.; Pastorello, A.; Cappellaro, E.; Benetti, S.; Tomasella, L.; Elias-Rosa, N.; Tartaglia, L.; Terreran, G.; Turatto, M.

    2016-05-01

    The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic classification of AT2016bry, discovered by V. Tinella in UGC 11635, and preliminary photometric follow-up.

  11. Asiago spectroscopic classification of AT2016ajo

    NASA Astrophysics Data System (ADS)

    Terreran, G.; Pastorello, A.; Benetti, S.; Cappellaro, E.; Elias-Rosa, N.; Ochner, P.; Tartaglia, L.; Tomasella, L.; Turatto, M.

    2016-03-01

    The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic classification of AT2016ajo, discovered by Y. Ding, W. Gao and X. Gao in an anonymous galaxy near UGC 11344.

  12. CSP Spectroscopic Classification of LSQ16oi

    NASA Astrophysics Data System (ADS)

    Morrell, N.; Phillips, M.; Lira, P.; Ellman, N.; Baltay, C.; Rabinowitz, D.; Rostami, S.; Hsiao, E. Y.

    2016-02-01

    We report the spectroscopic classification of a La Silla-QUEST (LSQ) supernova (Baltay et al. 2013, PASP, 125, 683) taken using WFCCD on the 2.5-m du Pont Telescope as part of the Carnegie Supernova Project (CSP).

  13. Fast Hadamard Spectroscopic Imaging Techniques

    NASA Astrophysics Data System (ADS)

    Goelman, G.

    1994-07-01

    Fast Hadamard spectroscopic imaging (HSI) techniques are presented. These techniques combine transverse and longitudinal encoding to obtain multiple-volume localization. The fast techniques are optimized for nuclei with short T2 and long T1 relaxation times and are therefore suitable for in vivo31P spectroscopy. When volume coils are used in fast HSI techniques, the signal-to-noise ratio per unit time (SNRT) is equal to the SNRT in regular HSI techniques. When surface coils are used, fast HSI techniques give significant improvement of SNRT over conventional HSI. Several fast techniques which are different in total experimental time and pulse demands are presented. When the number of acquisitions in a single repetition time is not higher than two, fast HSI techniques can be used with surface coils and the B1 inhomogeneity does not affect the localization. Surface-coil experiments on phantoms and on human calf muscles in vivo are presented. In addition, it is shown that the localization obtained by the HSI techniques are independent of the repetition times.

  14. SDSS spectroscopic survey of stars

    SciTech Connect

    Ivezic, Zeljko; Schlegel, D.; Uomoto, A.; Bond, N.; Beers, T.; Allende Prieto, C.; Wilhelm, R.; Lee, Y.Sun; Sivarani, T.; Juric, M.; Lupton, R.; /Washington U., Seattle, Astron. Dept. /LBL, Berkeley /Johns Hopkins U. /Princeton U. /Michigan State U. /Texas U. /Texas Tech. /UC, Santa Cruz /Fermilab /Naval Observ., Flagstaff /Drexel U.

    2007-01-01

    In addition to optical photometry of unprecedented quality, the Sloan Digital Sky Survey (SDSS) is also producing a massive spectroscopic database. They discuss determination of stellar parameters, such as effective temperature, gravity and metallicity from SDSS spectra, describe correlations between kinematics and metallicity, and study their variation as a function of the position in the Galaxy. They show that stellar parameter estimates by Beers et al. show a good correlation with the position of a star in the g-r vs. u-g color-color diagram, thereby demonstrating their robustness as well as a potential for photometric parameter estimation methods. Using Beers et al. parameters, they find that the metallicity distribution of the Milky Way stars at a few kpc from the galactic plane is bimodal with a local minimum at [Z/Z{sub {circle_dot}}] {approx} -1.3. The median metallicity for the low-metallicity [Z/Z{sub {circle_dot}}] < =1.3 subsample is nearly independent of Galactic cylindrical coordinates R and z, while it decreases with z for the high-metallicity [Z/Z{sub {circle_dot}}] > -1.3 sample. they also find that the low-metallicity sample has {approx} 2.5 times larger velocity dispersion and that it does not rotate (at the {approx} 10 km/s level), while the rotational velocity of the high-metallicity sample decreases smoothly with the height above the galactic plane.

  15. SDSS spectroscopic survey of stars.

    NASA Astrophysics Data System (ADS)

    Ivezić, Ž.; Schlegel, D.; Uomoto, A.; Bond, N.; Beers, T.; Allende Prieto, C.; Wilhelm, R.; Lee, Y. Sun; Sivarani, T.; Jurić, M.; Lupton, R.; Rockosi, C.; Knapp, G.; Gunn, J.; Yanny, B.; Jester, S.; Kent, S.; Pier, J.; Munn, J.; Richards, G.; Newberg, H.; Blanton, M.; Eisenstein, D.; Hawley, S.; Anderson, S.; Harris, H.; Kiuchi, F.; Chen, A.; Bushong, J.; Sohi, H.; Haggard, D.; Kimball, A.; Barentine, J.; Brewington, H.; Harvanek, M.; Kleinman, S.; Krzesinski, J.; Long, D.; Nitta, A.; Snedden, S.; SDSS Collaboration

    In addition to optical photometry of unprecedented quality, the Sloan Digital Sky Survey (SDSS) is also producing a massive spectroscopic database. We discuss determination of stellar parameters, such as effective temperature, gravity and metallicity from SDSS spectra, describe correlations between kinematics and metallicity, and study their variation as a function of the position in the Galaxy. We show that stellar parameter estimates by Beers et al. show a good correlation with the position of a star in the g-r vs. u-g color-color diagram, thereby demonstrating their robustness as well as a potential for photometric parameter estimation methods. Using Beers et al. parameters, we find that the metallicity distribution of the Milky Way stars at a few kpc from the galactic plane is bimodal with a local minimum at [Z/Z_⊙] ˜ -1.3. The median metallicity for the low-metallicity [Z/Z_⊙]< -1.3 subsample is nearly independent of Galactic cylindrical coordinates R and z, while it decreases with z for the high-metallicity [Z/Z_⊙]> -1.3 sample. We also find that the low-metallicity sample has ˜2.5 times larger velocity dispersion and that it does not rotate (at the ˜10 km/s level), while the rotational velocity of the high-metallicity sample decreases smoothly with the height above the galactic plane.

  16. Spectroscopic studies of copper enzymes

    SciTech Connect

    Dooley, D.M.; Moog, R.; Zumft, W.; Koenig, S.H.; Scott, R.A.; Cote, C.E.; McGuirl, M.

    1986-05-01

    Several spectroscopic methods, including absorption, circular dichroism (CD), magnetic CD (MCD), X-ray absorption, resonance Raman, EPR, NMR, and quasi-elastic light-scattering spectroscopy, have been used to probe the structures of copper-containing amine oxidases, nitrite reductase, and nitrous oxide reductase. The basic goals are to determine the copper site structure, electronic properties, and to generate structure-reactivity correlations. Collectively, the results on the amine oxidases permit a detailed model for the Cu(II) sites in these enzymes to be constructed that, in turn, rationalizes the ligand-binding chemistry. Resonance Raman spectra of the phenylhydrazine and 2,4-dinitrophenyl-hydrazine derivatives of bovine plasma amine oxidase and models for its organic cofactor, e.g. pyridoxal, methoxatin, are most consistent with methoxatin being the intrinsic cofactor. The structure of the Cu(I) forms of the amine oxidases have been investigated by X-ray absorption spectroscopy (XAS); the copper coordination geometry is significantly different in the oxidized and reduced forms. Some anomalous properties of the amine oxidases in solution are explicable in terms of their reversible aggregation, which the authors have characterized via light scattering. Nitrite and nitrous oxide reductases display several novel spectral properties. The data suggest that new types of copper sites are present.

  17. Vibrational spectroscopic characterization of fluoroquinolones

    NASA Astrophysics Data System (ADS)

    Neugebauer, U.; Szeghalmi, A.; Schmitt, M.; Kiefer, W.; Popp, J.; Holzgrabe, U.

    2005-05-01

    Quinolones are important gyrase inhibitors. Even though they are used as active agents in many antibiotics, the detailed mechanism of action on a molecular level is so far not known. It is of greatest interest to shed light on this drug-target interaction to provide useful information in the fight against growing resistances and obtain new insights for the development of new powerful drugs. To reach this goal, on a first step it is essential to understand the structural characteristics of the drugs and the effects that are caused by the environment in detail. In this work we report on Raman spectroscopical investigations of a variety of gyrase inhibitors (nalidixic acid, oxolinic acid, cinoxacin, flumequine, norfloxacin, ciprofloxacin, lomefloxacin, ofloxacin, enoxacin, sarafloxacin and moxifloxacin) by means of micro-Raman spectroscopy excited with various excitation wavelengths, both in the off-resonance region (532, 633, 830 and 1064 nm) and in the resonance region (resonance Raman spectroscopy at 244, 257 and 275 nm). Furthermore DFT calculations were performed to assign the vibrational modes, as well as for an identification of intramolecular hydrogen bonding motifs. The effect of small changes in the drug environment was studied by adding successively small amounts of water until physiological low concentrations of the drugs in aqueous solution were obtained. At these low concentrations resonance Raman spectroscopy proved to be a useful and sensitive technique. Supplementary information was obtained from IR and UV/vis spectroscopy.

  18. Spectroscopic characterization of visbreaking tars

    SciTech Connect

    Scotti, R.; Clericuzio, M.; Pirovano, C.

    1995-12-31

    Visbreaking (VB) is a thermal cracking process, widely used in the refineries of Western Europe to obtain distillates (gasoil, naphtha) from a petroleum residue (feedstock). The visbroken residue (tar) is used to produce fuel oil, after addition of the appropriate amounts of cutter-stock. Even if the highest conversion of feedstock would be desirable, the severity of the VB process is limited by the stability of the resulting VB tars. The stability index (SI) here employed is: SI = I + V{sub cet}, where V{sub cet} is the maximum amount of n-cetane, expressed as ml of cetane for g of sample, that can be added before the flocculation of asphaltenes starts. VB tars having SI<1.1 are considered to be unstable and cannot be used in the preparation of fuel oils with the appropriate specifications. Several papers can be found in the literature dealing with the molecular changes occuring during the VB process. The present paper is aimed at verifying the amount of information that can be extracted from optical spectroscopies and, in particular, the possibility of directly monitoring the physico-chemical modifications caused by VB process. To this purpose a series of VB tars, produced from a single feedstock at different severities, were investigated by a number of spectroscopic techniques, viz.: NIR; UV-Vis; Fluorescence; {sup 1}H and {sup 13}C NUR, EPR.

  19. Handbook of Basic Atomic Spectroscopic Data

    National Institute of Standards and Technology Data Gateway

    SRD 108 Handbook of Basic Atomic Spectroscopic Data (Web, free access)   This handbook provides a selection of the most important and frequently used atomic spectroscopic data. The compilation includes data for the neutral and singly-ionized atoms of all elements hydrogen through einsteinium (Z = 1-99). The wavelengths, intensities, and spectrum assignments are given for each element, and the data for the approximately 12,000 lines of all elements are also collected into a single table.

  20. Identification and Spectroscopic Characterization of Nonheme Iron(III) Hypochlorite Intermediates†

    PubMed Central

    Draksharapu, Apparao; Angelone, Davide; Quesne, Matthew G.; Padamati, Sandeep K.; Gómez, Laura; Hage, Ronald; Costas, Miquel

    2015-01-01

    Abstract FeIII–hypohalite complexes have been implicated in a wide range of important enzyme‐catalyzed halogenation reactions including the biosynthesis of natural products and antibiotics and post‐translational modification of proteins. The absence of spectroscopic data on such species precludes their identification. Herein, we report the generation and spectroscopic characterization of nonheme FeIII–hypohalite intermediates of possible relevance to iron halogenases. We show that FeIII‐OCl polypyridylamine complexes can be sufficiently stable at room temperature to be characterized by UV/Vis absorption, resonance Raman and EPR spectroscopies, and cryo‐ESIMS. DFT methods rationalize the pathways to the formation of the FeIII‐OCl, and ultimately FeIV=O, species and provide indirect evidence for a short‐lived FeII‐OCl intermediate. The species observed and the pathways involved offer insight into and, importantly, a spectroscopic database for the investigation of iron halogenases. PMID:27478260

  1. Identification and Spectroscopic Characterization of Nonheme Iron(III) Hypochlorite Intermediates**

    PubMed Central

    Draksharapu, Apparao; Angelone, Davide; Quesne, Matthew G; Padamati, Sandeep K; Gómez, Laura; Hage, Ronald; Costas, Miquel; Browne, Wesley R; de Visser, Sam P

    2015-01-01

    FeIII–hypohalite complexes have been implicated in a wide range of important enzyme-catalyzed halogenation reactions including the biosynthesis of natural products and antibiotics and post-translational modification of proteins. The absence of spectroscopic data on such species precludes their identification. Herein, we report the generation and spectroscopic characterization of nonheme FeIII–hypohalite intermediates of possible relevance to iron halogenases. We show that FeIII-OCl polypyridylamine complexes can be sufficiently stable at room temperature to be characterized by UV/Vis absorption, resonance Raman and EPR spectroscopies, and cryo-ESIMS. DFT methods rationalize the pathways to the formation of the FeIII-OCl, and ultimately FeIV=O, species and provide indirect evidence for a short-lived FeII-OCl intermediate. The species observed and the pathways involved offer insight into and, importantly, a spectroscopic database for the investigation of iron halogenases. PMID:25663379

  2. Spectroscopic investigations of heme proteins

    NASA Astrophysics Data System (ADS)

    Ogilvie, Jennifer Pauline

    Using several novel spectroscopic techniques, we investigate the dynamics of heme proteins over the full range of time scales relevant to their function. With ˜10 femtosecond time resolution we use ultrafast pump-probe spectroscopy to gain insight into the earliest dynamics initiated by the photodissociation of the carbon monoxide ligand from myoglobin. Coherent oscillations that are driven by the bond-breaking event reveal several vibrational modes of the heme that provide the driving force for the initial motions along the pathway to protein function. Much later along this pathway we address the question of ligand escape from myoglobin. With this purpose we develop heterodyne-detected diffractive-optics-based phase-grating spectroscopy, which provides more than 2 orders of magnitude increase in sensitivity for the measurement of volume changes and energetics. The improved sensitivity allows us to directly observe the ligand escape, which occurs via a number of discrete routes through the protein. Following the escape process, we observe the full cycle of dynamics that is complete when the carbon monoxide ligand rebinds to the protein. Using a resonant probe we re-examine the dynamics of ligand escape from myoglobin using transient absorption and transient-grating spectroscopy. This study confirms the findings of the previous off-resonant work, and allows us to explore the relationship between the observables in the phase-grating experiment and other resonant spectroscopies. The various dynamical processes of myoglobin provide a basis for understanding the structure/function relationship at the single protein level. This lays the foundation for a description of protein-protein interactions such as cooperativity in hemoglobin.

  3. Spectroscopic investigation of protein corona

    NASA Astrophysics Data System (ADS)

    Choudhary, Poonam

    Nanotechnology has revolutionalized the landscape of modern science and technology, including materials, electronics, therapeutics, bioimaging, sensing, and the environment. Research in the past decade has examined the fate of nanomaterials in vitro and in vivo, as well as the interactions between nanoparticles and biological and ecosystems using primarily toxicological and ecotoxicological approaches. However, due to the versatility in the physical and physicochemical properties of nanoparticles, and due to the vast complexity of their hosting systems, the solubility, transformation, and biocompatibility of nanomaterials are still poorly understood. Nanotechnology has been undergoing tremendous development in recent decades, driven by realized perceived applications of nanomaterials in electronics, therapeutics, imaging, sensing, environmental remediation, and consumer products. Nanoparticles on entering the blood stream undergo an identity change, they become coated with proteins. There are different kind of proteins present in blood. Proteins compete for getting coated over the surface of nanoparticle and this whole entity of proteins coated over nanoparticle surface is called Protein Corona. Proteins tightly bound to the surface of nanoparticle form hard corona and the ones loosely bound on the outer surface form soft corona. This dissertation is aimed at spectroscopic investigation of Protein Corona. Chapter I of this dissertation offers a comprehensive review of the literature based on nanomaterials with the focus on carbon based nanomaterilas and introduction to Protein Corona. Chapter II is based different methods used for Graphene Synthesis,different types of defects and doping. In Chapter III influence of defects on Graphene Protein Corona was investigated. Chapter IV is based on the study of Apoptosis induced cell death by Gold and silver nanoparticles. In vitro study of effect of Protein Corona on toxicity of cells was done.

  4. sick: The Spectroscopic Inference Crank

    NASA Astrophysics Data System (ADS)

    Casey, Andrew R.

    2016-03-01

    There exists an inordinate amount of spectral data in both public and private astronomical archives that remain severely under-utilized. The lack of reliable open-source tools for analyzing large volumes of spectra contributes to this situation, which is poised to worsen as large surveys successively release orders of magnitude more spectra. In this article I introduce sick, the spectroscopic inference crank, a flexible and fast Bayesian tool for inferring astrophysical parameters from spectra. sick is agnostic to the wavelength coverage, resolving power, or general data format, allowing any user to easily construct a generative model for their data, regardless of its source. sick can be used to provide a nearest-neighbor estimate of model parameters, a numerically optimized point estimate, or full Markov Chain Monte Carlo sampling of the posterior probability distributions. This generality empowers any astronomer to capitalize on the plethora of published synthetic and observed spectra, and make precise inferences for a host of astrophysical (and nuisance) quantities. Model intensities can be reliably approximated from existing grids of synthetic or observed spectra using linear multi-dimensional interpolation, or a Cannon-based model. Additional phenomena that transform the data (e.g., redshift, rotational broadening, continuum, spectral resolution) are incorporated as free parameters and can be marginalized away. Outlier pixels (e.g., cosmic rays or poorly modeled regimes) can be treated with a Gaussian mixture model, and a noise model is included to account for systematically underestimated variance. Combining these phenomena into a scalar-justified, quantitative model permits precise inferences with credible uncertainties on noisy data. I describe the common model features, the implementation details, and the default behavior, which is balanced to be suitable for most astronomical applications. Using a forward model on low-resolution, high signal

  5. Multivariate statistical mapping of spectroscopic imaging data.

    PubMed

    Young, Karl; Govind, Varan; Sharma, Khema; Studholme, Colin; Maudsley, Andrew A; Schuff, Norbert

    2010-01-01

    For magnetic resonance spectroscopic imaging studies of the brain, it is important to measure the distribution of metabolites in a regionally unbiased way; that is, without restrictions to a priori defined regions of interest. Since magnetic resonance spectroscopic imaging provides measures of multiple metabolites simultaneously at each voxel, there is furthermore great interest in utilizing the multidimensional nature of magnetic resonance spectroscopic imaging for gains in statistical power. Voxelwise multivariate statistical mapping is expected to address both of these issues, but it has not been previously employed for spectroscopic imaging (SI) studies of brain. The aims of this study were to (1) develop and validate multivariate voxel-based statistical mapping for magnetic resonance spectroscopic imaging and (2) demonstrate that multivariate tests can be more powerful than univariate tests in identifying patterns of altered brain metabolism. Specifically, we compared multivariate to univariate tests in identifying known regional patterns in simulated data and regional patterns of metabolite alterations due to amyotrophic lateral sclerosis, a devastating brain disease of the motor neurons. PMID:19953514

  6. Far Ultraviolet Spectroscopic Explorer Measurements of Interstellar Fluorine

    NASA Astrophysics Data System (ADS)

    Federman, S. R.; Sheffer, Yaron; Lambert, David L.; Smith, V. V.

    2005-02-01

    The source of fluorine is not well understood, although core-collapse supernovae, Wolf-Rayet stars, and asymptotic giant branch stars have been suggested. A search for evidence of the ν-process during Type II supernovae is presented. Absorption from interstellar F I is seen in spectra of HD 208440 and HD 209339A acquired with the Far Ultraviolet Spectroscopic Explorer. In order to extract the column density for F I from the line at 954 Å, absorption from H2 has to be modeled and then removed. Our analysis indicates that for H2 column densities less than about 3×1020 cm-2, the amount of F I can be determined from λ954. For these two sight lines, there is no clear indication for enhanced F abundances resulting from the ν-process in a region shaped by past supernovae. Based on observations made with the NASA/CNES/CSA Far Ultraviolet Spectroscopic Explorer (FUSE), which is operated for NASA by the Johns Hopkins University under NASA contract NAS 5-32985.

  7. Spectroscopic characterizations of organic/inorganic nanocomposites

    NASA Astrophysics Data System (ADS)

    Govani, Jayesh R.

    2009-12-01

    contribution, too. The photoluminescence spectra of the crystal with inhibitor indicate the presence of chlorophyll, and hence, confirm the presence of Mg. This study provides evidence of Mg- and Zn-related inhibition of urinary calculi formation with the addition of RAL herbal extract, contributing, from the spectroscopic point of view, to an intricate subject. Our present investigation might serve as an important source of information on this tantalizing and multifaceted problem, which is not yet completely understood. (Abstract shortened by UMI.)

  8. Optical Spectroscopic Monitoring of Parachute Yarn Aging

    SciTech Connect

    Tallant, D.R.; Garcia, M.J.; Simpson, R.L.; Behr, V.L.; Whinery, L.D.; Peng, L.W.

    1999-04-01

    Optical spectroscopic techniques were evaluated as nondestructive monitors of the aging of parachutes in nuclear weapons. We analyzed thermally aged samples of nylon and Kevlar webbing by photoluminescence spectroscopy and reflection spectroscopy. Infrared analysis was also performed to help understand the degradation mechanisms of the polymer materials in the webbing. The photoluminescence and reflection spectra were analyzed by chemometric data treatment techniques to see if aged-induced changes in the spectra correlated to changes in measured tensile strength. A correlation was found between the shapes of the photoluminescent bands and the measured tensile strengths. Photoluminescent spectra can be used to predict the tensile strengths of nylon and Kevlar webbing with sufficient accuracy to categorize the webbing sample as above rated tensile strength, marginal or below rated tensile strength. The instrumentation required to perform the optical spectroscopic measurement can be made rugged, compact and portable. Thus, optical spectroscopic techniques offer a means for nondestructive field monitoring of parachutes in the enduring stockpile/

  9. Spectroscopic distances of 28 nearby star candidates

    NASA Astrophysics Data System (ADS)

    Jahreiß, H.; Meusinger, H.; Scholz, R.-D.; Stecklum, B.

    2008-06-01

    Aims: Twenty eight hitherto neglected candidates for the Catalogue of Nearby Stars (CNS) were investigated to verify their classification and to improve their distance estimates. All targets had at least a preliminary status of being nearby dwarf stars based on their large proper motions and relatively faint magnitudes. Better photometric and/or spectroscopic distances were required for selecting stars for further trigonometric parallax measurements. Methods: Low-resolution spectra were obtained with NASPEC at the Tautenburg 2 m telescope and with CAFOS at the Calar Alto 2.2 m telescope. The spectral types of M-type stars were determined by direct comparison of the target's spectra with those of comparison stars of known spectral types observed with the same instrument. The classification of earlier types was performed based on comparison with published spectral libraries. Results: For most of the target stars reliable spectral types could be determined and in combination with 2MASS photometry new improved distance estimates became available. The majority were classified as M dwarfs including 11 stars within 25 pc. The fainter component of LDS 1365, previously thought to form a nearby common proper motion pair, is according to our results an unrelated high-velocity background star. For several other nearby common proper motion pairs our distance estimates of the fainter components are in good agreement with Hipparcos distances of the brighter components. The three stars in our sample that were previously thought to be white dwarfs (GJ 2091, GJ 2094, GJ 2098) turned out to be more distant high-velocity F- to K-type (sub)dwarfs. For the star with the largest tangential velocity (GJ 2091; v_ tan>500 km s-1) we have additional evidence for its probable Galactic halo membership from a measured large radial velocity of 266 ± 25 km s-1 and from its UBV photometry indicating a low metallicity. Based on observations with the 2 m telescope of the Thüringer Landessternwarte

  10. Extreme conditions during multibubble cavitation: Sonoluminescence as a spectroscopic probe.

    PubMed

    Suslick, Kenneth S; Eddingsaas, Nathan C; Flannigan, David J; Hopkins, Stephen D; Xu, Hangxun

    2011-07-01

    We review recent work on the use of sonoluminescence (SL) to probe spectroscopically the conditions created during cavitation, both in clouds of collapsing bubbles (multibubble sonoluminescence, (MBSL)) and in single bubble events. The effective MBSL temperature can be controlled by the vapor pressure of the liquid or the thermal conductivity of the dissolved gas over a range from ∼1600 to ∼9000K. The effective pressure during MBSL is ∼300bar, based on atomic line shifts. Given nanosecond emission times, this means that cooling rates are >10(12)K/s. In sulfuric and phosphoric acid, the low volatility and high solubility of any sonolysis products make bubble collapse more efficient and evidence for an optically opaque plasma core is found. PMID:21247788

  11. 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

  12. Localized and Spectroscopic Orbitals: Squirrel Ears on Water.

    ERIC Educational Resources Information Center

    Martin, R. Bruce

    1988-01-01

    Reexamines the electronic structure of water considering divergent views. Discusses several aspects of molecular orbital theory using spectroscopic molecular orbitals and localized molecular orbitals. Gives examples for determining lowest energy spectroscopic orbitals. (ML)

  13. Asiago spectroscopic classification of AT 2016cvm

    NASA Astrophysics Data System (ADS)

    Tomasella, L.; Pastorello, A.; Benetti, S.; Cappellaro, E.; Elias-Rosa, N.; Ochner, P.; Tartaglia, L.; Terreran, G.; Turatto, M.

    2016-06-01

    The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic classification of AT 2016cvm (also known as PTSS-16hxs), discovered 20160613.771 by the PMO-Tsinghua Supernova Survey (PTSS) The observation was performed with the Asiago 1.82 m Copernico Telescope (+AFOSC; range 340-820 nm; resolution 1.4 nm).

  14. Asiago spectroscopic classification of four SNe

    NASA Astrophysics Data System (ADS)

    Pastorello, A.; Tartaglia, L.; Benetti, S.; Cappellaro, E.; Elias-Rosa, N.; Ochner, P.; Terreran, G.; Tomasella, L.; Turatto, M.

    2015-12-01

    The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic classifications of PS15cym in GALEXASC J011024.12+232124.1, CSS151130:014258+273410 in an anonymous galaxy, PSN J05225991-0008174 in UGC 3301 and ASASSN-15tj in SDSS J075527.63+520911.1 (ATel #8358).

  15. Spectroscopic Classification of Three PSST Transients

    NASA Astrophysics Data System (ADS)

    Blanchard, P.; Nicholl, M.; Berger, E.; Fong, W.; Chornock, R.

    2016-04-01

    We obtained spectroscopic observations on 2016 April 6 UT (range 3000-10600 Angstroms) of three transients reported by the Pan-STARRS Survey for Transients (PSST; Huber et al., ATel #7153; http://star.pst.qub.ac.uk/ps1threepi/) using IMACS mounted on the 6.5m Magellan/Baade Telescope.

  16. Asiago spectroscopic classification of ASASSN-15db

    NASA Astrophysics Data System (ADS)

    Ochner, P.; Pastorello, A.; Benetti, S.; Cappellaro, E.; Elias-Rosa, N.; Tartaglia, L.; Terreran, G.; Tomasella, L.; Turatto, M.

    2015-02-01

    The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic observation of ASASSN-15db in NGC 5996. The observation was performed with the Asiago 1.82m Copernico Telescope (+AFOSC; range 340-820 nm; resolution 1.4 nm), equipped with the CCD Andor IKON L936.

  17. Asiago spectroscopic classification of three SNe

    NASA Astrophysics Data System (ADS)

    Elias-Rosa, N.; Cappellaro, E.; Benetti, S.; Milan, M.; Miluzio, M.; Ochner, P.; Pastorello, A.; Tartaglia, L.; Terreran, G.; Tomasella, L.; Turatto, M.; Morales-Garoffolo, A.; Huang, F.

    2014-10-01

    The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic classification of two SNe. The observations were performed with the Asiago 1.82 m Copernico Telescope (+AFOSC; range 340-820 nm; resolution 1.2 nm).

  18. Spectroscopic mode identification in gamma Doradus stars

    NASA Astrophysics Data System (ADS)

    Rylvia Pollard, Karen

    2015-08-01

    The MUSICIAN programme at the University of Canterbury has been successfully identifying frequencies and pulsation modes in many gamma Doradus stars using hundreds of precise, high resolution spectroscopic observations. This paper describes some of these frequency and mode identifications and the emerging patterns of the programme.

  19. Laser Spectroscopic Measurement Of Temperature And Density

    NASA Technical Reports Server (NTRS)

    Mckenzie, Robert L.; Laufer, Gabriel

    1991-01-01

    Report discusses research on use of laser-induced fluorescence in oxygen and Raman scattering in air for simultaneous measurement of temperature and density of air. Major application of laser spectroscopic techniques, measurement of fluctuations of temperature and density in hypersonic flows in wind tunnels.

  20. Spectroscopic study in Z-pinch discharge

    SciTech Connect

    Garamoon, A.A.; Saudy, A.H.; Shark, W.

    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.

  1. FIRE NIR spectroscopic classifications of optical transients

    NASA Astrophysics Data System (ADS)

    Morrell, N.; Marion, G. H.; Kirshner, R. P.; Hsiao, E. Y.; Stritzinger, M.

    2014-09-01

    We report spectroscopic classifications of 5 supernovae based on near-infrared (NIR) spectroscopy (range 800-2400 nm) obtained on Sept. 3 UT with the FoldedPort Infrared Echellette (FIRE) spectrograph attached to the 6.5-m Magellan Baade Telescope.

  2. FIRE NIR spectroscopic classifications of optical transients

    NASA Astrophysics Data System (ADS)

    Hsiao, E. Y.; Marion, G. H.; Morrell, N.; Phillips, M. M.; Contreras, C.; Gall, C.; Stritzinger, M. D.; Wyrzykowski, L.; Kozlowski, S.; Udalski, A.; Kirshner, R. P.

    2013-12-01

    We report two spectroscopic classifications using near-infrared spectra (range 800-2400 nm) obtained with the FoldedPort Infrared Echellette (FIRE) spectrograph on the 6.5-m Magellan Baade Telescope. All redshifts are from the presumed hosts and approximately match the supernova redshifts.

  3. Asiago spectroscopic classification of ASASSN-16bn

    NASA Astrophysics Data System (ADS)

    Pastorello, A.; Benetti, S.; Tomasella, L.; Cappellaro, E.; Elias-Rosa, N.; Ochner, P.; Tartaglia, L.; Terreran, G.; Turatto, M.

    2016-02-01

    The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic classification of ASASSN-16bn (also known as SN 2016adn), discovered by the All Sky Automated Survey for SuperNOvae (ASAS-SN) in 2MASX J03103162+0416184.

  4. Asiago spectroscopic classification of PS15cyk

    NASA Astrophysics Data System (ADS)

    Tartaglia, L.; Pastorello, A.; Benetti, S.; Cappellaro, E.; Elias-Rosa, N.; Ochner, P.; Terreran, G.; Tomasella, L.; Turatto, M.

    2015-12-01

    The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic classification of PS15cyk in UGC 12687. The target is supplied by the Pan-STARRS Survey for Transients (see Huber et al., ATel #7153).

  5. Spectroscopic characterization of Ti-doped α-ZnAl2S4 spinel-type single crystals

    NASA Astrophysics Data System (ADS)

    Anghel, Sergiu; Boulon, Georges; Brenier, Alain; Fortin, Emery; Klokishner, Sophia; Koshchug, Dmitrii; Kulyuk, Leonid; Sushkevich, Konstantin

    2010-02-01

    The spectroscopic characteristics of the α-ZnAl2S4 wide bandgap semiconductor doped with Ti ions are investigated. It is shown, that the ZnAl2S4:Ti spinel-type crystals exhibit luminescence in the IR spectral range 0.8-1.4 µm. The observed spectroscopic characteristics are assigned to the emission bands arising from the ligand -Ti4+ charge transfer for octahedral sites of titanium that is in agreement with the experimental evidence for the absence of the EPR signal from Ti ions. A qualitative explanation of the experimental data is given.

  6. Spectroscopic characterization of Ti-doped α-ZnAl2S4 spinel-type single crystals.

    PubMed

    Anghel, Sergiu; Boulon, Georges; Brenier, Alain; Fortin, Emery; Klokishner, Sophia; Koshchug, Dmitrii; Kulyuk, Leonid; Sushkevich, Konstantin

    2010-02-10

    The spectroscopic characteristics of the α-ZnAl(2)S(4) wide bandgap semiconductor doped with Ti ions are investigated. It is shown, that the ZnAl(2)S(4):Ti spinel-type crystals exhibit luminescence in the IR spectral range 0.8-1.4 µm. The observed spectroscopic characteristics are assigned to the emission bands arising from the ligand -Ti(4+) charge transfer for octahedral sites of titanium that is in agreement with the experimental evidence for the absence of the EPR signal from Ti ions. A qualitative explanation of the experimental data is given. PMID:21386352

  7. The HITRAN 2008 Molecular Spectroscopic Database

    NASA Technical Reports Server (NTRS)

    Rothman, Laurence S.; Gordon, Iouli E.; Barbe, Alain; Benner, D. Chris; Bernath, Peter F.; Birk, Manfred; Boudon, V.; Brown, Linda R.; Campargue, Alain; Champion, J.-P.; Chance, Kelly V.; Coudert, L. H.; Sung, K.; Toth, R. A.

    2009-01-01

    This paper describes the status of the 2008 edition of the HITRAN molecular spectroscopic database. The new edition is the first official public release since the 2004 edition, although a number of crucial updates had been made available online since 2004. The HITRAN compilation consists of several components that serve as input for radiative-transfer calculation codes: individual line parameters for the microwave through visible spectra of molecules in the gas phase; absorption cross-sections for molecules having dense spectral features, i.e., spectra in which the individual lines are not resolved; individual line parameters and absorption cross sections for bands in the ultra-violet; refractive indices of aerosols, tables and files of general properties associated with the database; and database management software. The line-by-line portion of the database contains spectroscopic parameters for forty-two molecules including many of their isotopologues.

  8. Spectroscopic Sensitivity Workout: First-order modes

    NASA Astrophysics Data System (ADS)

    Brown, Thomas

    2003-07-01

    We will observe the primary flux standards G191B2B, GD71 and GD153, obtaining first-order spectra in all L-modes {G191B2B only in the CCD modes due to its high brightness in the UV}. By comparing observed and model spectra, we will update calibration reference files describing spectroscopic sensitivity {and CTE loss} as a function of time. On visit of GD71 will be spent on verifying the recently derived CTE formula for STIS Spectroscopic modes with the CCD, by stepping the target along the slit {7 positions} with two {short} exposure times. This will verify the results using the two-amplifier readout method, and provide high-S/N data at low intensity levels and low background level.

  9. Spectroscopic chemical analysis methods and apparatus

    NASA Technical Reports Server (NTRS)

    Hug, William F. (Inventor); Reid, Ray D. (Inventor)

    2009-01-01

    Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. Chemical analysis instruments employed in some embodiments include capillary and gel plane electrophoresis, capillary electrochromatography, high performance liquid chromatography, flow cytometry, flow cells for liquids and aerosols, and surface detection instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted simultaneously with native fluorescence spectroscopy to provide high levels of sensitivity and specificity in the same instrument.

  10. Spectroscopic chemical analysis methods and apparatus

    NASA Technical Reports Server (NTRS)

    Hug, William F. (Inventor); Reid, Ray D. (Inventor)

    2010-01-01

    Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. Chemical analysis instruments employed in some embodiments include capillary and gel plane electrophoresis, capillary electrochromatography, high performance liquid chromatography, flow cytometry, flow cells for liquids and aerosols, and surface detection instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted simultaneously with native fluorescence spectroscopy to provide high levels of sensitivity and specificity in the same instrument.

  11. Spectroscopic classification of Gaia16alf

    NASA Astrophysics Data System (ADS)

    Onori, F.; Fraser, M.; Jonker, P.; Wyrzykowski, L.; Blagorodnova, N.; Mattila, S.

    2016-04-01

    We report the spectroscopic classification of Gaia16alf, from medium resolution (R~1000; 330-990nm) spectra taken with the William Herschel Telescope + ISIS + R300B/R158R on the night of 2016 April 19. The spectrum is consistent with that of a Type Ia SN a few days before maximum light at a redshift of z=0.094.

  12. Studying Young Stars with Large Spectroscopic Surveys

    NASA Astrophysics Data System (ADS)

    Martell, Sarah L.

    2016-01-01

    Galactic archaeology is the study of the history of star formation and chemical evolution in the Milky Way, based on present-day stellar populations. Studies of young stars are a key anchor point for Galactic archaeology, since quantities like the initial mass function and the star formation rate can be studied directly in young clusters and star forming regions. Conversely, massive spectroscopic Galactic archaeology surveys can be used as a data source for young star studies.

  13. Spectroscopic Sensitivity Workout: First-order modes

    NASA Astrophysics Data System (ADS)

    Brown, Thomas

    2001-07-01

    This program is the basic sensitivity measurement for all supported MAMA and CCD first-order spectroscopic modes. It is run once in Cycle 10. Sensitivity measurements are done for all supported tilts of the gratings, at a S/N suitable to any particular setting, in order to get all measurements done in a reasonable number of orbits but still get a very accurate sensitivity measurement. Data for the newly available "pseudo-apertures" near CCD row 900 are also taken.

  14. Asiago spectroscopic classification of SN 2016eob

    NASA Astrophysics Data System (ADS)

    Ochner, P.; Tomasella, G. Terreran L.; Pastorello, A.; Benetti, S.; Cappellaro, E.; Elias-Rosa, N.; Turatto, M.; Yang, S.

    2016-08-01

    The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic classification of SN 2016eob. The transient was discovered by Leonini et al. 2016, TNS Astronomical Transient Report No. 3994, Italian Supernovae Search Project (ISSP), on UT 2016-08-03.11 in the galaxy UGC00005 (2 other supernovae exploded in this host: SN 2000da, SN 2003lq).

  15. The mass ratio in spectroscopic binaries

    NASA Astrophysics Data System (ADS)

    Ducati, J. R.; Penteado, E. M.; Turcati, R.

    2003-08-01

    The process of formation of binary and multiple stars is not yet fully understood. Possibilities range from simultaneous processes of condensation from the primeval nebula, to isolated star formation and eventual capture to form a double system. Models exist that predict success probabilities for each theoretical process, and comparison with observational data is crucial. Spectroscopic binaries are specially suited to be used as observational data, since several biases that can arise from general catalogues of binary stars can be avoided, including dominance of systems with large separations between components. A very important parameter in these studies is the mass ratio, the quocient of the masses of primary and secundary members. The histogram of mass ratios provides crucial information to models of binary formation, linked to condensation processes and evolutionaty rates.In this case, spectroscopic binaries can be chosen as the observational sample, provided that the spectrum of the primary is from a non-evolved, main-sequence star,whose mass can be derived reliably from its spectral type. Defining an adequate limiting magnitude (6.5), one avoids bias from eclipsing systems with high inclinations, since nearly all systems up to 6.5 mag were detected. In this paper, a critical review is presented of the existing methods for deriving the distribution of the mass ratios from spectroscopic binary orbital data. After showing the incorrectness of some results published in the litterature, the available data (Batten's 8th Catalogue, 1989) is discussed. Simulations for several distributions of mass ratios (constant, quadratic, etc) are performed. It is shown that the existing data permits only to assert that the spectroscopic binaries with small mass ratios (q < 0.4) are more frequent that those with large mass ratios (q = 0.9 to 1.0).

  16. Asiago spectroscopic classification of three SNe

    NASA Astrophysics Data System (ADS)

    Elias-Rosa, N.; Cappellaro, E.; Benetti, S.; Tomasella, L.; Ochner, P.; Pastorello, A.; Tartaglia, L.; Terreran, G.; Turatto, M.

    2015-09-01

    The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic classification of three SNe. Informations on these transients are also available from the "Bright Supernova" website (http://www.rochesterastronomy.org/snimages/), the CBAT Transient Object Followup Reports (http://www.cbat.eps.harvard.edu/index.html) and All-Sky Automated Survey for Supernovae (http://www.astronomy.ohio-state.edu/~assassin/index.shtml).

  17. 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.

  18. 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.

  19. The STIS CCD Spectroscopic Line Spread Functions

    NASA Technical Reports Server (NTRS)

    Gull, T.; Lindler, D.; Tennant, D.; Bowers, C.; Grady, C.; Hill, R. S.; Malumuth, E.

    2002-01-01

    We characterize the spectroscopic line spread functions of the spectroscopic CCD modes for high contrast objects. Our long range goal is to develop tools that accurately extract spectroscopic information of faint, point or extended sources in the vicinity of bright, point sources at separations approaching the realizable angular limits of HST with STIS. Diffracted and scattered light due to the HST optics, and scattered light effects within the STIS are addressed. Filter fringing, CCD fringing, window reflections, and scattering within the detector and other effects are noted. We have obtained spectra of several reference stars, used for flux calibration or for coronagraphic standards, that have spectral distributions ranging from very red to very blue. Spectra of each star were recorded with the star in the aperture and with the star blocked by either the F1 or F2 fiducial. Plots of the detected starlight along the spatial axis of the aperture are provided for four stars. With the star in the aperture, the line spread function is quite noticeable. Placing the star behind one of the fiducials cuts the scattered light and the diffracted light, is detectable even out to 1OOOOA. When the star is placed behind either fiducial, the scattered and diffracted light components, at three arcseconds displacement from the star, are below lop6 the peak of the star at wavelengths below 6000A; at the same angular distance, scattered light does contaminate the background longward of 6000A up to a level of 10(exp -5).

  20. Infrared spectroscopic imaging of kidney tumor tissue

    NASA Astrophysics Data System (ADS)

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

    2011-02-01

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

  1. LIBS spectroscopic classification relative to compressive sensing

    NASA Astrophysics Data System (ADS)

    Griffin, Steven T.; Jacobs, Eddie; Furxhi, Orges

    2011-05-01

    Laser Induced Breakdown Spectroscopy (LIBS) utilizes a diversity of standard spectroscopic techniques for classification of materials present in the sample. Pre-excitation processing sometimes limits the analyte to a short list of candidates. Prior art demonstrates that sparsity is present in the data. This is sometimes characterized as identification by components. Traditionally, spectroscopic identification has been accomplished by an expert reader in a manner typical for MRI images in the medicine. In an effort to automate this process, more recent art has emphasized the use of customized variations to standard classification algorithms. In addition, formal mathematical proofs for compressive sensing have been advanced. Recently the University of Memphis has been contracted by the Spectroscopic Materials Identification Center to advance and characterize the sensor research and development related to LIBS. Applications include portable standoff sensing for improvised explosive device detection and related law enforcement and military applications. Reduction of the mass, power consumption and other portability parameters is seen as dependent on classification choices for a LIBS system. This paper presents results for the comparison of standard LIBS classification techniques to those implied by Compressive Sensing mathematics. Optimization results and implications for portable LIBS design are presented.

  2. Proton spectroscopic imaging of human brain

    NASA Astrophysics Data System (ADS)

    Moonen, Chrit T. W.; Sobering, Geoffrey; Van Zijl, Peter C. M.; Gillen, Joe; Von Kienlin, Markus; Bizzi, Alberto

    Signals from water and fat can cause artifacts in proton spectroscopic imaging in the human brain. The major problem is variation of the B0 field over a range of several ppm within the sensitive volume of the standard whole-head coil. Here, the coherence-pathway formalism is used to describe and evaluate the origin of artifacts in a double spin-echo (PRESS) sequence. The attenuation of unwanted coherences using pulsed field gradients is described for homogeneous and inhomogeneous B0 fields. The effect of the following parameters on the quality of the spectroscopic images is analyzed: (a) directional order of plane selection, (b) positioning of phase-encode gradients in the sequence, (c) postprocessing spatial windowing, and (d) motion. It is shown that, for a typical echo time of 272 ms, it is not necessary to first select a region of interest within the brain borders when sufficient phase-encode steps are used. Examples of 2D proton spectroscopic images with a nominal voxel volume of 0.85 ml are given for a healthy volunteer and a patient with a low-grade glioma.

  3. Flux measurements using the BATSE spectroscopic detectors

    NASA Technical Reports Server (NTRS)

    Mcnamara, Bernard

    1993-01-01

    Among the Compton Gama-Ray Observatory instruments, the BATSE Spectroscopic Detectors (SD) have the distinction of being able to detect photons of energies less than about 20 keV. This is an interesting energy range for the examination of low mass X-ray binaries (LMXB's). In fact, Sco X-1, the prototype LMXB, is easily seen even in the raw BATSE spectroscopic data. The all-sky coverage afforded by these detectors offers a unique opportunity to monitor this source over time periods never before possible. The aim of this investigation was to test a number of ways in which both continous and discrete flux measurements can be obtained using the BATSE spectroscopic datasets. A instrumental description of a SD can be found in the Compton Workshop of Apr. 1989, this report will deal only with methods which can be used to analyze its datasets. Many of the items discussed below, particularly in regard to the earth occultation technique, have been developed, refined, and applied by the BATSE team to the reduction of BATSE LAD data. Code written as part of this project utilizes portions of that work. The following discussions will first address issues related to the reduction of SD datasets using the earth occultation technique. It will then discuss methods for the recovery of the flux history of strong sources while they are above the earth's limb. The report will conclude with recommended reduction procedures.

  4. The HITRAN2012 molecular spectroscopic database

    NASA Astrophysics Data System (ADS)

    Rothman, L. S.; Gordon, I. E.; Babikov, Y.; Barbe, A.; Chris Benner, D.; Bernath, P. F.; Birk, M.; Bizzocchi, L.; Boudon, V.; Brown, L. R.; Campargue, A.; Chance, K.; Cohen, E. A.; Coudert, L. H.; Devi, V. M.; Drouin, B. J.; Fayt, A.; Flaud, J.-M.; Gamache, R. R.; Harrison, J. J.; Hartmann, J.-M.; Hill, C.; Hodges, J. T.; Jacquemart, D.; Jolly, A.; Lamouroux, J.; Le Roy, R. J.; Li, G.; Long, D. A.; Lyulin, O. M.; Mackie, C. J.; Massie, S. T.; Mikhailenko, S.; Müller, H. S. P.; Naumenko, O. V.; Nikitin, A. V.; Orphal, J.; Perevalov, V.; Perrin, A.; Polovtseva, E. R.; Richard, C.; Smith, M. A. H.; Starikova, E.; Sung, K.; Tashkun, S.; Tennyson, J.; Toon, G. C.; Tyuterev, Vl. G.; Wagner, G.

    2013-11-01

    This paper describes the status of the 2012 edition of the HITRAN molecular spectroscopic compilation. The new edition replaces the previous HITRAN edition of 2008 and its updates during the intervening years. The HITRAN molecular absorption compilation is comprised of six major components structured into folders that are freely accessible on the internet. These folders consist of the traditional line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, infrared absorption cross-sections for molecules not yet amenable to representation in a line-by-line form, ultraviolet spectroscopic parameters, aerosol indices of refraction, collision-induced absorption data, and general tables such as partition sums that apply globally to the data. The new HITRAN is greatly extended in terms of accuracy, spectral coverage, additional absorption phenomena, and validity. Molecules and isotopologues have been added that address the issues of atmospheres beyond the Earth. Also discussed is a new initiative that casts HITRAN into a relational database format that offers many advantages over the long-standing sequential text-based structure that has existed since the initial release of HITRAN in the early 1970s.

  5. Spectroscopic imaging based approach for condom identification in condom contaminated fingermarks.

    PubMed

    Bradshaw, Robert; Wolstenholme, Rosalind; Ferguson, Leesa Susanne; Sammon, Chris; Mader, Kerstin; Claude, Emmanuelle; Blackledge, Robert D; Clench, Malcolm R; Francese, Simona

    2013-05-01

    Sexual offenders are increasingly reported to use condoms while committing the crime, mainly to prevent the transfer of DNA evidence. Although condoms are often removed from the crime scene, vaginal swabs can be taken from the victim to prove the presence of condom lubricants and therefore evidence of corpus delicti. However, late reporting to the police and the tendency of the victim to wash immediately after the crime, may compromise the detection of condom lubricants. Recently we showed that Matrix-Assisted Laser Desorption/Ionisation MS Imaging (MALDI MSI) of condom contaminated fingermarks enables images of the fingermark ridge pattern to be obtained simultaneously with the detection of the condom lubricant for two condom brands, thus becoming a potential alternative way to link the assailant to the crime. Building on the value of this information, it would be advantageous to identify the condom brand used during the sexual assault. Here we show the development of a multidisciplinary spectroscopic approach, including MALDI MSI, MS/MS, Raman microscopy and ATR-FTIR spectroscopy, applied to a range of condom brands/types. The techniques have complementary features and provide complementary information to retrieve a "condom brand spectroscopic fingerprint". Unique spectroscopic profiles would greatly aid in the screening and identification of the condom, thus adding intelligence to the case under investigation. PMID:23486747

  6. THE APOKASC CATALOG: AN ASTEROSEISMIC AND SPECTROSCOPIC JOINT SURVEY OF TARGETS IN THE KEPLER FIELDS

    SciTech Connect

    Pinsonneault, Marc H.; Epstein, Courtney; Johnson, Jennifer A.; Elsworth, Yvonne; Chaplin, William J.; Hekker, Saskia; Silva Aguirre, Victor; Stello, Dennis; Mészáros, Sz.; García, Rafael A.; Beck, Paul; Mathur, Savita; García Pérez, Ana; Girardi, Léo; Basu, Sarbani; Shetrone, Matthew; Allende Prieto, Carlos; Beers, Timothy C.; and others

    2015-01-01

    We present the first APOKASC catalog of spectroscopic and asteroseismic properties of 1916 red giants observed in the Kepler fields. The spectroscopic parameters provided from the Apache Point Observatory Galactic Evolution Experiment project are complemented with asteroseismic surface gravities, masses, radii, and mean densities determined by members of the Kepler Asteroseismology Science Consortium. We assess both random and systematic sources of error and include a discussion of sample selection for giants in the Kepler fields. Total uncertainties in the main catalog properties are of the order of 80 K in T {sub eff}, 0.06 dex in [M/H], 0.014 dex in log g, and 12% and 5% in mass and radius, respectively; these reflect a combination of systematic and random errors. Asteroseismic surface gravities are substantially more precise and accurate than spectroscopic ones, and we find good agreement between their mean values and the calibrated spectroscopic surface gravities. There are, however, systematic underlying trends with T {sub eff} and log g. Our effective temperature scale is between 0 and 200 K cooler than that expected from the infrared flux method, depending on the adopted extinction map, which provides evidence for a lower value on average than that inferred for the Kepler Input Catalog (KIC). We find a reasonable correspondence between the photometric KIC and spectroscopic APOKASC metallicity scales, with increased dispersion in KIC metallicities as the absolute metal abundance decreases, and offsets in T {sub eff} and log g consistent with those derived in the literature. We present mean fitting relations between APOKASC and KIC observables and discuss future prospects, strengths, and limitations of the catalog data.

  7. The APOKASC Catalog: An Asteroseismic and Spectroscopic Joint Survey of Targets in the Kepler Fields

    NASA Astrophysics Data System (ADS)

    Pinsonneault, Marc H.; Elsworth, Yvonne; Epstein, Courtney; Hekker, Saskia; Mészáros, Sz.; Chaplin, William J.; Johnson, Jennifer A.; García, Rafael A.; Holtzman, Jon; Mathur, Savita; García Pérez, Ana; Silva Aguirre, Victor; Girardi, Léo; Basu, Sarbani; Shetrone, Matthew; Stello, Dennis; Allende Prieto, Carlos; An, Deokkeun; Beck, Paul; Beers, Timothy C.; Bizyaev, Dmitry; Bloemen, Steven; Bovy, Jo; Cunha, Katia; De Ridder, Joris; Frinchaboy, Peter M.; García-Hernández, D. A.; Gilliland, Ronald; Harding, Paul; Hearty, Fred R.; Huber, Daniel; Ivans, Inese; Kallinger, Thomas; Majewski, Steven R.; Metcalfe, Travis S.; Miglio, Andrea; Mosser, Benoit; Muna, Demitri; Nidever, David L.; Schneider, Donald P.; Serenelli, Aldo; Smith, Verne V.; Tayar, Jamie; Zamora, Olga; Zasowski, Gail

    2014-12-01

    We present the first APOKASC catalog of spectroscopic and asteroseismic properties of 1916 red giants observed in the Kepler fields. The spectroscopic parameters provided from the Apache Point Observatory Galactic Evolution Experiment project are complemented with asteroseismic surface gravities, masses, radii, and mean densities determined by members of the Kepler Asteroseismology Science Consortium. We assess both random and systematic sources of error and include a discussion of sample selection for giants in the Kepler fields. Total uncertainties in the main catalog properties are of the order of 80 K in T eff, 0.06 dex in [M/H], 0.014 dex in log g, and 12% and 5% in mass and radius, respectively; these reflect a combination of systematic and random errors. Asteroseismic surface gravities are substantially more precise and accurate than spectroscopic ones, and we find good agreement between their mean values and the calibrated spectroscopic surface gravities. There are, however, systematic underlying trends with T eff and log g. Our effective temperature scale is between 0 and 200 K cooler than that expected from the infrared flux method, depending on the adopted extinction map, which provides evidence for a lower value on average than that inferred for the Kepler Input Catalog (KIC). We find a reasonable correspondence between the photometric KIC and spectroscopic APOKASC metallicity scales, with increased dispersion in KIC metallicities as the absolute metal abundance decreases, and offsets in T eff and log g consistent with those derived in the literature. We present mean fitting relations between APOKASC and KIC observables and discuss future prospects, strengths, and limitations of the catalog data.

  8. Spectroscopic Parameters of Lumbar Intervertebral Disc Material

    NASA Astrophysics Data System (ADS)

    Terbetas, G.; Kozlovskaja, A.; Varanius, D.; Graziene, V.; Vaitkus, J.; Vaitkuviene, A.

    2009-06-01

    There are numerous methods of investigating intervertebral disc. Visualization methods are widely used in clinical practice. Histological, imunohistochemical and biochemical methods are more used in scientific research. We propose that a new spectroscopic investigation would be useful in determining intervertebral disc material, especially when no histological specimens are available. Purpose: to determine spectroscopic parameters of intervertebral disc material; to determine emission spectra common for all intervertebral discs; to create a background for further spectroscopic investigation where no histological specimen will be available. Material and Methods: 20 patients, 68 frozen sections of 20 μm thickness from operatively removed intervertebral disc hernia were excited by Nd:YAG microlaser STA-01-TH third harmonic 355 nm light throw 0, 1 mm fiber. Spectrophotometer OceanOptics USB2000 was used for spectra collection. Mathematical analysis of spectra was performed by ORIGIN multiple Gaussian peaks analysis. Results: In each specimen of disc hernia were found distinct maximal spectral peaks of 4 types supporting the histological evaluation of mixture content of the hernia. Fluorescence in the spectral regions 370-700 nm was detected in the disc hernias. The main spectral component was at 494 nm and the contribution of the components with the peak wavelength values at 388 nm, 412 nm and 435±5 nm were varying in the different groups of samples. In comparison to average spectrum of all cases, there are 4 groups of different spectral signatures in the region 400-500 nm in the patient groups, supporting a clinical data on different clinical features of the patients. Discussion and Conclusion: besides the classical open discectomy, new minimally invasive techniques of treating intervertebral disc emerge (PLDD). Intervertebral disc in these techniques is assessed by needle, no histological specimen is taken. Spectroscopic investigation via fiber optics through the

  9. Experimental and theoretical spectroscopic studies of dye modification in synthetic Maya Blue pigment

    NASA Astrophysics Data System (ADS)

    Reza, Layra; Manciu, Felicia; Ramirez, Alejandra; Chianelli, Russell

    2009-03-01

    Maya pigments are hybrid organic/inorganic materials with multiple technology applications that possess unprecedented stability with respect to harsh environment conditions. In this investigation, we address the question of how the organic indigo dye modifies as it binds to the inorganic palygorskite clay to form a pigment similar to Maya Blue after a heating treatment is applied. Both infrared and Raman spectroscopic data demonstrate the disappearance of nitrogen-hydrogen (N-H) bonding, as the indigo molecule incorporates into the inorganic palygorskite material. This effect suggests a transformation of the dye from indigo to dehydroindigo. Furthermore, the Raman and infrared absorption results demonstrate partial elimination of the selection rules for the centrosymmetric indigo, which provides further evidence for this conversion. Theoretical spectroscopic studies are also addressed in this investigation to confirm the transformation of the dye into dehydroindigo.

  10. THIRTY NEW LOW-MASS SPECTROSCOPIC BINARIES

    SciTech Connect

    Shkolnik, Evgenya L.; Hebb, Leslie; Cameron, Andrew C.; Liu, Michael C.; Neill Reid, I. E-mail: Andrew.Cameron@st-and.ac.u E-mail: mliu@ifa.hawaii.ed

    2010-06-20

    As part of our search for young M dwarfs within 25 pc, we acquired high-resolution spectra of 185 low-mass stars compiled by the NStars project that have strong X-ray emission. By cross-correlating these spectra with radial velocity standard stars, we are sensitive to finding multi-lined spectroscopic binaries. We find a low-mass spectroscopic binary fraction of 16% consisting of 27 SB2s, 2 SB3s, and 1 SB4, increasing the number of known low-mass spectroscopic binaries (SBs) by 50% and proving that strong X-ray emission is an extremely efficient way to find M-dwarf SBs. WASP photometry of 23 of these systems revealed two low-mass eclipsing binaries (EBs), bringing the count of known M-dwarf EBs to 15. BD-22 5866, the ESB4, was fully described in 2008 by Shkolnik et al. and CCDM J04404+3127 B consists of two mid-M stars orbiting each other every 2.048 days. WASP also provided rotation periods for 12 systems, and in the cases where the synchronization time scales are short, we used P{sub rot} to determine the true orbital parameters. For those with no P{sub rot}, we used differential radial velocities to set upper limits on orbital periods and semimajor axes. More than half of our sample has near-equal-mass components (q > 0.8). This is expected since our sample is biased toward tight orbits where saturated X-ray emission is due to tidal spin-up rather than stellar youth. Increasing the samples of M-dwarf SBs and EBs is extremely valuable in setting constraints on current theories of stellar multiplicity and evolution scenarios for low-mass multiple systems.

  11. Are your Spectroscopic Data Being Used?

    NASA Astrophysics Data System (ADS)

    Gordon, Iouli E.; Rothman, Laurence S.; Wilzewski, Jonas

    2014-06-01

    Spectroscopy is an established and indispensable tool in science, industry, agriculture, medicine, surveillance, etc.. The potential user of spectral data, which is not available in HITRAN or other databases, searches the spectroscopy publications. After finding the desired publication, the user very often encounters the following problems: 1) They cannot find the data described in the paper. There can be many reasons for this: nothing is provided in the paper itself or supplementary material; the authors are not responding to any requests; the web links provided in the paper have long been broken; etc. 2) The data is presented in a reduced form, for instance through the fitted spectroscopic constants. While this is a long-standing practice among spectroscopists, there are numerous serious problems with this practice, such as users getting different energy and intensity values because of different representations of the solution to the Hamiltonian, or even just despairing of trying to generate usable line lists from the published constants. Properly providing the data benefits not only users but also the authors of the spectroscopic research. We will show that this increases citations to the spectroscopy papers and visibility of the research groups. We will also address the quite common issue when researchers obtain the data, but do not feel that they have time, interest or resources to write an article describing it. There are modern tools that would allow one to make these data available to potential users and still get credit for it. However, this is a worst case scenario recommendation, i.e., publishing the data in a peer-reviewed journal is still the preferred way. L. S. Rothman, I. E. Gordon, et al. "The HITRAN 2012 molecular spectroscopic database," JQSRT 113, 4-50 (2013).

  12. PRIMitive Asteroids Spectroscopic Survey - PRIMASS: First Results

    NASA Astrophysics Data System (ADS)

    de Leon, Julia; Pinilla-Alonso, Noemi; Campins, Humberto; Lorenzi, Vania; Licandro, Javier; Morate, David; Tanga, Paolo; Cellino, Alberto; Delbo, Marco

    2015-11-01

    NASA OSIRIS-REx and JAXA Hayabusa 2 sample-return missions have targeted two near-Earth asteroids: (101955) Bennu and (162173) 1999 JU3, respectively. These are primitive asteroids that are believed to originate in the inner belt, where five distinct sources have been identified: four primitive collisional families (Polana, Erigone, Sulamitis, and Clarissa), and a population of low-albedo and low-inclination background asteroids. Identifying and characterizing the populations from which these two NEAs might originate will enchance the science return of the two missions.With this main objective in mind, we initiated in 2010 a spectroscopic survey in the visible and the near-infrared to characterize the primitive collisional families in the inner belt and the low-albedo background population. This is the PRIMitive Asteroids Spectroscopic Survey - PRIMASS. So far we have obtained more than 200 spectra using telescopes located at different observatories. PRIMASS uses a variety of ground based facilities. Most of the spectra have been obtained using the 10.4m Gran Telescopio Canarias (GTC), and the 3.6m Telescopio Nazionale Galileo (TNG), both located at the El Roque de los Muchachos Observatory (La Palma, Spain), and the 3.0m NASA Infrared Telescope Facility on Mauna Kea (Hawai, USA).We present the first results from our on-going survey (de Leon et al. 2015; Pinilla-Alonso et al. 2015; Morate et al. 2015), focused on the Polana and the Erigone primitive families, with visible and near-infrared spectra of more than 200 objects, most of them with no previous spectroscopic data. Our survey is already the largest database of primitive asteroids spectra, and we keep obtaining data on the Sulamitis and the Clarissa families, as well as on the background low-albedo population.

  13. Spectroscopic ellipsometer for ultra thin film

    NASA Astrophysics Data System (ADS)

    Akashika, Kumiko; Shiota, Shuji; Yamaguchi, Shinji; Horie, Masahiro; Kobayashi, Masayoshi

    2008-03-01

    As semiconductor technology has advanced, the films have become thinner and changed to multi-layer films, such as gate dielectric construction. To deal with these trends, we are continuing development of our spectroscopic ellipsometer with elliptical polarization. We chose a Rotating-Analyzer Ellipsometer (RAE) configuration. The incident light in this type of device is usually polarized linearly, because polarizers do not disperse the light. But the incident light in the ellipsometer described in this paper is elliptical, which has a nearly circular polarization. In this paper, we introduce a technique for solving the dispersion problem.

  14. Spectroscopic diagnostics of tritium recycling in TFTR

    SciTech Connect

    Skinner, C.H.; Stotler, D.P.; Adler, H.; Ramsey, A.T.

    1995-03-01

    The authors present the first spectroscopic measurements of tritium Balmer-alpha (T{sub {alpha}}) emission from a fusion plasma. A Fabry-Perot interferometer is used to measure the H{sub {alpha}}, D{sub {alpha}}, T{sub {alpha}} spectrum in the current D-T a experimental campaign on TFTR and the contributions of H, D and T are separated by spectral analysis. The T{sub {alpha}} line was measurable at concentrations T{sub {alpha}}/(H{sub {alpha}} + D{sub {alpha}} + T{sub {alpha}}) down to 2%.

  15. The Gaia-ESO Public Spectroscopic Survey

    NASA Astrophysics Data System (ADS)

    Gilmore, G.; Randich, S.; Asplund, M.; Binney, J.; Bonifacio, P.; Drew, J.; Feltzing, S.; Ferguson, A.; Jeffries, R.; Micela, G.; Negueruela, I.; Prusti, T.; Rix, H.-W.; Vallenari, A.; Alfaro, E.; Allende-Prieto, C.; Babusiaux, C.; Bensby, T.; Blomme, R.; Bragaglia, A.; Flaccomio, E.; François, P.; Irwin, M.; Koposov, S.; Korn, A.; Lanzafame, A.; Pancino, E.; Paunzen, E.; Recio-Blanco, A.; Sacco, G.; Smiljanic, R.; Van Eck, S.; Walton, N.; Aden, D.; Aerts, C.; Affer, L.; Alcala, J.-M.; Altavilla, G.; Alves, J.; Antoja, T.; Arenou, F.; Argiroffi, C.; Asensio Ramos, A.; Bailer-Jones, C.; Balaguer-Nunez, L.; Bayo, A.; Barbuy, B.; Barisevicius, G.; Barrado y Navascues, D.; Battistini, C.; Bellas Velidis, I.; Bellazzini, M.; Belokurov, V.; Bergemann, M.; Bertelli, G.; Biazzo, K.; Bienayme, O.; Bland-Hawthorn, J.; Boeche, C.; Bonito, S.; Boudreault, S.; Bouvier, J.; Brandao, I.; Brown, A.; de Bruijne, J.; Burleigh, M.; Caballero, J.; Caffau, E.; Calura, F.; Capuzzo-Dolcetta, R.; Caramazza, M.; Carraro, G.; Casagrande, L.; Casewell, S.; Chapman, S.; Chiappini, C.; Chorniy, Y.; Christlieb, N.; Cignoni, M.; Cocozza, G.; Colless, M.; Collet, R.; Collins, M.; Correnti, M.; Covino, E.; Crnojevic, D.; Cropper, M.; Cunha, M.; Damiani, F.; David, M.; Delgado, A.; Duffau, S.; Edvardsson, B.; Eldridge, J.; Enke, H.; Eriksson, K.; Evans, N. W.; Eyer, L.; Famaey, B.; Fellhauer, M.; Ferreras, I.; Figueras, F.; Fiorentino, G.; Flynn, C.; Folha, D.; Franciosini, E.; Frasca, A.; Freeman, K.; Fremat, Y.; Friel, E.; Gaensicke, B.; Gameiro, J.; Garzon, F.; Geier, S.; Geisler, D.; Gerhard, O.; Gibson, B.; Gomboc, A.; Gomez, A.; Gonzalez-Fernandez, C.; Gonzalez Hernandez, J.; Gosset, E.; Grebel, E.; Greimel, R.; Groenewegen, M.; Grundahl, F.; Guarcello, M.; Gustafsson, B.; Hadrava, P.; Hatzidimitriou, D.; Hambly, N.; Hammersley, P.; Hansen, C.; Haywood, M.; Heber, U.; Heiter, U.; Held, E.; Helmi, A.; Hensler, G.; Herrero, A.; Hill, V.; Hodgkin, S.; Huelamo, N.; Huxor, A.; Ibata, R.; Jackson, R.; de Jong, R.; Jonker, P.; Jordan, S.; Jordi, C.; Jorissen, A.; Katz, D.; Kawata, D.; Keller, S.; Kharchenko, N.; Klement, R.; Klutsch, A.; Knude, J.; Koch, A.; Kochukhov, O.; Kontizas, M.; Koubsky, P.; Lallement, R.; de Laverny, P.; van Leeuwen, F.; Lemasle, B.; Lewis, G.; Lind, K.; Lindstrom, H. P. E.; Lobel, A.; Lopez Santiago, J.; Lucas, P.; Ludwig, H.; Lueftinger, T.; Magrini, L.; Maiz Apellaniz, J.; Maldonado, J.; Marconi, G.; Marino, A.; Martayan, C.; Martinez-Valpuesta, I.; Matijevic, G.; McMahon, R.; Messina, S.; Meyer, M.; Miglio, A.; Mikolaitis, S.; Minchev, I.; Minniti, D.; Moitinho, A.; Momany, Y.; Monaco, L.; Montalto, M.; Monteiro, M. J.; Monier, R.; Montes, D.; Mora, A.; Moraux, E.; Morel, T.; Mowlavi, N.; Mucciarelli, A.; Munari, U.; Napiwotzki, R.; Nardetto, N.; Naylor, T.; Naze, Y.; Nelemans, G.; Okamoto, S.; Ortolani, S.; Pace, G.; Palla, F.; Palous, J.; Parker, R.; Penarrubia, J.; Pillitteri, I.; Piotto, G.; Posbic, H.; Prisinzano, L.; Puzeras, E.; Quirrenbach, A.; Ragaini, S.; Read, J.; Read, M.; Reyle, C.; De Ridder, J.; Robichon, N.; Robin, A.; Roeser, S.; Romano, D.; Royer, F.; Ruchti, G.; Ruzicka, A.; Ryan, S.; Ryde, N.; Santos, N.; Sanz Forcada, J.; Sarro Baro, L. M.; Sbordone, L.; Schilbach, E.; Schmeja, S.; Schnurr, O.; Schoenrich, R.; Scholz, R.-D.; Seabroke, G.; Sharma, S.; De Silva, G.; Smith, M.; Solano, E.; Sordo, R.; Soubiran, C.; Sousa, S.; Spagna, A.; Steffen, M.; Steinmetz, M.; Stelzer, B.; Stempels, E.; Tabernero, H.; Tautvaisiene, G.; Thevenin, F.; Torra, J.; Tosi, M.; Tolstoy, E.; Turon, C.; Walker, M.; Wambsganss, J.; Worley, C.; Venn, K.; Vink, J.; Wyse, R.; Zaggia, S.; Zeilinger, W.; Zoccali, M.; Zorec, J.; Zucker, D.; Zwitter, T.; Gaia-ESO Survey Team

    2012-03-01

    The Gaia-ESO Public Spectroscopic Survey has begun and will obtain high quality spectroscopy of some 100000 Milky Way stars, in the field and in open clusters, down to magnitude 19, systematically covering all the major components of the Milky Way. This survey will provide the first homogeneous overview of the distributions of kinematics and chemical element abundances in the Galaxy. The motivation, organisation and implementation of the Gaia-ESO Survey are described, emphasising the complementarity with the ESA Gaia mission. Spectra from the very first observing run of the survey are presented.

  16. Spectroscopic methods in gas hydrate research.

    PubMed

    Rauh, Florian; Mizaikoff, Boris

    2012-01-01

    Gas hydrates are crystalline structures comprising a guest molecule surrounded by a water cage, and are particularly relevant due to their natural occurrence in the deep sea and in permafrost areas. Low molecular weight molecules such as methane and carbon dioxide can be sequestered into that cage at suitable temperatures and pressures, facilitating the transition to the solid phase. While the composition and structure of gas hydrates appear to be well understood, their formation and dissociation mechanisms, along with the dynamics and kinetics associated with those processes, remain ambiguous. In order to take advantage of gas hydrates as an energy resource (e.g., methane hydrate), as a sequestration matrix in (for example) CO(2) storage, or for chemical energy conservation/storage, a more detailed molecular level understanding of their formation and dissociation processes, as well as the chemical, physical, and biological parameters that affect these processes, is required. Spectroscopic techniques appear to be most suitable for analyzing the structures of gas hydrates (sometimes in situ), thus providing access to such information across the electromagnetic spectrum. A variety of spectroscopic methods are currently used in gas hydrate research to determine the composition, structure, cage occupancy, guest molecule position, and binding/formation/dissociation mechanisms of the hydrate. To date, the most commonly applied techniques are Raman spectroscopy and solid-state nuclear magnetic resonance (NMR) spectroscopy. Diffraction methods such as neutron and X-ray diffraction are used to determine gas hydrate structures, and to study lattice expansions. Furthermore, UV-vis spectroscopic techniques and scanning electron microscopy (SEM) have assisted in structural studies of gas hydrates. Most recently, waveguide-coupled mid-infrared spectroscopy in the 3-20 μm spectral range has demonstrated its value for in situ studies on the formation and dissociation of gas

  17. Vibrational spectroscopic study of fluticasone propionate

    NASA Astrophysics Data System (ADS)

    Ali, H. R. H.; Edwards, H. G. M.; Kendrick, J.; Scowen, I. J.

    2009-03-01

    Fluticasone propionate is a synthetic glucocorticoid with potent anti-inflammatory activity that has been used effectively in the treatment of chronic asthma. The present work reports a vibrational spectroscopic study of fluticasone propionate and gives proposed molecular assignments on the basis of ab initio calculations using BLYP density functional theory with a 6-31G* basis set and vibrational frequencies predicted within the quasi-harmonic approximation. Several spectral features and band intensities are explained. This study generated a library of information that can be employed to aid the process monitoring of fluticasone propionate.

  18. Spectroscopic needs for imaging dark energy experiments

    NASA Astrophysics Data System (ADS)

    Newman, Jeffrey A.; Abate, Alexandra; Abdalla, Filipe B.; Allam, Sahar; Allen, Steven W.; Ansari, Réza; Bailey, Stephen; Barkhouse, Wayne A.; Beers, Timothy C.; Blanton, Michael R.; Brodwin, Mark; Brownstein, Joel R.; Brunner, Robert J.; Carrasco Kind, Matias; Cervantes-Cota, Jorge L.; Cheu, Elliott; Chisari, Nora Elisa; Colless, Matthew; Comparat, Johan; Coupon, Jean; Cunha, Carlos E.; de la Macorra, Axel; Dell'Antonio, Ian P.; Frye, Brenda L.; Gawiser, Eric J.; Gehrels, Neil; Grady, Kevin; Hagen, Alex; Hall, Patrick B.; Hearin, Andew P.; Hildebrandt, Hendrik; Hirata, Christopher M.; Ho, Shirley; Honscheid, Klaus; Huterer, Dragan; Ivezić, Željko; Kneib, Jean-Paul; Kruk, Jeffrey W.; Lahav, Ofer; Mandelbaum, Rachel; Marshall, Jennifer L.; Matthews, Daniel J.; Ménard, Brice; Miquel, Ramon; Moniez, Marc; Moos, H. W.; Moustakas, John; Myers, Adam D.; Papovich, Casey; Peacock, John A.; Park, Changbom; Rahman, Mubdi; Rhodes, Jason; Ricol, Jean-Stephane; Sadeh, Iftach; Slozar, Anže; Schmidt, Samuel J.; Stern, Daniel K.; Anthony Tyson, J.; von der Linden, Anja; Wechsler, Risa H.; Wood-Vasey, W. M.; Zentner, Andrew R.

    2015-03-01

    Ongoing and near-future imaging-based dark energy experiments are critically dependent upon photometric redshifts (a.k.a. photo-z's): i.e., estimates of the redshifts of objects based only on flux information obtained through broad filters. Higher-quality, lower-scatter photo-z's will result in smaller random errors on cosmological parameters; while systematic errors in photometric redshift estimates, if not constrained, may dominate all other uncertainties from these experiments. The desired optimization and calibration is dependent upon spectroscopic measurements for secure redshift information; this is the key application of galaxy spectroscopy for imaging-based dark energy experiments.

  19. Spectroscopic enhancement in nanoparticles embedded glasses

    NASA Astrophysics Data System (ADS)

    Sahar, M. R.; Ghoshal, S. K.

    2014-09-01

    This presentation provides an overview of the recent progress in the enhancement of the spectroscopic characteristics of the glass embedded with nanoparticles (NPs). Some of our research activities with few significantly new results are highlighted and facilely analyzed. The science and technology dealing with the manipulation of the physical properties of rare earth doped inorganic glasses by embedding metallic NPs or nanoclusters produce the so-called 'nanoglass'. Meanwhile, the spectroscopic enhancement relates the intensity of the luminescence measured at certain transition. The enhancement which expectedly due to the 'plasmonics wave' (referring to the coherent coupling of photons to free electron oscillations called plasmon) occurs at the interface between a conductor and a dielectric. Plasmonics being an emerging concept in advanced optical material of nanophotonics has given this material the ability to exploit the optical response at nanoscale and opened up a new avenue in metal-based glass optics. There is a vast array of plasmonic NPs concepts yet to be explored, with applications spanning solar cells, (bio) sensing, communications, lasers, solid-state lighting, waveguides, imaging, optical data transfer, display and even bio-medicine. Localized surface plasmon resonance (LSPR) can enhance the optical response of nanoglass by orders of magnitude as observed. The luminescence enhancement and surface enhanced Raman scattering (SERS) are new paradigm of research. The enhancement of luminescence due to the influence of metallic NPs is the recurring theme of this paper.

  20. Spectroscopic chemical analysis methods and apparatus

    NASA Technical Reports Server (NTRS)

    Hug, William F. (Inventor); Reid, Ray D. (Inventor); Bhartia, Rohit (Inventor)

    2013-01-01

    Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. Chemical analysis instruments employed in some embodiments include capillary and gel plane electrophoresis, capillary electrochromatography, high performance liquid chromatography, flow cytometry, flow cells for liquids and aerosols, and surface detection instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted along with photoluminescence spectroscopy (i.e. fluorescence and/or phosphorescence spectroscopy) to provide high levels of sensitivity and specificity in the same instrument.

  1. Spectroscopic Modeling of Single Element Plasma

    SciTech Connect

    Ghomeishi, Mostafa; Yap, S. L.; Wong, C. S.; Saboohi, S.; Chan, L. S.

    2011-03-30

    A strategy for spectroscopic analysis of single element plasmas is through modeling. An experimental investigation or generation of a specified emission spectrum can be attempted based on the modeling results which are currently under investigating by many researchers in the world. In the emission spectroscopy, the K-shell emission is more interesting than emissions from other shells due to their unique EUV and SXR frequencies that can be applied in various scientific and industrial applications. Population information of our model is based on a steady state kinetic code which is calculated for a given electron temperature and an estimated electron density. Thus for each single element plasma it needs large amounts of experimental or theoretical database. Depending on the parameter of the plasma, theories based on local thermodynamic equilibrium (LTE) and non-LTE are considered. In the non-LTE case, the Corona model is used and the total absolute number densities are calculated based on the ion densities that are related to the electron density corresponds to the mean charge of the ions. The spectra generated by the model can then be compared with spectroscopic data obtained experimentally.

  2. Spectroscopic Ellipsometry Applications in Advanced Lithography Research

    NASA Astrophysics Data System (ADS)

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

    2005-09-01

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

  3. Spectroscopic enhancement in nanoparticles embedded glasses

    SciTech Connect

    Sahar, M. R. Ghoshal, S. K.

    2014-09-25

    This presentation provides an overview of the recent progress in the enhancement of the spectroscopic characteristics of the glass embedded with nanoparticles (NPs). Some of our research activities with few significantly new results are highlighted and facilely analyzed. The science and technology dealing with the manipulation of the physical properties of rare earth doped inorganic glasses by embedding metallic NPs or nanoclusters produce the so-called 'nanoglass'. Meanwhile, the spectroscopic enhancement relates the intensity of the luminescence measured at certain transition. The enhancement which expectedly due to the 'plasmonics wave' (referring to the coherent coupling of photons to free electron oscillations called plasmon) occurs at the interface between a conductor and a dielectric. Plasmonics being an emerging concept in advanced optical material of nanophotonics has given this material the ability to exploit the optical response at nanoscale and opened up a new avenue in metal-based glass optics. There is a vast array of plasmonic NPs concepts yet to be explored, with applications spanning solar cells, (bio) sensing, communications, lasers, solid-state lighting, waveguides, imaging, optical data transfer, display and even bio-medicine. Localized surface plasmon resonance (LSPR) can enhance the optical response of nanoglass by orders of magnitude as observed. The luminescence enhancement and surface enhanced Raman scattering (SERS) are new paradigm of research. The enhancement of luminescence due to the influence of metallic NPs is the recurring theme of this paper.

  4. Spectroscopic characterization of nitroaromatic landmine signature explosives

    NASA Astrophysics Data System (ADS)

    Hernandez-Rivera, Samuel P.; Manrique-Bastidas, Cesar A.; Blanco, Alejandro; Primera, Oliva M.; Pacheco, Leonardo C.; Castillo-Chara, Jairo; Castro, Miguel E.; Mina, Nairmen

    2004-09-01

    TNT and DNT are important explosives used as base charges of landmines and other explosive devices. They are often combined with RDX in specific explosive formulations. Their detection in vapor phase as well as in soil in contact with the explosives is important in landmine detection technology. The spectroscopic signatures of nitroaromatic compounds in neat forms: crystals, droplets, and recrystallized samples were determined by Raman Microspectroscopy (RS), Fourier Transform Infrared Microscopy (FTIR) and Fiber Optics Coupled - Fourier Transform Infrared Spectroscopy (FOC-FTIR) using a grazing angle (GA) probe. TNT exhibits a series of characteristic bands: vibrational signatures, which allow its detection in soil. The spectroscopic signature of neat TNT is dominated by strong bands about 1380 and 2970 cm-1. The intensity and position of these bands were found remarkably different in soil samples spiked with TNT. The 1380 cm-1 band is split into a number of bands in that region. The 2970 cm-1 band is reduced in intensity and new bands are observed about 2880 cm-1. The results are consistent with a different chemical environment of TNT in soil as compared to neat TNT. Interactions were found to be dependent on the physical source of the explosive. In the case of DNT-sand interactions, shifts in vibrational frequencies of the explosives as well as the substrates were found.

  5. EPSILON AURIGAE: AN IMPROVED SPECTROSCOPIC ORBITAL SOLUTION

    SciTech Connect

    Stefanik, Robert P.; Torres, Guillermo; Lovegrove, Justin; Latham, David W.; Zajac, Joseph; Pera, Vivian E.; Mazeh, Tsevi

    2010-03-15

    A rare eclipse of the mysterious object {epsilon} Aurigae will occur in 2009-2011. We report an updated single-lined spectroscopic solution for the orbit of the primary star based on 20 years of monitoring at the CfA, combined with historical velocity observations dating back to 1897. There are 518 new CfA observations obtained between 1989 and 2009. Two solutions are presented. One uses the velocities outside the eclipse phases together with mid-times of previous eclipses, from photometry dating back to 1842, which provide the strongest constraint on the ephemeris. This yields a period of 9896.0 {+-} 1.6 days (27.0938 {+-} 0.0044 years) with a velocity semi-amplitude of 13.84 {+-} 0.23 km s{sup -1} and an eccentricity of 0.227 {+-} 0.011. The middle of the current ongoing eclipse predicted by this combined fit is JD 2,455,413.8 {+-} 4.8, corresponding to 2010 August 5. If we use only the radial velocities, we find that the predicted middle of the current eclipse is nine months earlier. This would imply that the gravitating companion is not the same as the eclipsing object. Alternatively, the purely spectroscopic solution may be biased by perturbations in the velocities due to the short-period oscillations of the supergiant.

  6. Infrared Spectroscopic Imaging: The Next Generation

    PubMed Central

    Bhargava, Rohit

    2013-01-01

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

  7. High-Definition Infrared Spectroscopic Imaging

    PubMed Central

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

    2013-01-01

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

  8. Optoacoustic spectroscopic imaging of radiolucent foreign bodies

    NASA Astrophysics Data System (ADS)

    Page, Leland; Maswadi, Saher; Glickman, Randolph D.

    2010-03-01

    One of the leading causes of medical malpractice claims in emergency medicine is the misdiagnosis of the presence of foreign bodies. Radiolucent foreign bodies are especially difficult to differentiate from surrounding soft tissue, gas, and bone. Current imaging modalities employed for the detection of foreign bodies include: X-ray computed tomography, magnetic resonance, and ultrasound; however, there is no consensus as to which modality is optimal for diagnosis. Because many radiolucent foreign bodies have sufficient contrast for imaging in the optical domain, we are exploring the use of laser-induced optoacoustic imaging for the detection of foreign bodies, especially in craniofacial injuries, in which the foreign bodies are likely to lie within the penetration depth of visible and near infrared wavelengths. Tissue-simulating phantoms containing various common foreign bodies have been constructed. Images of these phantoms have been successfully generated using two laser-based optoacoustic imaging methods with different detection modalities. In order to enhance the image contrast, common foreign bodies are being scanned over a wide range of wavelengths to obtain the spectroscopic properties of the materials commonly associated with these foreign bodies. This spectroscopic characterization will help select specific wavelengths to be used for imaging specific objects and provide useful diagnostic data about the material properties of the object.

  9. Synergies between spectroscopic and asteroseismic surveys

    NASA Astrophysics Data System (ADS)

    Fu, Jianning; De Cat, Peter; Ren, An-Bing; Yang, Xiao-Hu; Catanzaro, Giovanni; Corbally, Christopher J.; Frasca, Antonio; Gray, Richard O.; Cecylia Molenda-Zakowicz, Joanna; Shi, Jian-Rong; Ali, Luo; Zhang, Haotong

    2015-08-01

    The NASA Kepler satellite has provided unprecedented high duty-cycle, high-precision light curves for a large number of stars by continuously monitoring a field of view in Cygnus-Lyra region, leading to great progress in both discovering exoplanets and characterizing planet-hosting stars by means of asteroseismic methods. The asteroseismic survey allows the investigation of stars covering the whole H-R diagram. However, the low precision of effective temperatures and surface gravities in the KIC10 catalogue and the lack of information on chemical composition, metallicity and rotation rate prevent asteroseismic modeling, requiring spectroscopic observations for thousands of asteroseismic targets in the Kepler field in a homogeneous way.In 2010, we initiated the LAMOST-Kepler project which aimed at collecting low-resolution spectra for as many objects from the KIC10 catalogue as possible, with the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), a 4-m telescope equipped with 4,000 optical fibers. The first round of observations has been completed in fall 2014, covering all the 14 sub-fields at least once, resulting in more than 100,000 low-resolution spectra. The stellar atmospheric parameters are then derived and the results have been confirmed to be consistent with those reported in the literature based on high-resolution spectroscopy.

  10. Spectroscopic observations and analysis of the peculiar SN1999aa

    SciTech Connect

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

    2003-12-10

    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 an SN 1991T-like object but with a relatively strong CaH and K absorption feature. The first clear sign of Si II lambda 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 1991 T-like objects. Furthermore, in the day -11 spectrum, evidence is found for an absorption feature that could be identified as high velocity C II lambda 6580 or H alpha. At the same epoch C III lambda 4648.8 at photospheric velocity is probably responsible for the absorption feature at 4500 8. 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 hydrodynamic models are briefly discussed.

  11. Rotational Spectroscopic and Theoretical Investigations on Benzene-Ethylene Complex

    NASA Astrophysics Data System (ADS)

    Aiswarya Lakshmi, P.; Arunan, E.

    2009-06-01

    Theoretical studies and condensed phase experimental studies point towards a π stacked structure for benzene dimer, for which experimental evidence has not been found yet. This structure has no dipole moment and hence microwave spectroscopy can not be used. Benzene and ethylene can dimerise to give π stacked complex which will have a net dipole moment. Rotational spectroscopic technique can be used to detect this π stacked structure, if present, in the gas phase. Depending upon the nature of interaction, in addition to the π stacked structure, other geometries are also possible where either benzene or ethylene can act as hydrogen bond donor. Theoretical investigations led to five different structures including the π stacked one. Pulsed Nozzle Fourier Transform Microwave Spectrometer has been used to study the rotational spectrum of the benzene-ethylene complex, with helium as the carrier gas. A total of 24 `a' dipole transitions were observed. Out of these 24 transitions, 20 lines were fitted to the structure with C_2H_4 as the hydrogen bond donor. In the observed transitions the K=0 lines show doubling. The line centres of the K=0 doublets were used along with K=1 transitions for the fitting. The fitted rotational constants are, A= 5.4(1) GHz, B= 1221.879(3) MHz, C=1206.794(4) MHz. Search and assignments for C_6H_6-C_2D_4 and C_6D_6-C_2H_4 complexes are in progress.

  12. Spectroscopic and photometric monitoring of southern post-AGB stars

    NASA Astrophysics Data System (ADS)

    Pooley, D. J.; Cottrell, P. L.; Pollard, K. R.; Albrow, M. D.

    2004-05-01

    We present the results of contemporaneous photometric and spectroscopic monitoring of 20 post-AGB stars from Mt John University Observatory. Photometric measures were carried our suing Johnson BV and Cousins RI filters, and the radial velocity measurements were acquired using spectra from an echelle spectrograph. Our program spanned five years and the stars covered a range of spectral types from B to K in order to investigate the behavior of post-AGB stars as they evolve away from the AGB. A number of stars proved to be variable inways incompatible with post-AGB models and are reclassified. Periodicities are presented for a number of stars. Photometrically, HD 70379 was found to be pulsating in two modes with periods of 85 and 97 d. The radial velocities also varied, with the peak amplitude occurring when the photometry was also changing most. AI CMi presented three different types of spectra associated with photometric brightness, with varying strengths of narrow emission lines and molecular bandheads. The Hα profiles in almost all of the stars show evidence of emission which varies on time scales of days to months. The Na D line profiles are generally complex showing between 4 and 7 components due to both circumstellar and interstellar material.

  13. Preliminary spectroscopic characterization of six toxins from Latin American scorpions.

    PubMed

    Possani, L; Steinmetz, W E; Dent, M A; Alagón, A C; Wüthrich, K

    1981-07-28

    This paper reports on spectroscopic studies of six toxins from the Latin American scorpions Centruroides noxius Hoffmann, Centruroides elegans Thorell and Tityus serrulatus Lutz and Mello. The isolation and purification of five of these toxins was described previously. The preparation of toxin II.9.2.2 from the venom of C. noxius is first described here. Circular dichroism and nuclear magnetic resonance spectra indicate similarities and differences between these scorpion toxins and previously characterized snake toxins. While there is evidence that the toxins from scorpions and snakes both contain extended beta-sheet secondary structures, the spectral properties of the scorpion toxins are overall of a different type from those of snake toxins. Among the six scorpion toxins those from T. serrulatus have spectral properties markedly different from those of the Centruroides species. Furthermore, thermal denaturation and amide proton exchange measurements showed that the globular structures of the Tityus toxins were markedly less stable and less rigid than those of the Centruroides toxins. PMID:7284435

  14. Spectroscopic Search for Water Ice on Jovian Trojan Asteroids

    NASA Astrophysics Data System (ADS)

    Yang, Bin; Jewitt, D.

    2006-09-01

    We are conducting a systematic study of the Jovian Trojans using the Subaru 8-m, UKIRT 4-m and IRTF 3-m telescopes atop Mauna Kea, Hawaii. Theoretical models show that the Jovian Trojans formed beyond the snow-line and they may contain considerable amounts of water ice. We seek spectroscopic evidence for this pristine ice. Object (4709) Ennomos has a geometric albedo of 0.13+/-0.02, which is significantly above the mean Trojan albedo of 0.041+/- 0.002 (Fernandez et al., 2003). An intriguing possibility is that the albedo of Ennomos is high because a recent impact has coated part of the surface with freshly excavated ice. We obtained near-IR (0.8-2.5 micron) spectra of (4709) Ennomos in search of the 1.5 and 2.0 micron bands of water ice. Four other Trojans, (911) Agamemnon, (617) Patroclus, (1143) Odysseus and (2797) Teucer, were also observed. These objects have been reported to show possible weak absorptions at 1.7 and 2.3 micron respectively (Emery and Brown, 2003). All five targets appear spectrally featureless, even in our highest signal-to-noise ratio data. We present the data and a simple model consisting of mixtures of water ice and a spectrally featureless material, to quantify the limits to surface ice.

  15. Spectroscopic diagnostics of organic chemistry in the protostellar environment

    NASA Technical Reports Server (NTRS)

    Charnley, S. B.; Ehrenfreund, P.; Kuan, Y. J.

    2001-01-01

    A combination of astronomical observations, laboratory studies, and theoretical modelling is necessary to determine the organic chemistry of dense molecular clouds. We present spectroscopic evidence for the composition and evolution of organic molecules in protostellar environments. The principal reaction pathways to complex molecule formation by catalysis on dust grains and by reactions in the interstellar gas are described. Protostellar cores, where warming of dust has induced evaporation of icy grain mantles, are excellent sites in which to study the interaction between gas phase and grain-surface chemistries. We investigate the link between organics that are observed as direct products of grain surface reactions and those which are formed by secondary gas phase reactions of evaporated surface products. Theory predicts observable correlations between specific interstellar molecules, and also which new organics are viable for detection. We discuss recent infrared observations obtained with the Infrared Space Observatory, laboratory studies of organic molecules, theories of molecule formation, and summarise recent radioastronomical searches for various complex molecules such as ethers, azaheterocyclic compounds, and amino acids.

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  18. Imaging spectroscopic ellipsometry of MoS2

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1993-08-01

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

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

    NASA Astrophysics Data System (ADS)

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

    1993-06-01

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

  1. Imaging spectroscopic ellipsometry of MoS2.

    PubMed

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

    2016-09-28

    Micromechanically exfoliated mono- and multilayers of molybdenum disulfide (MoS2) are investigated by spectroscopic imaging ellipsometry. In combination with knife edge illumination, MoS2 flakes can be detected and classified on arbitrary flat and also transparent substrates with a lateral resolution down to 1-2 µm. The complex dielectric functions from mono- and trilayer MoS2 are presented. They are extracted from a multilayer model to fit the measured ellipsometric angles employing an anisotropic and an isotropic fit approach. We find that the energies of the critical points of the optical constants can be treated to be independent of the utilized model, whereas the magnitude of the optical constants varies with the used model. The anisotropic model suggests a maximum absorbance for a MoS2 sheet supported by sapphire of about 14% for monolayer and of 10% for trilayer MoS2. Furthermore, the lateral homogeneity of the complex dielectric function for monolayer MoS2 is investigated with a spatial resolution of 2 µm. Only minor fluctuations are observed. No evidence for strain, for a significant amount of disorder or lattice defects can be found in the wrinkle-free regions of the MoS2 monolayer from complementary µ-Raman spectroscopy measurements. We assume that the minor lateral variation in the optical constants are caused by lateral modification in the van der Waals interaction presumably caused by the preparation using micromechanical exfoliation and viscoelastic stamping. PMID:27460278

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

    NASA Astrophysics Data System (ADS)

    Lim, Wanggi; Carey, Sean J.

    2014-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-11-01

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

  4. THE FIRST SPECTROSCOPICALLY RESOLVED SUB-PARSEC ORBIT OF A SUPERMASSIVE BINARY BLACK HOLE

    SciTech Connect

    Bon, E.; Jovanovic, P.; Bon, N.; Popovic, L. C.; Marziani, P.; Shapovalova, A. I.; Borka Jovanovic, V.; Borka, D.; Sulentic, J.

    2012-11-10

    One of the most intriguing scenarios proposed to explain how active galactic nuclei are triggered involves the existence of a supermassive binary black hole (BH) system in their cores. Here, we present an observational evidence for the first spectroscopically resolved sub-parsec orbit of a such system in the core of Seyfert galaxy NGC 4151. Using a method similar to those typically used for spectroscopic binary stars, we obtained radial velocity curves of the supermassive binary system, from which we calculated orbital elements and made estimates about the masses of the components. Our analysis shows that periodic variations in the light and radial velocity curves can be accounted for by an eccentric, sub-parsec Keplerian orbit with a 15.9 year period. The flux maximum in the light curve corresponds to the approaching phase of the secondary component toward the observer. According to the obtained results, we speculate that the periodic variations in the observed H{alpha} line shape and flux are due to shock waves generated by the supersonic motion of the components through the surrounding medium. Given the large observational effort needed to reveal this spectroscopically resolved binary orbital motion, we suggest that many such systems may exist in similar objects even if they are hard to find. Detecting more of them will provide us with insight into the BH mass growth process.

  5. Review of spectroscopic parameters for upper atmospheric measurements

    NASA Technical Reports Server (NTRS)

    Smith, M. A. H. (Editor)

    1985-01-01

    The workshop included communication of spectroscopic data requirements for the planned upper atmosphere research satellite (UARS) mission, review of the status of currently available spectroscopic parameters, and recommendation of additional studies. The objectives were accomplished and resulted in a series of general and specific recommendations for laboratory spectroscopy research to meet the needs of UARS and other atmospheric remote sensing programs.

  6. 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…

  7. Obtaining the Electron Angular Momentum Coupling Spectroscopic Terms, jj

    ERIC Educational Resources Information Center

    Orofino, Hugo; Faria, Roberto B.

    2010-01-01

    A systematic procedure is developed to obtain the electron angular momentum coupling (jj) spectroscopic terms, which is based on building microstates in which each individual electron is placed in a different m[subscript j] "orbital". This approach is similar to that used to obtain the spectroscopic terms under the Russell-Saunders (LS) coupling…

  8. Fundamental spectroscopic studies of carbenes and hydrocarbon radicals

    SciTech Connect

    Gottlieb, C.A.; Thaddeus, P.

    1993-12-01

    Highly reactive carbenes and carbon-chain radicals are studied at millimeter wavelengths by observing their rotational spectra. The purpose is to provide definitive spectroscopic identification, accurate spectroscopic constants in the lowest vibrational states, and reliable structures of the key intermediates in reactions leading to aromatic hydrocarbons and soot particles in combustion.

  9. Resolving Spectral Lines with a Periscope-Type DVD Spectroscope

    ERIC Educational Resources Information Center

    Wakabayashi, Fumitaka

    2008-01-01

    A new type of DVD spectroscope, the periscope type, is described and the numerical analysis of the observed emission and absorption spectra is demonstrated. A small and thin mirror is put inside and an eighth part of a DVD is used as a grating. Using this improved DVD spectroscope, one can observe and photograph visible spectra more easily and…

  10. Spectroscopic Signature of Aging in (delta)-Pu(Ga)

    SciTech Connect

    Chung, B W; Schwartz, A J; Ebbinghaus, B B; Fluss, M J; Haslam, J J; Blobaum, K M; Tobin, J G

    2005-04-15

    Resonant Photoemission, a variant of Photoelectron Spectroscopy, has been demonstrated to have sensitivity to aging of Pu samples. The spectroscopic results are correlated with resistivity measurements and are shown to be the fingerprint of mesoscopic or nanoscale internal damage in the Pu physical structure. This means that a spectroscopic signature of internal damage due to aging in Pu has been established.

  11. 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.

  12. Spectroscopic observations of the counterpart of IGR J00291+5934

    NASA Astrophysics Data System (ADS)

    Roelofs, G.; Jonker, P. G.; Steeghs, D.; Torres, M.; Nelemans, G.

    2004-12-01

    Spectroscopic observations of the optical counterpart of the millisecond X-ray pulsar IGR J00291+5934 (Atel #352, 353) reported in an Atel by Fox & Kulkarni were obtained (Dec 5 00:29-01:15 UT) with the ISIS spectrograph mounted on the 4.2m William Herschel Telescope on La Palma. Weather conditions were not optimal with a seeing of ~2" and thin clouds. The spectra show weak evidence for broad emission line features near the HeII line at 4686 Angstrom and near the Halpha line at 6563 Angstrom.

  13. Thirty New Low-mass Spectroscopic Binaries

    NASA Astrophysics Data System (ADS)

    Shkolnik, Evgenya L.; Hebb, Leslie; Liu, Michael C.; Reid, I. Neill; Collier Cameron, Andrew

    2010-06-01

    As part of our search for young M dwarfs within 25 pc, we acquired high-resolution spectra of 185 low-mass stars compiled by the NStars project that have strong X-ray emission. By cross-correlating these spectra with radial velocity standard stars, we are sensitive to finding multi-lined spectroscopic binaries. We find a low-mass spectroscopic binary fraction of 16% consisting of 27 SB2s, 2 SB3s, and 1 SB4, increasing the number of known low-mass spectroscopic binaries (SBs) by 50% and proving that strong X-ray emission is an extremely efficient way to find M-dwarf SBs. WASP photometry of 23 of these systems revealed two low-mass eclipsing binaries (EBs), bringing the count of known M-dwarf EBs to 15. BD-22 5866, the ESB4, was fully described in 2008 by Shkolnik et al. and CCDM J04404+3127 B consists of two mid-M stars orbiting each other every 2.048 days. WASP also provided rotation periods for 12 systems, and in the cases where the synchronization time scales are short, we used P rot to determine the true orbital parameters. For those with no P rot, we used differential radial velocities to set upper limits on orbital periods and semimajor axes. More than half of our sample has near-equal-mass components (q > 0.8). This is expected since our sample is biased toward tight orbits where saturated X-ray emission is due to tidal spin-up rather than stellar youth. Increasing the samples of M-dwarf SBs and EBs is extremely valuable in setting constraints on current theories of stellar multiplicity and evolution scenarios for low-mass multiple systems. Based on observations collected at the W. M. Keck Observatory, the Canada-France-Hawaii Telescope and by the WASP Consortium. The Keck Observatory is operated as a scientific partnership between the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation. The CFHT is operated by the National Research Council of Canada

  14. THE SPECTROSCOPIC DIVERSITY OF TYPE Ia SUPERNOVAE

    SciTech Connect

    Blondin, S.; Kirshner, R. P.; Mandel, K. S.; Challis, P.; Berlind, P.; Calkins, M.; Garnavich, P. M.; Jha, S. W.; Modjaz, M.; Riess, A. G.; Schmidt, B. P.

    2012-05-15

    We present 2603 spectra of 462 nearby Type Ia supernovae (SNe Ia), including 2065 previously unpublished spectra, obtained during 1993-2008 through the Center for Astrophysics Supernova Program. There are on average eight spectra for each of the 313 SNe Ia with at least two spectra. Most of the spectra were obtained with the FAST spectrograph at the Fred Lawrence Whipple Observatory 1.5 m telescope and reduced in a consistent manner, making this data set well suited for studies of SN Ia spectroscopic diversity. Using additional data from the literature, we study the spectroscopic and photometric properties of SNe Ia as a function of spectroscopic class using the classification schemes of Branch et al. and Wang et al. The width-luminosity relation appears to be steeper for SNe Ia with broader lines, although the result is not statistically significant with the present sample. Based on the evolution of the characteristic Si II {lambda}6355 line, we propose improved methods for measuring velocity gradients, revealing a larger range than previously suspected, from {approx}0 to {approx}400 km s{sup -1} day{sup -1} considering the instantaneous velocity decline rate at maximum light. We find a weaker and less significant correlation between Si II velocity and intrinsic B - V color at maximum light than reported by Foley et al., owing to a more comprehensive treatment of uncertainties and host galaxy dust. We study the extent of nuclear burning and the presence of unburnt carbon in the outermost layers of the ejecta and report new detections of C II {lambda}6580 in 23 early-time SN Ia spectra. The frequency of C II detections is not higher in SNe Ia with bluer colors or narrower light curves, in conflict with the recent results of Thomas et al. Based on nebular spectra of 27 SNe Ia, we find no relation between the FWHM of the iron emission feature at {approx}4700 A and {Delta}m{sub 15}(B) after removing the two low-luminosity SN 1986G and SN 1991bg, suggesting that the

  15. 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

  16. Melt Structure and Properties: a Spectroscopic Perspective

    NASA Astrophysics Data System (ADS)

    Stebbins, J.

    2006-12-01

    Entropy, volume, and their P/T derivatives are at the heart of models of the thermodynamics of silicate melts and magmas. Quantitative characterization of glass structure is leading to important new insights into the links from "Microscopic to Macroscopic" that can at least guide interpretations of data and in some cases even have predictive power. A few recent examples will be discussed here. The often-large configurational components to heat capacities, thermal expansivities, and compressibilities of melts strongly indicate that structural changes with temperature and pressure are of key importance. At least some aspects of thermal increases in configurational (as opposed to vibrational) disorder are amenable to spectroscopic detection, either with in situ methods or on glasses with varying quench rates and thus varying fictive temperatures. In some systems, such changes are now clear, and can be shown to make significant contributions to properties. These include network cation coordination in systems such as borate liquids (BO4 to BO3 at higher T), and Al-Si disordering in aluminosilicates. In general, however, progress in this rich problem has only begun. It has long been suspected from thermodynamic analyses (and theoretical simulations) that configurational changes in melts play a key role in volume compression at high pressure, over and above that which can be expressed in "normal" equations of state or from those expected from bond compression and bending. Scattering and spectroscopic studies have revealed some of the important aspects of pressure-induced structural changes, but again we are just at the beginning of full understanding. For example, binary silicate glasses quenched from high-P melts clearly record some systematic increases in Si coordination, while aluminosilicates record systematic pressure and compositional (modifier cation field strength) effects on Al coordination in recovered samples with large, quenched-in density increases

  17. Super-resolution spectroscopic microscopy via photon localization.

    PubMed

    Dong, Biqin; Almassalha, Luay; Urban, Ben E; Nguyen, The-Quyen; Khuon, Satya; Chew, Teng-Leong; Backman, Vadim; Sun, Cheng; Zhang, Hao F

    2016-01-01

    Traditional photon localization microscopy analyses only the spatial distributions of photons emitted by individual molecules to reconstruct super-resolution optical images. Unfortunately, however, the highly valuable spectroscopic information from these photons have been overlooked. Here we report a spectroscopic photon localization microscopy that is capable of capturing the inherent spectroscopic signatures of photons from individual stochastic radiation events. Spectroscopic photon localization microscopy achieved higher spatial resolution than traditional photon localization microscopy through spectral discrimination to identify the photons emitted from individual molecules. As a result, we resolved two fluorescent molecules, which were 15 nm apart, with the corresponding spatial resolution of 10 nm-a four-fold improvement over photon localization microscopy. Using spectroscopic photon localization microscopy, we further demonstrated simultaneous multi-colour super-resolution imaging of microtubules and mitochondria in COS-7 cells and showed that background autofluorescence can be identified through its distinct emission spectra. PMID:27452975

  18. Super-resolution spectroscopic microscopy via photon localization

    NASA Astrophysics Data System (ADS)

    Dong, Biqin; Almassalha, Luay; Urban, Ben E.; Nguyen, The-Quyen; Khuon, Satya; Chew, Teng-Leong; Backman, Vadim; Sun, Cheng; Zhang, Hao F.

    2016-07-01

    Traditional photon localization microscopy analyses only the spatial distributions of photons emitted by individual molecules to reconstruct super-resolution optical images. Unfortunately, however, the highly valuable spectroscopic information from these photons have been overlooked. Here we report a spectroscopic photon localization microscopy that is capable of capturing the inherent spectroscopic signatures of photons from individual stochastic radiation events. Spectroscopic photon localization microscopy achieved higher spatial resolution than traditional photon localization microscopy through spectral discrimination to identify the photons emitted from individual molecules. As a result, we resolved two fluorescent molecules, which were 15 nm apart, with the corresponding spatial resolution of 10 nm--a four-fold improvement over photon localization microscopy. Using spectroscopic photon localization microscopy, we further demonstrated simultaneous multi-colour super-resolution imaging of microtubules and mitochondria in COS-7 cells and showed that background autofluorescence can be identified through its distinct emission spectra.

  19. Super-resolution spectroscopic microscopy via photon localization

    PubMed Central

    Dong, Biqin; Almassalha, Luay; Urban, Ben E.; Nguyen, The-Quyen; Khuon, Satya; Chew, Teng-Leong; Backman, Vadim; Sun, Cheng; Zhang, Hao F.

    2016-01-01

    Traditional photon localization microscopy analyses only the spatial distributions of photons emitted by individual molecules to reconstruct super-resolution optical images. Unfortunately, however, the highly valuable spectroscopic information from these photons have been overlooked. Here we report a spectroscopic photon localization microscopy that is capable of capturing the inherent spectroscopic signatures of photons from individual stochastic radiation events. Spectroscopic photon localization microscopy achieved higher spatial resolution than traditional photon localization microscopy through spectral discrimination to identify the photons emitted from individual molecules. As a result, we resolved two fluorescent molecules, which were 15 nm apart, with the corresponding spatial resolution of 10 nm—a four-fold improvement over photon localization microscopy. Using spectroscopic photon localization microscopy, we further demonstrated simultaneous multi-colour super-resolution imaging of microtubules and mitochondria in COS-7 cells and showed that background autofluorescence can be identified through its distinct emission spectra. PMID:27452975

  20. The CHARA Catalog of Orbital Elements of Spectroscopic Binary Stars

    NASA Astrophysics Data System (ADS)

    Taylor, Stuart F.; Harvin, James A.; McAlister, Harold A.

    2003-05-01

    Optical interferometry is entering a new age, with several ground-based long-baseline observatories now making observations of unprecedented resolution. Interferometers bring a new level of resolution to bear on spectroscopic binaries, enabling the full extraction of the physical parameters for the component stars with high accuracy. In the case of double-lined systems, a geometrically determined orbital parallax becomes available as well. The first step in preparing to observe spectroscopic binaries is to list them, which has not been done since the 1989 publication of the Eighth Catalogue of the Orbital Elements of Spectroscopic Binaries by Batten et al. We present a new catalog with roughly half again as many listings as the Eighth Catalogue. Angular separation predictions are made for each catalog entry. The numbers of spectroscopic binaries available for study as a function of several important observational parameters are explored, and in particular, the number of spectroscopic binaries as a function of expected separation is discussed.

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

    NASA Technical Reports Server (NTRS)

    Gehrz, Robert D.

    1997-01-01

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

  2. Interpreting Evidence.

    ERIC Educational Resources Information Center

    Munsart, Craig A.

    1993-01-01

    Presents an activity that allows students to experience the type of discovery process that paleontologists necessarily followed during the early dinosaur explorations. Students are read parts of a story taken from the "American Journal of Science" and interpret the evidence leading to the discovery of Triceratops and Stegosaurus. (PR)

  3. Structural and spectroscopic changes to natural nontronite induced by experimental impacts between 10 and 40 GPa

    NASA Astrophysics Data System (ADS)

    Friedlander, Lonia R.; Glotch, Timothy D.; Bish, David L.; Dyar, M. Darby; Sharp, Thomas G.; Sklute, Elizabeth C.; Michalski, Joseph R.

    2015-05-01

    Many phyllosilicate deposits remotely detected on Mars occur within bombarded terrains. Shock metamorphism from meteor impacts alters mineral structures, producing changed mineral spectra. Thus, impacts have likely affected the spectra of remotely sensed Martian phyllosilicates. We present spectral analysis results for a natural nontronite sample before and after laboratory-generated impacts over five peak pressures between 10 and 40 GPa. We conducted a suite of spectroscopic analyses to characterize the sample's impact-induced structural and spectral changes. Nontronite becomes increasingly disordered with increasing peak impact pressure. Every infrared spectroscopic technique used showed evidence of structural changes at shock pressures above ~25 GPa. Reflectance spectroscopy in the visible near-infrared region is primarily sensitive to the vibrations of metal-OH and interlayer H2O groups in the nontronite octahedral sheet. Midinfrared (MIR) spectroscopic techniques are sensitive to the vibrations of silicon and oxygen in the nontronite tetrahedral sheet. Because the tetrahedral and octahedral sheets of nontronite deform differently, impact-driven structural deformation may contribute to differences in phyllosilicate detection between remote sensing techniques sensitive to different parts of the nontronite structure. Observed spectroscopic changes also indicated that the sample's octahedral and tetrahedral sheets were structurally deformed but not completely dehydroxylated. This finding is an important distinction from previous studies of thermally altered phyllosilicates in which dehydroxylation follows dehydration in a stepwise progression preceding structural deformation. Impact alteration may thus complicate mineral-specific identifications based on the location of OH-group bands in remotely detected spectra. This is a key implication for Martian remote sensing arising from our results.

  4. Neutron Spectroscopic factors of 56Ni

    NASA Astrophysics Data System (ADS)

    Sanetullaev, A.; Ghosh, T. K.; Lynch, W. G.; Bazin, D.; Chajecki, Z.; Coupland, Daniel; Hodges, R.; Lee, Jenny; Henzl, V.; Henzlova, D.; Rogers, A. M.; Sun, Z. Y.; Tsang, M. B.; Winkelbauer, J.; Youngs, M.; Famiano, M.; Clement, R. R. C.; Howard, M. E.; Cizewski, J. A.; O'Malley, P. D.; Manning, B.; Charity, R. J.; Charity, L. G.; Shapira, D.; Shmitt, K. T.

    2011-10-01

    The exact shell-structure of the unstable doubly-magic nucleus 56Ni has attracted a lot of interest recently. To test if 56Ni is a good core, 56Ni(p, d)55Ni transfer reactions were measured using 56Ni beam at two different energies, 37 MeV/u and 80 MeV/u, in inverse kinematics in two experiments. The second measurement was done in order to test the sensitivity of reaction cross sections and models to reaction energies. The measurements were performed at NSCL using HiRA array and S800 spectrometer. Spectroscopic factors have been extracted for the first experiment. The results show good agreement with shell-model calculations. Preliminary results of the measurements with 80 MeV/u beam will be presented as well. This work is funded by NSF under Grant No. PHY-0606007.

  5. Spectroscopic characterization of isomerization transition states.

    PubMed

    Baraban, Joshua H; Changala, P Bryan; Mellau, Georg Ch; Stanton, John F; Merer, Anthony J; Field, Robert W

    2015-12-11

    Transition state theory is central to our understanding of chemical reaction dynamics. We demonstrate a method for extracting transition state energies and properties from a characteristic pattern found in frequency-domain spectra of isomerizing systems. This pattern-a dip in the spacings of certain barrier-proximal vibrational levels-can be understood using the concept of effective frequency, ω(eff). The method is applied to the cis-trans conformational change in the S1 state of C2H2 and the bond-breaking HCN-HNC isomerization. In both cases, the barrier heights derived from spectroscopic data agree extremely well with previous ab initio calculations. We also show that it is possible to distinguish between vibrational modes that are actively involved in the isomerization process and those that are passive bystanders. PMID:26659051

  6. SPECTROSCOPIC CONFIRMATION OF THE PISCES OVERDENSITY

    SciTech Connect

    Kollmeier, Juna A.; Shectman, Stephen; Thompson, Ian B.; Preston, George W.; Simon, Joshua D.; Crane, Jeffrey D.; Gould, Andrew; Ivezic, Zeljko; Sesar, Branimir

    2009-11-10

    We present spectroscopic confirmation of the 'Pisces Overdensity', also known as 'Structure J', a photometric overdensity of RR Lyrae stars discovered by the Sloan Digital Sky Survey at an estimated photometric distance of approx85 kpc. We measure radial velocities for eight RR Lyrae stars within Pisces. We find that five of the eight stars have heliocentric radial velocities within a narrow range of -87 km s{sup -1} < v{sub r} < -67 km s{sup -1}, suggesting that the photometric overdensity is mainly due to a physically associated system, probably a dwarf galaxy or a disrupted galaxy. Two of the remaining three stars differ from one another by only 9 km s{sup -1}, but it would be premature to identify them as a second system.

  7. Mobile Spectroscopic Instrumentation in Archaeometry Research.

    PubMed

    Vandenabeele, Peter; Donais, Mary Kate

    2016-01-01

    Mobile instrumentation is of growing importance to archaeometry research. Equipment is utilized in the field or at museums, thus avoiding transportation or risk of damage to valuable artifacts. Many spectroscopic techniques are nondestructive and micro-destructive in nature, which preserves the cultural heritage objects themselves. This review includes over 160 references pertaining to the use of mobile spectroscopy for archaeometry. Following a discussion of terminology related to mobile instrumental methods, results of a literature survey on their applications for cultural heritage objects is presented. Sections devoted to specific techniques are then provided: Raman spectroscopy, X-ray fluorescence spectrometry, Fourier transform infrared spectroscopy, laser-induced breakdown spectroscopy, and less frequently used techniques. The review closes with a discussion of combined instrumental approaches. PMID:26767631

  8. Asiago spectroscopic classification of ASASSN-16bp

    NASA Astrophysics Data System (ADS)

    Tomasella, L.; Pastorello, A.; Benetti, S.; Cappellaro, E.; Elias-Rosa, N.; Ochner, P.; Tartaglia, L.; Terreran, G.; Turatto, M.

    2016-02-01

    The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic classification of ASASSN-16bp ( = AT 2016adq), discovered by All Sky Automated Survey for SuperNovae ASAS-SN (see Shappee et al. 2014, ApJ, 788, 48 and http://www.astronomy.ohio-state.edu/~assassin/index.shtml ), in CGCG 336-041 (Atel #8666) The observation was performed with the Asiago 1.82 m Copernico Telescope (+AFOSC; range 340-820 nm; resolution 1.4 nm). Name | Discovery UT | Obs. Date UT |z | Type | Phase |Notes ASASSN-16bp | 20160209.61 | 20160211.11 |0.034194 | Ia | ~10d | (1) (1) Also known as SN2016adq in CGCG 336-041 (z=0.034194, d=145 Mpc, via NED).

  9. Terahertz broadband spectroscopic investigations of amino acid

    NASA Astrophysics Data System (ADS)

    Zhu, De-chong; Zhang, Liang-liang; Zhong, Hua; Zhang, Cun-lin

    2011-08-01

    We present an experimental terahertz (THz) spectroscopic investigation of amino acid using an air-breakdown-coherent detection (ABCD) system. The strong and ultra-broadband (0.1 to 10THz) terahertz radiations generated by two-color laser induced air plasma and measured by coherent heterodyne detection. The broadband THz reflection spectra of L-Lysine (C6H14N2O2) and L-Arginine (C6H14N2O2) are obtained. To solve the phase-retrieval problem in RTDS, the absorption signatures of the materials are extracted directly from the first derivative of the relative reflectance with respect to frequency. The absorption features of the two amino acids are characterized in the 0.5~6 THz region. It is found that both the two amino acids have an absorption peak at 1.10 THz.

  10. Selective spectroscopic methods for water analysis

    SciTech Connect

    Vaidya, B.

    1997-06-24

    This dissertation explores in large part the development of a few types of spectroscopic methods in the analysis of water. Methods for the determination of some of the most important properties of water like pH, metal ion content, and chemical oxygen demand are investigated in detail. This report contains a general introduction to the subject and the conclusions. Four chapters and an appendix have been processed separately. They are: chromogenic and fluorogenic crown ether compounds for the selective extraction and determination of Hg(II); selective determination of cadmium in water using a chromogenic crown ether in a mixed micellar solution; reduction of chloride interference in chemical oxygen demand determination without using mercury salts; structural orientation patterns for a series of anthraquinone sulfonates adsorbed at an aminophenol thiolate monolayer chemisorbed at gold; and the role of chemically modified surfaces in the construction of miniaturized analytical instrumentation.

  11. Spectroscopic Needs for Imaging Dark Energy Experiments

    DOE PAGESBeta

    Newman, Jeffrey A.; Slosar, Anze; Abate, Alexandra; Abdalla, Filipe B.; Allam, Sahar; Allen, Steven W.; Ansari, Reza; Bailey, Stephen; Barkhouse, Wayne A.; Beers, Timothy C.; et al

    2015-03-15

    Ongoing and near-future imaging-based dark energy experiments are critically dependent upon photometric redshifts (a.k.a. photo-z’s): i.e., estimates of the redshifts of objects based only on flux information obtained through broad filters. Higher-quality, lower-scatter photo-z’s will result in smaller random errors on cosmological parameters; while systematic errors in photometric redshift estimates, if not constrained, may dominate all other uncertainties from these experiments. The desired optimization and calibration is dependent upon spectroscopic measurements for secure redshift information; this is the key application of galaxy spectroscopy for imaging-based dark energy experiments. Hence, to achieve their full potential, imaging-based experiments will require large setsmore » of objects with spectroscopically-determined redshifts, for two purposes: Training: Objects with known redshift are needed to map out the relationship between object color and z (or, equivalently, to determine empirically-calibrated templates describing the rest-frame spectra of the full range of galaxies, which may be used to predict the color-z relation). The ultimate goal of training is to minimize each moment of the distribution of differences between photometric redshift estimates and the true redshifts of objects, making the relationship between them as tight as possible. The larger and more complete our “training set” of spectroscopic redshifts is, the smaller the RMS photo-z errors should be, increasing the constraining power of imaging experiments; Requirements: Spectroscopic redshift measurements for ~30,000 objects over >~15 widely-separated regions, each at least ~20 arcmin in diameter, and reaching the faintest objects used in a given experiment, will likely be necessary if photometric redshifts are to be trained and calibrated with conventional techniques. Larger, more complete samples (i.e., with longer exposure times) can improve photo-z algorithms and reduce

  12. Spectroscopic Active Galaxies and Clusters Explorer

    NASA Astrophysics Data System (ADS)

    Ferrari, L.; Bagliani, D.; Bardi, A.; Battistelli, E.; Birkinshaw, M.; Colafrancesco, S.; Conte, A.; Debernardis, P.; Degregori, S.; Depetris, M.; de Zotti, G.; Donati, A.; Franceschini, A.; Gatti, F.; Gervasi, M.; Gonzalez-Nuevo, J.; Lamagna, L.; Luzzi, G.; Maiolino, M.; Marchegiani, P.; Mariani, A.; Masi, S.; Massardi, M.; Mauskopf, P.; Nati, L.; Nati, F.; Natoli, P.; Piacentini, F.; Polenta, G.; Porciani, M.; Savini, G.; Schillaci, A.; Spinelli, S.; Tartari, A.; Tavanti, M.; Tortora, A.; Vaccari, M.; Vaccarone, R.; Zannoni, M.

    2009-12-01

    We present a concept for the payload SAGACE, the Spectroscopic Active Galaxies And Cluster Explorer, devoted to study the evolution of Universe structures using different observables, all of them in the mm/submm wavelength. The SAGACE payload is made of a passively cooled 3 m telescope, a cryogenic Fourier Transform Spectrometer (FTS) and detector arrays to be operated at 0.3 K by a 3He fridge. The detectors are Ti/Au Transition Edge Sensor (TES) bolometers with a NEP<10-17 W/Hz12. A phase-A study has been recently completed for this experiment, in the framework of the call for small missions of the Italian Space Agency.

  13. The first spectroscopic observation of germanium carbide

    NASA Astrophysics Data System (ADS)

    Ruiz, Jose I.

    Electronic spectroscopy was used to obtain gas phase spectrum of the germanium carbide molecule in emission from a corona excited supersonic expansion source. The (2) 3pi -- X 3pi electronic transition was observed around the 21250 cm-1 region. In this system, vibrational bands and the rotational lines of the O = 0, 1, and 2 components were obtained and analyzed. The equilibrium transition energy is found at 21120.3 cm-1 and the fundamental vibrational frequency for the lowest energy ground state O = 2 component is 795.3 cm -1. This is the first spectroscopic observation of germanium carbide. An unsuccessful attempt to obtain the first electronic emission spectrum of aluminum boride is also described.

  14. Laser spectroscopic measurement of helium isotope ratios.

    SciTech Connect

    Wang, L.-B.; Mueller, P.; Holt, R. J.; Lu, Z.-T.; O'Connor, T. P.; Sano, Y.; Sturchio, N.; Univ. of Illinois; Univ. of Tokyo; Univ. of Illinois at Chicago

    2003-06-13

    A sensitive laser spectroscopic method has been applied to the quantitative determination of the isotope ratio of helium at the level of {sup 3}He/{sup 4}He = 10{sup -7}--10{sup -5}. The resonant absorption of 1083 nm laser light by the metastable {sup 3}He atoms in a discharge cell was measured with the frequency modulation saturation spectroscopy technique while the abundance of {sup 4}He was measured by a direct absorption technique. The results on three different samples extracted from the atmosphere and commercial helium gas were in good agreement with values obtained with mass spectrometry. The achieved 3{sigma} detection limit of {sup 3}He in helium is 4 x 10{sup -9}. This demonstration required a 200 {mu}L STP sample of He. The sensitivity can be further improved, and the required sample size reduced, by several orders of magnitude with the addition of cavity enhanced spectroscopy.

  15. Compact fluorescence spectroscopic tool for cancer detection

    NASA Astrophysics Data System (ADS)

    Nadeau, Valerie; Hamdan, Khaled; Hewett, Jacqueline; Makaryceva, Juljia; Tait, Iain; Cuschieri, Alfred; Padgett, Miles J.

    2002-05-01

    We describe a compact fluorescence spectroscopic tool for in vivo point monitoring of aminolaevulinic acid (ALA)-induced protoporphyrin IX (PpIX) fluorescence and autofluorescence, as a non-invasive method of differentiating normal and cancerous tissue. This instrument incorporates a 405nm diode laser with a shutter to prevent exposure of tissue to harmful light doses and reduce photobleaching, a bifurcated optical fibre to allow illumination of tissue and collection of fluorescence with a single fibre, a compact grating spectrometer for collection of spectra and a PC for system control. We present spectra obtained using this system both during routine gastro-intestinal (GI) endoscopy for cancer detection and during photodynamic therapy (PDT) of anal intraepithelial neoplasia (AIN) for monitoring of treatment progress. These results illustrate the potential of the system to be used for fluorescence monitoring in a variety of clinical applications.

  16. Spectroscopic diagnostics of high temperature plasmas

    SciTech Connect

    Moos, W.

    1990-01-01

    A three-year research program for the development of novel XUV spectroscopic diagnostics for magnetically confined fusion plasmas is proposed. The new diagnostic system will use layered synthetic microstructures (LSM) coated, flat and curved surfaces as dispersive elements in spectrometers and narrow band XUV filter arrays. In the framework of the proposed program we will develop impurity monitors for poloidal and toroidal resolved measurements on PBX-M and Alcator C-Mod, imaging XUV spectrometers for electron density and temperature fluctuation measurements in the hot plasma core in TEXT or other similar tokamaks and plasma imaging devices in soft x-ray light for impurity behavior studies during RF heating on Phaedrus T and carbon pellet ablation in Alcator C-Mod. Recent results related to use of multilayer in XUV plasma spectroscopy are presented. We also discuss the latest results reviewed to q{sub o} and local poloidal field measurements using Zeeman polarimetry.

  17. Volume-limited Spectroscopic Binary Statistics

    NASA Astrophysics Data System (ADS)

    Fisher, J.; Schröder, K.-P.; Smith, R. C.

    2004-08-01

    We derive the period (P), primary mass (m[1]) and mass ratio (q) distributions of the local population of field binaries by studying a volume-limited sample of 371 spectroscopic binaries (SBs) in the solar neighbourhood d ≤ 100 pc and M[v] ≤ 4. The sample was collated using the Batten catalogue, data of R.F. Griffin and the HIPPARCOS catalogue. The SB2s are used to calibrate a Monte-Carlo approach to the q distribution of SB1s, giving a total q distribution confirming a peak at q ≈ 1. Completenesses and parameter-specific biases are also assessed. A substantial number of systems with intermediate to long periods are found which may have significant consequences for the mass-distribution of WDs.

  18. Spectroscopic detection of nitrogen concentrations in sagebrush

    SciTech Connect

    J. J. MITCHELL; N. F. GLENN; T.T. SANKEY; D. R. DERRYBERRY; R. C. HRUSKA; M. O. Anderson

    2012-07-01

    The ability to estimate foliar nitrogen (N) in semi-arid landscapes can yield information on nutritional status and improve our limited understanding of controls on canopy photosynthesis. We examined two spectroscopic methods for estimating sagebrush dried leaf and live shrub N content: first derivative reflectance (FDR) and continuum removal. Both methods used partial least squares (PLS) regression to select wavebands most significantly correlated with N concentrations in the samples. Sagebrush dried leaf spectra produced PLS models (R2 = 0.76–0.86) that could predict N concentrations within the dataset more accurately than PLS models generated from live shrub spectra (R2 = 0.41–0.63). Inclusion of wavelengths associated with leaf water in the FDR transformations appeared to improve regression results. Findings are encouraging and warrant further exploration into sagebrush reflectance spectra to characterize N concentrations.

  19. Spectroscopic characterization of isomerization transition states

    NASA Astrophysics Data System (ADS)

    Baraban, Joshua H.; Changala, P. Bryan; Mellau, Georg Ch.; Stanton, John F.; Merer, Anthony J.; Field, Robert W.

    2015-12-01

    Transition state theory is central to our understanding of chemical reaction dynamics. We demonstrate a method for extracting transition state energies and properties from a characteristic pattern found in frequency-domain spectra of isomerizing systems. This pattern—a dip in the spacings of certain barrier-proximal vibrational levels—can be understood using the concept of effective frequency, ωeff. The method is applied to the cis-trans conformational change in the S1 state of C2H2 and the bond-breaking HCN-HNC isomerization. In both cases, the barrier heights derived from spectroscopic data agree extremely well with previous ab initio calculations. We also show that it is possible to distinguish between vibrational modes that are actively involved in the isomerization process and those that are passive bystanders.

  20. Fourier transform infrared spectroscopic study of truffles

    NASA Astrophysics Data System (ADS)

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

    2006-01-01

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

  1. Spectroscopic characterization of genetically modified flax fibers

    NASA Astrophysics Data System (ADS)

    Dymińska, L.; Gągor, A.; Hanuza, J.; Kulma, A.; Preisner, M.; Żuk, M.; Szatkowski, M.; Szopa, J.

    2014-09-01

    The principal goal of this paper is an analysis of flax fiber composition. Natural and genetically modified flax fibers derived from transgenic flax have been analyzed. Development of genetic engineering enables to improve the quality of fibers. Three transgenic plant lines with different modifications were generated based on fibrous flax plants as the origin. These are plants with: silenced cinnamyl alcohol dehydrogenase (CAD) gene; overexpression of polygalacturonase (PGI); and expression of three genes construct containing β-ketothiolase (phb A), acetoacetyl-CoA reductase (phb B), and poly-3-hydroxybutyric acid synthase (phb C). Flax fibers have been studied by FT-IR spectroscopy. The integral intensities of the IR bands have been used for estimation of the chemical content of the normal and transgenic flaxes. The spectroscopic data were compared to those obtained from chemical analysis of flax fibers. X-ray studies have been used to characterize the changes of the crystalline structure of the flax cellulose fibers.

  2. Search for planets by spectroscopic methods

    NASA Technical Reports Server (NTRS)

    Serkowski, K.

    1980-01-01

    Spectroscopic means of detecting the motion of a star around a star-planet barycenter are considered. The precision of such an observation, which requires a radial velocity error of not more than 5 m/sec, is discussed in relation to the spectral resolutions of the detectors utilized. The University of Arizona radial velocity spectrometer is then presented, with particular attention given to the location of the absorption cell in a beam of light from an incandescent bulb, high-accuracy wavelength calibration involving the use of a Fabry-Perot interferometer in front of an echelle spectrograph, and future plans for the use of light reflected from a Fabry-Perot etalon to improve transmittance. On the basis of these techniques, it is expected that radial velocities with accuracies sufficient for the detection of extrasolar planets will be obtained.

  3. Spectroscopic behavior of bioconjugated quantum dots

    NASA Astrophysics Data System (ADS)

    Chornokur, G.; Ostapenko, S.; Emirov, Yu; Korsunska, N. E.; Sellers, T.; Phelan, C.

    2008-07-01

    We report on a short-wavelength, 'blue' spectral shift of the photoluminescence (PL) spectrum in CdSeTe/ZnS core/shell quantum dots (QDs) caused by bioconjugation with several monoclonal cancer-related antibodies (ABs). Scanning PL spectroscopy was performed on samples dried on solid substrates at various temperatures. The influence of the AB chemical origin on the PL spectral shift was observed. The QD-AB conjugation reaction was confirmed using the agarose gel electrophoresis technique. The spectral shift was strongly increased and the process facilitated when the samples were dried above room temperature. The PL spectroscopic mapping revealed a profile of the PL spectral shift across the dried QD-AB spot. A mechanism of the blue shift is attributed to changes in the QD electronic energy levels caused by a local stress applied to the bioconjugated QD.

  4. Parallel detecting, spectroscopic ellipsometers/polarimeters

    DOEpatents

    Furtak, Thomas E.

    2002-01-01

    The parallel detecting spectroscopic ellipsometer/polarimeter sensor has no moving parts and operates in real-time for in-situ monitoring of the thin film surface properties of a sample within a processing chamber. It includes a multi-spectral source of radiation for producing a collimated beam of radiation directed towards the surface of the sample through a polarizer. The thus polarized collimated beam of radiation impacts and is reflected from the surface of the sample, thereby changing its polarization state due to the intrinsic material properties of the sample. The light reflected from the sample is separated into four separate polarized filtered beams, each having individual spectral intensities. Data about said four individual spectral intensities is collected within the processing chamber, and is transmitted into one or more spectrometers. The data of all four individual spectral intensities is then analyzed using transformation algorithms, in real-time.

  5. Spectroscopic Needs for Imaging Dark Energy Experiments

    SciTech Connect

    Newman, Jeffrey A.; Slosar, Anze; Abate, Alexandra; Abdalla, Filipe B.; Allam, Sahar; Allen, Steven W.; Ansari, Reza; Bailey, Stephen; Barkhouse, Wayne A.; Beers, Timothy C.; Blanton, Michael R.; Brodwin, Mark; Brownstein, Joel R.; Brunner, Robert J.; Carrasco-Kind, Matias; Cervantes-Cota, Jorge; Chisari, Nora Elisa; Colless, Matthew; Comparat, Johan; Coupon, Jean; Cheu, Elliott; Cunha, Carlos E.; de la Macorra, Alex; Dell’Antonio, Ian P.; Frye, Brenda L.; Gawiser, Eric J.; Gehrels, Neil; Grady, Kevin; Hagen, Alex; Hall, Patrick B.; Hearin, Andrew P.; Hildebrandt, Hendrik; Hirata, Christopher M.; Ho, Shirley; Honscheid, Klaus; Huterer, Dragan; Ivezic, Zeljko; Kneib, Jean -Paul; Kruk, Jeffrey W.; Lahav, Ofer; Mandelbaum, Rachel; Marshall, Jennifer L.; Matthews, Daniel J.; Menard, Brice; Miquel, Ramon; Moniez, Marc; Moos, H. W.; Moustakas, John; Papovich, Casey; Peacock, John A.; Park, Changbom; Rhodes, Jason; Sadeh, Iftach; Schmidt, Samuel J.; Stern, Daniel K.; Tyson, J. Anthony; von der Linden, Anja; Wechsler, Risa H.; Wood-Vasey, W. M.; Zentner, A.

    2015-03-15

    Ongoing and near-future imaging-based dark energy experiments are critically dependent upon photometric redshifts (a.k.a. photo-z’s): i.e., estimates of the redshifts of objects based only on flux information obtained through broad filters. Higher-quality, lower-scatter photo-z’s will result in smaller random errors on cosmological parameters; while systematic errors in photometric redshift estimates, if not constrained, may dominate all other uncertainties from these experiments. The desired optimization and calibration is dependent upon spectroscopic measurements for secure redshift information; this is the key application of galaxy spectroscopy for imaging-based dark energy experiments. Hence, to achieve their full potential, imaging-based experiments will require large sets of objects with spectroscopically-determined redshifts, for two purposes: Training: Objects with known redshift are needed to map out the relationship between object color and z (or, equivalently, to determine empirically-calibrated templates describing the rest-frame spectra of the full range of galaxies, which may be used to predict the color-z relation). The ultimate goal of training is to minimize each moment of the distribution of differences between photometric redshift estimates and the true redshifts of objects, making the relationship between them as tight as possible. The larger and more complete our “training set” of spectroscopic redshifts is, the smaller the RMS photo-z errors should be, increasing the constraining power of imaging experiments; Requirements: Spectroscopic redshift measurements for ~30,000 objects over >~15 widely-separated regions, each at least ~20 arcmin in diameter, and reaching the faintest objects used in a given experiment, will likely be necessary if photometric redshifts are to be trained and calibrated with conventional techniques. Larger, more complete samples (i.e., with longer exposure times) can improve photo-z algorithms and reduce scatter

  6. Highlights of the Brazilian Solar Spectroscope

    NASA Astrophysics Data System (ADS)

    Sawant, H. S.; Cecatto, J. R.; Mészárosová, H.; Faria, C.; Fernandes, F. C. R.; Karlický, M.; de Andrade, M. C.

    2009-07-01

    The digital, decimetric (950-2500 MHz) Brazilian Solar Spectroscope (BSS, Sawant, H.S., Subramanian, K.R., Faria, C., et al. Brazilian Solar Spectroscope (BSS). Solar Phys. 200, 167-176, 2001) with high time (10-1000 ms) and frequency (1-10 MHz) resolution is in regular operation since April, 1998, at the National Space Research Institute (INPE) at São José dos Campos, Brazil. The BSS has now been upgraded with a new digital data acquisition and data processing system. The new version of the BSS has improved the observational possibilities with the capability to record up to 200 frequency channels available in the selectable frequency range 950-2500 MHz. The GPS receiver permits the acquisition of data with time accuracy in the order of 0.1 ms. The software system of the BSS is composed by two distinct modules: the first, data acquisition system provides a flexible Graphical User Interface (GUI) that allows one to choose the observational parameters. The second module is the real time visualization system that permits real time visualization of the observed dynamic spectrum and additionally allows procedures for visualization and preliminary analysis of the recorded solar spectra. Using the new visualization system, we have realized two new types of dm-radio fine structures: narrow band type III bursts with positive as well as negative group frequency drift and dots emissions arranged in zebra-like and fiber-like chains. Furthermore, we have found flare generated fast wave trains according to their tadpole signature in wavelet power spectra for a decimetric type IV radio event (June 6, 2000 flare).

  7. Spectroscopic data for thermal infrared remote sensing

    NASA Technical Reports Server (NTRS)

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

    1995-01-01

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

  8. Are your Spectroscopic Data being used?

    NASA Astrophysics Data System (ADS)

    Gordon, Iouli E.; Rothman, Laurence S.; Wilzewski, Jonas S.

    2014-06-01

    Spectroscopy is an established and indispensable tool in science, industry, agriculture, medicine, surveillance, etc.. The potential user of spectral data which is not available in HITRAN1 or other databases, searches the spectroscopy publications. After finding the desired publication, the user very often encounters the following problems: 1) They cannot find the data described in the paper. There can be many reasons for this: nothing is provided in the paper itself or supplementary material; the authors are not responding to any requests; the web links provided in the paper have long been broken, etc.. 2) The data is presented in a reduced form, for instance through the fitted spectroscopic constants. While this is a long-standing practice among spectroscopists, there are numerous serious problems with this practice, such as users getting different energy and intensity values because of different representations of the solution to the Hamiltonian, or even just despairing of trying to generate usable line lists from the published constants. Properly providing the data benefits not only users but also the authors of the spectroscopic research. We will show that this increases citations to the spectroscopy papers and visibility of the research groups. We will also address the quite common issue when researchers obtain the data, but do not feel that they have time, interest or resources to write an article describing it. There are modern tools that allow one to make these data available to potential users and still get credit for it. However, this is a worst case scenario recommendation, i.e., publishing the data in a peer-reviewed journal is still the preferred way.

  9. 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

  10. Spectroscopic detection of chemotherapeutics and antioxidants

    NASA Astrophysics Data System (ADS)

    Latka, Ines; Grüner, Roman; Matthäus, Christian; Dietzek, Benjamin; Werncke, W.; Lademann, Jürgen; Popp, Jürgen

    2012-06-01

    The hand-foot-syndrome presents a severe dermal side-effect of chemotherapeutic cancer treatment. The cause of this side-effect is the elimination of systemically administered chemotherapeutics with the sweat. Transported to the skin surface, the drugs subsequently penetrate into the skin in the manner of topically applied substances. Upon accumulation of the chemotherapeutics in the skin the drugs destroy cells and tissue - in the same way as they are supposed to act in cancer cells. Aiming at the development of strategies to illuminate the molecular mechanism underlying the handfoot- syndrome (and, in a second step, strategies to prevent this severe side-effect), it might be important to evaluate the concentration and distribution of chemotherapeutics and antioxidants in the human skin. The latter can be estimated by the carotenoid concentration, as carotenoids serve as marker substances for the dermal antioxidative status.Following the objectives outlined above, this contribution presents a spectroscopic study aiming at the detection and quantification of carotenoids and selected chemotherapeutics in human skin. To this end, spontaneous Raman scattering and coherent anti-Stokes Raman scattering (CARS) microspectroscopy are combined with two-photon excited fluorescence. While the latter technique is Please verify that (1) all pages are present, (2) all figures are correct, (3) all fonts and special characters are correct, and (4) all text and figures fit within the red margin lines shown on this review document. Complete formatting information is available at http://SPIE.org/manuscripts Return to your MySPIE To Do List at http://myspie.org and approve or disapprove this submission. Your manuscript will not be published without this approval.restricted to the detection of fluorescent chemotherapeutics, e.g., doxorubicin, the vibrational spectroscopic techniques can - in principle - be applied to any type of analyte molecules. Furthermore, we will present the

  11. Raman spectroscopic investigations of hydrothermal solutions

    SciTech Connect

    Yang, M.M.

    1988-01-01

    There is still very little information about the stoichiometries, structures and stabilities of metal complexes at high temperatures and pressures. Raman spectroscopy is ideally suited to probe and study concentrated electrolyte solutions at the molecular level. This thesis includes the design and construction of a Raman cell operable up to 300C and 15MPa. In order to obtain quantitative thermodynamic information from Raman spectroscopic measurements, a chemically inert internal standard must be used. Perchlorate is commonly used for this purpose at low temperatures, but it may be unstable at high temperatures and its explosive properties make it undesirable. A new preferred internal standard; trifluoromethanesulfonic acid is introduced and its spectra p to 300C discussed. The use of this compound as a high temperature internal standard enabled stepwise stability constants of zinc-bromo complexes to be determined. Although bromide is not an important ligand in geologic systems, its chemical similarity to chloride can provide insights into the study of zinc-chloro species which do not have very informative Raman spectra. The importance of organic ligands in geologic settings such as the Mississippi-Valley Type Pb-Zn sulfide deposits is now being realized. Chapter four presents the first high temperature spectroscopic measurements of lead and zinc acetate aqueous solutions. Not only do these studies verify the stability of lead and zinc acetate complexes up to 250 C but they also show that the type of complex formed is a function of pH, metal-ligand ratio and temperature, thus having important implications for zoning of Pb-Zn sulfide deposits.

  12. Ultrasonic separation of a suspension for in situ spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Nogo, Kosuke; Qi, Wei; Mori, Keita; Ogawa, Satoshi; Inohara, Daichi; Hosono, Satsuki; Kawashima, Natsumi; Nishiyama, Akira; Wada, Kenji; Ishimaru, Ichiro

    2016-04-01

    Application of spectroscopic techniques to suspensions is difficult because optical scattering caused by solid particles reduces the accuracy. At the extreme, dense suspensions like blood cannot be analyzed by spectroscopic techniques. In the present study, an ultrasonic standing wave was used to agglomerate fluorescent particles in an aqueous ethanol suspension at the nodes of the standing wave. Relatively clear liquid regions, which contained few particles that could cause optical scattering, appeared around the anti-nodes and were used for spectroscopic imaging. This produced a spectrum that was similar to that of clear aqueous ethanol without any fluorescent particles.

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

    NASA Astrophysics Data System (ADS)

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

    2002-03-01

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

  14. Silicon immersion gratings and their spectroscopic applications

    NASA Astrophysics Data System (ADS)

    Ge, Jian; Zhao, Bo; Powell, Scott; Fletcher, Adam; Wan, Xiaoke; Chang, Liang; Jakeman, Hali; Koukis, Dimitrios; Tanner, David B.; Ebbets, Dennis; Weinberg, Jonathan; Lipscy, Sarah; Nyquist, Rich; Bally, John

    2012-09-01

    Silicon immersion gratings (SIGs) offer several advantages over the commercial echelle gratings for high resolution infrared (IR) spectroscopy: 3.4 times the gain in dispersion or ~10 times the reduction in the instrument volume, a multiplex gain for a large continuous wavelength coverage and low cost. We present results from lab characterization of a large format SIG of astronomical observation quality. This SIG, with a 54.74 degree blaze angle (R1.4), 16.1 l/mm groove density, and 50x86 mm2 grating area, was developed for high resolution IR spectroscopy (R~70,000) in the near IR (1.1-2.5 μm). Its entrance surface was coated with a single layer of silicon nitride antireflection (AR) coating and its grating surface was coated with a thin layer of gold to increase its throughput at 1.1-2.5 μm. The lab measurements have shown that the SIG delivered a spectral resolution of R=114,000 at 1.55 μm with a lab testing spectrograph with a 20 mm diameter pupil. The measured peak grating efficiency is 72% at 1.55 μm, which is consistent with the measurements in the optical wavelengths from the grating surface at the air side. This SIG is being implemented in a new generation cryogenic IR spectrograph, called the Florida IR Silicon immersion grating spectrometer (FIRST), to offer broad-band high resolution IR spectroscopy with R=72,000 at 1.4-1.8 um under a typical seeing condition in a single exposure with a 2kx2k H2RG IR array at the robotically controlled Tennessee State University 2-meter Automatic Spectroscopic Telescope (AST) at Fairborn Observatory in Arizona. FIRST is designed to provide high precision Doppler measurements (~4 m/s) for the identification and characterization of extrasolar planets, especially rocky planets in habitable zones, orbiting low mass M dwarf stars. It will also be used for other high resolution IR spectroscopic observations of such as young stars, brown dwarfs, magnetic fields, star formation and interstellar mediums. An optimally designed

  15. Two Remarkable Spectroscopic Categories of Young O Stars from the VLT-FLAMES Tarantula Survey

    NASA Astrophysics Data System (ADS)

    Walborn, N. R.; Sana, H.; Taylor, W. D.; Simón-Díaz, S.; Evans, C. J.

    2012-12-01

    The spectral and spatial characteristics of two special categories of O stars found in the VFTS dataset are presented. One of them comprises very rapid rotators, including several more extreme than any previously known. These objects are distributed around the peripheries of the main 30 Doradus clusters, suggesting a runaway nature for which their radial velocities already provide preliminary supporting evidence. The other category consists of a large number of Vz stars, previously hypothesized on spectroscopic grounds to be on or very near the ZAMS. Their distribution is the inverse of that of the rapid rotators: the Vz are strongly concentrated to the ionizing clusters, plus a newly recognized band of recent and current star formation to the north, which provides strong circumstantial evidence for their extreme youth.

  16. Iridium Ziegler-Type Hydrogenation Catalysts Made from [(1,5-COD)Ir( -O2C8H15)]2 and AlEt3: Spectroscopic and Kinetic Evidence for the Irn Species Present and for Nanoparticles as the Fastest Catalyst

    SciTech Connect

    Alley, W.; Hamdemir, I; Wang, Q; Frenkel, A; Li, L; Yang, J; Menard, L; Nuzzo, R; Ozkar, S; Finke, R

    2010-01-01

    considering the similar, but not identical results from the different analytical methods; furthermore, (ii) the mean Ir{sub n} species are practically the same regardless of the Al/Ir ratio employed, suggesting that the observed changes in catalytic activity at different Al/Ir ratios are primarily the result of changes in the form or function of the Al-derived component (and not due to significant AlEt{sub 3}-induced changes in initial Ir{sub n} nuclearity). However (iii), during hydrogenation, a shift in the population of Ir species toward roughly 1.0-1.6 nm, fcc Ir(0){sub {approx}40-150}, Ziegler nanoclusters occurs with, significantly, (iv) a concomitant increase in catalytic activity. Importantly, and although catalysis by discrete subnanometer Ir species is not ruled out by this study, (v) the increases in activity with increased nanocluster size, plus Hg(0) poisoning studies, provide the best evidence to date that the approximately 1.0-1.6 nm, fcc Ir(0){sub {approx}40-150}, heterogeneous Ziegler nanoclusters are the fastest catalysts in this industrially related catalytic hydrogenation system (and in the simplest, Ockham's Razor interpretation of the data). In addition, (vi) Ziegler nanoclusters are confirmed to be an unusual, hydrocarbon-soluble, highly coordinatively unsaturated, Lewis-acid containing, and highly catalytically active type of nanocluster for use in other catalytic applications and other areas.

  17. Apparatus and method for spectroscopic analysis of scattering media

    DOEpatents

    Strobl, Karlheinz; Bigio, Irving J.; Loree, Thomas R.

    1994-01-01

    Apparatus and method for spectroscopic analysis of scattering media. Subtle differences in materials have been found to be detectable from plots of intensity as a function of wavelength of collected emitted and scattered light versus wavelength of excitation light.

  18. FORS2 spectroscopic classification of DECam SN candidates

    NASA Astrophysics Data System (ADS)

    Anderson, J.; Bufano, F.; Forster, F.; Hamuy, M.; Gonzalez-Gaitan, S.; Galbany, L.; Kuncarayakti, Hanin; Pignata, G.

    2014-03-01

    We report the spectroscopic classification of 3 SNe discovered by the DECam high cadence transient search (see ATELs #5956, #5949), using FORS2 on the UT1 telescope at Cerro Paranal (through DDT proposal 292.D-042). ...

  19. Asiago spectroscopic classification of PSN J13480490+6149153

    NASA Astrophysics Data System (ADS)

    Terreran, G.; Turatto, M.; Benetti, S.; Cappellaro, E.; Elias-Rosa, N.; Ochner, P.; Pastorello, A.; Tartaglia, L.; Tomasella, L.

    2015-08-01

    The Asiago Transient Classification Program (Tomasella et al. 2014, AN, 335, 841) reports the spectroscopic classification of PSN J13480490+6149153 in the galaxy UGC 8734 discovered by E. Briggs, D. Post, Jack Newton, and Tim Puckett.

  20. Submillimeter-Wave Spectroscopic Instruments: Multi-functional Atmospheric Characterization

    NASA Astrophysics Data System (ADS)

    Mehdi, I.; Gulkis, S.; Allen, M. A.; Schlecht, E.; Chattopadhyay, G.

    2012-10-01

    Submillimeter-wave spectroscopic instruments provide unique capability in terms of providing quantitative measurements of trace gas compositions in planetary atmospheres. Such instruments also provide temporal and wind velocity mapping capability.

  1. Spectroscopic Classification of PS16ccj with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Pan, Y.-C.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-05-01

    We report the classification of PS16ccj from spectroscopic observation with KOSMOS on the Mayall telescope. The observation was made on 2016 May 05 UT. We classify PS16ccj as a SN Ia near maximum light.

  2. Spectroscopic Classifications of AT2016esx with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Kilpatrick, C. D.; Siebert, M. R.; Coulter, D. A.; Foley, R. J.; Pan, Y.-C.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-08-01

    We report a classification of ASASSN-16io = AT2016esx from spectroscopic observations with KOSMOS on the KPNO Mayall 4-m telescope. Targets were supplied by the All-Sky Automated Survey for Supernovae (ASAS-SN).

  3. Spectroscopic Classification of the Type Ia Supernova LSQ14asu

    NASA Astrophysics Data System (ADS)

    Walker, E. S.; Hadjiyska, E.; Rabinowitz, D.; Baltay, C.; Ellman, N.; McKinnon, R.; Feindt, U.; Nugent, P.; Phillips, Mark; Morrell, Nidia; Hsiao, Eric

    2014-04-01

    We report the spectroscopic classification of a La Silla-QUEST (LSQ) supernova (see Baltay et al. 2013, PASP, 125, 683) taken using WFCCD on the 2.5-m du Pont Telescope as part of the Carnegie Supernova Survey. ...

  4. Spectroscopic classification of three supernovae with the Nordic Optical Telescope

    NASA Astrophysics Data System (ADS)

    Mattila, S.; Elias-Rosa, N.; Lundqvist, P.; Stritzinger, M.; Kuncarayakti, H.; Harmanen, J.; Pastorello, A.; Benetti, S.; Cappellaro, E.; Blagorodnova, N.; Davis, S.; Dong, S.; Fraser, M.; Gall, C.; Harrison, D.; Hodgkin, S.; Hsiao, E. Y.; Jonker, P.; Kangas, T.; Kankare, E.; Kostrzewa-Rutkowska, Z.; Nielsen, M.; Ochner, Paolo; Prieto, J. L.; Reynolds, T.; Romero-Canizales, C.; Taddia, F.; Tartaglia, L.; Terreran, G.; Tomasella, L.; Wyrzykowski, L.

    2016-04-01

    The NOT Unbiased Transient Survey (NUTS) collaboration reports the spectroscopic classifications of supernovae Gaia16akk, ASASSN-16ek, and ASASSN-16eq in an anonymous host galaxy, GALEXASC J072024.60+325058.8, and UGC 11898 respectively.

  5. A spectroscopic refractometer based on plasmonic interferometry

    NASA Astrophysics Data System (ADS)

    Feng, Jing; Pacifici, Domenico

    2016-02-01

    We describe the design, fabrication, and testing of a spectroscopic refractometer that employs plasmonic interferometry to measure the optical dielectric functions of materials in the visible range. The proposed device, dubbed a plasmonic refractometer, consists of an array of slit-groove plasmonic interferometers etched in a ˜300 nm-thick metal film (silver or gold) with arm lengths varying in steps of 25 nm up to ˜8 μm. The nano-groove in each interferometer is able to generate propagating surface plasmon polaritons efficiently in a broad wavelength range, without requiring prism- or grating-coupling configurations. An integrated microfluidic channel ensures uniform delivery of dielectric materials in liquid phase. Spectrally resolved plasmonic interferograms are generated by measuring light transmission spectra through the slit of each slit-groove plasmonic interferometer and plotting the normalized intensity as a function of arm length (0.26-8.16 μm) and incident wavelength (400-800 nm) for various combinations of metal/dielectric materials. Fits of the plasmonic interferograms with a surface plasmon interference model allow determination of the refractive index dispersion of a broad class of dielectric materials, over a wide range of wavelengths and dielectric constants. As proof of concept, we extract and report the dielectric functions of representative materials, such as silver, gold, water, methanol, and ethanol.

  6. Spectroscopic Subsystems in Nearby Wide Binaries

    NASA Astrophysics Data System (ADS)

    Tokovinin, Andrei

    2015-12-01

    Radial velocity (RV) monitoring of solar-type visual binaries has been conducted at the CTIO/SMARTS 1.5 m telescope to study short-period systems. The data reduction is described, and mean and individual RVs of 163 observed objects are given. New spectroscopic binaries are discovered or suspected in 17 objects, and for some of them the orbital periods could be determined. Subsystems are efficiently detected even in a single observation by double lines and/or by the RV difference between the components of visual binaries. The potential of this detection technique is quantified by simulation and used for statistical assessment of 96 wide binaries within 67 pc. It is found that 43 binaries contain at least one subsystem, and the occurrence of subsystems is equally probable in either primary or secondary components. The frequency of subsystems and their periods matches the simple prescription proposed by the author. The remaining 53 simple wide binaries with a median projected separation of 1300 AU have an RV difference distribution between their components that is not compatible with the thermal eccentricity distribution f (e) = 2e but rather matches the uniform eccentricity distribution.

  7. Highlights of the Brazilian Solar Spectroscope (bss)

    NASA Astrophysics Data System (ADS)

    Sawant, Hanumant; Cecatto, José; Meszarosova, Hana; Faria, Claudio; Fernandes, Francisco; Karlicky, Marian; Andrade, Maria

    The digital, decimetric (1000-2500 MHz) Brazilian Solar Spectroscope (BSS) with high time (10- 1000 ms) and frequency (1-10 MHz) resolution is in regular operation since April, 1998, at the National Space Research Institute (INPE) at Sao Jose dos Campos, Brazil. The BSS has now been upgraded with a new digital data acquisition and data processing system. The new version of the BSS has a 14 bit A/D unit which permits improved combination of the observational parameters with a capability to record up to 200 frequency channels available in a selectable frequency range of 1000-2500 MHz. It permits data acquisition up to 5 ms time resolution with a limited number of frequency channels. The software system of the BSS is composed by two distinct modules: The first, data acquisition system provides a flexible Graphical User Interface (GUI) that allows one to choose a number of observational parameters. The second module is the real time visualization system that permits real time visualization of the observed dynamic spectrum and additionally has procedures for visualization and preliminary analysis of the recorded solar spectra. Using the new visualization system, we have realized two new types of dm-radio fine structures: narrow band type III bursts with positive/negative group frequency drift and dots-emissions arranged in zebras and fibers.

  8. New infrared spectroscopic database for bromine nitrate

    NASA Astrophysics Data System (ADS)

    Wagner, Georg; Birk, Manfred

    2016-08-01

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

  9. Spectroscopic Orbits for Kepler FOV Eclipsing Binaries

    NASA Astrophysics Data System (ADS)

    Matson, Rachel A.; Gies, Douglas R.; Williams, Stephen J.; Guo, Zhao

    2013-02-01

    We are currently involved in a four year program of precise eclipsing binary photometry with the NASA Kepler Observatory. Our goal is to search for variations in minimum light timing for intermediate mass eclipsing binaries. Such periodic variations will reveal the reflex motion caused by any distant, low mass object that orbits the close binary. it Kepler's unprecedented accuracy and continuous observations provide a unique opportunity to detect the low mass companions that are predicted to result from the angular momentum of the natal cloud. The goal of this proposal is to obtain blue spectra of short period (0.9-6d) eclipsing binaries, derive radial velocities, and produce a double-lined spectroscopic orbit (as well as estimates of the stellar effective temperatures, gravities, and metallicities). Combined with the it Kepler light curve, we will determine very accurate masses and radii for the members of the close binary, which will yield the mass-inclination product M_3 sin i for any companions detected by light travel time or other effects. An extended sample of eclipsing binaries with longer periods (up to 50d) is now being investigated to test whether the presence of a tertiary companion declines with increasing period. We propose to obtain a single spectrum at quadrature for the brightest 48 stars in this expanded sample to characterize the effective temperatures and total mass contained in these systems.

  10. Galaxy Evolution Spectroscopic Explorer: Scientific Rationale

    NASA Technical Reports Server (NTRS)

    Heap, Sara; Ninkov, Zoran; Robberto, Massimo; Hull, Tony; Purves, Lloyd

    2016-01-01

    GESE is a mission concept consisting of a 1.5-m space telescope and UV multi-object slit spectrograph designed to help understand galaxy evolution in a critical era in the history of the universe, where the rate of star-formation stopped increasing and started to decline. To isolate and identify the various processes driving the evolution of these galaxies, GESE will obtain rest-frame far-UV spectra of 100,000 galaxies at redshifts, z approximately 1-2. To obtain such a large number of spectra, multiplexing over a wide field is an absolute necessity. A slit device such as a digital micro-mirror device (DMD) or a micro-shutter array (MSA) enables spectroscopy of a hundred or more sources in a single exposure while eliminating overlapping spectra of other sources and blocking unwanted background like zodiacal light. We find that a 1.5-m space telescope with a MSA slit device combined with a custom orbit enabling long, uninterrupted exposures (approximately 10 hr) are optimal for this spectroscopic survey. GESE will not be operating alone in this endeavor. Together with x-ray telescopes and optical/near-IR telescopes like Subaru/Prime Focus Spectrograph, GESE will detect "feedback" from young massive stars and massive black holes (AGN's), and other drivers of galaxy evolution.

  11. Surface spectroscopic characterization of titanium implant materials

    NASA Astrophysics Data System (ADS)

    Lausmaa, Jukka; Kasemo, Bengt; Mattsson, Håkan

    1990-04-01

    Titanium is one of the most commonly used biomaterials for dental and orthopedic applications. Its excellent tissue compatibility is mainly due to the properties of the stable oxide layer which is present on the surface. This paper reports a detailed spectroscopic characterization of the surface composition of non-alloyed Ti implant materials, prepared according to procedures commonly used in clinical practice (machining, ultrasonic cleaning and sterilization). The main methods of characterization are XPS and AES, and complementary information is obtained by SIMS, EDX and NMA (nuclear microanalysis). The surface of the implants is found to consist of a thin surface oxide which is covered by a carbon-dominated contamination layer. By comparison with reference spectra from single crystal TiO 2 (rutile) the composition of the surface oxide is shown to be mainly TiO 2, with minor amounts of suboxides and TiN x. The thickness of the surface oxides is 2-6 nm, depending on the method of sterilization. The surface contamination layer is found to vary considerably from sample to sample and consists of mainly hydrocarbons with trace amounts of Ca, N, S, P, Cl. Some differences in surface composition between directly prepared surfaces, and some possible contamination sources, are identified and discussed shortly.

  12. Spectroscopic Survey Of Delta Scuti Stars

    NASA Astrophysics Data System (ADS)

    Kahraman Alicavus, Filiz; Niemczura, Ewa; Polinska, Magdalena; Helminiak, Krzysztof G.; Lampens, Patricia; Molenda-Zakowicz, Joanna; Ukita, Nobuharu; Kambe, Eiji

    2016-07-01

    We present the results of a spectroscopic study of pulsating stars of Delta Scuti type. The spectral types and luminosity classes, fundamental atmospheric parameters (the effective temperature, surface gravity, microturbulent velocity), detailed chemical composition and projected rotational velocities of a significant number of Delta Scuti-type stars were derived. The spectral classification was performed by comparing the spectra of our targets with the spectra of standard stars. The atmospheric parameters were determined by using different methods. The initial atmospheric parameters were derived from the analysis of photometric indices, the spectral energy distribution and the hydrogen lines, while the final atmospheric parameters were obtained from the analysis of iron lines. The spectrum synthesis method was used to determine chemical compositions of the investigated stars. As a result, we derived accurate atmospheric parameters, the projected rotational velocities and the abundance patterns of analysed sample. These results allow us to examine the position of Delta Scuti-type stars in the H-R diagram, and to investigate the effect of the rotational velocity on pulsation properties and a chemical difference between the Delta Scuti-type stars and the Gamma Doradus and A-F type hybrid stars.

  13. 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.

  14. HEXA: a machine for spectroscopic cartography

    NASA Astrophysics Data System (ADS)

    Barrado, D.; Aceituno, J.; Galadí, D.; Iglesias-Páramo, J.; Sánchez, S. F.

    2013-05-01

    We have performed a conceptual and viability study for HEXA, a 6.5 m aperture, wide-field telescope, with high multiplexing factor, framed in the strategic plan for the Calar Alto observatory in 2014-2018 and beyond, centred on the scientific cases arisen from the current need for wide-field spectroscopic surveys with very large multiplexing capability. The baseline design considers a field-of-view of 1.5°, multiplexing factor around or over 500 and possible spectral resolutions in the interval R = 5000 - 50 000, with instruments placed on two Nasmyth platforms. Other variants are also considered, including Ritchey-Chrétien and prime-focus solutions. The telescope concept is described, together with the instruments that have already undergone, or that are still undergoing, the conceptual design process: CEO, an innovative Imaging Fourier Transform spectrograph. GEA, a Gaia-inspired drift-scanning slitless spectrograph. BRONTESS, a fast and simple camera for guiding and ToO work. A PMAS-based multi-IFU, highly multiplexed spectrograph. And the multi-fibre spectrograph GYGES. Some of the instrument concepts analysed are based on the versatile fiber-positioner HECATE (with a minimum of 361 positioners). Some of the fibre-based instruments would allow, too, fibres entering a battery of CAF{É}-type high-res spectrographs.

  15. IMPROVED SPECTROSCOPIC PARAMETERS FOR TRANSITING PLANET HOSTS

    SciTech Connect

    Torres, Guillermo; Holman, Matthew J.; Carter, Joshua A.; Fischer, Debra A.; Sozzetti, Alessandro; Buchhave, Lars A.; Winn, Joshua N.

    2012-10-01

    We report homogeneous spectroscopic determinations of the effective temperature, metallicity, and projected rotational velocity for the host stars of 56 transiting planets. Our analysis is based primarily on the stellar parameter classification (SPC) technique. We investigate systematic errors by examining subsets of the data with two other methods that have often been used in previous studies (Spectroscopy Made Easy (SME) and MOOG). The SPC and SME results, both based on comparisons between synthetic spectra and actual spectra, show strong correlations between T{sub eff}, [Fe/H], and log g when solving for all three quantities simultaneously. In contrast the MOOG results, based on a more traditional curve-of-growth approach, show no such correlations. To combat the correlations and improve the accuracy of the temperatures and metallicities, we repeat the SPC analysis with a constraint on log g based on the mean stellar density that can be derived from the analysis of the transit light curves. Previous studies that have not taken advantage of this constraint have been subject to systematic errors in the stellar masses and radii of up to 20% and 10%, respectively, which can be larger than other observational uncertainties, and which also cause systematic errors in the planetary mass and radius.

  16. High-end spectroscopic diffraction gratings: design and manufacturing

    NASA Astrophysics Data System (ADS)

    Glaser, Tilman

    2015-02-01

    Diffraction gratings are key components for spectroscopic systems. For high-end applications, they have to meet advanced requirements as, e.g., maximum efficiency, lowest possible scattered light level, high numerical aperture, and minimal aberrations. Diffraction gratings are demanded to allow spectrometer designs with highest resolution, a maximal étendue, and minimal stray light, built within a minimal volume. This tutorial is intended to provide an overview of different high-end spectroscopic gratings, their theoretical design and manufacturing technologies.

  17. [Spectroscopic characteristics of novel Psidium meroterpenoids isolated from guava leaves].

    PubMed

    Ouyang, Wen; Zhu, Xiao-ai; Liu, Xiao-juan; Yie, Shu-min; Zhao, Litchao; Su, Lei; Cao, Yong

    2015-07-01

    Recently, novel Psidium meroterpenoids were reported in the guava leaves. According to careful analysis of the spectral data of literatures, the spectroscopic characteristics and biosynthetic pathway of Psidium meroterpenoids were summarized in this paper. The results showed that Psidium meroterpenoids had distinct spectroscopic features and reasonable biosynthetic routines, however the number order of carbon atoms was not consistent in the reported literatures. It was concluded that Psidium meroterpenoids were the characteristic chemical constituents of Psidium guajava Linn. PMID:26666047

  18. Spectroscopic characteristics of chromium doped mullite glass-ceramics

    SciTech Connect

    Wojtowicz, A.J.; Meng, W.; Lempicki, A.; Beall, G.H.; Hall, D.W.; Chin, T.C.

    1988-06-01

    Characteristics of chromium doped mullite ceramics are discussed with reference to possible laser applications. Dominant features are attributed to large and inherent spectroscopic inhomogeneity of mullite. The spectroscopic data are analyzed using a generalized McCumber theory. The peak stimulated emission cross section is 0.54 x 10/sup -20/ cm/sup 2/. This, together with preliminary single-pass measurements, indicate that gain for mullite is about 2.6 times smaller than gain for alexandrite.

  19. Theoretical interpretation of electron energy-loss spectroscopic images

    DOE PAGESBeta

    Allen, L. J.; D'Alfonso, Adrian J.; Findlay, Scott D.; Oxley, Mark P.; Bosman, M.; Keast, V. J.; Cossgriff, E. C.; Behan, G.; Nellist, P. D.; Kirkland, Angus I.

    2008-04-10

    In this paper, we discuss the theory of electron energy-loss spectroscopic images in scanning transmission electron microscopy. Three case studies are presented which have as common themes issues of inelastic scattering, coherence and image interpretation. The first is a state-by-state inelastic transitions analysis of a spectroscopic image which does not admit direct visual interpretation. The second compares theory and experiment for two-dimensional mapping. Finally, the third considers imaging in three dimensions via depth sectioning.

  20. Whispering Gallery Optical Resonator Spectroscopic Probe and Method

    NASA Technical Reports Server (NTRS)

    Anderson, Mark S. (Inventor)

    2014-01-01

    Disclosed herein is a spectroscopic probe comprising at least one whispering gallery mode optical resonator disposed on a support, the whispering gallery mode optical resonator comprising a continuous outer surface having a cross section comprising a first diameter and a second diameter, wherein the first diameter is greater than the second diameter. A method of measuring a Raman spectrum and an Infra-red spectrum of an analyte using the spectroscopic probe is also disclosed.

  1. The status of spectroscopic data for the exoplanet characterisation missions

    NASA Astrophysics Data System (ADS)

    Tennyson, Jonathan; Yurchenko, Sergei N.

    2015-12-01

    The status of laboratory spectroscopic data for exoplanet characterisation missions such as EChO is reviewed. For many molecules (eg H 2O, CO, CO 2, H3+, O 2, O 3) the data are already available. For the other species work is actively in progress constructing this data. Much of the is work is being undertaken by ExoMol project (www.exomol.com). This information can be used to construct a mission-specific spectroscopic database.

  2. Correlations of experimental isotope shifts with spectroscopic and mass observables

    SciTech Connect

    Cakirli, R. B.; Casten, R. F.; Blaum, K.

    2010-12-15

    Experimental differential observables relating to mean square charge radii, spectroscopic, and mass observables of even-even nuclei are presented for different regions in the nuclear chart. They exhibit remarkable correlations, not heretofore recognized, that provide a new perspective on structural evolution, especially in exotic nuclei. This can also be a guide for future measurements of charge radii, spectroscopic observables, and masses, as well as for future theoretical approaches.

  3. THE zCOSMOS 10k-BRIGHT SPECTROSCOPIC SAMPLE

    SciTech Connect

    Lilly, Simon J.; Maier, Christian; Carollo, Marcella; Caputi, Karina; Le Brun, Vincent; Kneib, Jean-Paul; Le Fevre, Olivier; De la Torre, Sylvain; De Ravel, Loic; Mainieri, Vincenzo; Mignoli, Marco; Zamorani, Gianni; Bardelli, Sandro; Bolzonella, Micol; Coppa, Graziano; Scodeggio, Marco; Contini, Thierry; Bongiorno, Angela; Cucciati, Olga

    2009-10-01

    We present spectroscopic redshifts of a large sample of galaxies with I {sub AB} < 22.5 in the COSMOS field, measured from spectra of 10,644 objects that have been obtained in the first two years of observations in the zCOSMOS-bright redshift survey. These include a statistically complete subset of 10,109 objects. The average accuracy of individual redshifts is 110 km s{sup -1}, independent of redshift. The reliability of individual redshifts is described by a Confidence Class that has been empirically calibrated through repeat spectroscopic observations of over 600 galaxies. There is very good agreement between spectroscopic and photometric redshifts for the most secure Confidence Classes. For the less secure Confidence Classes, there is a good correspondence between the fraction of objects with a consistent photometric redshift and the spectroscopic repeatability, suggesting that the photometric redshifts can be used to indicate which of the less secure spectroscopic redshifts are likely right and which are probably wrong, and to give an indication of the nature of objects for which we failed to determine a redshift. Using this approach, we can construct a spectroscopic sample that is 99% reliable and which is 88% complete in the sample as a whole, and 95% complete in the redshift range 0.5 < z < 0.8. The luminosity and mass completeness levels of the zCOSMOS-bright sample of galaxies is also discussed.

  4. Elemental evidence

    NASA Astrophysics Data System (ADS)

    Carlowicz, Michael

    He set out to prove that ocean sediments contain elevated levels of the rare element iridium because of the natural weathering of the continents. Instead, what Ariel Anbar found was new evidence that a meteorite may have had a role in the mass extinctions that marked the end of the Cretaceous era.By studying the geochemical properties of iridium, Anbar, a professor of earth and environmental sciences and chemistry at the University of Rochester, found that the residence time—a measure of the rate at which an element settles out of water into sediments—of iridium in ocean water is 2000 to 20,000 years. That finding suggests that a large deposit of iridium could have lingered in the world's oceans long enough to explain the thickness of the iridium-rich sediment layers at the K-T boundary.

  5. Fishy evidence

    NASA Astrophysics Data System (ADS)

    Adding to the ongoing debate over the mass extinctions that marked the end of the Cretaceous period, a paleontologist from Purdue University recently uncovered a bed of 65-million-year old fish bones that bears the fingerprints of a meteorite impact. Gathering the fossils from Seymour Island, near the Antarctic Peninsula, William Zinsmeister discovered what he has termed a "horizon of death," a 12-square-kilometer bone bed resting just above a layer of iridium. The element is rare on Earth but common to most meteorites.The Purdue professor of geosciences believes the site provides strong evidence that the impact of an extraterrestrial object played at least some part in the mass extinctions that marked the end of the Cretaceous.

  6. On determining dose rate constants spectroscopically

    SciTech Connect

    Rodriguez, M.; Rogers, D. W. O.

    2013-01-15

    Purpose: To investigate several aspects of the Chen and Nath spectroscopic method of determining the dose rate constants of {sup 125}I and {sup 103}Pd seeds [Z. Chen and R. Nath, Phys. Med. Biol. 55, 6089-6104 (2010)] including the accuracy of using a line or dual-point source approximation as done in their method, and the accuracy of ignoring the effects of the scattered photons in the spectra. Additionally, the authors investigate the accuracy of the literature's many different spectra for bare, i.e., unencapsulated {sup 125}I and {sup 103}Pd sources. Methods: Spectra generated by 14 {sup 125}I and 6 {sup 103}Pd seeds were calculated in vacuo at 10 cm from the source in a 2.7 Multiplication-Sign 2.7 Multiplication-Sign 0.05 cm{sup 3} voxel using the EGSnrc BrachyDose Monte Carlo code. Calculated spectra used the initial photon spectra recommended by AAPM's TG-43U1 and NCRP (National Council of Radiation Protection and Measurements) Report 58 for the {sup 125}I seeds, or TG-43U1 and NNDC(2000) (National Nuclear Data Center, 2000) for {sup 103}Pd seeds. The emitted spectra were treated as coming from a line or dual-point source in a Monte Carlo simulation to calculate the dose rate constant. The TG-43U1 definition of the dose rate constant was used. These calculations were performed using the full spectrum including scattered photons or using only the main peaks in the spectrum as done experimentally. Statistical uncertainties on the air kerma/history and the dose rate/history were Less-Than-Or-Slanted-Equal-To 0.2%. The dose rate constants were also calculated using Monte Carlo simulations of the full seed model. Results: The ratio of the intensity of the 31 keV line relative to that of the main peak in {sup 125}I spectra is, on average, 6.8% higher when calculated with the NCRP Report 58 initial spectrum vs that calculated with TG-43U1 initial spectrum. The {sup 103}Pd spectra exhibit an average 6.2% decrease in the 22.9 keV line relative to the main peak when

  7. The Spectroscopic Evolution of Nova Cygni 1992

    NASA Astrophysics Data System (ADS)

    Moro-Martin, A.; Garnavich, P. M.; Noriega-Crespo, A.; Alpert, A.

    1996-12-01

    Optical spectroscopic observations of Nova Cygni 1992 spanning 4 years are modeled in this study. The data were obtained primarily with the DAO 1.8m telescope and cover a wavelength range from ~ 3200 - 8000 Angstroms. The observations begin on May 92 (85 days after the outburst) and end on June 1996, i.e. during most of the optically thin evolutionary phase. The spectra were modeled in a relatively straightforward way by using the flux predicted by a photoionization code [1] for most of the emission lines (down to 0.1% of Hβ ) and transforming these numbers into a synthetic spectrum. There are, however, significant differences in the detailed procedure in comparison with similar works [2]. First, the photoionization models were run at a fixed abundance value for the most prominent elements (i.e. H, He, C, O, N, Ne, Fe, etc) over the entire time sequence. Second, the brightest lines, e.g. [Ne V], [Ne III], [O III] and the Balmer lines, were initially used as guide to match the observations. The rest of the spectra, which includes the fainter lines, were then directly predicted by the photoionization code. Considering the complicated structure of the shell [3], the lack of well defined values of its gas density and our limited knowledge of the time evolution of the surface temperature of the photoionization source, the comparison between models and observations agrees remarkably well. It was found that the time evolution of some of the Iron coronal lines, [Fe VII] 6087 Angstroms and [Fe X] 6374 Angstroms, closely follows that of the X-rays [4]. [1] Ferland, G.J 1993, CLOUDY, U. of Kentucky Dept. Phys & Astr. Internal Report. [2] Austin et al. 1992, AJ, 111, 869 [3] Paresce, Livio, Hack & Korista (1995) A&A, 299, 823 [4] Krautter et al. (1996), ApJ, 456, 788

  8. Raman Spectroscopic Investigation of Dyes in Spices

    NASA Astrophysics Data System (ADS)

    Uhlemann, Ute; Ramoji, Anuradha; Rösch, Petra; Da Costa Filho, Paulo Augusto; Robert, Fabien; Popp, Jürgen

    2010-08-01

    In this study, a number of synthetic colorants for spices have been investigated by means of Raman spectroscopy, resonance Raman spectroscopy, and surface enhanced (resonance) Raman spectroscopy (SER(S)). The aim of the study was the determination of limits of detection for each dye separately and in binary mixtures of dyes in spiked samples of the spices. Most of the investigated dyes have been azo dyes, some being water-soluble, the other being fat-soluble. Investigating the composition of food preparations is an ongoing and important branch of analytical sciences. On one hand, new ingredients have to be analyzed with regard to their contents, on the other hand, raw materials that have been tampered have to be eliminated from food production processes. In the last decades, the various Raman spectroscopic methods have proven to be successful in many areas of life and materials sciences. The ability of Raman spectroscopy to distinguish even structural very similar analytes by means of their vibrational fingerprint will also be important in this study. Nevertheless, Raman scattering is a very weak process that is oftentimes overlaid by matrix interferences or fluorescence. In order to achieve limits of detection in the nanomolar range, the signal intensity has to be increased. According to the well-known equations, there are several ways of achieving this increase: •increasing sample concentration •increasing laser power •decreasing the laser wavelength •using electronic resonance •increasing the local electromagnetic field In this study, nearly all of the above-mentioned principles were applied. In a first step, all dyes were investigated in solution at different concentrations to determine a limit of detection. In the second step, spiked spice samples have been extracted with a variety of solvents and process parameters tested. To lower the limit of detection even further, SERS spectroscopy has been used as well in as out of electronic resonance.

  9. The SPHEREx All-Sky Spectroscopic Survey

    NASA Astrophysics Data System (ADS)

    Unwin, Stephen C.; SPHEREx Science Team, SPHEREx Project Team

    2016-06-01

    SPHEREx is a mission to conduct an optical-near-IR survey of the entire sky with a spectrum at every pixel location. It was selected by NASA for a Phase A study in its Small Explorer Program; if selected, development would begin in 2016, and the observatory would start a 2-year prime mission in 2020. An all-sky spectroscopic survey can be used to tackle a wide range of science questions. The SPHEREx science team is focusing on three: (1) Probing the physics of inflation through measuring non-Gaussianity from the study of large-scale structure; (2) Studying the origin of water and biogenic molecules in a wide range of physical and chemical environments via ice absorption spectra; (3) Charting the history of star formation in the universe through intensity mapping of the large-scale spatial power. The instrument is a small wide-field telescope operating in the range of 0.75 - 4.8 µm at a spectral resolution of 41.5 in the optical and 150 at the long-wavelength end. It observes in a sun-sync low-earth orbit, covering the sky like WISE and COBE. SPHEREx is a simple instrument that requires no new technology. The Phase A design has substantial technical and resource margins and can be built with low risk. It is a partnership between Caltech and JPL, with Ball Aerospace and the Korea Astronomy and Space Science Institute as major partners. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. © 2016 California Institute of Technology. Government sponsorship acknowledged.

  10. Soft tissue imaging with photon counting spectroscopic CT

    NASA Astrophysics Data System (ADS)

    Shikhaliev, Polad M.

    2015-03-01

    The purpose of this work was experimental investigation of photon counting spectroscopic CT (PCS-CT) imaging of anatomical soft tissue with clinically relevant size. The imaging experiments were performed using a spectroscopic CT system based on CdZnTe photon counting detector with two rows of pixels, 256 pixels in each row, 1  ×  1 mm2 pixel size, and 25.6 cm detector length. The detector could split the x-ray energy spectrum to 5 regions (energy bins), and acquire 5 multi-energy (spectroscopic) CT images in a single CT scan. A sample of round shaped anatomical soft tissue of 14 cm diameter including lean and fat was used for imaging. To avoid the negative effect of anatomical noise on quantitative analysis, a spectroscopic CT phantom with tissue equivalent solid materials was used. The images were acquired at 60, 90, and 120 kVp tube voltages, and spectroscopic image series were acquired with 3 and 5 energy bins. Spectroscopic CT numbers were introduced and used to evaluate an energy selective image series. The anatomical soft tissue with 14 cm diameter was visualized with good quality and without substantial artifacts by the photon counting spectroscopic CT system. The effects of the energy bin crosstalk on spectroscopic CT numbers were quantified and analyzed. The single and double slice PCS-CT images were acquired and compared. Several new findings were observed, including the effect of soft tissue non-uniformity on image artifacts, unique status of highest energy bin, and material dependent visualization in spectroscopic image series. Fat-lean decomposition was performed using dual energy subtraction and threshold segmentation methods, and compared. Using K-edge filtered x-rays improved fat-lean decomposition as compared to conventional x-rays. Several new and important aspects of the PCS-CT were investigated. These include imaging soft tissue with clinically relevant size, single- and double-slice PCS-CT imaging, using spectroscopic CT

  11. Soft tissue imaging with photon counting spectroscopic CT.

    PubMed

    Shikhaliev, Polad M

    2015-03-21

    The purpose of this work was experimental investigation of photon counting spectroscopic CT (PCS-CT) imaging of anatomical soft tissue with clinically relevant size. The imaging experiments were performed using a spectroscopic CT system based on CdZnTe photon counting detector with two rows of pixels, 256 pixels in each row, 1  ×  1 mm(2) pixel size, and 25.6 cm detector length. The detector could split the x-ray energy spectrum to 5 regions (energy bins), and acquire 5 multi-energy (spectroscopic) CT images in a single CT scan. A sample of round shaped anatomical soft tissue of 14 cm diameter including lean and fat was used for imaging. To avoid the negative effect of anatomical noise on quantitative analysis, a spectroscopic CT phantom with tissue equivalent solid materials was used. The images were acquired at 60, 90, and 120 kVp tube voltages, and spectroscopic image series were acquired with 3 and 5 energy bins. Spectroscopic CT numbers were introduced and used to evaluate an energy selective image series. The anatomical soft tissue with 14 cm diameter was visualized with good quality and without substantial artifacts by the photon counting spectroscopic CT system. The effects of the energy bin crosstalk on spectroscopic CT numbers were quantified and analyzed. The single and double slice PCS-CT images were acquired and compared. Several new findings were observed, including the effect of soft tissue non-uniformity on image artifacts, unique status of highest energy bin, and material dependent visualization in spectroscopic image series. Fat-lean decomposition was performed using dual energy subtraction and threshold segmentation methods, and compared. Using K-edge filtered x-rays improved fat-lean decomposition as compared to conventional x-rays. Several new and important aspects of the PCS-CT were investigated. These include imaging soft tissue with clinically relevant size, single- and double-slice PCS-CT imaging, using spectroscopic CT

  12. Effects of molecular conformation on the spectroscopic properties of 4,4‧-disubstituted benzylideneanilines

    NASA Astrophysics Data System (ADS)

    Fang, Zhengjun; Wu, Feng; Yi, Bing; Cao, Chenzhong; Xie, Xin

    2016-01-01

    The relationship between the molecular conformation and spectroscopic properties of unsymmetrical 4,4‧-disubstituted benzylideneanilines, was explored by the combination of experiment and reference data. Crystal structure information and spectroscopic behaviors of the seventeen samples p-X-C6H4CHdbnd NC6H4-p-Y (X = NMe2, OMe, Me, Cl, CN, or NO2, Ydbnd NMe2, OMe, Me, Cl, CN, or NO2) were provided for this study. Among these seventeen compounds, nine ones were synthesized firstly, and five crystal structures were determined and analyzed. It was observed that the twist angle of the aniline ring with respect to the rest of the molecule (τ) is systematically controlled by the substituent at the aromatic ring. The correlation results show that the UV maximum absorption in wavenumbers (υmax) is dependent on the substituent at the aromatic ring and the dihedral angle τ of the titled molecules, and a sine function of τ (sin(τ)) is suitable to modify the substituent effects on the υmax. However, the dihedral angle τ has a limited effect on the values of 13C NMR chemical shifts δC(Cdbnd N). The results indicate that the dihedral angle τ has an significant effect on UV spectra of Schiff bases with different parent structure although there is something different about the parameter metrics. While it has a relatively limited effect on the values of δC(Cdbnd N) in both unsymmetrical and unsymmetrical Schiff bases. This study provides an sufficient evidence of the molecular conformation on spectroscopic properties of Schiff bases.

  13. The source regions of the solar wind revealed by UV/EUV spectroscopic observations

    NASA Astrophysics Data System (ADS)

    Xia, L.

    2012-06-01

    The heating of the solar corona and the origin and acceleration of the solar wind are among the important unsolved problems of space plasma and solar physics. During the SOHO era, coronal holes as source regions of the fast solar wind have been investigated by using UV/EUV spectroscopic data observed with high-resolution spectrometers. At the base of the coronal hole, a detailed picture concerning the origin of the fast solar wind was first obtained by SUMER observations. For example, the Dopplergram deduced from the line profile of Ne VIII and other transition-region lines showed strong evidence that the wind originates in the chromospheric network and starts flowing out of the corona in magnetic funnels. Solar wind mass is suggested to be supplied through supergranule-scale magnetoconvection in the chromosphere and transition region. However, the spectral lines used in these studies are mainly obtained in the transition region and the behaviours of the nascent solar wind at higher temperatures have not yet been understood. Recent spectroscopic and imaging observations with instruments on Hinode and SDO provide further information about the coronal holes seen in EUV lines formed in the solar corona. Some interesting results, e.g., ubiquitous episodic outflow (jets) and enhanced emission in the blue wing of coronal line profiles, are found from the new observations. The purpose of this presentation is to review recent research progress on solar-wind source regions revealed by UV/EUV spectroscopic and imaging observations. Such observational studies and further interpretations of the data may provide crucial constraints and implications for future studies on both observations and theoretical models concerning coronal heating and acceleration of the nascent solar wind.

  14. Mineralogy and inorganic chemistry of naturally occurring biogenic iron oxyhydroxides: Spectroscopic evidence of thermal maturation

    NASA Astrophysics Data System (ADS)

    Haddad, A.; Fakra, S.; Orcutt, B. N.; Toner, B.; Edwards, K. J.

    2011-12-01

    Microbial mats were sampled at four sites at the Lo'ihi Seamount and examined for changes in mineralogy and inorganic chemistry via synchrotron-sourced X-ray Absorption Spectroscopy (XAS). These mats are rich in iron oxyhydroxides with morphologies similar to those produced by iron oxidizing microorganisms related to Zetaproteobacteria such as Mariprofundus ferroxydans, which have been shown to be present and active in all of these mat ecosystems. The same particle morphologies are observed consistently at all four sites, which range in temperature (4 - 40°C) and hydrothermal activity (dead to very active). Fe L-edge XAS reveals no significant differences in Fe speciation between the morphologies. Mineralogy, however, as reflected in O 1s XAS measurements, appears to be a function of thermal maturation with the hottest site harboring more crystalline particles. Morphology does not factor into the changes in mineralogy. These measurements are confirmed by Fe 1s XAS spectroscopy. The C 1s XAS spectroscopy is highly variable and may be related to overall maturation (age) or undetermined factors. Elucidating the effect of thermal maturation on biogenic iron oxhydroxide particles is essential to understanding the environmental influences on their preservation in the rock record.

  15. Spectroscopic evidence of uranium immobilization in acidic wetlands by natural organic matter and plant roots

    DOE PAGESBeta

    Li, Dien; Kaplan, Daniel I.; Chang, Hyun-Shik; Seaman, John C.; Jaffé, Peter R.; Koster van Groos, Paul; Scheckel, Kirk G.; Segre, Carlo U.; Chen, Ning; Jiang, De-Tong; et al

    2015-03-03

    Biogeochemistry of uranium in wetlands plays important roles in U immobilization in storage ponds of U mining and processing facilities but has not been well understood. The objective of this work was to study molecular mechanisms responsible for high U retention by Savannah River Site (SRS) wetland sediments under varying redox and acidic (pH = 2.6–5.8) conditions using U L₃-edge X-ray absorption spectroscopy. Uranium in the SRS wetland sediments existed primarily as U(VI) bonded as a bidentate to carboxylic sites (U–C bond distance at ~2.88 Å), rather than phenolic or other sites of natural organic matter (NOM). In microcosms simulatingmore » the SRS wetland processes, U immobilization on roots was two orders of magnitude higher than on the adjacent brown or more distant white sands in which U was U(VI). Uranium on the roots were both U(IV) and U(VI), which were bonded as a bidentate to carbon, but the U(VI) may also form a U phosphate mineral. After 140 days of air exposure, all U(IV) was re-oxidized to U(VI) but remained as a bidentate bonding to carbon. This study demonstrated NOM and plant roots can highly immobilize U(VI) in the SRS acidic sediments, which has significant implication for the long-term stewardship of U-contaminated wetlands.« less

  16. Spectroscopic evidence of uranium immobilization in acidic wetlands by natural organic matter and plant roots

    SciTech Connect

    Li, Dien; Kaplan, Daniel I.; Chang, Hyun-Shik; Seaman, John C.; Jaffé, Peter R.; Koster van Groos, Paul; Scheckel, Kirk G.; Segre, Carlo U.; Chen, Ning; Jiang, De-Tong; Newville, Matthew; Lanzirotti, Antonio

    2015-03-03

    Biogeochemistry of uranium in wetlands plays important roles in U immobilization in storage ponds of U mining and processing facilities but has not been well understood. The objective of this work was to study molecular mechanisms responsible for high U retention by Savannah River Site (SRS) wetland sediments under varying redox and acidic (pH = 2.6–5.8) conditions using U L₃-edge X-ray absorption spectroscopy. Uranium in the SRS wetland sediments existed primarily as U(VI) bonded as a bidentate to carboxylic sites (U–C bond distance at ~2.88 Å), rather than phenolic or other sites of natural organic matter (NOM). In microcosms simulating the SRS wetland processes, U immobilization on roots was two orders of magnitude higher than on the adjacent brown or more distant white sands in which U was U(VI). Uranium on the roots were both U(IV) and U(VI), which were bonded as a bidentate to carbon, but the U(VI) may also form a U phosphate mineral. After 140 days of air exposure, all U(IV) was re-oxidized to U(VI) but remained as a bidentate bonding to carbon. This study demonstrated NOM and plant roots can highly immobilize U(VI) in the SRS acidic sediments, which has significant implication for the long-term stewardship of U-contaminated wetlands.

  17. SPECTROSCOPIC EVIDENCE FOR A 5.4 MINUTE ORBITAL PERIOD IN HM CANCRI

    SciTech Connect

    Roelofs, Gijs H. A.; Rau, Arne; Marsh, Tom R.; Steeghs, Danny; Groot, Paul J.; Nelemans, Gijs E-mail: arau@mpe.mpg.de

    2010-03-10

    HM Cancri is a candidate ultracompact binary white dwarf with an apparent orbital period of only 5.4 minutes, as suggested by X-ray and optical light-curve modulations on that period, and by the absence of longer-period variability. In this Letter, we present Keck-I spectroscopy which shows clear modulation of the helium emission lines in both radial velocity and amplitude on the 5.4 minute period and no other. The data strongly suggest that the binary is emitting He I 4471 from the irradiated face of the cooler, less massive star, and He II 4686 from a ring around the more massive star. From their relative radial velocities, we measure a mass ratio q = 0.50 {+-} 0.13. We conclude that the observed 5.4 minute period almost certainly represents the orbital period of an interacting binary white dwarf. We thus confirm that HM Cnc is the shortest period binary star known: a unique test for stellar evolution theory, and one of the strongest known sources of gravitational waves for LISA.

  18. Spectroscopic evidence supporting the gravitational lens hypothesis for 1635+267 A,B

    NASA Technical Reports Server (NTRS)

    Turner, Edwin L.; Hillenbrand, Lynne A.; Schneider, Donald P.; Hewitt, Jacqueline N.; Burke, Bernard F.

    1988-01-01

    The gravitational lens hypothesis is tested for 1613+267 A,B by comparing the detailed line widths and shapes of the 2799-A Mg II and semiforbidden 1909-A C-III lines in each component. Following subtraction of an interpolating polynomial fit to the continua and the determination of a single optimum scaling factor (an amplification ratio of 2.83), reasonable agreement between the profiles of both lines in the two composites is obtained. Comparison of these lines to those in an unrelated quasar with a similar redshift and apparent magnitude does not produce a good match. It is suggested that the observed match in the 1635+267 A,B spectra arises from gravitational lensing.

  19. Spectroscopic Evidence of Anthropogenic Compounds Extraction from Polymers by Fluorescent Dissolved Organic Matter in Natural Water

    NASA Astrophysics Data System (ADS)

    Miranda, M.; Trojzuck, A.; Voss, D.; Gassmann, S.; Zielinski, O.

    2016-04-01

    FDOM is one of the most important carriers of anthropogenic compounds in natural waters. It can combine with environmental contaminants and polymers to form diverse chemical structures. To this end, here a microfluidic chip was designed for the analysis of these changes in fluorescent dissolved organic matter (FDOM) fingerprints due to thermal treatment and varying time intervals of exposure. Excitation Emission Matrix Spectroscopy (EEMS) approach was utilized to detect and identify the inherent compounds in sampled FDOM. Strong direct correlations were founded, Spearman rank correlation values (ρ = 0.85 at α = 0.1, n = 4) and linear correlation R2 = 0.8359 were noted between thermal treatment pattern 2 and fluorescence intensity of samples. Materials, acrylic based glue and cyclic olefin copolymer (COC) polymer, used to design the microfluidic sensor were determined to possess unique spectral features in the ultraviolet to green spectrum using EEMS. The study therefore provides an insight on methods to identify contaminants in natural waters. This underlines the potential of optical sensors providing measurements at fast intervals, enabling environmental monitoring.

  20. Raman spectroscopic evidence for colinear arrangement in the solid state of thermochromic distibanes

    NASA Astrophysics Data System (ADS)

    Bürger, H.; Eujen, R.; Becker, G.; Mundt, O.; Westerhausen, M.; Witthauer, C.

    1983-04-01

    The IR and Raman spectra of the compounds (CH 3) 2SbSb(CH 3) 2 (I), [(CH 3) 3Si] 2SbSb[Si(CH 3) 3] 2 (II), [(CH 3) 3Si] 2AsAs[Si(CH 3) 3] 2 (III) and (C 6H 5) 2SbSb(C 6H 5) 2 (IV) have been studied in the liquid and solid states. Given assignments for I to III are based on normal coordinate analyses, and force constants are reported. The solid state Raman spectra of I and II exhibit strong lines near 50 cm -1, which are assigned to the longitudinal acoustic mode of an infinite linear chain of Sb atoms. Intermolecular Sb…Sb force constants, 0.125 and 0.18 N cm -1, are determined for I and II respectively.

  1. Spectroscopic Evidence for Exceptional Thermal Contribution to Electron-Beam Induced Fragmentation

    SciTech Connect

    Caldwell, Marissa A.; Haynor, Ben; Aloni, Shaul; Ogletree, D. Frank; Wong, H.-S. Philip; Urban, Jeffrey J.; Milliron, Delia J.

    2010-11-16

    While electron beam induced fragmentation (EBIF) has been reported to result in the formation of nanocrystals of various compositions, the physical forces driving this phenomenon are still poorly understood. We report EBIF to be a much more general phenomenon than previously appreciated, operative across a wide variety of metals, semiconductors and insulators. In addition, we leverage the temperature dependent bandgap of several semiconductors to quantify -- using in situ cathodoluminescence spectroscopy -- the thermal contribution to EBIF, and find extreme temperature rises upwards of 1000K.

  2. Spectroscopic evidence of uranium immobilization in acidic wetlands by natural organic matter and plant roots.

    PubMed

    Li, Dien; Kaplan, Daniel I; Chang, Hyun-Shik; Seaman, John C; Jaffé, Peter R; Koster van Groos, Paul; Scheckel, Kirk G; Segre, Carlo U; Chen, Ning; Jiang, De-Tong; Newville, Matthew; Lanzirotti, Antonio

    2015-03-01

    Biogeochemistry of uranium in wetlands plays important roles in U immobilization in storage ponds of U mining and processing facilities but has not been well understood. The objective of this work was to study molecular mechanisms responsible for high U retention by Savannah River Site (SRS) wetland sediments under varying redox and acidic (pH = 2.6-5.8) conditions using U L3-edge X-ray absorption spectroscopy. Uranium in the SRS wetland sediments existed primarily as U(VI) bonded as a bidentate to carboxylic sites (U-C bond distance at ∼2.88 Å), rather than phenolic or other sites of natural organic matter (NOM). In microcosms simulating the SRS wetland processes, U immobilization on roots was 2 orders of magnitude higher than on the adjacent brown or more distant white sands in which U was U(VI). Uranium on the roots were both U(IV) and U(VI), which were bonded as a bidentate to carbon, but the U(VI) may also form a U phosphate mineral. After 140 days of air exposure, all U(IV) was reoxidized to U(VI) but remained as a bidentate bonding to carbon. This study demonstrated NOM and plant roots can highly immobilize U(VI) in the SRS acidic sediments, which has significant implication for the long-term stewardship of U-contaminated wetlands. PMID:25634067

  3. Spectroscopic evidence for uranium bearing precipitates in vadose zone sediments at the Hanford 300-area site

    USGS Publications Warehouse

    Arai, Y.; Marcus, M.A.; Tamura, N.; Davis, J.A.; Zachara, J.M.

    2007-01-01

    Uranium (U) solid-state speciation in vadose zone sediments collected beneath the former North Process Pond (NPP) in the 300 Area of the Hanford site (Washington) was investigated using multi-scale techniques. In 30 day batch experiments, only a small fraction of total U (???7.4%) was released to artificial groundwater solutions equilibrated with 1% pCO2. Synchrotron-based micro-X-ray fluorescence spectroscopy analyses showed that U was distributed among at least two types of species: (i) U discrete grains associated with Cu and (ii) areas with intermediate U concentrations on grains and grain coatings. Metatorbernite (Cu[UO2]2[PO 4]2??8H2O) and uranophane (Ca[UO 2]2[SiO3(OH)]2?? 5H 2O) at some U discrete grains, and muscovite at U intermediate concentration areas, were identified in synchrotron-based micro-X-ray diffraction. Scanning electron microscopy/energy dispersive X-ray analyses revealed 8-10 ??m size metatorbernite particles that were embedded in C-, Al-, and Si-rich coatings on quartz and albite grains. In ??- and bulk-X-ray absorption structure (??-XAS and XAS) spectroscopy analyses, the structure of metatorbernite with additional U-C and U-U coordination environments was consistently observed at U discrete grains with high U concentrations. The consistency of the ??- and bulk-XAS analyses suggests that metatorbernite may comprise a significant fraction of the total U in the sample. The entrapped, micrometer-sized metatorbernite particles in C-, Al-, and Si-rich coatings, along with the more soluble precipitated uranyl carbonates and uranophane, likely control the long-term release of U to water associated with the vadose zone sediments. ?? 2007 American Chemical Society.

  4. Spectroscopic evidence for a type II Weyl semimetallic state in MoTe2

    DOE PAGESBeta

    Huang, Lunan; McCormick, Timothy M.; Ochi, Masayuki; Zhao, Zhiying; Suzuki, Michi -To; Arita, Ryotaro; Wu, Yun; Mou, Daixiang; Cao, Huibo; Yan, Jiaqiang; et al

    2016-07-11

    In a type I Dirac or Weyl semimetal, the low-energy states are squeezed to a single point in momentum space when the chemical potential μ is tuned precisely to the Dirac/Weyl point1, 2, 3, 4, 5, 6. Recently, a type II Weyl semimetal was predicted to exist, where the Weyl states connect hole and electron bands, separated by an indirect gap7, 8, 9, 10. This leads to unusual energy states, where hole and electron pockets touch at the Weyl point. Here we present the discovery of a type II topological Weyl semimetal state in pure MoTe2, where two sets ofmore » Weyl points (W±2 , W±3) exist at the touching points of electron and hole pockets and are located at different binding energies above EF. Using angle-resolved photoemission spectroscopy, modelling, density functional theory and calculations of Berry curvature, we identify the Weyl points and demonstrate that they are connected by different sets of Fermi arcs for each of the two surface terminations. We also find new surface ‘track states’ that form closed loops and are unique to type II Weyl semimetals. Lastly, this material provides an exciting, new platform to study the properties of Weyl fermions.« less

  5. Photometric and spectroscopic evidence for a dense ring system around Centaur Chariklo

    NASA Astrophysics Data System (ADS)

    Duffard, R.; Pinilla-Alonso, N.; Ortiz, J. L.; Alvarez-Candal, A.; Sicardy, B.; Santos-Sanz, P.; Morales, N.; Colazo, C.; Fernández-Valenzuela, E.; Braga-Ribas, F.

    2014-08-01

    Context. A stellar occultation observed on 3rd June 2013 revealed the presence of two dense and narrow rings separated by a small gap around the Centaur object (10 199) Chariklo. The composition of these rings is not known. We suspect that water ice is present in the rings, as is the case for Saturn and other rings around the giant planets. Aims: In this work, we aim to determine if the variability in the absolute magnitude of Chariklo and the temporal variation of the spectral ice feature, even when it disappeared in 2007, can be explained by an icy ring system whose aspect angle changes with time. Methods: We explained the variations on the absolute magnitude of Chariklo and its ring by modeling the light reflected by a system as the one described above. Using X-shooter at VLT, we obtained a new reflectance spectra. We compared this new set of data with the ones available in the literature. We showed how the water ice feature is visible in 2013 in accordance with the ring configuration, which had an opening angle of nearly 34° in 2013. Finally, we also used models of light scattering to fit the visible and near-infrared spectra that shows different characteristics to obtain information on the composition of Chariklo and its rings. Results: We showed that absolute photometry of Chariklo from the literature and new photometric data that we obtained in 2013 can be explained by a ring of particles whose opening angle changes as a function of time. We used the two possible pole solutions for the ring system and found that only one of them, α = 151.30 ± 0.5, δ = 41.48 ± 0.2° (λ = 137.9 ± 0.5, β = 27.7 ± 0.2°), provides the right variation of the aspect angle with time to explain the photometry, whereas the other possible pole solution fails to explain the photometry. From spectral modeling, we derived the composition of the Chariklo surface and that of the rings using the result on the pole solution. Chariklo surface is composed with about 60% of amorphous carbon, 30% of silicates and 10% of organics; no water ice was found on the surface. The ring, on the other hand, contains 20% of water ice, 40-70% of silicates, and 10-30% of tholins and small quantities of amorphous carbon. Partially based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile. DDT 291.C-5035(A). Based on observations carried out at the 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.

  6. Spectroscopic evidence for ternary surface complexes in the lead(II)-malonic acid-hematite system

    USGS Publications Warehouse

    Lenhart, J.J.; Bargar, J.R.; Davis, J.A.

    2001-01-01

    Using extended X-ray absorption fine structure (EXAFS) and attenuated total reflectance Fourier-transform infrared (ATR-FTIR) measurements, we examined the sorption of Pb(II) to hematite in the presence of malonic acid. Pb LIII-edge EXAFS measurements performed in the presence of malonate indicate the presence of both Fe and C neighbors, suggesting that a major fraction of surface-bound malonate is bonded to adsorbed Pb(II). In the absence of Pb(II), ATR-FTIR measurements of sorbed malonate suggest the formation of more than one malonate surface complex. The dissimilarity of the IR spectrum of malonate sorbed on hematite to those for aqueous malonate suggest at least one of the sorbed malonate species is directly coordinated to surface Fe atoms in an inner-sphere mode. In the presence of Pb, little change is seen in the IR spectrum for sorbed malonate, indicating that geometry of malonate as it coordinates to sorbed Pb(II) adions is similar to the geometry of malonate as it coordinates to Fe in the hematite surface. Fits of the raw EXAFS spectra collected from pH 4 to pH 8 result in average Pb-C distances of 2.98 to 3.14 A??, suggesting the presence of both four- and six-membered Pb-malonate rings. The IR results are consistent with this interpretation. Thus, our results suggest that malonate binds to sorbed Pb(II) adions, forming ternary metal-bridging surface complexes. ?? 2001 Academic Press.

  7. A different mechanism for the reductive dechlorination of chlorinated ethenes: Kinetic and spectroscopic evidence

    SciTech Connect

    Lesage, S.; Brown, S.; Millar, K.

    1998-08-01

    Reductive dechlorination is the most common reaction in the remediation of groundwater and soils contaminated with chlorinated compounds. The reaction that occurs in anaerobic bacteria can also be catalyzed by vitamin B12 and titanium citrate. Reductive dechlorination without the release of chlorinated ethene intermediates from the chloroalkylcobalamin complexes is proposed as an alternate reaction pathway for the reductive dechlorination of chlorinated ethenes. The revised scheme is supported by (a) the identification of several chloroalkylcobalamin intermediates by direct liquid injection of the reaction mixtures into an electrospray mass spectrometer, (b) the simultaneous presence of all the dechlorination intermediates in the mixtures, and (c) gas chromatographic data showing rapid formation of ethene and acetylene in the presence of a large excess of the primary substrates. Homolytic cleavage and titanium-catalyzed elimination are presented as competing mechanisms for the formation of the products from the alkylcobalamin intermediates. The distribution of dechlorination products was dependent on the availability of titanium from different chelating agents. This means that it may be possible to favor the formation of the fully dechlorinated products and to reduce the release of undesirable intermediates such as vinyl chloride by adjusting the amount and type of titanium chelate used.

  8. Spectroscopic Evidence of Keto-enol Tautomerism in Deliquesced Malonic Acid Particles

    SciTech Connect

    Ghorai, Suman; Laskin, Alexander; Tivanski, Alexei V.

    2011-04-11

    Scanning Transmission X-ray Microscopy combined with Near Edge X-ray Absorption Fine Structure Spectroscopy (STXM/NEXAFS), and optical microscopy coupled with Fourier Transform Infrared Spectroscopy (micro-FTIR) have been applied to observe hygroscopic growth and chemical changes in malonic acid particles deposited on substrates. Extent of the hygroscopic growth of particles has been quantified in terms of the corresponding water-to-solute ratios (WSR) based on STXM/NEXAFS and micro-FTIR data sets. WSR values derived separately from two applied methods displayed a remarkable agreement with previous data reported in the literature. Comparison of NEXAFS and FTIR spectra acquired at different relative humidity (RH) shows efficient keto-enol tautomerization of malonic acid, with the enol form dominated at higher RH. The keto-enol equilibrium constants were calculated using relevant peak intensities in the carbon and oxygen K-edge NEXAFS spectra as a function of RH.

  9. Spectroscopic evidence of xanthine compounds fluorescence quenching effect on water-soluble porphyrins

    NASA Astrophysics Data System (ADS)

    Makarska-Bialokoz, Magdalena

    2015-02-01

    The formation of π-stacked complexes between water-soluble porphyrins: 4,4‧,4″,4″‧-(21H,23H-porphine-5,10,15,20-tetrayl)tetrakis-(benzoic acid) (H2TCPP), 5,10,15,20-tetrakis(4-sulfonatophenyl)-21H,23H-porphine (H2TPPS4), 5,10,15,20-tetrakis[4-(trimethylammonio)phenyl]-21H,23H-porphine tetra-p-tosylate (H2TTMePP), 5,10,15,20-tetrakis(1-methyl-4-pyridyl)-21H,23H-porphine tetra-p-tosylate (H2TMePyP), the Cu(II) complexes of H2TTMePP and H2TMePyP, as well as chlorophyll a with xanthine, theophylline (1,3-dimethylxanthine) and theobromine (3,7-dimethylxanthine) has been studied analysing their absorption and steady-state fluorescence spectra in aqueous (or acetone in case of chlorophyll a) solution. During titration by the compounds from xanthine group the bathochromic effect in the porphyrin absorption spectra as well as the hypochromicity of the porphyrin Soret maximum can be noticed. The fluorescence quenching effect observed during interactions in the systems examined suggests the process of static quenching. The association and fluorescence quenching constants are of the order of magnitude of 103 - 102 mol-1. The results obtained show that xanthine and its derivatives can quench the fluorescence of the porphyrins according to the number of methyl groups in the molecule of quencher.

  10. Spectroscopic evidence of β-turn in N-glycated peptidomimetics related to leucine-enkephalin

    NASA Astrophysics Data System (ADS)

    Vass, E.; Hollósi, M.; Kveder, M.; Kojić-Prodić, B.; Čudić, M.; Horvat, Š.

    2000-11-01

    The conformational differences caused by N-glycation of the amide bond in endogenous opioid pentapeptide leucine-enkephalin (Tyr-Gly-Gly-Phe-Leu) have been explored in solution using FTIR spectroscopy, NMR and molecular modelling. The compounds studied include protected and unprotected enkephalin analogues N-alkylated at the second (Gly 2) amino acid residue with a 6-deoxy- D-galactose moiety ( 1- 3). Comparison of the amide I component bands in the FTIR spectra, measured in trifluoroethanol (TFE), CHCl 3 and DMSO, revealed significant differences in the intensity as well as shifts in component band frequencies for glycopeptides 1- 3. We found that only the FTIR spectrum of the fully protected compound 1 indicated the presence of a higher population of β-turns, while the spectra of the partially protected and unprotected glycopeptides 2 and 3 reflected the dominance of unordered or open structures, with some low population of turns. The observed NOE connectivities in CDCl 3 for both isomers of the fully protected compound 1, the all-trans one and another with Tyr 1-Gly 2 peptide bond in cis conformation, indicate the presence of a β-like turn conformation. Molecular dynamics simulations of the glycopeptide 1 obtained by unconstrained energy minimization of trans- and cis- 1 shows that one of trans form conformations is consistent with β-turn whereas cis isomer has revealed less-compact turn.

  11. Spectroscopic Evidence of Uranium Immobilization in Acidic Wetlands by Natural Organic Matter and Plant Roots

    EPA Science Inventory

    Biogeochemistry of uranium in wetlands plays important roles in U immobilization in storage ponds of U mining and processing facilities but has not been well understood. The objective of this work was to study molecular mechanisms responsible for high U retention by Savannah Ri...

  12. Spectroscopic evidence for nanosecond protein relaxation after photodissociation of myoglobin-CO.

    PubMed

    Esquerra, R M; Goldbeck, R A; Kim-Shapiro, D B; Kliger, D S

    1998-12-15

    Nanosecond time-resolved absorption and magnetic optical rotatory dispersion (MORD) measurements of photolyzed myoglobin-CO visible bands (500-650 nm) are presented. These measurements reveal a 400 ns process, spectrally distinct from ligand recombination, that accounts for 7% of the observed spectral evolution in the visible absorption bands and 4% in the MORD. The time-resolved MORD, more sensitive to heme coordination geometry than absorption, suggests that this process is most likely associated with protein relaxation on the distal side of the heme pocket, perhaps accompanying rehydration of the deoxymyoglobin photoproduct or accommodation of protein side chains to ligand escape. PMID:9860868

  13. Spectroscopic analysis of chromium bioremediation products

    NASA Astrophysics Data System (ADS)

    Varadharajan, C.; Nico, P. S.; Yang, L.; Marcus, M. A.; Steefel, C.; Larsen, J. T.; Beller, H. R.; Brodie, E. L.

    2010-12-01

    Remediation of chromium contamination frequently involves reducing the toxic and soluble hexavalent form, Cr(VI), to the relatively harmless and mostly immobile trivalent state, Cr(III). The objective of this study is to identify the biogeochemical reactions that control in situ chromium reduction in the presence of different dominant electron acceptors, i.e., NO3-, Fe(III), and SO42-. It was hypothesized that indirect, abiotic reduction of Cr(VI) by reduced metabolic products [Fe(II) and sulfides] would dominate over direct enzymatic reduction by denitrifying, iron-reducing, or sulfate-reducing bacteria. It is further hypothesized that the enzymatic reduction of Cr(VI) would produce relatively pure chromium hydroxide precipitates, whereas indirect reduction would result in mixed Cr-Fe hydroxide solid phases. Flow-through columns containing homogenized sediments from the 100H site at Hanford, WA were subjected to nitrate-, sulfate- or iron-reducing conditions in the presence of 5 µM Cr(VI) and 5 mM lactate. Cr(VI) was depleted in the effluent solutions from the nitrate- and sulfate-reducing columns; however only a small amount of Cr(VI) was removed under iron-reducing conditions. Preliminary analysis of micro X-ray absorption spectra indicate that the untreated and iron-reducing column sediments contained pre-existing Cr in the form of primary minerals, e.g. chromite and/or Cr-bearing micas. However, there was an increase in the relative abundance of mixed-phase Cr-Fe hydroxides, i.e., Cr1-xFex(OH)3 in the nitrate- and sulfate-treated columns. A possible explanation for the observations is that the production of Fe(II) was enhanced under the nitrate- and sulfate- reducing conditions, and was most likely sulfide-driven in the latter case. The Fe(II) was subsequently available for reduction of Cr(VI) resulting in the mixed-phase precipitates. The results from the spectroscopic analysis support the hypothesis that Fe(II)-mediated Cr reduction prevails over direct

  14. The Ultraviolet Spectroscopic Legacy of HST

    NASA Astrophysics Data System (ADS)

    Ayres, Thomas R.

    2016-01-01

    Hubble Space Telescope has been a spectacularly successful platform for spectroscopy in the diagnostic-rich far-ultraviolet (FUV: 120-170 nm) and near-ultraviolet (NUV: 170-310 nm) regions. HST has hosted four generations of UV instruments, beginning with Faint Object Spectrograph (FOS) and Goddard High-Resolution Spectrograph (GHRS) in the original 1990 payload, followed by Space Telescope Imaging Spectrograph (STIS) in 1997, and more recently Cosmic Origins Spectrograph (COS) as part of Servicing Mission 4 in 2009. The latter two instruments have contributed by far the lion's share of HST's spectroscopic archive: STIS, because of its longevity (thirteen years in operation so far, although with a hiatus between 2004-2009); and COS because of its high sensitivity, which allows efficient observations, and thus many more targets in a typical GO program. STIS benefits from a compact echelle design, and the sharp stable imaging of HST, to provide high-resolution (3-7 km s-1) spectra of bright objects, including stars, nebulae, quasars, novae, and so forth. COS achieves astounding sensitivity in the FUV by a sophisticated design that compensates for the spherical abberation of HST's primary mirror, disperses the target's light, and focuses the spectral image all with just a single optical element. While the spectral resolution of COS (about 18 km s-1) is not as high as that of STIS, it is adequate for diverse investigations, including faint broad-lined AGN at the edge of the Universe, hot stars in nearby galaxies, and magnetically active planet-hosting red dwarfs in the solar neighborhood. Thanks in part to the "UV Initiative" in recent HST proposal cycles, there have been several large efforts involving both STIS and COS, to assemble important spectral collections, including full UV atlases of representative hot and cool stars at high resolution with STIS; long time series of archetype AGN ("reverberation mapping") with COS; and hundreds of sightlines to distant

  15. Spectroscopic Fingerprint of Phase-Incoherent Superconductivity in the Underdoped Bi2Sr2CaCu2O8+δ

    SciTech Connect

    Lee, J.; Davis, J.; Fujita, K.; Schmidt, A.R.; Kim, C.K.; Eisaki, H.; Uchida, S.

    2009-08-28

    A possible explanation for the existence of the cuprate 'pseudogap' state is that it is a d-wave superconductor without quantum phase rigidity. Transport and thermodynamic studies provide compelling evidence that supports this proposal, but few spectroscopic explorations of it have been made. One spectroscopic signature of d-wave superconductivity is the particle-hole symmetric 'octet' of dispersive Bogoliubov quasiparticle interference modulations. Here we report on this octet's evolution from low temperatures to well into the underdoped pseudogap regime. No pronounced changes occur in the octet phenomenology at the superconductor's critical temperature T{sub c}, and it survives up to at least temperature T {approx} 1.5 T{sub c}. In this pseudogap regime, we observe the detailed phenomenology that was theoretically predicted for quasiparticle interference in a phase-incoherent d-wave superconductor. Thus, our results not only provide spectroscopic evidence to confirm and extend the transport and thermodynamics studies, but they also open the way for spectroscopic explorations of phase fluctuation rates, their effects on the Fermi arc, and the fundamental source of the phase fluctuations that suppress superconductivity in underdoped cuprates.

  16. The CHARA Catalog of Orbital Elements of Spectroscopic Binary Stars

    NASA Astrophysics Data System (ADS)

    Taylor, S. F.; McAlister, H. A.; Harvin, J. A.

    2003-12-01

    Optical interferometry is entering a new age with several ground-based longbaseline observatories now making observations of unprecedented resolution. Interferometers bring a new level of resolution to bear on spectroscopic binaries, enabling the full extraction of the physical parameters for the component stars with high accuracy. In the case of double-lined systems, a geometrically determined orbital parallax becomes available as well. The first step in preparing to observe spectroscopic binaries is to list them, which has not been done since the 1989 publication of the Eighth Catalogue of the Orbital Elements of Spectroscopic Binaries by Batten, et al. (1989). We present a new catalog with roughly half again as many listings as the Eighth Catalog. Angular separation predictions are made for each catalog entry. The numbers of spectroscopic binaries available for study as a function of several important observational parameters are explored, and in particular, the number of spectroscopic binaries as a function of expected separation is discussed. CHARA gratefully acknowledges the support of the National Science Foundation, the offices of the Dean of the College of Arts and Sciences, the Vice President for Research at Georgia State University, the W.M. Keck Foundation, and the David and Lucile Packard Foundation.

  17. ON THE SPECTROSCOPIC CLASSES OF NOVAE IN M33

    SciTech Connect

    Shafter, A. W.; Darnley, M. J.; Bode, M. F.; Ciardullo, R.

    2012-06-20

    We report the initial results from an ongoing multi-year spectroscopic survey of novae in M33. The survey resulted in the spectroscopic classification of six novae (M33N 2006-09a, 2007-09a, 2009-01a, 2010-10a, 2010-11a, and 2011-12a) and a determination of rates of decline (t{sub 2} times) for four of them (2006-09a, 2007-09a, 2009-01a, and 2010-10a). When these data are combined with existing spectroscopic data for two additional M33 novae (2003-09a and 2008-02a), we find that five of the eight novae with available spectroscopic class appear to be members of either the He/N or Fe IIb (hybrid) classes, with only two clear members of the Fe II spectroscopic class. This initial finding is very different from what would be expected based on the results for M31 and the Galaxy where Fe II novae dominate, and the He/N and Fe IIb classes together make up only {approx}20% of the total. It is plausible that the increased fraction of He/N and Fe IIb novae observed in M33 thus far may be the result of the younger stellar population that dominates this galaxy, which is expected to produce novae that harbor generally more massive white dwarfs than those typically associated with novae in M31 or the Milky Way.

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

    SciTech Connect

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

    2013-08-01

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

  19. Multiple-perturbation two-dimensional (2D) correlation analysis for spectroscopic imaging data

    NASA Astrophysics Data System (ADS)

    Shinzawa, Hideyuki; Hashimoto, Kosuke; Sato, Hidetoshi; Kanematsu, Wataru; Noda, Isao

    2014-07-01

    A series of data analysis techniques, including multiple-perturbation two-dimensional (2D) correlation spectroscopy and kernel analysis, were used to demonstrate how these techniques can sort out convoluted information content underlying spectroscopic imaging data. A set of Raman spectra of polymer blends consisting of poly(methyl methacrylate) (PMMA) and polyethylene glycol (PEG) were collected under varying spatial coordinates and subjected to multiple-perturbation 2D correlation analysis and kernel analysis by using the coordinates as perturbation variables. Cross-peaks appearing in asynchronous correlation spectra indicated that the change in the spectral intensity of the free Cdbnd O band of the PMMA band occurs before that of the Cdbnd O⋯Hsbnd O band arising from the molecular interaction between PMMA and PEG. Kernel matrices, generated by carrying out 2D correlation analysis on principal component analysis (PCA) score images, revealed subtle but important discrepancy between the patterns of the images, providing additional interpretation to the PCA in an intuitively understandable manner. Consequently, the results provided apparent spectroscopic evidence that PMMA and PEG in the blends are partially miscible at the molecular level, allowing the PMMAs to respond to the perturbations in different manner.

  20. A SPECTROSCOPICALLY NORMAL TYPE Ic SUPERNOVA FROM A VERY MASSIVE PROGENITOR

    SciTech Connect

    Valenti, Stefano; Pastorello, Andrea; Benetti, Stefano; Cappellaro, Enrico; Tomasella, Lina; Turatto, Massimo; Taubenberger, Stefan; Aramyan, Levon; Botticella, Maria Teresa; Fraser, Morgan; Smartt, Stephen J.; Magill, Lindsay; Kotak, Rubina; Wright, Darryl E.; Elias-Rosa, Nancy; Ergon, Mattias; Sollerman, Jesper; Magnier, Eugene; Price, Paul A.

    2012-04-20

    We present observations of the Type Ic supernova (SN Ic) 2011bm spanning a period of about one year. The data establish that SN 2011bm is a spectroscopically normal SN Ic with moderately low ejecta velocities and with a very slow spectroscopic and photometric evolution (more than twice as slow as SN 1998bw). The Pan-STARRS1 retrospective detection shows that the rise time from explosion to peak was {approx}40 days in the R band. Through an analysis of the light curve and the spectral sequence, we estimate a kinetic energy of {approx}7-17 foe and a total ejected mass of {approx}7-17 M{sub Sun }, 5-10 M{sub Sun} of which is oxygen and 0.6-0.7 M{sub Sun} is {sup 56}Ni. The physical parameters obtained for SN 2011bm suggest that its progenitor was a massive star of initial mass 30-50 M{sub Sun }. The profile of the forbidden oxygen lines in the nebular spectra shows no evidence of a bi-polar geometry in the ejected material.

  1. Spectroscopic Orbits for 15 Late-type Stars

    NASA Astrophysics Data System (ADS)

    Willmarth, Daryl W.; Fekel, Francis C.; Abt, Helmut A.; Pourbaix, Dimitri

    2016-08-01

    Spectroscopic orbital elements are determined for 15 stars with periods from 8 to 6528 days with six orbits computed for the first time. Improved astrometric orbits are computed for two stars and one new orbit is derived. Visual orbits were previously determined for four stars, four stars are members of multiple systems, and five stars have Hipparcos “G” designations or have been resolved by speckle interferometry. For the nine binaries with previous spectroscopic orbits, we determine improved or comparable elements. For HD 28271 and HD 200790, our spectroscopic results support the conclusions of previous authors that the large values of their mass functions and lack of detectable secondary spectrum argue for the secondary in each case being a pair of low-mass dwarfs. The orbits given here may be useful in combination with future interferometric and Gaia satellite observations.

  2. Addressing spectroscopic quality of covariant density functional theory

    NASA Astrophysics Data System (ADS)

    Afanasjev, A. V.

    2015-03-01

    The spectroscopic quality of covariant density functional theory has been accessed by analyzing the accuracy and theoretical uncertainties in the description of spectroscopic observables. Such analysis is first presented for the energies of the single-particle states in spherical and deformed nuclei. It is also shown that the inclusion of particle-vibration coupling improves the description of the energies of predominantly single-particle states in medium and heavy-mass spherical nuclei. However, the remaining differences between theory and experiment clearly indicate missing physics and missing terms in covariant energy density functionals. The uncertainties in the predictions of the position of two-neutron drip line sensitively depend on the uncertainties in the prediction of the energies of the single-particle states. On the other hand, many spectroscopic observables in well deformed nuclei at ground state and finite spin only weakly depend on the choice of covariant energy density functional.

  3. The Dominion Astrophysical Observatory Spectroscopic Plate and Science Archives

    NASA Astrophysics Data System (ADS)

    Bohlender, D.; Griffin, E.

    2012-09-01

    We briefly describe two archiving efforts being undertaken at the Herzberg Institute of Astrophysics and the Canadian Astronomy Data Centre to ensure that more than 90 years of spectroscopic data from the two telescope of the Dominion Astrophysical Observatory (DAO) are safely preserved and made readily available to archival researchers around the world in a standard digital form. The DAO Spectroscopic Plate Archive project involves the digitization and conversion to FITS format of more than 100,000 spectroscopic plates obtained with the DAO 1.8 m Plaskett and 1.2 m telescopes since 1918 and 1962 respectively. In parallel, the DAO Science Archive has been established to automatically store newly acquired CCD FITS files and their associated metadata and make these available to PIs within a few minutes of acquisition as well as any archive users after a one-year proprietary period.

  4. Update on New Spectroscopic Orbits of Potential Interferometric Binaries

    NASA Astrophysics Data System (ADS)

    Fekel, Francis C.; Williamson, Michael; Muterspaugh, Matthew; Tomkin, Jocelyn

    2015-08-01

    We update the status of a program to obtain radial velocities from high-resolution, red-wavelength spectra to improve the orbits of bright known spectroscopic binaries that are potential targets of ground-based interferometers. Of the 51 systems that have been extensively observed in this project, four or 8% have been found spectroscopically to have a long period companion, making the systems at least triple. Most of the 25 systems still to be published are solar-type stars or late-type giants, and we have detected the secondary of nine former single-lined spectroscopic binaries. The combination of spectroscopy and astrometry from interferometric observations will result in three-dimensional orbits and will produce systems with mass uncertainties less than 1% and well determined distances. Orbital inclinations for some of our stars can also be obtained with astrometry from the GAIA mission.

  5. Spectroscopic characterization of nanocrystalline chromium nitride (CrN).

    PubMed

    Mangamma, G; Sairam, T N; Dash, S; Rajalakshmi, M; Kamruddin, M; Mittal, V K; Narasimhan, S V; Arora, A K; Sundar, C S; Tyagi, A K; Raj, Baldev

    2007-03-01

    Nanocrystalline chromiuim nitride has been synthesised by direct gas phase nitridation of nanocrystalline chromia at 1100 degrees C in ammonia-atmosphere. XRD of this material showed formation of single phase CrN with particle size around 20 nm. AFM studies showed particle distribution along with some soft agglomerated nanostructures. Nanocrystalline Cr2O3 and partially-as well as fully--converted nanocrystalline CrN were also investigated using various spectroscopic techniques like XPS, FT-IR, and Raman for gaining insight into the conversion pathways. Spectroscopic investigations of these materials clearly indicate that complete conversion of CrN occurs by nitriding at 1100 degrees C for 4 hrs. The salient spectroscopic features of these nanocrystalline materials with respect to their microcrystalline counterparts are discussed. PMID:17450861

  6. Passive Spectroscopic Diagnostics for Magnetically-confined Fusion Plasmas

    SciTech Connect

    Stratton, B. C.; Biter, M.; Hill, K. W.; Hillis, D. L.; Hogan, J. T.

    2007-07-18

    Spectroscopy of radiation emitted by impurities and hydrogen isotopes plays an important role in the study of magnetically-confined fusion plasmas, both in determining the effects of impurities on plasma behavior and in measurements of plasma parameters such as electron and ion temperatures and densities, particle transport, and particle influx rates. This paper reviews spectroscopic diagnostics of plasma radiation that are excited by collisional processes in the plasma, which are termed 'passive' spectroscopic diagnostics to distinguish them from 'active' spectroscopic diagnostics involving injected particle and laser beams. A brief overview of the ionization balance in hot plasmas and the relevant line and continuum radiation excitation mechanisms is given. Instrumentation in the soft X-ray, vacuum ultraviolet, ultraviolet, visible, and near-infrared regions of the spectrum is described and examples of measurements are given. Paths for further development of these measurements and issues for their implementation in a burning plasma environment are discussed.

  7. Quantification of UV-Visible and Laser Spectroscopic Techniques for Materials Accountability and Process Control

    SciTech Connect

    Czerwinski, Kenneth; Weck, Phil

    2013-09-13

    UV-Visible spectroscopy studies. The use of TRLFS to examine Cm and U will provide data to evaluate lifetime, peak location, and peak ratios (mainly for U). The bases for the spectroscopic techniques have been investigated, providing fundamental evidence for the application’s utility.

  8. Spectroscopic studies of gas-phase molecular clusters

    NASA Astrophysics Data System (ADS)

    Wong, Chi-Kin

    Spectroscopic investigations of hydrogen-bonding and van der Waals' interactions in molecular clusters were studied by the techniques of infrared predissociation and resonance-enhanced multiphoton ionization spectroscopies (REMPI). Ab initio calculations were applied in conjunction for data interpretation. The infrared predissociation spectroscopy of CN-·(H 2O)n (n = 2--6) clusters was reported in the region of 2950--3850 cm-1. The hydrogen bondings for the C-site and N-site binding, and among the water molecules were identified for n = 2 to 4. A spectral transition was observed for n = 5 and 6, implying that the anion was surface-bound onto the water aggregates in larger clusters. The infrared predissociation spectroscopy of Br-·(NH 3) and I-·(NH3) n (n = 1--3) clusters was reported in the region of 3050--3450 cm-1. For the Br -·(NH3) complex, a dominating ionic NH stretch appeared at 3175 cm-1, and the weaker free NH stretch appeared at 3348 cm-1. The observed spectrum was consistent to the structure in which there was one nearly linear hydrogen bond between Br- and the NH3 moiety. For the I- ·(NH3) complex, five distinct IR absorption bands were observed in the spectrum. The spectrum was not consistent with basic frequency patterns of three geometries considered in the ab initio calculations---complex with one, two and three hydrogen bondings between I- and the NH3 moiety. Substantial inhomogenous broadening were displayed in the spectra for I- ·(NH3)n (n = 2--3), suggesting the presence of multiple isomers. The REMPI spectroscopy of the bound 4p 2pi 1/2 and 2pi3/2 states, and the dissociative 3d 2Sigma+1/2 state in the Al·Ar complex was reported. The dissociative spectrum at Al+ channel suggested the coupling of the 4p 2pi 1/2,3/2 states to the repulsive 3d 2Sigma+1/2 state. The spin-electronic coupling was further manifested in the dissociative Al+ spectrum of the 3d 2Sigma+1/2 state. Using the potential energy curves obtained from ab initio

  9. Infrared laser spectroscopic trace gas sensing

    NASA Astrophysics Data System (ADS)

    Sigrist, Markus

    2016-04-01

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

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

    SciTech Connect

    Bardayan, D. W.; Nesaraja, C. D.; Pain, S. D.; Smith, M. S.; O'Malley, P. D.; Cizewski, J. A.; Hatarik, R.; Peters, W. A.; Blackmon, J. C.; Chae, K. Y.; Jones, K. L.; Moazen, B. H.; Paulauskas, S.; Pittman, S. T.; Schmitt, K. T.; Chipps, K. A.; Kozub, R. L.; Shriner, J. F. Jr.; Matei, C.

    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. A survey of third components in spectroscopic and eclipsing systems

    NASA Astrophysics Data System (ADS)

    Herczeg, T. J.

    1988-03-01

    A magnitude-limited (V = 6.8) survey of systems found in the Seventh Catalogue of Spectroscopic Binaries (Batten et al., 1978) is used to investigate internally stable triple systems of the type ab-c. Emphasis is placed on systems where the close pair is a spectroscopic or eclipsing binary with orbital dimensions of the order of 1-2 AU or less. With allowance for observational bias, the ratio of double to multiple systems is found to approach 1:1. Multiplicities in the W UMa system and in cataclysmic variables are also considered.

  12. SB9: The ninth catalogue of spectroscopic binary orbits

    NASA Astrophysics Data System (ADS)

    Pourbaix, D.; Tokovinin, A. A.; Batten, A. H.; Fekel, F. C.; Hartkopf, W. I.; Levato, H.; Morrell, N. I.; Torres, G.; Udry, S.

    2004-09-01

    The Ninth Catalogue of Spectroscopic Binary Orbits (http://sb9.astro.ulb.ac.be) continues the series of compilations of spectroscopic orbits carried out over the past 35 years by Batten and collaborators. As of 2004 May 1st, the new Catalogue holds orbits for 2386 systems. Some essential differences between this catalogue and its predecessors are outlined and three straightforward applications are presented: (1) completeness assessment: period distribution of SB1s and SB2s; (2) shortest periods across the H-R diagram; (3) period-eccentricity relation.

  13. Tailored interfaces for metal-matrix composites - fundamental considerations. Annual report, 1 October 1989-30 September 1990

    SciTech Connect

    Fine, M.E.; Weertman, J.R.

    1990-10-31

    The objective of this research is to determine the interface properties needed for successful metal matrix composites and to learn how to achieve these properties. A number of factors have been selected for the study. These are thermodynamic stability of the interface, nature of the bonding across the interface, energy and structure of the interface, and role of adsorption at the interface. A number of systems have been chosen to probe these factors; namely, Al/TiC, Al/alpha-Al2O3, A1/MgAl2O4(spinel), Al/Al3(Tix, Zr1-x), Mg/SiC, Mg/MgO, and Mg/Al2O3. Techniques for preparing all of these composites have been worked out, including mechanical alloying followed by extrusion, arc melting, and liquid metal infiltration. MMCs also were obtained from Martin Marietta and Dow. Microstructures of the resulting MMCs are presented and discussed along with preliminary studies of some of the interfaces using transmission electron microscopy. In comparison to Al/SiC, Al/TiC and Mg/SiC show no evidence of chemical reaction at the interface during processing. Al/MgAl2O4(spinel) has superior mechanical properties to Al/alpha-AlO3, both prepared identically.

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

    NASA Technical Reports Server (NTRS)

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

    1988-01-01

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

  15. 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.

  16. 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

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

    NASA Astrophysics Data System (ADS)

    Kurhekar, Anil Sudhakar; Apte, Prakash R.

    2013-02-01

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

  18. 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.

  19. Fourier-transform Raman spectroscopic study of pigments in native American Indian rock art: Seminole Canyon

    NASA Astrophysics Data System (ADS)

    Edwards, H. G. M.; Drummond, L.; Russ, J.

    1998-10-01

    Samples of rock art (ca. 3000-4200 years BP) from the Lower Pecos region of Texas, near the confluences of the Pecos and Devils rivers with the Rio Grande, have been analysed using Raman microscopy. This rock art represents some of the finest pictographs known in North America. The red pigment is confirmed to be red ochre (iron (III) oxide and clay) whereas the black pigment is manganese (IV) oxide. White areas of the paintings are identified as calcium oxalate monohydrate (whewellite), whose presence could indicate the previous colonisation of the shelter walls by lichens. The black pigmented areas only contained Raman spectroscopic evidence for organic matter which was probably used as a binding agent.

  20. Gypsum-hosted endolithic communities of the Lake St. Martin impact structure, Manitoba, Canada: spectroscopic detectability and implications for Mars

    NASA Astrophysics Data System (ADS)

    Rhind, T.; Ronholm, J.; Berg, B.; Mann, P.; Applin, D.; Stromberg, J.; Sharma, R.; Whyte, L. G.; Cloutis, E. A.

    2014-09-01

    There is increasing evidence that Mars may have once been a habitable environment. Gypsum is targeted in the search for Martian biosignatures because it can host extensive cryptoendolithic communities in extreme terrestrial environments and is widespread on Mars. In this study the viability of using different spectroscopy-based techniques to identify the presence of gypsum endolithic communities was investigated by analysing various cryptoendoliths collected from the Lake St. Martin impact crater (LSM), a Mars analogue site found in Manitoba, Canada. Concurrently, the cryptoendolithic microbial community structure present was also analysed to aid in assigning spectroscopic features to microbial community members. Two main morphologies of endolithic communities were collected from gypsum deposits at LSM: true cryptoendolithic communities and annular deposits on partially buried boulders and cobbles <1 cm below the soil surface. Endolithic communities were found to be visibly present only in gypsum with a high degree of translucency and could occur as deep as 3 cm below the exterior surface. The bacterial community was dominated by a phylum (Chloroflexi) that has not been previously observed in gypsum endoliths. The exterior surfaces of gypsum boulders and cobbles are devoid of spectroscopic features attributable to organic molecules and detectable by reflectance, Raman, or ultraviolet-induced fluorescence spectroscopies. However, exposed interior surfaces show unique endolithic signatures detectable by each spectroscopic technique. This indicates that cryptoendolithic communities can be detected via spectroscopy-based techniques, provided they are either partially or fully exposed and enough photon-target interactions occur to enable detection.

  1. Evidence For The Production Of Slow Antiprotonic Hydrogen In Vacuum

    SciTech Connect

    Zurlo, N.; Rizzini, E. Lodi; Venturelli, L.; Amoretti, M.; Macri, M.; Testera, G.; Variola, A.; Amsler, C.; Pruys, H.; Regenfus, C.; Bonomi, G.; Carraro, C.; Lagomarsino, V.; Manuzio, G.; Cesar, C. L.; Charlton, M.; Joergensen, L. V.; Madsen, N.; Mitchard, D.; Werf, D. P. van der

    2006-10-13

    We present evidence showing how antiprotonic hydrogen, the quasistable antiproton (p)-proton bound system, has been synthesized following the interaction of antiprotons with the molecular ion H{sub 2}{sup +} in a nested Penning trap environment. From a careful analysis of the spatial distributions of antiproton annihilation events, evidence is presented for antiprotonic hydrogen production with sub-eV kinetic energies in states around n=70, and with low angular momenta. The slow antiprotonic hydrogen may be studied using laser spectroscopic techniques.

  2. Evidence for the production of slow antiprotonic hydrogen in vacuum.

    PubMed

    Zurlo, N; Amoretti, M; Amsler, C; Bonomi, G; Carraro, C; Cesar, C L; Charlton, M; Doser, M; Fontana, A; Funakoshi, R; Genova, P; Hayano, R S; Jørgensen, L V; Kellerbauer, A; Lagomarsino, V; Landua, R; Rizzini, E Lodi; Macrì, M; Madsen, N; Manuzio, G; Mitchard, D; Montagna, P; Posada, L G; Pruys, H; Regenfus, C; Rotondi, A; Testera, G; Van der Werf, D P; Variola, A; Venturelli, L; Yamazaki, Y

    2006-10-13

    We present evidence showing how antiprotonic hydrogen, the quasistable antiproton (p)-proton bound system, has been synthesized following the interaction of antiprotons with the molecular ion H2+ in a nested Penning trap environment. From a careful analysis of the spatial distributions of antiproton annihilation events, evidence is presented for antiprotonic hydrogen production with sub-eV kinetic energies in states around n=70, and with low angular momenta. The slow antiprotonic hydrogen may be studied using laser spectroscopic techniques. PMID:17155325

  3. [Authentication of Trace Material Evidence in Forensic Science Field with Infrared Microscopic Technique].

    PubMed

    Jiang, Zhi-quan; Hu, Ke-liang

    2016-03-01

    In the field of forensic science, conventional infrared spectral analysis technique is usually unable to meet the detection requirements, because only very a few trace material evidence with diverse shapes and complex compositions, can be extracted from the crime scene. Infrared microscopic technique is developed based on a combination of Fourier-transform infrared spectroscopic technique and microscopic technique. Infrared microscopic technique has a lot of advantages over conventional infrared spectroscopic technique, such as high detection sensitivity, micro-area analysisand nondestructive examination. It has effectively solved the problem of authentication of trace material evidence in the field of forensic science. Additionally, almost no external interference is introduced during measurements by infrared microscopic technique. It can satisfy the special need that the trace material evidence must be reserved for witness in court. It is illustrated in detail through real case analysis in this experimental center that, infrared microscopic technique has advantages in authentication of trace material evidence in forensic science field. In this paper, the vibration features in infrared spectra of material evidences, including paints, plastics, rubbers, fibers, drugs and toxicants, can be comparatively analyzed by means of infrared microscopic technique, in an attempt to provide powerful spectroscopic evidence for qualitative diagnosis of various criminal and traffic accident cases. The experimental results clearly suggest that infrared microscopic technique has an incomparable advantage and it has become an effective method for authentication of trace material evidence in the field of forensic science. PMID:27400510

  4. Inhibition of urinary calculi -- a spectroscopic study

    NASA Astrophysics Data System (ADS)

    Manciu, Felicia; Govani, Jayesh; Durrer, William; Reza, Layra; Pinales, Luis

    2008-10-01

    Although a considerable number of investigations have already been undertaken and many causes such as life habits, metabolic disorders, and genetic factors have been noted as sources that accelerate calculi depositions and aggregations, there are still plenty of unanswered questions regarding efficient inhibition and treatment mechanisms. Thus, in an attempt to acquire more insights, we propose here a detailed scientific study of kidney stone formation and growth inhibition based on a traditional medicine approach with Rotula Aquatica Lour (RAL) herbal extracts. A simplified single diffusion gel growth technique was used for synthesizing the samples for the present study. The unexpected Zn presence in the sample with RAL inhibitor, as revealed by XPS measurements, explains the inhibition process and the dramatic reflectance of the incident light observed in the infrared transmission studies. Raman data demonstrate potential binding of the inhibitor with the oxygen of the kidney stone. Photoluminescence results corroborate to provide additional evidence of Zn-related inhibition.

  5. THE X-RAY VARIABILITY OF A LARGE, SERENDIPITOUS SAMPLE OF SPECTROSCOPIC QUASARS

    SciTech Connect

    Gibson, Robert R.; Brandt, W. N.

    2012-02-10

    We analyze the X-ray variability of 264 Sloan Digital Sky Survey spectroscopic quasars using the Chandra public archive. This data set consists of quasars with spectroscopic redshifts out to z Almost-Equal-To 5 and covers rest-frame timescales up to {Delta}t{sub sys} Almost-Equal-To 2000 days, with three or more X-ray observations available for 82 quasars. It therefore samples longer timescales and higher luminosities than previous large-scale analyses of active galactic nucleus (AGN) variability. We find significant ({approx}>3{sigma}) variation in Almost-Equal-To 30% of the quasars overall; the fraction of sources with detected variability increases strongly with the number of available source counts up to Almost-Equal-To 70% for sources with {>=}1000 counts per epoch. Assuming that the distribution of fractional variation is Gaussian, its standard deviation is Almost-Equal-To 16% on {approx}>1 week timescales, which is not enough to explain the observed scatter in quasar X-ray-to-optical flux ratios as being due to variability alone. We find no evidence in our sample that quasars are more variable at higher redshifts (z > 2), as has been suggested in previous studies. Quasar X-ray spectra vary similarly to some local Seyfert AGNs in that they steepen as they brighten, with evidence for a constant, hard spectral component that is more prominent in fainter stages. We identify one highly variable Narrow Line Seyfert 1-type spectroscopic quasar in the Chandra Deep Field-North. We constrain the rate of kilosecond-timescale flares in the quasar population using Almost-Equal-To 8 months of total exposure and also constrain the distribution of variation amplitudes between exposures; extreme changes (>100%) are quite rare, while variation at the 25% level occurs in <25% of observations. [O III] {lambda}5007 A emission may be stronger in sources with lower levels of X-ray variability; if confirmed, this would represent an additional link between small-scale (corona) and

  6. Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Pan, Y.-C.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-06-01

    We report the following classifications of optical transients from spectroscopic observations with KOSMOS on the KPNO Mayall 4-m telescope. Targets were supplied by the Pan-STARRS Survey for Transients (PSST), All-Sky Automated Survey for Supernovae (ASAS-SN) and MASTER.

  7. Review of Spectroscopic Data for Measurements of Stratospheric Species

    NASA Technical Reports Server (NTRS)

    Goldman, A. (Editor); Hoell, J. M., Jr. (Editor)

    1980-01-01

    Results and recommendations from a two day workshop are discussed. A review of the current status of experimental and theoretical spectroscopic data on molecules of stratospheric interest is given along with recommendations for additional research. Methods for disseminating new and existing data are also discussed.

  8. MOLECULAR OPTICAL SPECTROSCOPIC TECHNIQUES FOR HAZARDOUS WASTE SITE SCREENING

    EPA Science Inventory

    The U.S. Environmental Protection Agency is interested in field screening hazardous waste sites for contaminants in the soil and surface and ground water. his study is an initial technical overview of the principal molecular spectroscopic techniques and instrumentation currently ...

  9. Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Pan, Y.-C.; Downing, S.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-01-01

    We report the following classifications of optical transients from spectroscopic observations with the KOSMOS on the Mayall telescope. Targets were supplied by the All-Sky Automated Survey for Supernovae (ASAS-SN), Catalina Real-Time Transient Survey (CRTS) and the CBAT Transient Object Followup Reports.

  10. LEAD SORPTION ON RUTHENIUM OXIDE: A MACROSCOPIC AND SPECTROSCOPIC STUDY

    EPA Science Inventory

    The sorption and desorption of Pb on RuO2 xH2O were examined kinetically and thermodynamically via spectroscopic and macroscopic investigations. X-ray absorption spectroscopy (XAS) was employed to determine the sorption mechanism with regard to identity of nearest atomic neighbo...

  11. Ultraminiature one-shot Fourier-spectroscopic tomography

    NASA Astrophysics Data System (ADS)

    Sato, Shun; Qi, Wei; Kawashima, Natsumi; Nogo, Kosuke; Hosono, Satsuki; Nishiyama, Akira; Wada, Kenji; Ishimaru, Ichiro

    2016-02-01

    We propose one-shot Fourier-spectroscopic tomography as a method of ultraminiature spectroscopic imaging. The apparatus used in this technique consists solely of a glass slab with a portion of its surface polished at a certain inclination angle-a device we term a relative-inclination phase shifter-simply mounted on an infinite-distance-corrected optical imaging system. For this reason, the system may be ultraminiaturized to sizes on the order of a few tens of millimeters. Moreover, because our technique uses a near-common-path wavefront-division phase-shift interferometer and has absolutely no need for a mechanical drive unit, it is highly robust against mechanical vibrations. In addition, because the proposed technique uses Fourier-transform spectroscopy, it offers highly efficient light utilization and an outstanding signal-to-noise ratio compared to devices that incorporate distributed or hyperspectral acousto-optical tunable filters. The interferogram, which is a pattern formed by interference of waves at all wavelengths, reflects the spatial variation in the intensity of the interference depending on the magnitude of the phase shift. We first discuss the design of the phase shifter and the results of tests to validate the principles underlying one-shot Fourier-spectroscopic tomography. We then report the results of one-dimensional spectroscopic imaging using this technique.

  12. Supramolecular Inclusion in Cyclodextrins: A Pictorial Spectroscopic Demonstration

    ERIC Educational Resources Information Center

    Haldar, Basudeb; Mallick, Arabinda; Chattopadhyay, Nitin

    2008-01-01

    A spectroscopic experiment is presented that reveals that the hydrophobically end-modified water-soluble polymeric fluorophore, pyrene end-capped poly(ethylene oxide) (PYPY), interacts differently with [alpha], [beta], and [gamma]-cyclodextrins (CD) to form supramolecular inclusion complexes. The emission spectrum of PYPY in aqueous solution shows…

  13. Spectroscopic orbit for HDE 245770 A0535+26

    SciTech Connect

    Hutchings, J.B.

    1984-04-01

    Optical spectroscopic data are examined using the X-ray intensity period of 111 days. Optical and X-ray pulse-timing orbit parameters agree well and indicate an eccentricity of approximately 0.3. Masses of the stars and periastron effects are discussed. 6 references.

  14. Spectroscopic Classification of PS16chs with SOAR/Goodman

    NASA Astrophysics Data System (ADS)

    Miller, J. A.; Hounsell, R. A.; Pan, Y.-C.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-05-01

    We report the classification of PS16chs from spectroscopic observation with the Goodman spectrograph on the SOAR telescope. The observation was made on 2016 May 08 UT. We classify PS16chs as a SN Ia near maximum light at z = 0.19.

  15. Time-resolved spectroscopic techniques in laser medicine

    NASA Astrophysics Data System (ADS)

    Ortega-Martínez, Roberto; Román-Moreno, Carlos J.; Rodríguez-Rosales, Antonio A.

    2000-10-01

    Spectroscopic lasers techniques are very useful for the detection and treatment of cancer and removing atherosclerotic plaque. Photobiology and photochemical studies, with the new generation of lasers high resolution time-resolved optical tomography is mentioned. A brief review of some of these applications is discussed and a partial list of recent references is given.

  16. Eta Car's spectroscopic event begins to differ from 2009

    NASA Astrophysics Data System (ADS)

    Davidson, Kris; Mehner, Andrea; Humphreys, Roberta; Ishibash, K.; Martin, J. C.

    2014-08-01

    The middle of eta Car's 2014.6 spectroscopic event (periastron passage) occurred in mid-August (ATEL #6334, #6336, #6357, #6368, #6380). HST/STIS observations on July 13, July 30, and August 15 strongly suggest that the exotic He II 4687 emission is reappearing sooner than in the 2009.1 event.

  17. Contribution to the Wednesday afternoon discussion on spectroscopic factors

    SciTech Connect

    Barbieri, C.

    2005-10-14

    This part of the discussion would like to review the concept of spectroscopic factors and how they relate to measured cross sections and nuclear correlations. A profound knowledge of how correlations affect the spectral function can help to better understand transfer reactions. Nowadays, we have a fairly complete picture for protons in stable nuclei but a lot remain to be learned regarding exotic species.

  18. Spectroscopic probes of vibrationally excited molecules at chemically significant energies

    SciTech Connect

    Rizzo, T.R.

    1993-12-01

    This project involves the application of multiple-resonance spectroscopic techniques for investigating energy transfer and dissociation dynamics of highly vibrationally excited molecules. Two major goals of this work are: (1) to provide information on potential energy surfaces of combustion related molecules at chemically significant energies, and (2) to test theoretical modes of unimolecular dissociation rates critically via quantum-state resolved measurements.

  19. Optical Spectroscopic Diagnostics Of Dusty Plasma In RF Discharge

    SciTech Connect

    Orazbayev, S. A.; Jumagulov, M. N.; Dosbolayev, M. K.; Silamiya, M.; Ramazanov, T. S.; Boufendi, L.

    2011-11-29

    The parameters of the buffer plasma containing dust particles were measured by means of spectroscopic methods. The change in the emission spectrum of the buffer plasma with addition of dust was observed. It seems to relate to changing in temperature and number density of electrons due to the influence of dusts.

  20. 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 nℓj=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.

  1. Arsenate Adsorption On Ruthenium Oxides: A Spectroscopic And Kinetic Investigation

    EPA Science Inventory

    Arsenate adsorption on amorphous (RuO2•1.1H2O) and crystalline (RuO2) ruthenium oxides was evaluated using spectroscopic and kinetic methods to elucidate the adsorption mechanism. Extended X-ray absorption fine structure spectroscopy (EXAFS) was ...

  2. Pollution Police: How to Determine Spectroscopic Selection Rules

    ERIC Educational Resources Information Center

    Selco, Jodye I.; Beery, Janet

    2004-01-01

    Students employ mathematics and physical chemistry in a project called Pollution Police to establish spectroscopic selection rules, and apply them to detect environmental contaminants from infrared spectra. This interdisciplinary project enables students to gain multiple information on molecular symmetry, and its role in the development of…

  3. Extraction, Purification, and Spectroscopic Characterization of a Mixture of Capsaicinoids

    ERIC Educational Resources Information Center

    Wagner, Carl E.; Cahill, Thomas M.; Marshall, Pamela A.

    2011-01-01

    This laboratory experiment provides a safe and effective way to instruct undergraduate organic chemistry students about natural-product extraction, purification, and NMR spectroscopic characterization. On the first day, students extract dried habanero peppers with toluene, perform a pipet silica gel column to separate carotenoids from…

  4. A Visual-Spectroscopic Orbit for the Binary Sigma 248

    NASA Astrophysics Data System (ADS)

    Torres, Guillermo

    1995-06-01

    Spectroscopic studies of visual binaries with angular separations less than about 1" have so far had great difficulty in providing the individual radial velocities for the components, because of the small velocity differences that are typical in these systems. The recent introduction of TODCOR, a two-dimensional cross-correlation technique (Zucker and Mazeh 1994), promises to change the situation, bridging the gap between the wider pairs resolvable at the telescope, and the classical double-lined spectroscopic binaries, with large velocity amplitudes. We present the first example of an application of TODCOR to such a case: the study of the close visual pair Sigma 248. We report our high-resolution low signal-to-noise spectroscopic observations of the system over the past seven years, which happen to cover the periastron passage. Using TODCOR, we are able to disentangle the light from the two stars in our composite spectra and obtain radial velocities for both components despite the small velocity difference. By combining our velocities with all available astrometric observations of the pair we derive for the first time a visual-spectroscopic orbital solution, with a period of about 310 years. We obtain also the orbital parallax of the system, corresponding to a distance of 60 parsecs, as well as the individual masses, which are consistent with early K-type dwarfs. (SECTION: Stars)

  5. The spectroscopic foundation of CO2 climate forcing

    NASA Astrophysics Data System (ADS)

    Mlynczak, M. G.; Daniels, T.; Kratz, D. P.; Collins, W.; Feldman, D.; Lawler, J. E.; Anderson, L. W.; Fahey, D. W.; Hunt, L. A.

    2015-12-01

    The radiative forcing (RF) of carbon dioxide (CO2) is the leading contribution to climate change from anthropogenic activities. Calculating CO2 RF requires detailed knowledge of spectral line parameters and lineshape functions for thousands of infrared absorption lines. A reliable spectroscopic characterization of CO2 forcing is therefore a critical input to scientific and policy-oriented assessments of present climate and future climate change. Our study is partly motivated by a recent assertion that CO2 RF values, and hence predictions of climate sensitivity to elevated CO2, have a significant high bias because the CO2 spectroscopic parameters being used are incorrect. Our results show that CO2 RF in a variety of atmospheres is remarkably insensitive to known uncertainties in the three main CO2 spectroscopic parameters: the line strengths, half widths, and line shapes. We demonstrate that this is due largely to the definition of CO2 RF, which is the difference between the CO2 longwave net flux at the tropopause for doubled CO2 concentrations from the preindustrial era. We also assess the effects of sub-Lorentzian wings of CO2 lines and find that the computed RF is largely insensitive to the spectral lineshape function. Overall, the spectroscopic uncertainty in present-day CO2 RF is less than a few percent. Our study highlights the basics and subtleties of RF calculations, addressing interests of the expert and non-expert.

  6. FIRE NIR spectroscopic classifications of ASASSN-15as

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

    We report the spectroscopic classification of ASASSN-15as (ATel #6919) using a near-infrared spectrum (range 800-2500 nm) obtained on Jan 14.31 UT with the FoldedPort Infrared Echellette (FIRE) spectrograph on the 6.5-m Magellan Baade Telescope at Las Campanas Observatory.

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  8. FIRE NIR spectroscopic classifications of ASASSN-15fy

    NASA Astrophysics Data System (ADS)

    Morrell, N.; Phillips, M. M.; Hsiao, E. Y.; Stritzing, Maximilian

    2015-04-01

    We report the spectroscopic classification of ASASSN-15fy (ATel #7348) using a near-infrared spectrum (range 800-2500 nm) obtained on Apr 7.41 UT with the FoldedPort Infrared Echellette (FIRE) spectrograph on the 6.5-m Magellan Baade Telescope at Las Campanas Observatory.

  9. Spectroscopic Classifications of Optical Transients with Mayall/KOSMOS

    NASA Astrophysics Data System (ADS)

    Pan, Y.-C.; Kilpatrick, C. D.; Siebert, M. R.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-08-01

    We report the following classifications of optical transients from spectroscopic observations with KOSMOS on the KPNO Mayall 4-m telescope. Targets were supplied by the Pan-STARRS Survey for Transients (PSST) and the All-Sky Automated Survey for Supernovae (ASAS-SN).

  10. Spectroscopic Classifications of Optical Transients with SOAR/Goodman

    NASA Astrophysics Data System (ADS)

    Miller, J. A.; Hounsell, R. A.; Pan, Y.-C.; Kilpatrick, C. D.; Foley, R. J.; Jha, S. W.; Rest, A.; Scolnic, D.

    2016-08-01

    We report a classification of optical transients from spectroscopic observations with the Goodman spectrograph on the SOAR telescope. Targets were supplied by the All-Sky Automated Survey for Supernovae (ASAS-SN) and the Pan-STARRS Survey for Transients (PSST).

  11. Spectroscopic Classification of ASASSN-16bx and ASASSN-16cy

    NASA Astrophysics Data System (ADS)

    Frank, S.; Prieto, J. L.; Stanek, K. Z.

    2016-03-01

    We report optical spectroscopic observations of ASASSN-16bx (ATel #8712) and ASASSN-16cy (ATel #8801) obtained by S. Frank on UT 2016 March 14-15 with OSMOS (range 398-686 nm) mounted on the MDM 2.4m telescope at KPNO.

  12. CSP spectroscopic classification of J11405890-442957

    NASA Astrophysics Data System (ADS)

    Morrell, N.; Hsiao, E. Y.; Phillips, M.; Di Mille, F.; Osip, D.; Palunas, P.; Beletsky, Y.

    2014-04-01

    The Carnegie Supernova Project reports the spectroscopic classification of PSN J11405890-442957 (discovered by G. Bock from the BOSS collaboration) based on an optical sepctrum (range 370-950 nm) obtained at Las Campanas Observatory with the 6.5-m Magellan Baade telescope (+IMACS) on April 19, UT. ...

  13. The GEISA Spectroscopic Database System in its latest Edition

    NASA Astrophysics Data System (ADS)

    Jacquinet-Husson, N.; Crépeau, L.; Capelle, V.; Scott, N. A.; Armante, R.; Chédin, A.

    2009-04-01

    GEISA (Gestion et Etude des Informations Spectroscopiques Atmosphériques: Management and Study of Spectroscopic Information)[1] is a computer-accessible spectroscopic database system, designed to facilitate accurate forward planetary radiative transfer calculations using a line-by-line and layer-by-layer approach. It was initiated in 1976. Currently, GEISA is involved in activities related to the assessment of the capabilities of IASI (Infrared Atmospheric Sounding Interferometer on board the METOP European satellite -http://earth-sciences.cnes.fr/IASI/)) through the GEISA/IASI database[2] derived from GEISA. Since the Metop (http://www.eumetsat.int) launch (October 19th 2006), GEISA/IASI is the reference spectroscopic database for the validation of the level-1 IASI data, using the 4A radiative transfer model[3] (4A/LMD http://ara.lmd.polytechnique.fr; 4A/OP co-developed by LMD and Noveltis with the support of CNES). Also, GEISA is involved in planetary research, i.e.: modelling of Titan's atmosphere, in the comparison with observations performed by Voyager: http://voyager.jpl.nasa.gov/, or by ground-based telescopes, and by the instruments on board the Cassini-Huygens mission: http://www.esa.int/SPECIALS/Cassini-Huygens/index.html. The updated 2008 edition of GEISA (GEISA-08), a system comprising three independent sub-databases devoted, respectively, to line transition parameters, infrared and ultraviolet/visible absorption cross-sections, microphysical and optical properties of atmospheric aerosols, will be described. Spectroscopic parameters quality requirement will be discussed in the context of comparisons between observed or simulated Earth's and other planetary atmosphere spectra. GEISA is implemented on the CNES/CNRS Ether Products and Services Centre WEB site (http://ether.ipsl.jussieu.fr), where all archived spectroscopic data can be handled through general and user friendly associated management software facilities. More than 350 researchers are

  14. Role of Optical Spectroscopic Methods in Neuro-Oncological Sciences

    PubMed Central

    Bahreini, Maryam

    2015-01-01

    In the surgical treatment of malignant tumors, it is crucial to characterize the tumor as precisely as possible. The determination of the exact tumor location as well as the analysis of its properties is very important in order to obtain an accurate diagnosis as early as possible. In neurosurgical applications, the optical, non-invasive and in situ techniques allow for the label-free analysis of tissue, which is helpful in neuropathology. In the past decades, optical spectroscopic methods have been investigated drastically in the management of cancer. In the optical spectroscopic techniques, tissue interrogate with sources of light which are ranged from the ultraviolet to the infrared wavelength in the spectrum. The information accumulation of light can be in a reflection which is named reflectance spectroscopy; or interactions with tissue at different wavelengths which are called fluorescence and Raman spectroscopy. This review paper introduces the optical spectroscopic methods which are used to characterize brain tumors (neuro-oncology). Based on biochemical information obtained from these spectroscopic methods, it is possible to identify tumor from normal brain tissues, to indicate tumor margins, the borders towards normal brain tissue and infiltrating gliomas, to distinguish radiation damage of tissues, to detect particular central nervous system (CNS) structures to identify cell types using particular neurotransmitters, to detect cells or drugs which are optically labeled within therapeutic intermediations and to estimate the viability of tissue and the prediction of apoptosis beginning in vitro and in vivo. The label-free, optical biochemical spectroscopic methods can provide clinically relevant information and need to be further exploited to develop a safe and easy-to-use technology for in situ diagnosis of malignant tumors. PMID:25987969

  15. Role of optical spectroscopic methods in neuro-oncological sciences.

    PubMed

    Bahreini, Maryam

    2015-01-01

    In the surgical treatment of malignant tumors, it is crucial to characterize the tumor as precisely as possible. The determination of the exact tumor location as well as the analysis of its properties is very important in order to obtain an accurate diagnosis as early as possible. In neurosurgical applications, the optical, non-invasive and in situ techniques allow for the label-free analysis of tissue, which is helpful in neuropathology. In the past decades, optical spectroscopic methods have been investigated drastically in the management of cancer. In the optical spectroscopic techniques, tissue interrogate with sources of light which are ranged from the ultraviolet to the infrared wavelength in the spectrum. The information accumulation of light can be in a reflection which is named reflectance spectroscopy; or interactions with tissue at different wavelengths which are called fluorescence and Raman spectroscopy. This review paper introduces the optical spectroscopic methods which are used to characterize brain tumors (neuro-oncology). Based on biochemical information obtained from these spectroscopic methods, it is possible to identify tumor from normal brain tissues, to indicate tumor margins, the borders towards normal brain tissue and infiltrating gliomas, to distinguish radiation damage of tissues, to detect particular central nervous system (CNS) structures to identify cell types using particular neurotransmitters, to detect cells or drugs which are optically labeled within therapeutic intermediations and to estimate the viability of tissue and the prediction of apoptosis beginning in vitro and in vivo. The label-free, optical biochemical spectroscopic methods can provide clinically relevant information and need to be further exploited to develop a safe and easy-to-use technology for in situ diagnosis of malignant tumors. PMID:25987969

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

    SciTech Connect

    Limoges, M.-M.; Bergeron, P. E-mail: bergeron@astro.umontreal.c

    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.

  17. Interpretation of Spectroscopic Markers of Hydrogen Bonds.

    PubMed

    Scheiner, Steve

    2016-07-18

    Quantum calculations are used to examine whether an AH⋅⋅⋅D H-bond is unambiguously verified by a downfield shift of the bridging proton's NMR signal or a red (or blue) shift of the AH stretching frequency in the IR spectrum. It is found that such IR band shifts will occur even if the two groups experience weak or no attractive force, or if they are drawn in so close together that their interaction is heavily repulsive. The mere presence of a proton-acceptor molecule can affect the chemical shielding of a position occupied by a protondonor by virtue of its electron density, even if there is no H-bond present. This density-induced shielding is heavily dependent on position around the proton-acceptor atom, and varies from one group to another. Evidence of a hydrogen bond rests on the measurement of a proton deshielding in excess of what is caused purely by the presence of the proton acceptor species. PMID:27043717

  18. Nonlinear spectroscopic studies of interfacial molecular ordering

    SciTech Connect

    Superfine, R.

    1991-07-01

    The second order nonlinear optical processes of second harmonic generation and sum frequency generation are powerful new probes of surfaces. They possess unusual surface sensitivity due to the symmetry properties of the nonlinear susceptibility. In particular, infrared-visible sum frequency generation (SFG) can obtain the vibrational spectrum of sub-monolayer coverages of molecules. In this thesis, we explore the unique information that can be obtained from SFG. We take advantage of the sensitivity of SFG to the conformation of alkane chains to study the interaction between adsorbed liquid crystal molecules and surfactant treated surfaces. The sign of the SFG susceptibility depends on the sign of the molecular polarizability and the orientation, up or down, of the molecule. We experimentally determine the sign of the susceptibility and use it to determine the absolute orientation to obtain the sign of the molecular polarizability and show that this quantity contains important information about the dynamics of molecular charge distributions. Finally, we study the vibrational spectra and the molecular orientation at the pure liquid/vapor interface of methanol and water and present the most detailed evidence yet obtained for the structure of the pure water surface. 32 refs., 4 figs., 2 tabs.

  19. Spectroscopic properties and stability of hemocyanins

    NASA Astrophysics Data System (ADS)

    Hristova, Rumijana; Dolashka, Pavlina; Stoeva, Stanka; Voelter, Wolfgang; Salvato, Benedetto; Genov, Nicolay

    1997-03-01

    The stability towards thermal and chemical (guanidine hydrochloride) denaturation of oxy- and apo-hemocyanins from the arthropodan organisms Homarus americanus, Maia squinado, Palinurus vulgaris and Carcinus maenas as well as from the molluscs Rapana thomasiana and Viviparus ater have been investigated by fluorescence spectroscopy and circular dichroism. The H. americanus hemocyanin showed an extreme thermostability in comparison to the other investigated hemocyanins. The critical temperature of deviation from linearity ( Tc) of the Arrhenius plot, ln( Q-1 - 1) vs. 1/T, where Q is the protein quantum yield of fluorescence, was calculated to be 87°C for this respiratory protein. The Tc-values for the other hemocyanins range between 63 and 76°C. The respective activation energies for the radiationless thermal deactivation of the excited indole chromophores were calculated to be 37.0-50.5 kJ mol -1. Guanidine hydrochloride is an efficient denaturant for hemocyanins. The protein unfolding was monitored by circular dichroism. The free energy of stabilization in water, Δ GDH 2O , at 25°C and pH 7.5, was calculated to be in the range 8.0-21.6 kJ mol -1. The highest Δ GDH 2O -values were calculated for the Rapana thomasiana hemocyanin. Upon excitation at 295 or 280 nm the fluorescence emission of the investigated hemocyanins is dominated by 'buried' tryptophyl chromophores. The removal of the copper-dioxygen system from the active site led to 3.8-7.9-fold increase of the protein fluorescence quantum yield and to a red shift of the emission maximum position. Evidently, the tryptophyl fluorescence is significantly quenched in the oxy-hemocyanins.

  20. DAO Spectroscopic Study of Nova Cygni 1992

    NASA Astrophysics Data System (ADS)

    Garnavich, Peter M.

    1992-12-01

    for evidence of coronal lines in the optical.

  1. Spectroscopic Binaries in the Orion Nebula Cluster and NGC 2264

    NASA Astrophysics Data System (ADS)

    Kounkel, Marina; Hartmann, Lee; Tobin, John J.; Mateo, Mario; Bailey, John I., III; Spencer, Meghin

    2016-04-01

    We examine the spectroscopic binary population for two massive nearby regions of clustered star formation, the Orion Nebula Cluster (ONC) and NGC 2264, supplementing the data presented by Tobin et al. with more recent observations and more extensive analysis. The inferred multiplicity fraction up to 10 au based on these observations is 5.3 ± 1.2% for NGC 2264 and 5.8 ± 1.1% for the ONC; these values are consistent with the distribution of binaries in the field in the relevant parameter range. Eight of the multiple systems in the sample have enough epochs to perform an initial fit for the orbital parameters. Two of these sources are double-lined spectroscopic binaries; for them, we determine the mass ratio. Our reanalysis of the distribution of stellar radial velocities toward these clusters presents a significantly better agreement between stellar and gas kinematics than was previously thought.

  2. Automated shimming of B0 for spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Tropp, James; Derby, Kevin A.; Hawryszko, Christine; Sugiura, Satoshi; Yamagata, Hitoshi

    A method for automated shimming of B0 in whole body imaging magnets is demonstrated. The method employs spectroscopic imaging [ T. R. Brown, B. M. Kincaid, and K. Ugurbil, Proc. Natl. Acad. Sci. USA, 79, 3532, 1982 ] of 1H to map the B0 field of the region of interest with the subject in situ. Correction currents for the shims, based on prior measurement of shim fields versus shim currents, are then calculated and applied by computer. The chief application of the method is shimming for multivoxel spectroscopy examinations in vivo wherein it is shown to produce marked improvement of 31P spectra from spectroscopic imaging exams of brain and calf muscle, in normal and diseased subjects.

  3. Orbital lesions: proton spectroscopic phase-dependent contrast MR imaging.

    PubMed

    Atlas, S W; Grossman, R I; Axel, L; Hackney, D B; Bilaniuk, L T; Goldberg, H I; Zimmerman, R A

    1987-08-01

    Thirteen orbital lesions in 12 patients were evaluated with both conventional spin-echo magnetic resonance (MR) imaging and phase-dependent proton spectroscopic imaging. This technique, which makes use of small differences in the resonant frequencies of water and fat protons, provides excellent high-resolution images with simultaneous chemical shift information. In this method, there is 180 degrees opposition of phase between fat protons and water protons at the time of the gradient echo, resulting in signal cancellation in voxels containing equal signals from fat and water. In this preliminary series, advantages of spectroscopic images in orbital lesions included better lesion delineation, with superior anatomic definition of orbital apex involvement; more specific characterization of high-intensity hemorrhage with a single pulse sequence; elimination of potential confusion from chemical shift misregistration artifact; further clarification of possible intravascular flow abnormalities; and improved apparent intralesional contrast. PMID:3602394

  4. 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

  5. Spectroscopic Studies of the Several Isomers of UO3

    SciTech Connect

    Sweet, Lucas E.; Reilly, Dallas D.; Abrecht, David G.; Buck, Edgar C.; Meier, David E.; Su, Yin-Fong; Brauer, Carolyn S.; Schwantes, Jon M.; Tonkyn, Russell G.; Szecsody, James E.; Blake, Thomas A.; Johnson, Timothy J.

    2013-09-26

    Uranium trioxide is known to adopt seven different structural forms. While these structural forms have been well characterized using x-ray or neutron diffraction techniques, little work has been done to characterize their spectroscopic properties, particularly of the pure phases. Since the structural isomers of UO3 all have similar thermodynamic stabilities and most tend to hydrolyze under open atmospheric conditions, mixtures of UO3 phases and the hydrolysis products are common. Much effort went into isolating pure phases of UO3. Utilizing x-ray diffraction as a sample identification check, UV/Vis/NIR spectroscopic signatures of α-UO3, β-UO3, γ-UO3 and UO2(OH)2 products were obtained. The spectra of the pure phases can now be used to characterize typical samples of UO3, which are often mixtures of isomers.

  6. Toward proton MR spectroscopic imaging of stimulated brain function

    SciTech Connect

    Singh, M. . Dept. of Radiology)

    1992-08-01

    With the objective of complementing local cerebral metabolic studies of PET, and as a prelude to spectroscopic imaging, the authors have performed the first localized proton spectroscopic study of the stimulated human auditory cortex. Water suppressed localized spectroscopy (voxel size 3cm [times] 3cm [times] 3cm enclosing the auditory cortex, Te = 272ms, Tr = 3s) was performed on a 1.5T MRI/MRS system and spectra were acquired during stimulation with a 1kHz tone presented at 2Hz. Measurements were conducted for 30-40 min with a temporal resolution of 3.2 min (64 averages per time block). Results included in this paper from six subjects show a lactate peak which increases during stimulation compared to baseline values. These results suggest an increase in anaerobic glycolysis during stimulation and provide unique and valuable information that should complement glucose metabolism and flood flow studies of PET.

  7. 4MOST: 4m Multi Object Spectroscopic Telescope

    NASA Astrophysics Data System (ADS)

    Depagne, Éric

    4MOST (4m Multi Object Spectroscopic Telescope) is a spectroscopic facility that will be installed on ESO's VISTA around 2020. The science rationale of this facility are to be found in the ASTRONET Science Vision for European Astronomy (de Zeeuw & Molster, (eds) A Science Vision for European Astronomy, Astronet 2007. ISBN 978-3-923524-62-4). Specifically fundamental contribution can be made to the Extreme Universe (Dark Energy & Dark Matter, Black holes), Galaxy Formation & Evolution, and the Origin of Stars science cases in the ASTRONET Science Vision. The unique capabilities of the 4MOST facility are due to by its large field-of-view, high multiplex, its broad optical spectral wavelength coverage

  8. The magnetic field of the hot spectroscopic binary HD 5550

    NASA Astrophysics Data System (ADS)

    Neiner, C.; Alecian, E.

    2015-12-01

    HD 5550 is a spectroscopic binary composed of two A stars observed with Narval at TBL in the frame of the BinaMIcS (Binarity and Magnetic Interactions in various classes of Stars) Large Program. One component of the system is found to be an Ap star with a surprisingly weak dipolar field of ˜65 G. The companion is an Am star for which no magnetic field is detected, with a detection threshold on the dipolar field of ˜40 G. The system is tidally locked, the primary component is synchronised with the orbit, but the system is probably not completely circularised yet. This work is only the second detailed study of magnetic fields in a hot short-period spectroscopic binary. More systems are currently being observed with both Narval at TBL and ESPaDOnS at CFHT within the BinaMIcS project, with the goal of understanding how magnetism can impact binary evolution and vice versa.

  9. Benford analysis: A useful paradigm for spectroscopic analysis

    NASA Astrophysics Data System (ADS)

    Bhole, Gaurav; Shukla, Abhishek; Mahesh, T. S.

    2015-10-01

    Benford's law is a statistical inference to predict the frequency of significant digits in naturally occurring numerical databases. In such databases this law predicts a higher occurrence of the digit 1 in the most significant place and decreasing occurrences to other larger digits. Although counter-intuitive at first sight, Benford's law has seen applications in a wide variety of fields like physics, earth-science, biology, finance, etc. In this work, we have explored the use of Benford's law for various spectroscopic applications. Although, we use NMR signals as our databases, the methods described here may also be extended to other spectroscopic techniques. In particular, with the help of Benford analysis, we demonstrate emphasizing weak NMR signals and spectral corrections. We also explore a potential application of Benford analysis in the image-processing of MRI data.

  10. Spectroscopic and Interferometric Measurements of Nine K Giant Stars

    NASA Astrophysics Data System (ADS)

    Baines, Ellyn K.; Döllinger, Michaela P.; Guenther, Eike W.; Hatzes, Artie P.; Hrudkovu, Marie; van Belle, Gerard T.

    2016-09-01

    We present spectroscopic and interferometric measurements for a sample of nine K giant stars. These targets are of particular interest because they are slated for stellar oscillation observations. Our improved parameters will directly translate into reduced errors in the final masses for these stars when interferometric radii and asteroseismic densities are combined. Here, we determine each star’s limb-darkened angular diameter, physical radius, luminosity, bolometric flux, effective temperature, surface gravity, metallicity, and mass. When we compare our interferometric and spectroscopic results, we find no systematic offsets in the diameters and the values generally agree within the errors. Our interferometric temperatures for seven of the nine stars are hotter than those determined from spectroscopy with an average difference of about 380 K.

  11. Spectroscopic characteristics of chromium-doped mullite glass-ceramics

    SciTech Connect

    Wojtowicz, A.J.; Meng, W.; Lempicki, A.; Beall, G.H.; Hall, D.W.

    1988-06-01

    The chromium (3+) ion has been widely used as an optical activator in solid-state, tunable laser materials. High octahedral field-stabilization energy and resistance against both oxidation and reduction minimize the dependence of chromium (3+) on the solid-state host matrix. However, the high sensitivity of electronic structure on crystal field strength makes the appropriate choice of host the condition for success. Characteristics of chromium-doped mullite ceramics are discussed with reference to possible laser applications. Dominant features are attributed to large and inherent spectroscopic inhomogeneity of mullite. The spectroscopic data are analyzed using a generalized McCumber theory. The peak-stimulated emission cross section is 0.54 x 10 to the -20 sq cm. This together with preliminary single-pass measurements, indicate that gain for mullite is about 2.6 times smaller than gain for alexandrite.

  12. MAMA Spectroscopic Sensitivity and Focus Monitor Cycle 21

    NASA Astrophysics Data System (ADS)

    Sana, Hugues

    2013-10-01

    Monitor sensitivity of each MAMA grating mode to detect any change due tocontamination or other causes. Also monitor the STIS focus in a spectroscopic and animaging mode.Obtain exposures in each of the 2 low-resolution MAMA spectroscopic modes every 4 months, in each of the 2 medium-resolution modes once a year, and in each of the 4 echelle modes every 3 months,using unique calibration standards for each mode, and ratio the results to the firstobservations to detect any trends. In addition, each L-mode sequence will be preceded by twospectroscopic ACQ/PEAKs with the CCD/G230LB and crossed linear patterns, with the purpose of measuringthe focus {PSF across the dispersion as a function of UV wavelength}; and each M-mode sequence will be preceded by aCCD/F28X50OII direct image also to monitor the focus.Whenever possible, obtain parallel airglow spectra with COS.

  13. MAMA Spectroscopic Sensitivity and Focus Monitor Cycle 19

    NASA Astrophysics Data System (ADS)

    Bostroem, Azalee

    2011-10-01

    Monitor sensitivity of each MAMA grating mode to detect any change due tocontamination or other causes. Also monitor the STIS focus in a spectroscopic and animaging mode.Obtain exposures in each of the 2 low-resolution MAMA spectroscopic modes every 4 months, in each of the 2 medium-resolution modes once a year, and in each of the 4 echelle modes every 3 months,using unique calibration standards for each mode, and ratio the results to the firstobservations to detect any trends. In addition, each L-mode sequence will be preceded by twospectroscopic ACQ/PEAKs with the CCD/G230LB and crossed linear patterns, with the purpose of measuringthe focus {PSF across the dispersion as a function of UV wavelength}; and each M-mode sequence will be preceded by aCCD/F28X50OII direct image also to monitor the focus.Whenever possible, obtain parallel airglow spectra with COS.

  14. MAMA Spectroscopic Sensitivity and Focus Monitor Cycle 18

    NASA Astrophysics Data System (ADS)

    Osten, Rachel

    2010-09-01

    Monitor sensitivity of each MAMA grating mode to detect any change due tocontamination or other causes. Also monitor the STIS focus in a spectroscopic and animaging mode.Obtain exposures in each of the 2 low-resolution MAMA spectroscopic modes every 4 months, in each of the 2 medium-resolution modes once a year, and in each of the 4 echelle modes every 3 months,using unique calibration standards for each mode, and ratio the results to the firstobservations to detect any trends. In addition, each L-mode sequence will be preceded by twospectroscopic ACQ/PEAKs with the CCD/G230LB and crossed linear patterns, with the purpose of measuringthe focus {PSF across the dispersion as a function of UV wavelength}; and each M-mode sequence will be preceded by aCCD/F28X50OII direct image also to monitor the focus.Whenever possible, obtain parallel airglow spectra with COS.

  15. MAMA Spectroscopic Sensitivity and Focus Monitor Cycle 20

    NASA Astrophysics Data System (ADS)

    Holland, Stephen

    2012-10-01

    Monitor sensitivity of each MAMA grating mode to detect any change due tocontamination or other causes. Also monitor the STIS focus in a spectroscopic and animaging mode.Obtain exposures in each of the 2 low-resolution MAMA spectroscopic modes every 4 months, in each of the 2 medium-resolution modes once a year, and in each of the 4 echelle modes every 3 months,using unique calibration standards for each mode, and ratio the results to the firstobservations to detect any trends. In addition, each L-mode sequence will be preceded by twospectroscopic ACQ/PEAKs with the CCD/G230LB and crossed linear patterns, with the purpose of measuringthe focus {PSF across the dispersion as a function of UV wavelength}; and each M-mode sequence will be preceded by aCCD/F28X50OII direct image also to monitor the focus.Whenever possible, obtain parallel airglow spectra with COS.

  16. Spectroscopic Constants of the Known Electronic States of Lead Monofluoride

    SciTech Connect

    McRaven, C.P.; Sivakumar, P.; Shafer-Ray, N.E.; Hall, G.E.; Sears, T.J.

    2010-08-01

    Based on measurements made by mass-resolved 1 + 1{prime} + 1{double_prime} resonance-enhanced multiphoton ionization spectroscopy, we have determined new molecular constants describing the rotational and fine structure levels of the B, D, E, and F states of the most abundant isotopic variant {sup 208}Pb{sup 19}F, and we summarize the spectroscopic constants for all the know electronic states of the radical. Many spectroscopic constants for the isotopologues {sup 206}Pb{sup 19}F and {sup 207}Pb{sup 19}F have also been determined. The symmetry of the D-state is found to be {sup 2}{pi}{sub 1/2}, and the F-state is found to be an {Omega} = 3/2 state.

  17. Computation of Spectroscopic Factors with the Coupled-Cluster Method

    SciTech Connect

    Jensen, O.; Hagen, Gaute; Papenbrock, T.; Dean, David Jarvis; Vaagen, J. S.

    2010-01-01

    We present a calculation of spectroscopic factors within coupled-cluster theory. Our derivation of algebraic equations for the one-body overlap functions are based on coupled-cluster equation-of-motion solutions for the ground and excited states of the doubly magic nucleus with mass number A and the odd-mass neighbor with mass A-1. As a proof-of-principle calculation, we consider ^{16}O and the odd neighbors ^{15}O and ^{15}N, and compute the spectroscopic factor for nucleon removal from ^{16}O. We employ a renormalized low-momentum interaction of the V_{low-k} type derived from a chiral interaction at next-to-next-to-next-to-leading order. We study the sensitivity of our results by variation of the momentum cutoff, and then discuss the treatment of the center of mass.

  18. Spectroscopic and Lasing Properties of Rare-Earth Ion Based Laser Materials

    NASA Astrophysics Data System (ADS)

    Petrin, Roger Ronald

    Scope and method of study. The spectroscopic and lasing properties of several rare-earth based laser materials were investigated. The dynamics of energy transfer in Tm,Ho:YAG were studied using time-resolved spectroscopy. The results were used in a rate equation based computer simulation of laser operation. Absorption, fluorescence, and fluorescence excitation spectroscopy were used to investigate the origin of blue emission in Nd:YAG, Nd:GSGG, and Nd:ZBAN. Alexandrite laser pumped lasing properties of Nd:ZBAN were also studied. The effects of a pump wavelength dependent loss mechanism were examined using a rate equation based computer simulation of the Nd:ZBAN laser system. Findings and conclusions. Evidence for energy migration in the rm Tm^{3+} ^3H_4 multiplet was found. A mechanism producing green emission involving excited state absorption of pump photons from the Ho^ {3+} metastable state was also identified. Rate parameters for the relevant energy transfer processes for Tm,Ho:YAG were determined through spectroscopic measurements. Using the spectroscopically determined rate parameters and no fitting parameters, computer simulations of laser operation were able to reproduce the relaxation oscillations and the time delay between the pump and lasing output previously observed experimentally. The origin of the blue emission observed in Nd:YAG and Nd:GSGG was identified as the ^2P_{3/2} multiplet. An excited state absorption process involving a pump photon and an ion excited to the ^4F_ {5/2}, ^2H_{9/2} multiplets was found to populate the ^2P _{3/2} multiplet. Similar processes were also identified in the Nd:ZBAN system and the first laser operation of this material in bulk form was reported. Computer simulations indicated that only in materials with slow non-radiative decay processes and in systems with high peak power pump sources would excited state absorption of pump photons from levels above the metastable state be an important loss mechanism in Nd^{3

  19. Identifying the Young Low-mass Stars within 25 pc. I. Spectroscopic Observations

    NASA Astrophysics Data System (ADS)

    Shkolnik, Evgenya; Liu, Michael C.; Reid, I. Neill

    2009-07-01

    We have completed a high-resolution (R ≈ 60,000) optical spectroscopic survey of 185 nearby M dwarfs identified using ROSAT data to select active, young objects with fractional X-ray luminosities comparable to or greater than Pleiades members. Our targets are drawn from the NStars 20 pc census and the Moving-M sample with distances determined from parallaxes or spectrophotometric relations. We limited our sample to 25 pc from the Sun, prior to correcting for pre-main-sequence overluminosity or binarity. Nearly half of the resulting M dwarfs are not present in the Gliese catalog and have no previously published spectral types. We identified 30 spectroscopic binaries (SBs) from the sample, which have strong X-ray emission due to tidal spin-up rather than youth. This is equivalent to a 16% SB fraction, with at most a handful of undiscovered SBs. We estimate upper limits on the age of the remaining M dwarfs using spectroscopic youth indicators such as surface gravity-sensitive indices (CaH and K I). We find that for a sample of field stars with no metallicity measurements, a single CaH gravity index may not be sufficient, as higher metallicities mimic lower gravity. This is demonstrated in a subsample of metal-rich radial velocity (RV) standards, which appear to have low surface gravity as measured by the CaH index, yet show no other evidence of youth. We also use additional youth diagnostics such as lithium absorption and strong Hα emission to set more stringent age limits. Eleven M dwarfs with no Hα emission or absorption are likely old (>400 Myr) and were caught during an X-ray flare. We estimate that our final sample of the 144 youngest and nearest low-mass objects in the field is less than 300 Myr old, with 30% of them being younger than 150 Myr and four very young (lap10 Myr), representing a generally untapped and well-characterized resource of M dwarfs for intensive planet and disk searches. Based on observations collected at the W. M. Keck Observatory and

  20. Photometric and spectroscopic study of cD galaxies

    NASA Astrophysics Data System (ADS)

    Kemp, S. N.; Pérez-Hernández, Ernesto; Ramírez-Siordia, Víctor Hugo

    2016-02-01

    We have carried out photometry and spectroscopy on a sample of 10 cD galaxies. The photometry shows, in general, fairly flat and red profile colours, implying an envelope with the same stellar population as the central galaxy. This may indicate a possible primordial origin for both structures, consistent with ideas of downsizing. Preliminary spectroscopic results are generally in agreement with the photometry, with for example younger populations at large radii for A2199, but A2589 has only younger populations.

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

    NASA Astrophysics Data System (ADS)

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

    2013-02-01

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

  2. Multidimensional MR spectroscopic imaging of prostate cancer in vivo.

    PubMed

    Thomas, M Albert; Nagarajan, Rajakumar; Huda, Amir; Margolis, Daniel; Sarma, Manoj K; Sheng, Ke; Reiter, Robert E; Raman, Steven S

    2014-01-01

    Prostate cancer (PCa) is the second most common type of cancer among men in the United States. A major limitation in the management of PCa is an inability to distinguish, early on, cancers that will progress and become life threatening. One-dimensional (1D) proton ((1)H) MRS of the prostate provides metabolic information such as levels of choline (Ch), creatine (Cr), citrate (Cit), and spermine (Spm) that can be used to detect and diagnose PCa. Ex vivo high-resolution magic angle spinning (HR-MAS) of PCa specimens has revealed detection of more metabolites such as myo-inositol (mI), glutamate (Glu), and glutamine (Gln). Due to the J-modulation and signal overlap, it is difficult to quantitate Spm and other resonances in the prostate clearly by single- and multivoxel-based 1D MR spectroscopy. This limitation can be minimized by adding at least one more spectral dimension by which resonances can be spread apart, thereby increasing the spectral dispersion. However, recording of multivoxel-based two-dimensional (2D) MRS such as J-resolved spectroscopy (JPRESS) and correlated spectroscopy (L-COSY) combined with 2D or three-dimensional (3D) magnetic resonance spectroscopic imaging (MRSI) using conventional phase-encoding can be prohibitively long to be included in a clinical protocol. To reduce the long acquisition time required for spatial encoding, the echo-planar spectroscopic imaging (EPSI) technique has been combined with correlated spectroscopy to give four-dimensional (4D) echo-planar correlated spectroscopic imaging (EP-COSI) as well as J-resolved spectroscopic imaging (EP-JRESI) and the multi-echo (ME) variants. Further acceleration can be achieved using non-uniform undersampling (NUS) and reconstruction using compressed sensing (CS). Earlier versions of 2D MRS, theory of 2D MRS, spectral apodization filters, newer developments and the potential role of multidimensional MRS in PCa detection and management will be reviewed here. PMID:23904127

  3. Gold nanotip array for ultrasensitive electrochemical sensing and spectroscopic monitoring.

    PubMed

    Jiang, Yueyue; Meng, Fanben; Qi, Dianpeng; Cai, Pingqiang; Yin, Zongyou; Shao, Fangwei; Zhang, Hua; Boey, Freddy; Chen, Xiaodong

    2013-07-01

    A gold nanotip array platform with a combination of ultrasensitive electrochemical sensing and spectroscopic monitoring capability is reported. Adenosine triphosphate is detected down to 1 pM according to the impedance changes in response to aptamer-specific binding. Furthermore, the local molecular information can be monitored at the individual plasmonic nanotips, and hence provide the capability for a better understanding of complex biological processes. PMID:23362212

  4. Asiago spectroscopic classification of SN2016aa in PGC 22658

    NASA Astrophysics Data System (ADS)

    Ciabattari, F.; Tomasella, L.; Pastorello, A.; Benetti, S.; Cappellaro, E.; Elias-Rosa, N.; Ochner, P.; Tartaglia, L.; Terreran, G.; Turatto, M.; Briganti, F.; Caimmi, M.; Campaner, P.; Donati, S.; Mazzoni, E.

    2016-02-01

    We report the spectroscopic classification of SN2016aa in PGC 22658 through observations obtained with the 1.82-m Copernico Telescope in Asiago (+ AFOSC; range 340-820 nm, resolution 1.3 nm). A low signal-to-noise spectrogram obtained on Jan 04.97 UT indicates that SN2016aa is a Type II SNe, a few weeks after the explosion.

  5. Spectroscopic and lasing properties of Ho:Tm:LuAG

    NASA Technical Reports Server (NTRS)

    Barnes, Norman P.; Filer, Elizabeth D.; Naranjo, Felipe L.; Rodriguez, Waldo J.; Kokta, Milan R.

    1993-01-01

    Ho:Tm:LuAG has been grown, examined spectroscopically, and lased at 2.1 microns. Ho:Tm:LuAG was selected for this experimental investigation when quantum-mechanical modeling predicted that it would be a good laser material for Ho laser operation on one of the 5I7 to 5I8 transitions. Lasing was achieved at 2.100 microns, one of the three wavelengths predicted to be most probable for laser action.

  6. Terahertz spectroscopic imaging of a rabbit VX2 hepatoma model

    NASA Astrophysics Data System (ADS)

    Park, Jae Yeon; Choi, Hyuck Jae; Cho, Kyoung-Sik; Kim, Kyu-Rae; Son, Joo-Hiuk

    2011-03-01

    Terahertz (THz) spectroscopic imaging technique was applied to classify the tumor region in the rabbit liver with VX2 hepatocellular carcinoma. Within the measurement range of 0.1-2 THz, the average reflectance values for all tumor samples were more than 4% higher than those for healthy cells, and the terahertz measurements correlated well with histological analysis results. This study on paraffin-embedded tissues showed the alteration of cell density and protein content in tumors, excluding the effect of water.

  7. Spectroscopic investigation of silver in soda-lime glass

    NASA Astrophysics Data System (ADS)

    Borsella, E.; Gonella, F.; Mazzoldi, P.; Quaranta, A.; Battaglin, G.; Polloni, R.

    1998-03-01

    Spectral and time-resolved luminescence of silver in ion-exchanged soda-lime glass are investigated for samples with different Ag concentrations. The evolution of the observed spectroscopic features are correlated with structural changes in the silver environment from a marked ionic position with a weak influence of the surroundings to a configuration characterized by stronger silver-lattice coupling and Ag +-Ag + correlation effects.

  8. QUANTIFYING THE BIASES OF SPECTROSCOPICALLY SELECTED GRAVITATIONAL LENSES

    SciTech Connect

    Arneson, Ryan A.; Brownstein, Joel R.; Bolton, Adam S. E-mail: joelbrownstein@astro.utah.edu

    2012-07-01

    Spectroscopic selection has been the most productive technique for the selection of galaxy-scale strong gravitational lens systems with known redshifts. Statistically significant samples of strong lenses provide a powerful method for measuring the mass-density parameters of the lensing population, but results can only be generalized to the parent population if the lensing selection biases are sufficiently understood. We perform controlled Monte Carlo simulations of spectroscopic lens surveys in order to quantify the bias of lenses relative to parent galaxies in velocity dispersion, mass axis ratio, and mass-density profile. For parameters typical of the SLACS and BELLS surveys, we find (1) no significant mass axis ratio detection bias of lenses relative to parent galaxies; (2) a very small detection bias toward shallow mass-density profiles, which is likely negligible compared to other sources of uncertainty in this parameter; (3) a detection bias toward smaller Einstein radius for systems drawn from parent populations with group- and cluster-scale lensing masses; and (4) a lens-modeling bias toward larger velocity dispersions for systems drawn from parent samples with sub-arcsecond mean Einstein radii. This last finding indicates that the incorporation of velocity-dispersion upper limits of non-lenses is an important ingredient for unbiased analyses of spectroscopically selected lens samples. In general, we find that the completeness of spectroscopic lens surveys in the plane of Einstein radius and mass-density profile power-law index is quite uniform, up to a sharp drop in the region of large Einstein radius and steep mass-density profile, and hence that such surveys are ideally suited to the study of massive field galaxies.

  9. Raman spectroscopic characterization on cervical neoplasm in biopsy direction

    NASA Astrophysics Data System (ADS)

    Shin, Hsiao Hsin; Tsai, Yan Sheng; Wang, Tao Yuan; Chu, Shou Chia; Chiang, Huihua Kenny

    2007-02-01

    Raman spectroscopy was applied to distinguish the spectroscopic information between normal cervical tissues (14) and cervical neoplasia (17), including low grade squamous intraepithelial lesions (6) and high grade squamous intraepithelial lesions (11). Standard pathological sections of these cervical tissues were measured from superficial to stroma layers. We have normalized significant Raman peaks, 1250 and 1579-1656 cm -1 by taking a ratio over a stationary Raman at 1004 cm -1, and successfully discriminated between normal and neoplasm cervical tissues.

  10. Short-time spectroscopic measurement of the temperature of solids

    NASA Astrophysics Data System (ADS)

    Mach, H.

    1984-02-01

    The short-time temperature rise dependent deformation caused by shocks on solids were measured with radiation pyrometric and spectroscopic methods. The methods can only be applied on solids emitting a measurable radiation and are based on spectral radiation and the temperature of the solid. The Planck-Kirchhoff radiation laws and the measuring method are presented. The measuring equipment consists of an image reproducing optical device and a photodetector with spectral or interference filters for wavelength selection.

  11. Iterative methods for determination of parameters of spectroscopic binaries

    NASA Astrophysics Data System (ADS)

    Dworak, T. Z.

    The paper contains the description of iterative methods for determinations of geometric and physical parameters of spectroscopic binaries, especially for computation of orbit plane inclination i and radii of components, which cannot be determined from observations. These methods are based of some considerations given in the previous paper (Dworak 1975). The methods have been tested using data for eclipsing binaries, taken from the catalogues of Batten et al. (1978) and Koch et al. (1970).

  12. List of Estimated Angular Separations of Spectroscopic Binaries

    NASA Astrophysics Data System (ADS)

    Halbwachs, J. L.

    1981-04-01

    The angular separations of the spectroscopic binaries considered in Batten et al. (1978) were calculated. 431 systems (visual binaries excepted), with separations higher than 0".001 are reported, and 361 systems are classed into categories, according to whether their separations are lying between 0".001 and 0".0005, 0".0005 and 0".0002, 0".0002 and 0".0001. 162 systems are found to be closer than 0".0001.

  13. Spectroscopic Factors and Barrier Penetrabilities in Cluster Radioactivity

    SciTech Connect

    Kuklin, S.N.; Adamian, G.G.; Antonenko, N.V.

    2005-09-01

    The cold cluster decay model is presented in the framework of a dinuclear system concept. Spectroscopic factors are extracted from barrier penetrabilities and measured half-lives. The deformation of the light cluster and residual nucleus is shown to affect the nucleus-nucleus potential and decay characteristics. Half-lives are predicted for neutron-deficient actinides and intermediate-mass nuclei. The connection between spontaneous fission and cluster radioactivity is discussed.

  14. Spectroscopic observations of spatial and temporal variations on Venus

    NASA Technical Reports Server (NTRS)

    Young, A. T.; Young, L. G.; Woszczyk, A.

    1974-01-01

    Details of the Table Mountain spectroscopic patrol of Venus in September-October 1972 are given. The data indicate systematic variation over the disc, with more CO2 absorption near the terminator than at the limb, and slightly more in the southern than in the northern hemisphere. The semiregular four-day variation, reported to occur simultaneously over the disk at 8689 A by Young et al. (1973), is confirmed by observations of the 7820 A and 7883 A CO2 bands.

  15. TLUSTY: Stellar Atmospheres, Accretion Disks, and Spectroscopic Diagnostics

    NASA Astrophysics Data System (ADS)

    Hubeny, Ivan; Lanz, Thierry

    2011-09-01

    TLUSTY is a user-oriented package written in FORTRAN77 for modeling stellar atmospheres and accretion disks and wide range of spectroscopic diagnostics. In the program's maximum configuration, the user may start from scratch and calculate a model atmosphere of a chosen degree of complexity, and end with a synthetic spectrum in a wavelength region of interest for an arbitrary stellar rotation and an arbitrary instrumental profile. The user may also model the vertical structure of annuli of an accretion disk.

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

    PubMed

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

    2015-12-01

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

  17. The white dwarfs within 25 pc of the Sun: Kinematics and spectroscopic subtypes

    SciTech Connect

    Sion, Edward M.; McCook, George P.; Wasatonic, Richard; Myszka, Janine; Holberg, J. B.; Oswalt, Terry D. E-mail: george.mccook@villanova.edu E-mail: janine.myszka@villanova.edu E-mail: toswalt@fit.edu

    2014-06-01

    We present the fractional distribution of spectroscopic subtypes, range and distribution of surface temperatures, and kinematical properties of the white dwarfs (WDs) within 25 pc of the Sun. There is no convincing evidence of halo WDs in the total 25 pc sample of 224 WDs. There is also little to suggest the presence of genuine thick disk subcomponent members within 25 pc. It appears that the entire 25 pc sample likely belongs to the thin disk. We also find no significant kinematic differences with respect to spectroscopic subtypes. The total DA to non-DA ratio of the 25 pc sample is 1.8, a manifestation of deepening envelope convection, which transforms DA stars with sufficiently thin H surface layers into non-DAs. We compare this ratio with the results of other studies. We find that at least 11% of the WDs within 25 pc of the Sun (the DAZ and DZ stars) have photospheric metals that likely originate from accretion of circumstellar material (debris disks) around them. If this interpretation is correct, then it suggests the possibility that a similar percentage have planets, asteroid-like bodies, or debris disks orbiting them. Our volume-limited sample reveals a pileup of DC WDs at the well-known cutoff in DQ WDs at T {sub eff} ∼ 6000 K. Mindful of small number statistics, we speculate on its possible evolutionary significance. We find that the incidence of magnetic WDs in the 25 pc sample is at least 8% in our volume-limited sample, dominated by cool WDs. We derive approximate formation rates of DB and DQ degenerates and present a preliminary test of the evolutionary scenario that all cooling DB stars become DQ WDs via helium convective dredge-up with the diffusion tail of carbon extending upward from their cores.

  18. Chromophore-labelled, luminescent platinum complexes: syntheses, structures, and spectroscopic properties.

    PubMed

    Stacey, Oliver J; Ward, Benjamin D; Coles, Simon J; Horton, Peter N; Pope, Simon J A

    2016-06-21

    Ligands based upon 4-carboxamide-2-phenylquinoline derivatives have been synthesised with solubilising octyl hydrocarbon chains and tethered aromatic chromophores to give naphthyl (), anthracenyl () and pyrenyl () ligand variants, together with a non-chromophoric analogue () for comparison. (1)H NMR spectroscopic studies of the ligands showed that two non-interchangeable isomers exist for and while only one isomer exists for and . Supporting DFT calculations on suggest that the two isomers may be closely isoenergetic with a relatively high barrier to exchange of ca. 100 kJ mol(-1). These new ligands were cyclometalated with Pt(ii) to give complexes [Pt()(acac)] (acac = acetylacetonate). The spectroscopically characterised complexes were studied using multinuclear NMR spectroscopy including (195)Pt{(1)H} NMR studies which revealed δPtca. -2785 ppm for [Pt()(acac)]. X-ray crystallographic studies were undertaken on [Pt()(acac)] and [Pt()(acac)], each showing the weakly distorted square planar geometry at Pt(ii); the structure of [Pt()(acac)] showed evidence for intermolecular Pt-Pt interactions. The UV-vis. absorption studies show that the spectral profiles for [Pt()(acac)] are a composite of the organic chromophore centred bands and a broad (1)MLCT (5d → π*) band (ca. 440 nm) associated with the complex. Luminescence studies showed that complexes [Pt()(acac)] are dual emissive with fluorescence characteristic of the tethered fluorophore and long-lived phosphorescence attributed to (3)MLCT emission. In the case of the pyrenyl derivative, [Pt()(acac)], the close energetic matching of the (3)MLCT and (3)LCpyr excited states led to an elongation of the (3)MLCT emission lifetime (τ = 42 μs) under degassed solvent conditions, suggestive of energy transfer processes between the two states. PMID:27241625

  19. The White Dwarfs within 25 pc of the Sun: Kinematics and Spectroscopic Subtypes

    NASA Astrophysics Data System (ADS)

    Sion, Edward M.; Holberg, J. B.; Oswalt, Terry D.; McCook, George P.; Wasatonic, Richard; Myszka, Janine

    2014-06-01

    We present the fractional distribution of spectroscopic subtypes, range and distribution of surface temperatures, and kinematical properties of the white dwarfs (WDs) within 25 pc of the Sun. There is no convincing evidence of halo WDs in the total 25 pc sample of 224 WDs. There is also little to suggest the presence of genuine thick disk subcomponent members within 25 pc. It appears that the entire 25 pc sample likely belongs to the thin disk. We also find no significant kinematic differences with respect to spectroscopic subtypes. The total DA to non-DA ratio of the 25 pc sample is 1.8, a manifestation of deepening envelope convection, which transforms DA stars with sufficiently thin H surface layers into non-DAs. We compare this ratio with the results of other studies. We find that at least 11% of the WDs within 25 pc of the Sun (the DAZ and DZ stars) have photospheric metals that likely originate from accretion of circumstellar material (debris disks) around them. If this interpretation is correct, then it suggests the possibility that a similar percentage have planets, asteroid-like bodies, or debris disks orbiting them. Our volume-limited sample reveals a pileup of DC WDs at the well-known cutoff in DQ WDs at T eff ~ 6000 K. Mindful of small number statistics, we speculate on its possible evolutionary significance. We find that the incidence of magnetic WDs in the 25 pc sample is at least 8% in our volume-limited sample, dominated by cool WDs. We derive approximate formation rates of DB and DQ degenerates and present a preliminary test of the evolutionary scenario that all cooling DB stars become DQ WDs via helium convective dredge-up with the diffusion tail of carbon extending upward from their cores.

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

    PubMed

    Deiner, L Jay; Farjami, Elaheh

    2015-01-01

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

  1. Spectroscopic analysis of a novel Nd3+-activated barium borate glass for broadband laser amplification

    NASA Astrophysics Data System (ADS)

    Vázquez, G. V.; Muñoz H., G.; Camarillo, I.; Falcony, C.; Caldiño, U.; Lira, A.

    2015-08-01

    Spectroscopic parameters of a novel Nd3+-activated barium borate (BBONd) glass have been analyzed for broadband laser amplification. The Judd-Ofelt (JO) intensity parameters were determined through a systematic analysis of the absorption spectrum of Nd3+ ions in the BBONd glass. High values of the JO intensity parameters reveal a great centro-symmetrical loss of the Nd3+ sites and high covalency degree of the ligand field. The very high Ω6 intensity parameter value makes evident both a great structural distortion of the Nd3+ sites and a strong electron-phonon coupling between Nd3+ and free OH- ions, which is consistent with the phonon energy maximum (3442.1 cm-1) recorded by Raman spectroscopy. This strong electron-phonon coupling favors high effective bandwidth and gain bandwidth values of the laser emission (4F3/2 → 4I11/2) of Nd3+ ions. The electric-dipole oscillator strengths of all the Nd3+ absorption transitions, and in particular that of the hypersensitive transition (4I9/2 → 4G5/2), are enhanced by this great structural distortion of the host. Broadband laser amplification of the 4F3/2 → 4I11/2 emission (1062 nm) of Nd3+ ions in the BBONd glass pumped at 805 nm (4I9/2 → 4F5/2 + 2H9/2) is evaluated through the main fluorescent parameters in competition with non-radiative processes. In general, the BBONd glass exhibits spectroscopic parameters comparable with those reported in the literature for broadband laser amplification into the IR region.

  2. Spectroscopic Studies on Organic Matter from Triassic Reptile Bones, Upper Silesia, Poland

    PubMed Central

    Surmik, Dawid; Boczarowski, Andrzej; Balin, Katarzyna; Dulski, Mateusz; Szade, Jacek; Kremer, Barbara; Pawlicki, Roman

    2016-01-01

    Fossil biomolecules from an endogenous source were previously identified in Cretaceous to Pleistocene fossilized bones, the evidence coming from molecular analyses. These findings, however, were called into question and an alternative hypothesis of the invasion of the bone by bacterial biofilm was proposed. Herewith we report a new finding of morphologically preserved blood-vessel-like structures enclosing organic molecules preserved in iron-oxide-mineralized vessel walls from the cortical region of nothosaurid and tanystropheid (aquatic and terrestrial diapsid reptiles) bones. These findings are from the Early/Middle Triassic boundary (Upper Roetian/Lowermost Muschelkalk) strata of Upper Silesia, Poland. Multiple spectroscopic analyses (FTIR, ToF-SIMS, and XPS) of the extracted "blood vessels" showed the presence of organic compounds, including fragments of various amino acids such as hydroxyproline and hydroxylysine as well as amides, that may suggest the presence of collagen protein residues. Because these amino acids are absent from most proteins other than collagen, we infer that the proteinaceous molecules may originate from endogenous collagen. The preservation of molecular signals of proteins within the "blood vessels" was most likely made possible through the process of early diagenetic iron oxide mineralization. This discovery provides the oldest evidence of in situ preservation of complex organic molecules in vertebrate remains in a marine environment. PMID:26977600

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

    SciTech Connect

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

    2001-11-29

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

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

    SciTech Connect

    Wilson, Jennifer C.; Laloo, Andrew Elohim; Singh, Sanjesh; Ferro, Vito

    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-β-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.

  5. 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.

  6. Spectroscopic Studies on Organic Matter from Triassic Reptile Bones, Upper Silesia, Poland.

    PubMed

    Surmik, Dawid; Boczarowski, Andrzej; Balin, Katarzyna; Dulski, Mateusz; Szade, Jacek; Kremer, Barbara; Pawlicki, Roman

    2016-01-01

    Fossil biomolecules from an endogenous source were previously identified in Cretaceous to Pleistocene fossilized bones, the evidence coming from molecular analyses. These findings, however, were called into question and an alternative hypothesis of the invasion of the bone by bacterial biofilm was proposed. Herewith we report a new finding of morphologically preserved blood-vessel-like structures enclosing organic molecules preserved in iron-oxide-mineralized vessel walls from the cortical region of nothosaurid and tanystropheid (aquatic and terrestrial diapsid reptiles) bones. These findings are from the Early/Middle Triassic boundary (Upper Roetian/Lowermost Muschelkalk) strata of Upper Silesia, Poland. Multiple spectroscopic analyses (FTIR, ToF-SIMS, and XPS) of the extracted "blood vessels" showed the presence of organic compounds, including fragments of various amino acids such as hydroxyproline and hydroxylysine as well as amides, that may suggest the presence of collagen protein residues. Because these amino acids are absent from most proteins other than collagen, we infer that the proteinaceous molecules may originate from endogenous collagen. The preservation of molecular signals of proteins within the "blood vessels" was most likely made possible through the process of early diagenetic iron oxide mineralization. This discovery provides the oldest evidence of in situ preservation of complex organic molecules in vertebrate remains in a marine environment. PMID:26977600

  7. Direct visualization of both DNA and RNA quadruplexes in human cells via an uncommon spectroscopic method.

    PubMed

    Laguerre, Aurélien; Wong, Judy M Y; Monchaud, David

    2016-01-01

    Guanine-rich DNA or RNA sequences can fold into higher-order, four-stranded structures termed quadruplexes that are suspected to play pivotal roles in cellular mechanisms including the control of the genome integrity and gene expression. However, the biological relevance of quadruplexes is still a matter of debate owing to the paucity of unbiased evidences of their existence in cells. Recent reports on quadruplex-specific antibodies and small-molecule fluorescent probes help dispel reservations and accumulating evidences now pointing towards the cellular relevance of quadruplexes. To better assess and comprehend their biology, developing new versatile tools to detect both DNA and RNA quadruplexes in cells is essential. We report here a smart fluorescent probe that allows for the simple detection of quadruplexes thanks to an uncommon spectroscopic mechanism known as the red-edge effect (REE). We demonstrate that this effect could open avenues to greatly enhance the ability to visualize both DNA and RNA quadruplexes in human cells, using simple protocols and fluorescence detection facilities. PMID:27535322

  8. Direct visualization of both DNA and RNA quadruplexes in human cells via an uncommon spectroscopic method

    PubMed Central

    Laguerre, Aurélien; Wong, Judy M. Y.; Monchaud, David

    2016-01-01

    Guanine-rich DNA or RNA sequences can fold into higher-order, four-stranded structures termed quadruplexes that are suspected to play pivotal roles in cellular mechanisms including the control of the genome integrity and gene expression. However, the biological relevance of quadruplexes is still a matter of debate owing to the paucity of unbiased evidences of their existence in cells. Recent reports on quadruplex-specific antibodies and small-molecule fluorescent probes help dispel reservations and accumulating evidences now pointing towards the cellular relevance of quadruplexes. To better assess and comprehend their biology, developing new versatile tools to detect both DNA and RNA quadruplexes in cells is essential. We report here a smart fluorescent probe that allows for the simple detection of quadruplexes thanks to an uncommon spectroscopic mechanism known as the red-edge effect (REE). We demonstrate that this effect could open avenues to greatly enhance the ability to visualize both DNA and RNA quadruplexes in human cells, using simple protocols and fluorescence detection facilities. PMID:27535322

  9. Spectroscopic features of cytochrome P450 reaction intermediates

    PubMed Central

    Luthra, Abhinav; Denisov, Ilia G.; Sligar, Stephen G.

    2010-01-01

    Preface Cytochromes P450 constitute a broad class of heme monooxygenase enzymes with more than 11,500 isozymes which have been identified in organisms from all biological kingdoms [1]. These enzymes are responsible for catalyzing dozens chemical oxidative transformations such as hydroxylation, epoxidation, N-demethylation, etc., with very broad range of substrates [2-3]. Historically these enzymes received their name from ‘pigment 450’ due to the unusual position of the Soret band in UV-Vis absorption spectra of the reduced CO-saturated state [4-5]. Despite detailed biochemical characterization of many isozymes, as well as later discoveries of other ‘P450-like heme enzymes’ such as nitric oxide synthase and chloroperoxidase, the phenomenological term ‘cytochrome P450’ is still commonly used as indicating an essential spectroscopic feature of the functionally active protein which is now known to be due to the presence of a thiolate ligand to the heme iron [6]. Heme proteins with an imidazole ligand such as myoglobin and hemoglobin as well as an inactive form of P450 are characterized by Soret maxima at 420 nm [7]. This historical perspective highlights the importance of spectroscopic methods for biochemical studies in general, and especially for heme enzymes, where the presence of the heme iron and porphyrin macrocycle provides rich variety of specific spectroscopic markers available for monitoring chemical transformations and transitions between active intermediates of catalytic cycle. PMID:21167809

  10. Single-particle spectroscopic factors for spherical nuclei

    SciTech Connect

    Gnezdilov, N. V.; Saperstein, E. E. Tolokonnikov, S. V.

    2015-01-15

    Within the self-consistent theory of finite Fermi systems, the total single-particle spectroscopic factors for seven doubly magic nuclei of {sup 40}Ca, {sup 48}Ca, {sup 56}Ni, {sup 78}Ni, {sup 100}Sn, {sup 132}Sn, and {sup 208}Pb and for the {sup 188–212}Pb chain of semimagic even lead isotopes are calculated by the energy-density-functional method implemented with a functional in the form proposed by Fayans and his coauthors. The spectroscopic factor is expressed in terms of the Z factor, which is the residue of the single-particle Green’s function at the single-particle pole. The total Z factor calculated in the present study involves both effects of coupling to phonons and the volume Z factor, which is due to the fact that the mass operator features an energy dependence not associated with surface phonons. The volume Z factor is on the same order of magnitude as the phonon-coupling contribution. The volume effect depends only slightly on the nuclear species and on the single-particle state λ. On the contrary, the phonon contribution to the total spectroscopic factor changes upon going over from one state to another and from one nuclear species to another.

  11. Does DFT-SAPT method provide spectroscopic accuracy?

    SciTech Connect

    Shirkov, Leonid; Makarewicz, Jan

    2015-02-14

    Ground state potential energy curves for homonuclear and heteronuclear dimers consisting of noble gas atoms from He to Kr were calculated within the symmetry adapted perturbation theory based on the density functional theory (DFT-SAPT). These potentials together with spectroscopic data derived from them were compared to previous high-precision coupled cluster with singles and doubles including the connected triples theory calculations (or better if available) as well as to experimental data used as the benchmark. The impact of midbond functions on DFT-SAPT results was tested to study the convergence of the interaction energies. It was shown that, for most of the complexes, DFT-SAPT potential calculated at the complete basis set (CBS) limit is lower than the corresponding benchmark potential in the region near its minimum and hence, spectroscopic accuracy cannot be achieved. The influence of the residual term δ(HF) on the interaction energy was also studied. As a result, we have found that this term improves the agreement with the benchmark in the repulsive region for the dimers considered, but leads to even larger overestimation of potential depth D{sub e}. Although the standard hybrid exchange-correlation (xc) functionals with asymptotic correction within the second order DFT-SAPT do not provide the spectroscopic accuracy at the CBS limit, it is possible to adjust empirically basis sets yielding highly accurate results.

  12. Single-particle spectroscopic factors for spherical nuclei

    NASA Astrophysics Data System (ADS)

    Gnezdilov, N. V.; Saperstein, E. E.; Tolokonnikov, S. V.

    2015-01-01

    Within the self-consistent theory of finite Fermi systems, the total single-particle spectroscopic factors for seven doubly magic nuclei of 40Ca, 48Ca, 56Ni, 78Ni, 100Sn, 132Sn, and 208Pb and for the 188-212Pb chain of semimagic even lead isotopes are calculated by the energy-density-functional method implemented with a functional in the form proposed by Fayans and his coauthors. The spectroscopic factor is expressed in terms of the Z factor, which is the residue of the single-particle Green's function at the single-particle pole. The total Z factor calculated in the present study involves both effects of coupling to phonons and the volume Z factor, which is due to the fact that the mass operator features an energy dependence not associated with surface phonons. The volume Z factor is on the same order of magnitude as the phonon-coupling contribution. The volume effect depends only slightly on the nuclear species and on the single-particle state λ. On the contrary, the phonon contribution to the total spectroscopic factor changes upon going over from one state to another and from one nuclear species to another.

  13. Characterization of semicrystalline polymers after nanoimprint by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

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

  14. Evaluation of Her2 status using photoacoustic spectroscopic CT techniques

    NASA Astrophysics Data System (ADS)

    Shaffer, Michael; Kruger, Robert; Reinecke, Daniel; Chin-Sinex, Helen; Mendonca, Marc; Stantz, Keith M.

    2010-02-01

    Purpose: The purpose of this study is to determine the feasibility of using photacoustic CT spectroscopy(PCT-s) to track a near infrared dye conjugated with trastuzumab in vivo. Materials and Methods: An animal model was developed which contained both high and low Her2 expression tumor xenografts on the same mouse. The tumors were imaged at multiple wavelengths (680- 950nm) in the PCT scanner one day prior to injection of the near infrared conjugated probe. Baseline optical imaging data was acquired and the probe was then injected via the tail vein. Fluorescence data was acquired over the next week, PCT spectroscopic data was also acquired during this timeframe. The mice were sacrificed and tumors were extirpated and sent to pathology for IHC staining to verify Her2 expression levels. The optical fluorescence images were analyzed to determine probe uptake dynamics. Reconstructed PCT spectroscopic data was analyzed using IDL routines to deconvolve the probe signal from endogenous background signals, and to determine oxygen saturation. Results: The location of the NIR conjugate was able to be identified within the tumor utilizing IDL fitting routines, in addition oxygen saturation, and hemoglobin concentrations were discernible from the spectroscopic data. Conclusion: Photacoustic spectroscopy allows for the determination of in vivo tumor drug delivery at greater depths than can be determined from optical imaging techniques.

  15. jSIPRO - analysis tool for magnetic resonance spectroscopic imaging.

    PubMed

    Jiru, Filip; Skoch, Antonin; Wagnerova, Dita; Dezortova, Monika; Hajek, Milan

    2013-10-01

    Magnetic resonance spectroscopic imaging (MRSI) involves a huge number of spectra to be processed and analyzed. Several tools enabling MRSI data processing have been developed and widely used. However, the processing programs primarily focus on sophisticated spectra processing and offer limited support for the analysis of the calculated spectroscopic maps. In this paper the jSIPRO (java Spectroscopic Imaging PROcessing) program is presented, which is a java-based graphical interface enabling post-processing, viewing, analysis and result reporting of MRSI data. Interactive graphical processing as well as protocol controlled batch processing are available in jSIPRO. jSIPRO does not contain a built-in fitting program. Instead, it makes use of fitting programs from third parties and manages the data flows. Currently, automatic spectra processing using LCModel, TARQUIN and jMRUI programs are supported. Concentration and error values, fitted spectra, metabolite images and various parametric maps can be viewed for each calculated dataset. Metabolite images can be exported in the DICOM format either for archiving purposes or for the use in neurosurgery navigation systems. PMID:23870172

  16. Combining spectroscopic and photometric surveys: Same or different sky?

    NASA Astrophysics Data System (ADS)

    Eriksen, Martin; Gaztañaga, Enrique

    2015-08-01

    This paper looks at the combined constraints from a photometric and spectroscopic survey. These surveys will measure cosmology using weak lensing (WL), galaxy clustering, baryon acoustic oscillations (BAO) and redshift space distortions (RSD). We find, contrary to some findings in the recent literature, that overlapping surveys can give important benefits when measuring dark energy. We therefore try to clarify the status of this issue with a full forecast of two stage-IV surveys using a new approach to properly account for covariance between the different probes in the overlapping samples. The benefit of the overlapping survey can be traced back to two factors: additional observables and sample variance cancellation. Both needs to be taken into account and contribute equally when combining 3D power spectrum and 2D correlations for lensing. With an analytic example we also illustrate that for optimal constraints, one should minimize the (Pearson) correlation coefficient between cosmological and nuisance parameters and maximize the one among nuisance parameters (e.g. galaxy bias) in the two samples. This can be achieved by increasing the overlap between the spectroscopic and photometric surveys. We show how BAO, WL and RSD contribute to this benefit and also look at some other survey designs, such as photometric redshift errors and spectroscopic density.

  17. AN H-BAND SPECTROSCOPIC METALLICITY CALIBRATION FOR M DWARFS

    SciTech Connect

    Terrien, Ryan C.; Mahadevan, Suvrath; Bender, Chad F.; Deshpande, Rohit; Ramsey, Lawrence W.; Bochanski, John J.

    2012-03-10

    We present an empirical near-infrared (NIR) spectroscopic method for estimating M dwarf metallicities, based on features in the H band, as well as an implementation of a similar published method in the K band. We obtained R {approx} 2000 NIR spectra of a sample of M dwarfs using the NASA IRTF-SpeX spectrograph, including 22 M dwarf metallicity calibration targets that have FGK companions with known metallicities. The H-band and K-band calibrations provide equivalent fits to the metallicities of these binaries, with an accuracy of {+-}0.12 dex. We derive the first empirically calibrated spectroscopic metallicity estimate for the giant planet-hosting M dwarf GJ 317, confirming its supersolar metallicity. Combining this result with observations of eight other M dwarf planet hosts, we find that M dwarfs with giant planets are preferentially metal-rich compared to those that host less massive planets. Our H-band calibration relies on strongly metallicity-dependent features in the H band, which will be useful in compositional studies using mid- to high-resolution NIR M dwarf spectra, such as those produced by multiplexed surveys like SDSS-III APOGEE. These results will also be immediately useful for ongoing spectroscopic surveys of M dwarfs.

  18. HIPPARCOS PHOTOCENTRIC ORBITS OF 72 SINGLE-LINED SPECTROSCOPIC BINARIES

    SciTech Connect

    Ren Shulin; Fu Yanning E-mail: fyn@pmo.ac.cn

    2013-03-15

    By fitting the Hipparcos Intermediate Astrometric Data (HIAD), photocentric orbits can be obtained for the single-lined spectroscopic binaries (SB1s). In previous work, a simplifying approximation used in the fitting process was that the photocenter coincides with the primary, but simple arguments based on a mass-luminosity relation show that this approximation will introduce non-negligible deviation into photocentric orbits of a few SB1s. By fitting the revised HIAD without the approximation, the present paper tries to provide reliable photocentric orbits for those SB1s in the 9th Catalogue of Orbits of Spectroscopic Binaries having a reliable spectroscopic orbit of period between 50 days and 3.2 years. After a stringent assessment and screening process, we finally accept the photocentric orbits of 72 systems. Among these results, 37 orbits are obtained here for the first time. So far, only three of these systems are resolved with a known relative orbit. For each of them, the paired photocentric and relative orbits are in reasonably good agreement. For the 25 systems with a main-sequence primary, the masses of component stars and the semimajor axes of relative orbits are estimated for the purpose of planning ground-based observations.

  19. Photometric and Spectroscopic Analysis of the Eclipsing Binary DQ Velorum

    NASA Astrophysics Data System (ADS)

    Barría, D.; Mennickent, R. E.; Schmidtobreick, L.; Djurašević, G.; Kołaczkowski, Z.; Michalska, G.; Vučković, M.; Niemczura, E.

    In order to obtain the main stellar and orbital parameters of the Double Periodic Variable DQ Velorum, we have carried out a series of spectroscopic and photometric observations covering several orbital cycles. We disentangle DQ Vel composite spectra and measure radial velocities using an iterative method for double spectroscopic binaries. We obtain the spectroscopic mass ratio q=0.31±0.03 from the radial velocity curves. We compare our single-lined spectra with a grid of synthetic spectra and estimate the temperature of the stars. We also model the V-band light curve using a fitting method based on the simplex algorithm including an accretion disc. We find that DQ Vel is a semi-detached system consisting on a B3V gainer (T_{g}=18500±500 K) and an A1III donor star (T_{d}=9400±100 K) plus an extended accretion disc around the gainer. We compare the stellar and disc parameters of DQ Vel with the DPV V393 Sco to investigate the nature and evolution of these two similar DPV systems.

  20. Parallel multithread computing for spectroscopic analysis in optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Trojanowski, Michal; Kraszewski, Maciej; Strakowski, Marcin; Pluciński, Jerzy

    2014-05-01

    Spectroscopic Optical Coherence Tomography (SOCT) is an extension of Optical Coherence Tomography (OCT). It allows gathering spectroscopic information from individual scattering points inside the sample. It is based on time-frequency analysis of interferometric signals. Such analysis requires calculating hundreds of Fourier transforms while performing a single A-scan. Additionally, further processing of acquired spectroscopic information is needed. This significantly increases the time of required computations. During last years, application of graphical processing units (GPU's) was proposed to reduce computation time in OCT by using parallel computing algorithms. GPU technology can be also used to speed-up signal processing in SOCT. However, parallel algorithms used in classical OCT need to be revised because of different character of analyzed data. The classical OCT requires processing of long, independent interferometric signals for obtaining subsequent A-scans. The difference with SOCT is that it requires processing of multiple, shorter signals, which differ only in a small part of samples. We have developed new algorithms for parallel signal processing for usage in SOCT, implemented with NVIDIA CUDA (Compute Unified Device Architecture). We present details of the algorithms and performance tests for analyzing data from in-house SD-OCT system. We also give a brief discussion about usefulness of developed algorithm. Presented algorithms might be useful for researchers working on OCT, as they allow to reduce computation time and are step toward real-time signal processing of SOCT data.

  1. Raman spectroscopic studies of disordered ferroelectric oxides

    NASA Astrophysics Data System (ADS)

    Savvinov, Alexey A.

    behavior of well know relaxor systems, such as PbMg1/3Nb2/3O3 (PMN) and Pb1-x LaxTiO3 (PLT). Raman scattering was studied in model relaxor ferroelectrics PbSc 1/2Ta1/2O3 (PST) and PMN and in related low-permittivity materials SrAl1/2Ta1/2O3 (SAT), SrAl 1/2Nb1/2O3 (SAN) and BaMg1/3Ta 2/3O3 (BMT). Comparative analysis of the Raman spectra gives evidence that complex perovskites of this type consist of nanoscale clusters with the 1:1 B-site order, irrelevant to whether a stoichiometric composition for the B cations is 1:1 or 1:2. This result is in agreement with the recent microstructure studies of both PST and PMN by direct methods. The low-permittivity compounds reveal the static basic spectrum for the corresponding 1:1 or 1:2 compositions. The basic spectrum is modified in relaxors by dynamic effects in the course of evolution to the ferroelectric state. Model relaxors PST and PMN show clearly such dynamic effects as mode broadening and a central peak. In A-site substituted complex perovskite PLT systems micro-Raman results indicate that the crystal structure of the PLT films was strongly influenced by the La contents. The dielectric properties of PLT thin films were studied in the temperature range 80--700 K and results indicate that PLT thin films undergo normal-to-relaxor ferroelectric transformation with 30 at% La content in PLT films. The observed behavior is evaluated in terms of diffuseness and Vogel-Fulcher relationship, which is typical for relaxor ferroelectrics. It is consistent with typical relaxor behavior of disordered materials with polar nanoregions.

  2. 4MOST - 4-meter Multi-Object Spectroscopic Telescope

    NASA Astrophysics Data System (ADS)

    Quirrenbach, Andreas; Consortium, 4MOST

    2015-08-01

    4MOST is a wide-field, high-multiplex spectroscopic survey facility under development for the 4m VISTA telescope of the European Southern Observatory. 4MOST will provide the spectroscopic complement to the large area surveys coming from space missions like Gaia, eROSITA, Euclid, and PLATO and from ground-based facilities like VISTA, VST, DES, LSST and SKA.The 4MOST baseline concept features a 2.5 degree diameter field-of-view with ~2400 fibers in the focal surface that are configured by a fiber positioner based on the tilting spine principle. The fibers feed two types of spectrographs: ~1600 fibers go to two spectrographs with resolution R>5000 (λ~390-930 nm) and ~800 fibers to a spectrograph with R>18,000 (λ~392-437 nm & 515-572 nm & 605-675 nm).4MOST will have a unique operations concept in which 5 year public surveys from both the consortium and the ESO community will be combined and observed in parallel during each exposure, resulting in more than 25 million spectra of targets spread over a large fraction of the southern sky. The 4MOST Facility Simulator (4FS) was developed to demonstrate the feasibility of this observing concept. 4MOST has been accepted for implementation by ESO with operations expected to start by the end of 2020.Gaia’s spectroscopic limits mean that radial velocity information starts to peter out at about 10 kpc, even for the most luminous stars. With 4MOST we will be able to obtain metallicities and [α/Fe] ratios of horizontal branch (HB) and red giant branch (RGB) stars out to ≈50 kpc and accurate radial velocities (σV ≈ 2 km/s) to 100 kpc. This will answer many open questions about the structure and formation of the Milky Way.Beginning in 2016 eROSITA will carry out a full sky X-ray survey that will probe to approximately 50 times fainter fluxes than the very successful ROSAT all sky survey but with dramatically better angular resolution of FWHM˜25ʺ and much better energy resolution.eROSITA will discover 3 million X

  3. Effect of content of Mg(NO3)2 x 6H2O on fabrication of alpha-alumina nanopowders by thermal decomposition of ammonium aluminum carbonate (AACH).

    PubMed

    Oh, Yong-Taeg; Shin, Dong-Chan

    2011-02-01

    An alpha-Al2O3 and MgAl2O3 spinel phase doped alpha-Al2O3 nanopowders were fabricated by the thermal decomposition and synthetic of ammonium aluminum carbonate hydroxide (AACH). Crystallite size of 5 to 8 nm were fabricated when reaction temperature of AACH was low, 8 degrees C, and the highest [NH4+][AlO(OH)2-][HCO3] ionic concentration of pH 10 from the ammonium hydrogen carbonate (AHC) aqueous solution. The phase transformation of amorphous-s, theta-, alpha-Al2O3, MgAl2O3 spinel phases was examined at each temperature according to the amount of Mg(NO3)2 x 6H2O and AACH. A time-temperature-transformation (TTT) diagram for thermal decomposition in air was determined. Homogeneous, spherical alpha-Al2O3 nanopowders with a particle size of 60 nm were obtained by firing the crystallites, which had been synthesized from AACH at pH 10 and 8 degrees C, at 1050 degrees C for 6 h in air. PMID:21456289

  4. Hard X-Ray Flare Source Sizes Measured with the Ramaty High Energy Solar Spectroscopic Imager

    NASA Technical Reports Server (NTRS)

    Dennis, Brian R.; Pernak, Rick L.

    2009-01-01

    Ramaty High Energy Solar Spectroscopic Imager (RHESSI) observations of 18 double hard X-ray sources seen at energies above 25 keV are analyzed to determine the spatial extent of the most compact structures evident in each case. The following four image reconstruction algorithms were used: Clean, Pixon, and two routines using visibilities maximum entropy and forward fit (VFF). All have been adapted for this study to optimize their ability to provide reliable estimates of the sizes of the more compact sources. The source fluxes, sizes, and morphologies obtained with each method are cross-correlated and the similarities and disagreements are discussed. The full width at half-maximum (FWHM) of the major axes of the sources with assumed elliptical Gaussian shapes are generally well correlated between the four image reconstruction routines and vary between the RHESSI resolution limit of approximately 2" up to approximately 20" with most below 10". The FWHM of the minor axes are generally at or just above the RHESSI limit and hence should be considered as unresolved in most cases. The orientation angles of the elliptical sources are also well correlated. These results suggest that the elongated sources are generally aligned along a flare ribbon with the minor axis perpendicular to the ribbon. This is verified for the one flare in our list with coincident Transition Region and Coronal Explorer (TRACE) images. There is evidence for significant extra flux in many of the flares in addition to the two identified compact sources, thus rendering the VFF assumption of just two Gaussians inadequate. A more realistic approximation in many cases would be of two line sources with unresolved widths. Recommendations are given for optimizing the RHESSI imaging reconstruction process to ensure that the finest possible details of the source morphology become evident and that reliable estimates can be made of the source dimensions.

  5. Assertions and Evidence.

    ERIC Educational Resources Information Center

    Cassidy, Michael; Medsker, Karen

    2003-01-01

    Discusses the need to provide evidence when making claims, particularly when reporting research results. Suggests evidence should be precise; be wary of generalizations; question authority; and link the manuscript together in a coherent manner. (LRW)

  6. Proton Magnetic Resonance Spectroscopy and MRI Reveal No Evidence for Brain Mitochondrial Dysfunction in Children with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Corrigan, Neva M.; Shaw, Dennis. W. W.; Richards, Todd L.; Estes, Annette M.; Friedman, Seth D.; Petropoulos, Helen; Artru, Alan A.; Dager, Stephen R.

    2012-01-01

    Brain mitochondrial dysfunction has been proposed as an etiologic factor in autism spectrum disorder (ASD). Proton magnetic resonance spectroscopic imaging ([superscript 1]HMRS) and MRI were used to assess for evidence of brain mitochondrial dysfunction in longitudinal samples of children with ASD or developmental delay (DD), and cross-sectionally…

  7. Evidence of double layer/capacitive charging in carbon nanomaterial-based solid contact polymeric ion-selective electrodes.

    PubMed

    Cuartero, Maria; Bishop, Josiah; Walker, Raymart; Acres, Robert G; Bakker, Eric; De Marco, Roland; Crespo, Gaston A

    2016-08-11

    This paper presents the first direct spectroscopic evidence for double layer or capacitive charging of carbon nanomaterial-based solid contacts in all-solid-state polymeric ion-selective electrodes (ISEs). Here, we used synchrotron radiation-X-ray photoelectron spectroscopy (SR-XPS) and SR valence band (VB) spectroscopy in the elucidation of the charging mechanism of the SCs. PMID:27405722

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

    NASA Astrophysics Data System (ADS)

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

    2010-10-01

    spectroscopic evidences suggested that the removal power of C. racemosa depends on its metabolic activities and not only on a simple adsorption process.

  9. A Question of Evidence

    ERIC Educational Resources Information Center

    Todd, Ross J.

    2008-01-01

    Broadly defined, evidence-based practice (EBP) is fundamentally about professional practice being informed and guided by best available evidence of what works. The EBP movement had its origins in the early 1990s in the United Kingdom in medicine and health care services. Sackett et al. defined evidence-based medicine as the "conscientious,…

  10. Some Thoughts on Evidence

    ERIC Educational Resources Information Center

    Cassidy, Michael; Medsker, Karen

    2004-01-01

    Evidence seems to be a particularly newsworthy topic these days, prominent in stories about weapons of mass destruction, the President's record in the National Guard, Martha Stewart's stock sales, global warming and the EPA, and so forth. "Evidence," not surprisingly, derives from "evident," which the American Heritage Dictionary defines as…

  11. Spectroscopic characterization of Er-doped KPb 2Cl 5 laser crystals

    NASA Astrophysics Data System (ADS)

    Jenkins, N. W.; Bowman, S. R.; O'Connor, S.; Searles, S. K.; Ganem, Joseph

    2003-06-01

    A discussion of the spectroscopic properties of the low-phonon energy laser host material potassium lead chloride, KPb 2Cl 5, doped with trivalent erbium is presented. In this paper we present room temperature spectroscopic measurements and subsequent analysis based on the Judd-Ofelt model. Additionally, Stark level energies of the Er 3+ ions in the crystal were determined from spectroscopic measurements performed at cryogenic temperatures.

  12. Spectroscopic Methods of Remote Sensing for Vegetation Characterization

    NASA Astrophysics Data System (ADS)

    Kokaly, R. F.

    2013-12-01

    Imaging spectroscopy (IS), often referred to as hyperspectral remote sensing, is one of the latest innovations in a very long history of spectroscopy. Spectroscopic methods have been used for understanding the composition of the world around us, as well as, the solar system and distant parts of the universe. Continuous sampling of the electromagnetic spectrum in narrow bands is what separates IS from previous forms of remote sensing. Terrestrial imaging spectrometers often have hundreds of channels that cover the wavelength range of reflected solar radiation, including the visible, near-infrared (NIR), and shortwave infrared (SWIR) regions. In part due to the large number of channels, a wide variety of methods have been applied to extract information from IS data sets. These can be grouped into several broad classes, including: multi-channel indices, statistical procedures, full spectrum mixing models, and spectroscopic methods. Spectroscopic methods carry on the more than 150 year history of laboratory-based spectroscopy applied to material identification and characterization. Spectroscopic methods of IS relate the positions and shapes of spectral features resolved by airborne and spaceborne sensors to the biochemical and physical composition of vegetation in a pixel. The chlorophyll 680nm, water 980nm, water 1200nm, SWIR 1700nm, SWIR 2100nm, and SWIR 2300nm features have been the subject of study. Spectral feature analysis (SFA) involves isolating such an absorption feature using continuum removal (CR) and calculating descriptors of the feature, such as center position, depth, width, area, and asymmetry. SFA has been applied to quantify pigment and non-pigment biochemical concentrations in leaves, plants, and canopies. Spectral feature comparison (SFC) utilizes CR of features in each pixel's spectrum and linear regression with continuum-removed features in reference spectra in a library of known vegetation types to map vegetation species and communities. SFC has

  13. New Developments of Broadband Cavity Enhanced Spectroscopic Techniques

    NASA Astrophysics Data System (ADS)

    Walsh, A.; Zhao, D.; Linnartz, H.; Ubachs, W.

    2013-06-01

    In recent years, cavity enhanced spectroscopic techniques, such as cavity ring-down spectroscopy (CRDS), cavity enhanced absorption spectroscopy (CEAS), and broadband cavity enhanced absorption spectroscopy (BBCEAS), have been widely employed as ultra-sensitive methods for the measurement of weak absorptions and in the real-time detection of trace species. In this contribution, we introduce two new cavity enhanced spectroscopic concepts: a) Optomechanical shutter modulated BBCEAS, a variant of BBCEAS capable of measuring optical absorption in pulsed systems with typically low duty cycles. In conventional BBCEAS applications, the latter substantially reduces the signal-to-noise ratio (S/N), consequently also reducing the detection sensitivity. To overcome this, we incorporate a fast optomechanical shutter as a time gate, modulating the detection scheme of BBCEAS and increasing the effective duty cycle reaches a value close to unity. This extends the applications of BBCEAS into pulsed samples and also in time-resolved studies. b) Cavity enhanced self-absorption spectroscopy (CESAS), a new spectroscopic concept capable of studying light emitting matter (plasma, flames, combustion samples) simultaneously in absorption and emission. In CESAS, a sample (plasma, flame or combustion source) is located in an optically stable cavity consisting of two high reflectivity mirrors, and here it acts both as light source and absorbing medium. A high detection sensitivity of weak absorption is reached without the need of an external light source, such as a laser or broadband lamp. The performance is illustrated by the first CESAS result on a supersonically expanding hydrocarbon plasma. We expect CESAS to become a generally applicable analytical tool for real time and in situ diagnostics. A. Walsh, D. Zhao, W. Ubachs, H. Linnartz, J. Phys. Chem. A, {dx.doi.org/10.1021/jp310392n}, in press, 2013. A. Walsh, D. Zhao, H. Linnartz Rev. Sci. Instrum. {84}(2), 021608 2013. A. Walsh, D. Zhao

  14. Application of optical spectroscopic techniques for disease diagnosis

    NASA Astrophysics Data System (ADS)

    Saha, Anushree

    Optical spectroscopy, a truly non-invasive tool for remote diagnostics, is capable of providing valuable information on the structure and function of molecules. However, most spectroscopic techniques suffer from drawbacks, which limit their application. As a part of my dissertation work, I have developed theoretical and experimental methods to address the above mentioned issues. I have successfully applied these methods for monitoring the physical, chemical and biochemical parameters of biomolecules involved in some specific life threatening diseases like lead poisoning and age-related macular degeneration (AMD). I presented optical studies of melanosomes, which are one of the vital organelles in the human eye, also known to be responsible for a disease called age-related macular degeneration (AMD), a condition of advanced degeneration which causes progressive blindness. I used Raman spectroscopy, to first chemically identify the composition of melanosome, and then monitor the changes in its functional and chemical behavior due to long term exposure to visible light. The above study, apart from explaining the role of melanosomes in AMD, also sets the threshold power for lasers used in surgeries and other clinical applications. In the second part of my dissertation, a battery of spectroscopic techniques was successfully applied to explore the different binding sites of lead ions with the most abundant carrier protein molecule in our circulatory system, human serum albumin. I applied optical spectroscopic tools for ultrasensitive detection of heavy metal ions in solution which can also be used for lead detection at a very early stage of lead poisoning. Apart from this, I used Raman microspectroscopy to study the chemical alteration occurring inside a prostate cancer cell as a result of a treatment with a low concentrated aqueous extract of a prospective drug, Nerium Oleander. The experimental methods used in this study has tremendous potential for clinical

  15. The Origin, Composition and History of Comets from Spectroscopic Studies

    NASA Astrophysics Data System (ADS)

    Allamandola, L. J.

    1997-12-01

    A wealth of information essential to understanding the composition and physical structure of cometary ice and hence gain deep insight into the comet's origin and history, can be gleaned by carrying out a full range of spectroscopic studies on the returned sample. These studies ought to be among the first performed as they are generally non-destructive and will provide a broad data bank which will be crucial in planning subsequent analysis. Examples of the spectroscopic techniques along with relative sensitivities and transitions probed, are discussed. Different kind of "spectroscopy" is summarized, with emphasis placed on the kind of information each provides. Infrared spectroscopy should be the premier method of analysis as the mid-IR absorption spectrum of a substance contains more global information about the identity and structure of that material than any other property. In fact, the greatest strides in our understanding of the composition of interstellar ices (thought by many to be the primordial material from which comets have formed) have been taken during the past ten years or so because this was when high quality infrared spectra of the interstellar medium (ISM) first became available. The interpretation of the infrared spectra of mixtures, such as expected in comets, is often (not always) ambiguous. Consequently, a full range of other non-destructive, complementary spectroscopic measurements are required to fully characterize the material, to probe for substances for which the IR is not well suited and to lay the groundwork for future analysis. Given the likelihood that the icy component (including some of the organic and mineral phases) of the returned sample will be exceedingly complex, these techniques must be intensely developed over the next decade and then made ready to apply flawlessly to what will certainly be one of the most precious, and most challenging, samples ever analyzed.

  16. Spectroscopic Observations of Fe XVIII in Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Teriaca, Luca; Warren, Harry P.; Curdt, Werner

    2012-08-01

    The large uncertainties associated with measuring the amount of high temperature emission in solar active regions (ARs) represents a significant impediment to making progress on the coronal heating problem. Most current observations at temperatures of 3 MK and above are taken with broadband soft X-ray instruments. Such measurements have proven difficult to interpret unambiguously. Here, we present the first spectroscopic observations of the Fe XVIII 974.86 Å emission line in an on-disk AR taken with the SUMER instrument on SOHO. Fe XVIII has a peak formation temperature of 7.1 MK and provides important constraints on the amount of impulsive heating in the corona. Detailed evaluation of the spectra and comparison of the SUMER data with soft X-ray images from the X-Ray Telescope on Hinode confirm that this line is unblended. We also compare the spectroscopic data with observations from the Atmospheric Imaging Assembly (AIA) 94 Å channel on the Solar Dynamics Observatory. The AIA 94 Å channel also contains Fe XVIII, but is blended with emission formed at lower temperatures. We find that it is possible to remove the contaminating blends and form relatively pure Fe XVIII images that are consistent with the spectroscopic observations from SUMER. The observed spectra also contain the Ca XIV 943.63 Å line that, although a factor 2-6 weaker than the Fe XVIII 974.86 Å line, allows us to probe the plasma around 3.5 MK. The observed ratio between the two lines indicates (isothermal approximation) that most of the plasma in the brighter Fe XVIII AR loops is at temperatures between 3.5 and 4 MK.

  17. THE BARYON OSCILLATION SPECTROSCOPIC SURVEY OF SDSS-III

    SciTech Connect

    Dawson, Kyle S.; Ahn, Christopher P.; Bolton, Adam S.; Schlegel, David J.; Bailey, Stephen; Anderson, Scott F.; Bhardwaj, Vaishali; Aubourg, Eric; Bautista, Julian E.; Beifiori, Alessandra; Berlind, Andreas A.; Bizyaev, Dmitry; Brewington, Howard; Blake, Cullen H.; Blanton, Michael R.; Blomqvist, Michael; Borde, Arnaud; Brandt, W. N.; and others

    2013-01-01

    The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the scale of baryon acoustic oscillations (BAO) in the clustering of matter over a larger volume than the combined efforts of all previous spectroscopic surveys of large-scale structure. BOSS uses 1.5 million luminous galaxies as faint as i = 19.9 over 10,000 deg{sup 2} to measure BAO to redshifts z < 0.7. Observations of neutral hydrogen in the Ly{alpha} forest in more than 150,000 quasar spectra (g < 22) will constrain BAO over the redshift range 2.15 < z < 3.5. Early results from BOSS include the first detection of the large-scale three-dimensional clustering of the Ly{alpha} forest and a strong detection from the Data Release 9 data set of the BAO in the clustering of massive galaxies at an effective redshift z = 0.57. We project that BOSS will yield measurements of the angular diameter distance d{sub A} to an accuracy of 1.0% at redshifts z = 0.3 and z = 0.57 and measurements of H(z) to 1.8% and 1.7% at the same redshifts. Forecasts for Ly{alpha} forest constraints predict a measurement of an overall dilation factor that scales the highly degenerate D{sub A} (z) and H {sup -1}(z) parameters to an accuracy of 1.9% at z {approx} 2.5 when the survey is complete. Here, we provide an overview of the selection of spectroscopic targets, planning of observations, and analysis of data and data quality of BOSS.

  18. The Origin, Composition and History of Comets from Spectroscopic Studies

    NASA Technical Reports Server (NTRS)

    Allamandola, L. J.

    1997-01-01

    A wealth of information essential to understanding the composition and physical structure of cometary ice and hence gain deep insight into the comet's origin and history, can be gleaned by carrying out a full range of spectroscopic studies on the returned sample. These studies ought to be among the first performed as they are generally non-destructive and will provide a broad data bank which will be crucial in planning subsequent analysis. Examples of the spectroscopic techniques along with relative sensitivities and transitions probed, are discussed. Different kind of "spectroscopy" is summarized, with emphasis placed on the kind of information each provides. Infrared spectroscopy should be the premier method of analysis as the mid-IR absorption spectrum of a substance contains more global information about the identity and structure of that material than any other property. In fact, the greatest strides in our understanding of the composition of interstellar ices (thought by many to be the primordial material from which comets have formed) have been taken during the past ten years or so because this was when high quality infrared spectra of the interstellar medium (ISM) first became available. The interpretation of the infrared spectra of mixtures, such as expected in comets, is often (not always) ambiguous. Consequently, a full range of other non-destructive, complementary spectroscopic measurements are required to fully characterize the material, to probe for substances for which the IR is not well suited and to lay the groundwork for future analysis. Given the likelihood that the icy component (including some of the organic and mineral phases) of the returned sample will be exceedingly complex, these techniques must be intensely developed over the next decade and then made ready to apply flawlessly to what will certainly be one of the most precious, and most challenging, samples ever analyzed.

  19. Spectroscopic Binaries: Towards the 100-Year Time Domain

    NASA Astrophysics Data System (ADS)

    Griffin, R. F.

    2012-04-01

    Good measurements of visual binary stars (position angle and angular separation) have been made for nearly 200 years. Radial-velocity observers have exhibited less patience; when the orbital periods of late-type stars in the catalogue published in 1978 are sorted into bins half a logarithmic unit wide, the modal bin is the one with periods between 3 and 10 days. The same treatment of the writer's orbits shows the modal bin to be the one between 1000 and 3000 days. Of course the spectroscopists cannot quickly catch up the 200 years that the visual observers have been going, but many spectroscopic orbits with periods of decades, and a few of the order of a century, have been published. Technical developments have also been made in `visual' orbit determination, and orbits with periods of only a few days have been determined for certain `visual' binaries. In principle, therefore, the time domains of visual and spectroscopic binaries now largely overlap. Overlap is essential, as it is only by combining both techniques that orbits can be determined in three dimensions, as is necessary for the important objective of determining stellar masses accurately. Nevertheless the actual overlap-objects with accurate measurements by both techniques-remains disappointingly small. There have, however, been unforeseen benefits from the observation of spectroscopic binaries that have unconventionally long orbital periods, not a few of which have proved to be interesting and significant objects in their own right. It has also been shown that binary membership is more common than was once thought (orbits have even been determined for some of the IAU standard radial-velocity stars!); a recent study of the radial velocities of K giants that had been monitored for 45 years found a binary incidence of 30%, whereas a figure of 13.7% was given as recently as 2005 for a similar group.

  20. Vegetation's red edge: a possible spectroscopic biosignature of extraterrestrial plants.

    PubMed

    Seager, S; Turner, E L; Schafer, J; Ford, E B

    2005-06-01

    Earth's deciduous plants have a sharp order-of-magnitude increase in leaf reflectance between approximately 700 and 750 nm wavelength. This strong reflectance of Earth's vegetation suggests that surface biosignatures with sharp spectral features might be detectable in the spectrum of scattered light from a spatially unresolved extrasolar terrestrial planet. We assess the potential of Earth's step-function-like spectroscopic feature, referred to as the "red edge," as a tool for astrobiology. We review the basic characteristics and physical origin of the red edge and summarize its use in astronomy: early spectroscopic efforts to search for vegetation on Mars and recent reports of detection of the red edge in the spectrum of Earthshine (i.e., the spatially integrated scattered light spectrum of Earth). We present Earthshine observations from Apache Point Observatory (New Mexico) to emphasize that time variability is key to detecting weak surface biosignatures such as the vegetation red edge. We briefly discuss the evolutionary advantages of vegetation's red edge reflectance, and speculate that while extraterrestrial "light-harvesting organisms" have no compelling reason to display the exact same red edge feature as terrestrial vegetation, they might have similar spectroscopic features at different wavelengths than terrestrial vegetation. This implies that future terrestrial-planet-characterizing space missions should obtain data that allow time-varying, sharp spectral features at unknown wavelengths to be identified. We caution that some mineral reflectance edges are similar in slope and strength to vegetation's red edge (albeit at different wavelengths); if an extrasolar planet reflectance edge is detected care must be taken with its interpretation. PMID:15941381

  1. The HyperLeda spectroscopic archive in the Virtual Observatory

    NASA Astrophysics Data System (ADS)

    Prugniel, Ph.

    2008-10-01

    The spectroscopic archive in HyperLeda is a compilation of 1D spectra of stars and galaxies to be used as references or templates and to help for calibrations. The spectra were collected from many different sources, they were re-documented and transformed into a format proper for the Virtual Observatory. The archive is part of the HyperLeda project, and can be searched through the web interface: http://leda.univ-lyon1.fr It is also registered as a Virtual Observatory service (SSA).

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

    DOE PAGESBeta

    Dufek, Eric J.

    2014-08-28

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

  3. The double-lined spectroscopic binary Iota Pegasi

    NASA Technical Reports Server (NTRS)

    Fekel, F. C.; Tomkin, J.

    1983-01-01

    Reticon observations of the spectroscopic binary Iota Peg at 6430 A show the secondary star's weak, but well defined lines. Determinations have accordingly been made of the secondary velocity curve as well as that of the primary, together with the orbits and the minimum masses of the two components. The 1.31 + or - 0.02 and 0.81 + or - 0.01 solar mass minimum masses are sufficiently close to the expected actual masses to suggest eclipses, despite the relatively long, 10.2-day period. The spectral type of the secondary is estimated to be G8 V.

  4. Spectroscopic detectability of the molecular Aharonov-Bohm effect

    NASA Astrophysics Data System (ADS)

    Englman, R.

    2016-01-01

    It is theoretically shown that the emission spectra from an excited Jahn-Teller state in which the ions undergo a forced periodic trajectory have an M-shaped form, directly due to the sign change by the Berry-phase factor. The presence of a weak spectral sideline is noted and the effects of a nonlinear vibronic coupling are calculated. Experimental verifications of the results, e.g., on R'-centers in LiF, are proposed. The dip in the M-shaped emission line is a novel, and perhaps unique, spectroscopic manifestation of the "molecular Aharonov-Bohm effect."

  5. Spectroscopic detectability of the molecular Aharonov-Bohm effect.

    PubMed

    Englman, R

    2016-01-14

    It is theoretically shown that the emission spectra from an excited Jahn-Teller state in which the ions undergo a forced periodic trajectory have an M-shaped form, directly due to the sign change by the Berry-phase factor. The presence of a weak spectral sideline is noted and the effects of a nonlinear vibronic coupling are calculated. Experimental verifications of the results, e.g., on R'-centers in LiF, are proposed. The dip in the M-shaped emission line is a novel, and perhaps unique, spectroscopic manifestation of the "molecular Aharonov-Bohm effect." PMID:26772550

  6. 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.

  7. Multivariate Chemical Image Fusion of Vibrational Spectroscopic Imaging Modalities.

    PubMed

    Gowen, Aoife A; Dorrepaal, Ronan M

    2016-01-01

    Chemical image fusion refers to the combination of chemical images from different modalities for improved characterisation of a sample. Challenges associated with existing approaches include: difficulties with imaging the same sample area or having identical pixels across microscopic modalities, lack of prior knowledge of sample composition and lack of knowledge regarding correlation between modalities for a given sample. In addition, the multivariate structure of chemical images is often overlooked when fusion is carried out. We address these challenges by proposing a framework for multivariate chemical image fusion of vibrational spectroscopic imaging modalities, demonstrating the approach for image registration, fusion and resolution enhancement of chemical images obtained with IR and Raman microscopy. PMID:27384549

  8. Spectroscopic investigations of HBV 475 in optical regions

    SciTech Connect

    Tamura, Shinichi )

    1989-03-01

    High-resolution spectroscopic analyses of HBV 475 are presented based on emission-line profiles of H-alpha, H-gamma, He I 4921-A, He I 5016-A, forbidden O III 4959-A, 5007-A, Fe II 5018-A, and Fe II 4924-A. Radial-velocity analyses show that only a part of the line components coincides well with previous measurements. Other remarkable components are found which are shifted to either the violet or red sides, depending on the indicated phase. Highly resolved emission-line profiles reveal that they are not compatible with the calculated profiles of proposed theoretical models. 21 refs.

  9. Spectroscopic Feedback for High Density Data Storage and Micromachining

    DOEpatents

    Carr, Christopher W.; Demos, Stavros; Feit, Michael D.; Rubenchik, Alexander M.

    2008-09-16

    Optical breakdown by predetermined laser pulses in transparent dielectrics produces an ionized region of dense plasma confined within the bulk of the material. Such an ionized region is responsible for broadband radiation that accompanies a desired breakdown process. Spectroscopic monitoring of the accompanying light in real-time is utilized to ascertain the morphology of the radiated interaction volume. Such a method and apparatus as presented herein, provides commercial realization of rapid prototyping of optoelectronic devices, optical three-dimensional data storage devices, and waveguide writing.

  10. Resonance Raman spectroscopic studies of enzymesubstrate intermediates at 5 K

    NASA Astrophysics Data System (ADS)

    Kim, Munsok; Carey, Paul R.

    1991-01-01

    A simple and versatile system for resonance Raman (RR) spectroscopic analysis of enzymesubstrate complexes at liquid helium temperatures is described. The system allows us to record high-quality RR spectra for dithioacyl papain intermediates (MeO-Phe-Gly- and MeO-Gly-Gly-Phe-Gly-C (dbnd S)S-papain) in ice matrices at 5 K. Based on established structure-spectra correlations, it is concluded that the active-site conformation of the intermediates about the φ', ψ' glycinic linkages and cysteine-25 side chain is B-G+-PH both in ice matrices at 5 K and in solution at room temperature.

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

    SciTech Connect

    Eric J. Dufek

    2014-08-01

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

  12. Spectroscopic study of the extremely fast rotating star 44 Geminorum

    NASA Astrophysics Data System (ADS)

    Iliev, L.; Vennes, S.; Kawka, A.; Kubat, J.; Nemeth, P.; Borisov, G.; KRaus, M.

    Stars with extremely fast rotation represent interesting challenge to modern understanding of the stellar evolution. The reasons why such a spin-up process should occur during the evolution to otherwise normal star are still not well understood. Already in the beginning of the XX century Otto Struve proposed that fast rotation of the group of stars spectroscopically classified as Be could be the main reason for the formation of observed disks of circumstellar material around them. This circumstellar material is responsible for the emission lines observed in the spectrum of Be-stars as well as for the whole complex of spectral and photometrical patterns called in general Be-phenomenon.

  13. ITER perspective on fusion reactor diagnostics—A spectroscopic view

    NASA Astrophysics Data System (ADS)

    De Bock, M. F. M.; Barnsley, R.; Bassan, M.; Bertalot, L.; Brichard, B.; Bukreev, I. M.; Drevon, J. M.; Le Guern, F.; Hutton, R.; Ivantsivskiy, M.; Lee, H. G.; Leipold, F.; Maquet, P.; Marot, L.; Martin, V.; Mertens, P.; Mokeev, A.; Moser, L.; Mukhin, E. E.; Pak, S.; Razdobarin, A. G.; Reichle, R.; Seon, C. R.; Seyvet, F.; Simrock, S.; Udintsev, V.; Vayakis, G.; Vorpahl, C.

    2016-08-01

    The ITER tokamak requires diagnostics that on the one hand have a high sensitivity, high spatial and temporal resolution and a high dynamic range, while on the other hand are robust enough to survive in a harsh environment. In recent years significant progress has been made in addressing critical challenges to the development of spectroscopic (but also other) diagnostics. This contribution presents an overview of recent achievements in 4 topical areas: • First mirror protection and cleaning • Nuclear confinement • Radiation mitigation strategy for optical and electronic components • Calibration strategies

  14. Combining weak-lensing tomography and spectroscopic redshift surveys

    DOE PAGESBeta

    Cai, Yan -Chuan; Bernstein, Gary

    2012-05-11

    Redshift space distortion (RSD) is a powerful way of measuring the growth of structure and testing General Relativity, but it is limited by cosmic variance and the degeneracy between galaxy bias b and the growth rate factor f. The cross-correlation of lensing shear with the galaxy density field can in principle measure b in a manner free from cosmic variance limits, breaking the f-b degeneracy and allowing inference of the matter power spectrum from the galaxy survey. We analyze the growth constraints from a realistic tomographic weak lensing photo-z survey combined with a spectroscopic galaxy redshift survey over the samemore » sky area. For sky coverage fsky = 0.5, analysis of the transverse modes measures b to 2-3% accuracy per Δz = 0.1 bin at z < 1 when ~10 galaxies arcmin–2 are measured in the lensing survey and all halos with M > Mmin = 1013h–1M⊙ have spectra. For the gravitational growth parameter parameter γ (f = Ωγm), combining the lensing information with RSD analysis of non-transverse modes yields accuracy σ(γ) ≈ 0.01. Adding lensing information to the RSD survey improves \\sigma(\\gamma) by an amount equivalent to a 3x (10x) increase in RSD survey area when the spectroscopic survey extends down to halo mass 1013.5 (1014) h–1 M⊙. We also find that the σ(γ) of overlapping surveys is equivalent to that of surveys 1.5-2 times larger if they are separated on the sky. This gain is greatest when the spectroscopic mass threshold is 1013 -1014 h–1 M⊙, similar to LRG surveys. The gain of overlapping surveys is reduced for very deep or very shallow spectroscopic surveys, but any practical surveys are more powerful when overlapped than when separated. As a result, the gain of overlapped surveys is larger in the case when the primordial power spectrum normalization is uncertain by > 0.5%.« less

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

    SciTech Connect

    Field, R.W.; Silbey, R.J.

    1993-12-01

    The authors have initiated a program to perform spectroscopic and dynamic studies of small molecules. Large amplitude motions in excited acetylene were discussed along with plans to record the dispersed fluorescence (DF) and the stimulated emission pumping (SEP) spectra. SEP spectra were reported for the formyl radical. A Fourier transform spectrometer was discussed with respect to its ability to probe the structure of radicals. This instrument is capable of performing studies using various techniques such as magnetic rotation spectroscopy and sub-Doppler sideband-OODR Zeman (SOODRZ) spectroscopy.

  16. Spectroscopic and theoretical constraints on the differentiation of planetesimals

    NASA Astrophysics Data System (ADS)

    Moskovitz, Nicholas A.

    The differentiation of small proto-planetary bodies into metallic cores, silicate mantles and basaltic crusts was a common occurrence in the first few million years of Solar System history. In this thesis, observational and theoretical methods are employed to investigate this process. Particular focus is given to the basaltic, crustal remnants of those differentiated parent bodies. A visible-wavelength spectroscopic survey was designed and performed to constrain the population of basaltic asteroids in the Main Belt. The results of this survey were used to provide statistical constraints on the orbital and size-frequency distributions of these objects. These distributions imply that basaltic material is rare in the Main Belt (particularly beyond the 3:1 mean motion resonance at 2.5 AU), however relic fragments of crust from multiple differentiated parent bodies are likely present. To provide insight on the mineralogical diversity of basaltic asteroids in the Main Belt, we performed a series of near-infrared spectroscopic observations. We find that V-type asteroids in the inner belt have spectroscopic properties consistent with an origin from a single parent body, most likely the asteroid Vesta. Spectroscopic differences (namely band area ratio) between these asteroids and basaltic meteorites here on Earth are best explained by space weathering of the asteroid surfaces. We also report the discovery of unusual spectral properties for asteroid 10537 (1991 RY16), a V-type asteroid in the outer Main Belt that has an ambiguous mineralogical interpretation. We conclude this thesis with a theoretical investigation of the relevant stages in the process of differentiation. We show that if partial silicate melting occurs within the interior of a planetesimal then both core and crust formation could have happened on sub-million year (Myr) time scales. However, it is shown that the high temperatures necessary to facilitate these processes may have been affected by the migration

  17. The GEISA spectroscopic line parameters data bank in 1984

    NASA Technical Reports Server (NTRS)

    Husson, N.; Chedin, A.; Scott, N. A.; Bailly, D.; Graner, G.; Lacome, N.; Brown, L. R.; Orton, G.; Rinsland, C. P.; Smith, M. A. H.

    1986-01-01

    The 1984 update of the GEISA data bank, containing spectroscopic information on 323,521 lines corresponding to 36 molecules and 79 isotopic species in the spectal range 3 x 10 to the -6th/cm to 17,879/cm, is discussed. The bank compiles parameters describing the radiation absorption or emission properties of gases involved in the atmospheres of the earth and planets. Values of a new exponent which summarized the variation of the collision halfwidth with temperature are given for 10 molecules. Six new molecules, HOCl, N2, CH3Cl, H2O2, H2S, and HCOOH, are included in this edition.

  18. HR 1613, A Short-Period Spectroscopic Binary

    NASA Astrophysics Data System (ADS)

    Buggs, C.; Onouha, G.; Smith, B.; Burks, G. S.; Fekel, F. C.

    2004-12-01

    HR 1613, a barely naked-eye star in the constellation of Orion, is one of a number of bright, early-type stars that have few or no previous radial velocity measurements. Our observations show that it is a single-lined spectroscopic binary with a period of 8.11 days and a circular orbit. It has a spectral type of A9 V and is slowly rotating with v sin i = 12 km/s. The unseen secondary star is likely an M dwarf.

  19. Raman spectroscopic characterization and differentiation of seminal plasma

    NASA Astrophysics Data System (ADS)

    Huang, Zufang; Chen, Xiwen; Chen, Yanping; Chen, Jinhua; Dou, Min; Feng, Shangyuan; Zeng, Haishan; Chen, Rong

    2011-11-01

    Raman spectroscopy (RS) was applied for the analysis of seminal plasma in order to detect spectral parameters, which might be used for differentiating the normal and abnormal semen samples. Raman spectra of seminal plasma separated from normal and abnormal semen samples, showed a distinct difference in peak ratios between 1449 and 1418 cm-1 (P < 0.05). More efficient alternative method of using principal component analysis-linear discriminate analysis based on Raman spectroscopic data yielded a diagnostic sensitivity of 73% and specificity of 82%. The results suggest that RS combined with the multivariate analysis method has the potential for differentiating semen samples by examination of the corresponding seminal plasma.

  20. Spectroscopic characterization of uranium in evaporation basin sediments

    NASA Astrophysics Data System (ADS)

    Duff, M. C.; Morris, D. E.; Hunter, D. B.; Bertsch, P. M.

    2000-05-01

    Evaporation ponds in the San Joaquin Valley (SJV), CA, used for the containment of irrigation drainage waters contain elevated levels of uranium (U) resulting from the extensive leaching by carbonate-rich irrigation waters of the local agricultural soils that contain low levels of naturally-occurring U. The SJV ponds are subjected to changes in redox chemistry with cycles of drying and flooding. Our past studies have shown that U in the SJV Pond 14 surface sediments is present as mostly the oxidized and soluble form, U(VI). However, we were uncertain whether the U in the soil was only present as a U oxide of mixed stoichiometry, such as U 3O 8(s) (pitchblende) or other species. Here we present characterization information, which includes wet chemical and in situ spectroscopic techniques (X-ray absorption near-edge structure (XANES) and low temperature time-resolved luminescence spectroscopies) for samples from two SJV Pond sediments. Surface sediments from SJV Pond 16 were characterized for average oxidation state of U with XANES spectroscopy. The fraction of U(VI) to U(IV) in the Pond 16 sediments decreased with depth with U(IV) being the dominant oxidation state in the 5 cm to 15 cm depth. Two luminescent U(VI) species were identified in the surface sediments from Pond 14; a U(VI)-tricarbonate phase and another phase likely comprised of U(VI)-hydroxide or hydroxycarbonate. The luminescent U(VI) population in the Pond 16 sediments is dominated by species with comparable spectral characteristics to the U(VI)-hydroxide or hydroxycarbonate species found in the Pond 14 sediments. The luminescence spectroscopic results were complemented by wet chemical U leaching methods, which involved the use of carbonate and sulfuric acid solutions and oxidizing solutions of peroxide, hypochlorite and Mn(IV). Leaching was shown to decrease the total U concentration in the sediments in all cases. However, results from luminescence studies of the residual fraction in the leached