bluuebunny/crossref_metadata_2025_split huggingface dataset:
Etude des Spectres de Diffusion Raman Et d'Absorption Infrarouge des Cyanures de Sodium et de Potassium En Phase II et Phase III
Authors: Fontaine D. 
Published: May 2005

AbstractThe infrared and Raman spectra of potassium and sodium cyanides have been recorded in the two orthorhombic phases (Ising spin disordered phase II and ordered phase III). By comparing the intensity of the modes we show that the two crystals have a different behaviour, though they belong to the same space group. In particular, the two librational modes in phase II are accidentally degenerate in KCN (σ ≈︁ 116 cm−1 at T = 150 K), while they are widely separated in NaCN (σ = 218 cm−1 and 104 cm−1 at T = 250 K). In KCN the second mode seems due to the disorder. Some possible attributions for the translatory motions in phase III are given, based on coupling with the librational motions.
Raman spectra of chemisorbed bromine and iodine on zeolites
Authors: Rubim J. C. , Sala O. 
Published: May 2005

AbstractThe Raman spectra of bromine and iodine adsorbed on 5A and 13X zeolites from carbon tetrachloride solutions presented bands that were assigned to chemical and physical adsorption. Using a rotating cell and an oscillating optical system it was possible, choosing a convenient laser power, to aid the bands due to chemisorption.
Spectres de Diffusion Raman d'un Monocristal de CBr4 Monoclinique
Authors: Debeau M. , Pick R. M. 
Published: May 2005

AbstractThe polarized Raman spectra of monoclinic CBr4 are interpreted in terms of pseudo‐cubic site symmetry 42m. The large polarizability of Br atoms is responsible for the high intensity of the off‐diagonal terms of total symmetric tensors. Dipole–dipole coupling gives, for the v3 mode, a quite different behaviour from that of the other internal modes.
Raman spectrum of the ν2 band of H14N3
Authors: Bendtsen Jørgen 
Published: May 2005

AbstractThe rotational‐vibrational Raman Spectrum of the v2 band of H14N3 has been measured. The results of the analysis of the observed wavenumbers are v0 = 2140.308(4) cm−1, ΔB = −0.00312(1) cm−1 and ΔDj = −7(5)×10−9 cm−1. The Q‐branches of the hot band transitions v5→v2+v5 and v6→v2+v6 have been determined to be at 2129.3(1) cm−1.
Intensities of some vibrational bands in the pre‐resonance Raman spectra of quinoxaline, phthalazine and pyridazine
Authors: Aminzadeh A. , Fawcett V. , Long D. A. 
Published: May 2005

AbstractExperimental studies of the variation of intensity with excitation wavenumber of some a1 vibrational bands in the Stokes Raman spectra of the following molecules are reported: quinoxaline (1,4‐diazanaphthalene), phthalazine (2,3‐diazanaphthalene) and pyridazine (1,2‐diazabenzene). The results are discussed in terms of the Albrecht–Hutley theory of pre‐resonance Raman intensities and the electronic states involved in the pre‐resonance enhancement identified.
Vibrational spectra and bonding in nitrocyclopropane
Authors: Holtzclaw J. R. , Harris W. C. , Bush S. F. 
Published: May 2005

AbstractRaman spectra of nitrocyclopropane were recorded from 4000 to 30 cm−1 for the liquid and solid states. Infrared spectra were recorded from 4000 to 180 cm−1 for vapor phase and matrix isolated states. The low frequency torsional mode is located at 101 cm−1 in the liquid state (102 cm−1 in the solid state) and correlates well with the 84 cm−1 value for the vapor phase which is predicted on the basis of a torsional combination band in the infrared vapor phase spectrum. The calculated barrier to internal rotation for the vapor phase is 1645±50 cm−1, 4.70±0.15 kcal mol−1. A vibrational assignment is proposed for the first time and it supports structural arguments that there is significant pseudo‐conjugation between the cyclopropane ring orbitals and the substituent NO2 group. Finally, a detailed temperature study reveals no appreciable spectral change; hence, nitrocyclopropane appears to exist as a single Cs conformer over the range −173 to 100°C.
Conformational study of methotrexate binding to L. casei dihydrofolate reductase by laser Raman spectroscopy
Authors: Durig J. R. , Dunlap R. B. , Gerson D. J. 
Published: May 2005

AbstractFrom the Raman spectrum of aqueous L. casei dihydrofolate reductase the protein backbone was found to be predominantly random‐coil (∽45%), ∽30% β‐sheet and ∽25% α‐helical conformations. The Raman spectrum of the binary methotrexate‐dihydrofolate reductase complex showed the polypeptide backbone to be predominantly random‐coil (∽55%) and β‐sheet (∽38%) conformers with a very small percentage of α‐helix conformation. A change in the tyrosine doublet intensity (I860/I835) were observed upon binary complex formation. This change in intensity ratio supports a fluctuation in tyrosine hydrogen bonding environment in DHR upon complex formation. In the methotrexate–dihydrofolate reductase complex the pteridine ring of methotrexate was shown to be protonated. Comparison of the Raman spectra of the solution of the native enzyme and binary methotrexate complex supported the hypothesis of significant conformational changes in the L. casei dihydrofolate reductase upon complex formation.
Raman and infrared study of KHSO4 crystal
Authors: Goypiron A. , De Villepin J. , Novak A. 
Published: May 2005

AbstractThe Raman spectra of the low temperature phase single crystal of KHSO4 and of polycrystalline KDSO4 have been investigated at 300 and 90 K. Infrared spectra of polycrystalline samples have been recorded for compaison in the 4000 to 30 cm−1 range. An assignment of bands due to internal vibrations to their symmetry species (Raman) and in terms of approximate type of motion is given. a distinction between the bands corresponding to cyclic dimers and infinite chains is possible in the case of the OH group and most skeletal stretching vibrations. An interpretation of lattice bands using an oriented gas model is proposed. Hydrogen bonding in the KHSO4 crystal is discussed.
Core‐size marker resonance Raman bands of metallotetraphenylporphines
Authors: Stong J. D. , Spiro T. G. , Kubaska R. J. , Shupack S. I. 
Published: May 2005

AbstractResonance Raman spectra are reported for Ni(II), Cu(II), Pd(II) and Pt(II) tetraphenylporphine (TPP). Systematic examination of the resonance Raman frequencies of these and of previously reported TPP derivatives has revealed three bands which exhibit a linear correlation with porphyrin core size (Ct–N), near 1460 cm−1 (polarized), 1540 cm−1 (anomalously polarized) and 1570 cm−1 (polarized). Parameters derived from the correlations indicate a reasonable similarity between these TPP modes and those of biological‐type metalloporphyrins which also correlate with Ct–N.
Foreign‐gas pressure broadening of the pure rotational Raman spectrum of H2
Authors: Dayan E. , Viennot J. P. 
Published: May 2005

AbstractMeasurements of the width of the rotational Raman line, at 595 cm−1, of hydrogen in mixtures with N2, C2H4 and CO2 are reported at a series of perturbing gas pressures, up to 400 bar. The broadening is found to be characteristic of the foreign gas and is interpreted in term of the quadrupole–quadrupole interaction between hydrogen and the perturing molecule. It is shown that the quadrupole–quadrupole contribution is the dominant part of the anisotropic intermolecular potential.
Redetermination of some of the spectroscopic constants of the electronic ground state of di‐Nitrogen 14N2, 14N15N and 15N2 using coherent anti‐stokes Raman spectroscopy
Authors: Gilson T. R. , Beattie I. R. , Black J. D. , Greenhalgh D. A. , Jenny S. N. 
Published: May 2005

AbstractCalibrated coherent anti‐Stokes Raman (CARS) spectra have been recorded for the resolved Q branches of the vibrational fundamentals and first hot bands of 14N2, 14N15N and 15N2 at a temperature of 1200 K. The spectra show a convolved linewidth of 0.13 cm−1, and have been used to derive new values of spectroscopic constants, for the species observed, with specific reference to the position of the Q branch lines where J > 20 for v = 1–0, and J = 0–30 for v = 2–1. The critical overlap region of the fundamental and the hot band may now be computer simulated with confidence, which should be of considerable help in combustor thermometry using CARS.
Raman intensities, vibrational eigenvectors, electro‐optical parameters and force constants of SO42−, ClO4−, PO43, CO32− and NO3− anions in polycrystalline samples
Authors: Lopez‐Bote M. A. , Montero S. 
Published: May 2005

AbstractThe relative Raman intensities of the fundamental vibrational modes of the tetrahedral oxoanions SO42−, ClO4−, PO43 and of the plane trigonal oxoanions CO32− and NO3− have been measured from polycrystalline samples. Using the bond polarizability theory, the vibrational eigenvectors of F2(Td) and E' (D3h) species of these anions in different crystalline environments are derived from the above Raman intensity data. The results are consistent with those obtained through Wilson's GF method, although there exists a multiplicity of solutions. Relative values of SO, ClO, PO and NO bond polarizability parameters are reported. Comparison of these results with liquid state absolute values from the literature enables us to suggest a standard for measuring absolute Raman intensities in the solid phase.
Relaxation mode in SrTio3: A mode to test melting models?
Authors: Barbosa G. A. , Dos Santos J. I. 
Published: May 2005

AbstractIn this work, Raman spectra are presented from room temperature up to 800°C. Each spectrum is seen as a contribution of two processes—a ‘one‐phonon’ disordered process and a relaxation mode. The relaxation time associated with this mode shows a linear decrease with increasing temperature, going to zero as the melting point is approached.
Far‐infrared and Raman spectroscopy of the phase transition in CsCuCl3
Authors: Petzelt J. , Gregora I. , Vorlíček V. , Fousek J. , Březina B. , Kozlov G. V. , Volkov A. A. 
Published: May 2005

AbstractFar‐infrared reflectivity (30–400 cm−1), submillimetre and millimetre transmissivity (5–30 cm−1) and Raman scattering measurements on CsCuCl3 single crystals have been performed for several temperatures below and above the phase transition temperature Ttr = 423 K. The spectra above Ttr indicate the non‐polar D structure (CsNiCl3‐type) with a high degree of disorder. The millimetre permittivity is temperature independent in both phases in contrast to previous static measurements. Assignment of most modes is done by means of symmetry considerations. The A2 mode at 50 cm−1 which is connected with the Cs vibrations along the hexagonal axis, undergoes an increase of damping at Ttr which may be connected with the increased conductivity above Ttr. Well‐underdamped, very low‐frequency modes are observed in the A1 spectrum at 27 cm−1, A2 spectrum at 17 cm−1 and E2 spectrum at 24 cm−1. In accordance with the group‐theoretical expectation, they are believed to correspond to fluctuations of the amplitude and phase of the helicoidal modulation in the ordered phase and to fluctuations of the enantiomorphic modulation, respectively. CsCuCl3 presents the first example of a transition into a non‐polar phase where the symmetry analysis shows the soft mode (here the phason component) to be infrared‐active.
Bulk and surface phonon–polaritons in anistropic crystals
Authors: Merten L. , Borstel G. 
Published: May 2005

AbstractIn recent years the properties both of bulk and surface phonon‐polaritons in anisotropic crystals became more and more important. We owe a long line of pioneering work on phonen‐polaritons to Sergio Porto and his co‐workers. Of all complex anisotropic crystals α‐quartz was investigated most extensively with regards to bulk and surface phonon‐polaritons. Therefore α‐quartz in the following is treated as a model crystal for polaritons in anisotropic crystals. Both theoretical and experimental results on phonon–polaritons in α‐quartz are discussed in detail. Most of the experimental results are in quantitative agreement with theory and numerical calculations.
Single particle electron light scattering in heavily doped semiconductors
Authors: Ipatova I. P. , Subashiev A. V. , Voitenko V. A. 
Published: May 2005

AbstractEffects of impurity concentration fluctuations on the single particle light scattering in many‐valley semiconductors are considered. When ql » 1, where q is the light momentum and l is the electron mean free path, the long‐range mean square impurity potential only broadens the edge of the cross‐section at qvF = ω, νF being the Fermi velocity. In the opposite hydrodynamic limit ql « 1 the effects of the short‐range impurity fluctuation potential create the spectrum of Lorentzian shape. The integral cross‐section in this case is independent of the incident light frequency. The selection rules do not depend on the light momentum q.
Isomerie Rotationnelle du Formiate de Tertiobutyle: Etude par Spectrometrie de Vibration de I'Influence des Solvants et des Cations
Authors: Omura Yoko , Corset Jacques , Moravie Rose Marie 
Published: May 2005

AbstractRaman spectra of t t‐butyl formate HCOOC(CH3)3 were recorded in various solvents in the ν(CO) region and below 1000 cm−1 where appear the bands sensitive to the conformation. It is shown that, compared to the pure liquid, the cis‐trans equilibrium is shifted towards the trans, the more polar form, in polar solvents and towards the cis form in non‐polar solvents. For binary solutions HCOOC(CH3)3‐Ba(ClO4)z and ternary solutions HCOOC(CH3)3‐Ba(ClO4)2‐CH3CN, the infrared and Raman spectra, recorded in the same regions, show that the complexation of the ester carbonyl group by the Ba2+ cations favours the trans conformation as do the polar solvents. Through spectral analysis of the concentrated Ba(ClO4)2 ester solution and of the solvation number it is shown that the Ba2+ cation is octahedrally surrounded by the carbonyl groups of six molecules in its first solvation shell.
Comparative Raman studies of cytochrome b562 and cytochrome c
Authors: Srivastava R. B. , Pace C. , Yu Nai‐Teng 
Published: May 2005

AbstractResonance Raman spectra (excited at 413.1 nm) and excitation profiles (Q‐band region) of cytochrome b562 and cytochrome c were obtained with a sensitive vidicon multichannel Raman spectrometer.7 Comparison of the spectra reveals that two Raman lines at 690 and 700 cm−1 in cytochrome c may be assigned to CS stretch of the thioether bridges, which are absent in cytochrome b562. Four sets of doublet between 320 and 430 cm−1 are unique in cytochrome c among various hemoproteins may indicate the existence of two subtly distinct heme structures alternating in the ground state of cytochrome c. This unique spectral feature was not observed in heme octapeptide (reduced form in 0.25 M N‐acetyl‐methionine) which also contains the covalent thioether linkages. In addition, we compare the excitation profiles of a depolarized porphyrin ring mode at ∼ 750 cm−1 among cytochrome c, cytochrome b562 and Ni etioporphyrin. The effect of a Jahn‐Teller distortion observed in the 750 cm−1 profile of Ni etioporphyrin19 is shown to be absent in cytochrome c. The 750 cm−1 profiles in the Q‐band region are interpreted in terms of Herzberg‐Teller (B) and nonadiabatic (D) contributions with or without an origin shift.
Resonance Raman studies of transition metal peroxo complexes: 3‐The blue intermediate formed in the reaction of chromium(VI) with hydrogen peroxide in strongly acid solution
Authors: Hester R. E. , Nour E. M. 
Published: May 2005

AbstractResonance Raman spectra are reported for the short‐lived blue intermediate formed in the Cr(VI)‐H2O2 reaction in strongly acidic aqueous solution using several different excitation wavelengths. The spectra show a number of bands which are assigned to the different ν(CrO) modes and to the ν(OO) mode within the structure CrO5·H2O. The Raman band intensity profiles indicate that the resonànce effect is associated with the 590 nm absorption band, which is assigned to the charge‐transfer transition OCr(VI). The instability of the species is interpreted on the basis of the relatively low ν(CrO) and high ν(OO) wavenumber values.
Resonance Raman studies of transition metal peroxo complexes: 7—The peroxo‐dicobalt(III)‐ethylenediamine and L‐histidine complexes
Authors: Hester R. E. , Nour E. M. 
Published: May 2005

AbstractResonance Raman spectra have been determined for the μ‐peroxo complex [(en)2CoO2Co(en)2]4+ and μ‐peroxo‐μ‐hydroxo complex [(en)2CoO2(OH)Co(en)2]3+, where en = ethylenediamine. The spectra show bands at 799 and 795 cm−1, assigned to the ν(OO) mode in each complex, respectively, while the ν(CoO) mode occurs at ∼590 cm−1. However, two strong bands occur at 494 and 534 cm−1 in the spectrum of the μ‐peroxo complex and only one strong, broad band at 530 cm−1 occurs in the spectrum of the μ‐peroxo‐μ‐hydroxo complex. These are assigned to ν(CoN) modes in both complexes. The spectra of the complexes [(L‐his)2CoO2Co(L‐his)2] and [(L‐his)2CoO2(OH)Co(L‐his)2]− show bands at 811 and 805 cm−1 assigned to the ν(OO) mode, respectively, while the ν(CoO) mode is assigned at 600 and 590 cm−1, respectively. The ν(CoN) modes in both complexes are assigned at 530 and 493 cm−1. These bands are much stronger in the spectrum of the μ‐peroxo than in that of the μ‐peroxo‐μ‐hydroxo complexes. However, the obvious differences between the Raman spectra of the μ‐peroxo and μ‐peroxo‐μ‐hydroxo complexes are not in the ν(OO) and ν(CoO) bands but rather in the lower wavenumber ν(CoN) region. The ν(OO) band intensity excitation profiles demonstrate that the O2−2 →Co3+ charge transfer transition occurs at ∼352 and 360 nm for [(en)2CoO2Co(en)2]4+ and [(en)2CoO2(OH)Co(en)2]3+, respectively, and at 366 nm for the [(L‐his)CoO2(OH)Co(L‐his)]− complex.
Raman study of the phase transition in RbHSO4
Authors: Toupry N. , Poulet H. , Le Postollec M. 
Published: May 2005

AbstractRaman spectra of RbHSO4 have been recorded in the temperature range from 6 K to the melting point, 480 K. Analysis of the spectra show that the second order phase transition, at 264 K, Is of the order‐disorder type. No soft mode was found. The evolution of the ν(OH) mode frequency with temperature, is consistent with a change of orientation of the hydrogen bonds connecting the disordered SO3O(H) groups. The spectra are also consistent with the existence of a prototype phase which had been assumed to explain the pseudo‐orthorhombic symmetry of the paraelectric and ferroelectric phases.
Proposed method for calibration of rotation‐vibrational Raman spectra
Authors: Hills Graham W. 
Published: May 2005

AbstractAn approach is proposed to reduce the systematic error in the calibration of high‐resolution Raman spectra showing rovibrational structure. The method proposes recording, on the photographic plate, fluorescence from molecular iodine following excitation by the 5017 and 5145 Å argon ion lines of various rovibronic transitions in B Ou+ ← X1 Σg+. The accurately known wavenumbers for B → X, determined by Fourier transform spectroscopy, 11,13 would be used to calibrate the Raman spectrum. Since both the calibration and Raman spectra would be obtained from samples in the same cell inside the same laser, both would follow identical optical paths through the spectrograph to the plate and thus systematic shifts inherent to hollow‐cathode lamp calibration would be eliminated.
Raman spectra of dithioacetic acid‐d0 and d4 in dichloromethane
Authors: Randhawa H. S. , Walter W. 
Published: May 2005

AbstractThe Raman spectra of dithioacetic acid‐d0 and d4 were measured in dichloromethane (40% solution w/v) in the 0–4000 cm−1 region and of neat light dithiocarboxylic acid in the SH stretching region. These acids were found to exist mainly as open chain dimers in the solution phase and cyclic dimers in the liquid phase.
The association of surface enhanced raman scattering from cyanide at silver electrode surfaces with a stabilized oxide phase
Authors: Mahoney Merrick R. , Cooney Ralph P. 
Published: May 2005

AbstractSurface enhanced Raman scattering from cyanide in the electrochemical system, Ag/0.1 M Na2SO4, 0.01 M KCN (pH∼11), appears to arise from a cyanide stabilized oxide film which is pH sensitive and reducible.
A Raman spectroscopic study of methyl ammonium chloride: III—The internal vibrations in the 600–1700 cm−1 frequency region
Authors: Meinander N. , Forss S. , Bergström G. 
Published: May 2005

AbstractThe Raman spectra of the three solid phases of methyl ammonium chloride and its deuterated analogues have been measured and compared with IR results available in the literature. The static and correlation field splitting of the internal modes have been studied by the use of isotopic solid solutions. The methyl‐ammonium ions are found to be orientationally ordered in both γ‐ and β‐MAC. Evidence of at least local orientational order in α‐MAC is given. Spectra of the partly ammonium and methyl deuterated analogues show that the ammonium group is distorted in the low temperature phases, having approximately Cs symmetry in γ‐MAC and C1 symmetry in β‐MAC, and that the methyl group is slightly distorted in β‐MAC.
Etude par Diffusion Raman Isotrope de la Relaxation Vibrationnelle des Molecules de Thiophène et de Furanne
Authors: Pinan‐Lucarre J. P. , Loisel J. , Vincent‐Geisse J. 
Published: May 2005

AbstractPure thiophene and furan isotropic Raman bandprofiles (corresponding to different A1 totally symmetric bands) are investigated in function of temperature in the liquid and plastic phases. The vibrational band widths and correlation functions are derived. The results are interpreted by means of phenomenological models describing the bandwidths (Fischer and Laubereau, Oxtoby) and by means of Kubo‐Rothschild's model as regards the correlation functions. It is shown that other vibrational relaxation origins than dephasing processes must be considered in order to explain the whole experimental results. In particular, we point out the possible existence of intermolecular energy transfers which would the more easily occur as they take place between nearer vibrational levels.
Spectres Raman de Résonance de Dérivés Substitués de l'Hydroxyazobenzène en Solution Fortement Acide
Authors: Merlin J. C. , Lorriaux J. L. , Thomas E. W. , Dupaix A. 
Published: May 2005

AbstractResonance Raman spectra of azobenzene and some hydroxyazobenzene derivatives, in strong acid solution (HCI 6 M), are analysed. All the observed bands between 900 and 1700 cm−1 can be assigned to vibrational modes of the aromatic rings and the azo group, and give evidence for a trans azo type structure both for azobenzene and the para substituted hydroxyazobenzene derivatives studied. Resonance Raman spectra of six substituted 2‐(4′‐ hydroxyphenylazo)‐benzoic acid derivatives in strong acid solutions are investigated. The spectral features are rather different from the above studied hydroxyazobenzene derivatives, but can be explained on the basis of an azo type structure. A strong perturbation effect on the NN stretching mode is demonstrated using deuterium substitution. From the complexity of frequency shifts obtained on deuterium substitution, vibrational coupling between NH bending and many other vibrational modes is evident. A tentative assignment of the observed resonance Raman bands is proposed.
Lattice vibrations of crystalline diazepam (Valium)
Authors: Dumetz J. , Vergoten G. , Huvenne J. P. , Fleury G. 
Published: May 2005

AbstractLow frequency Raman spectra of diazepam have been recorded at various temperatures between 103 and 396 K. Far IR spectra are also reported at room temperature. The observed frequencies of the lattice modes are compared with those calculated using a semi‐empirical intermolecular potential. The transferability of the atom‐atom potentials leads to good agreement between the two sets of frequencies.