bluuebunny/crossref_metadata_2025 huggingface dataset:
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

The 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.
Illumination of flat or unstable samples for Raman measurements using optical fibres
Authors: Yamada Haruka , Yamamoto Yoichiro
Published: May 2005

By using optical fibres the sample surfaces can be illuminated widely and uniformly. This technique is useful for the Raman measurements of a small amount of surface species and also unstable surface species.
Relaxation mode in SrTio3: A mode to test melting models?
Authors: Barbosa G. A. , Dos Santos J. I.
Published: May 2005

In 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

Far‐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

In 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

Effects 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

Raman 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

Resonance 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

Resonance 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

Resonance 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

Raman 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

An 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

The 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

Surface 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

The 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

Pure 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

Resonance 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

Low 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.
Spectroscopic study of single crystal of β‐naphthol low‐frequency vibrations oriented gas model and lattice dynamics
Authors: Szostak M. M. , Sanquer M. , Meinnel J.
Published: May 2005

The polarized Raman and FIR spectra of a β‐naphthol single crystal have been recorded in the 10–200 cm−1 region. The spectra have been interpreted on the basis of an oriented gas model associated with lattice dynamic calculations assuming a ‘6‐exp.’ potential between non‐bonded atoms and a simple harmonic force constant between oxygen atoms linked by hydrogen bonds.
Etude Vibrationnelle de trans‐Dicyano‐4,5 Cyclohèxenes: 2—Spectres Raman et IR de Tertiobutyl‐3 Dicyano‐4,5 Cyclohexènes D0, D3 (‐3,6,6) et D5 (‐3,4,5,6,6) à Conformations Bloquées
Authors: Davidovics G. , Gedoux B. , Aycard J. P. , Pourcin J.
Published: May 2005

Raman and infrared spectroscopic investigation of 3r, 4t, 5c and 3r, 4c, 5t diastereoisomers of d0, ‐3,6,6 d3 and ‐3,4,5,6,6 d5, ‐3 tertiobutyl, ‐4,5 dicyano cyclohexenes in the solid and dissolved states is performed. From conformational and Teller Redlich product rule considerations, the whole fundamental vibrations are assigned. Specific vibrations relative to (XCCN)2 (X = H or D) groups with diequatorial or diaxial nitriles are outlined.
The infrared and Raman spectra of isoelectronic potassium imidosulphonate, K2NH(SO3)2 and potassium methylenedisulphonate, K2 CH2 (SO3)2
Authors: Hall John R. , Johnson Robert A.
Published: May 2005

The polycrystalline IR and Raman spectra (4000–50 cm−1) of isoelectronic K2NH(SO3)2 and K2CH2(SO3)2 have been recorded at 77 K. These salts are isomorphous at ambient temperature (space group C2/c (C2h6)) but K2NH(SO3)2 undergoes a phase change on cooling to 77 K. Possible low‐temperature structures for the latter are proposed and their predicted spectra are compared with the observed spectra. The phase change appears to be limited to an ordering of hydrogen atoms to give a structure with space symmetry P1(C11) with Z = 4. To assist with the band assignment, spectra of the 2H analogues of both salts and the 15N analogue of K2NH(SO3)2 have been recorded. Aqueous solution spectra, including qualitative Raman polarization data have also been obtained for the highly soluble salts (NH4)2NH(SO3)2 and Na2CH2(SO3)2·2.5H2O and their 2H analogues. For NH(SO3)22−, the skeletal modes are assigned frequencies of 858 cm−1 (νasymNS), 842 cm−1 (νsymNS) and c. 180 cm−1 (δNS2). The corresponding CH2(SO3)22− frequencies are 800 cm−1 (νasymCS), 776 cm−1 (νsymCS) and c. 180 cm−1 (δCS2). The SO3 groups show their characteristic frequencies which are very similar for both species.
Analyse Vibrationnelle et Structurale en Série Aliphatique Saturée 3—Spectres de Vibration de l'Acide Méthylmalonique et de ses Sels Alcalins en Solution Aqueuse
Authors: Delarbre Jean Louis , Bardet Lucette , Maury Luc
Published: May 2005

Raman and infrared spectra of méthylmalonic acid CH3CH (COOH)2, CH3CD(COOD)2 and its alkaline salts CH3CH(COOH)(COOD)2, CH3CD(COOD)(COOK) and CH3CH(COOK)2, CH3CD(COOK)2 in aqueous solution have been investigated from 3500 to 200 cm−1; an assignment of the fundamental vibrations is proposed. The analysis of the polarization ratio lead us to conclude that neutral salt belongs to point group Cs. The acid salt and the acid itself belong to point group C1 and cannot exhibit intramolecular hydrogen bonding.
Raman spectra of liquid cyclopropyl cyanide
Authors: Maillols Jacques , Tabacik Vlado , Sportouch Serge
Published: May 2005

The Raman spectra of liquid cyclopropyl cyanide (range 50–4000 cm−1) are reported and found considerably different from those published by Daly and Wiberley.1 A new assignment is given based on the study of both Raman and IR spectra (liquid and gas) and on a model NC treatment permitting to correlate them with the spectra of cyclopropane and acetonitrile.
Infrared excited resonance Raman spectra of lobster shell pigments in situ
Authors: Nelson W. H. , Carey P. R.
Published: May 2005

Resonance Raman spectra, obtained with 676.4 and 752.5 nm excitation, are reported for the carotenoid molecule astaxanthin in situ in the shell of a lobster. The spectra show unusual frequency shifts and absolute intensity behaviour in the case of 676.4 and 752.5 nm excitation, respectively, and support the hypothesis that the shell contains astaxanthin bearing pigments which have not yet been isolated and characterized.
Raman dispersion spectroscopy (RADIS): 1—Phenomenology
Authors: Mortensen O. Sonnich
Published: May 2005

RADIS is a novel spectroscopic technique for the investigation of vibronic states. It differs from the common alternative absorption spectroscopy in two significant ways: (a) there is a distinct RADIS spectrum for every band in the Raman spectrum versus just one absorption spectrum; (b) the observables in RADIS are determined by a tensor quantity, and so polarization measurements are useful and significant also for isotropic systems like molecules in solution. In this paper the phenomenology of RADIS is discussed, with special emphasis on molecules in solution. There are three different RADIS spectra for isotropic systems, namely (i) an intensity spectrum, (ii) a linear polarization spectrum and (iii) a circular polarization spectrum. From these one may obtain three different intensity spectra, one for each tensor invariant. A parametrization of these spectra is given. It is shown that the spectra have the form of a simple superposition of Lorentzians, with resonance frequencies determined by the energies of the adiabatic molecular states. Inhomogeneous broadening is treated by means of simple spectral convolution. It is shown that when the inhomogeneous lineshape is Lorentzian, the RADIS intensity retains its Lorentzian form, while a Gaussian lineshape leads to RADIS spectra described by the complex error function.
Raman scattering in optical fibers
Authors: Lan Guey‐Liou , Banerjee P. K. , Mitra S. S.
Published: May 2005

In this paper we review the light scattering spectra of optical fibers and present new data on Raman spectra of optical fibers. The results include Raman spectra of fused silica fibers and effects of dopants and irradiation‐Large scattering volumes available in optical fibers afford one to detect low dopant concentrations and relatively weak second order spectra. Low frequency Raman spectra of optical fibers shows the expected non‐Debye type anomaly.
Temperature and pressure Raman study of molecular motions in liquid CH2Cl2
Authors: Hacura Andrzej , Żerda Tadeusz W. , Kaczmarski Marceli
Published: May 2005

The Raman line shapes of three symmetric modes ν1, ν3 and ν4 have been measured in liquid dichloromethane as a function of pressure from 1 bar to 3 kbar and of temperature from 183 to 363 K. The reorientation relaxation times are found to increase with higher pressures and to decrease with increasing temperatures. The isotropic half‐width of the ν4 band behaves untypically, varying only insignificantly throughout the temperature and pressure range studied. The differences in frequency between the polarized and depolarized bands are also determined. The dipolar coupling mechanism is applied to interpret the effects observed.
On the role of exciton‐phonon interaction in the interpretation of the relative intensities in the Raman lattice spectrum of crystalline p‐chloroaniline
Authors: Szostak M. M. , Sanquer M. , Girard A.
Published: May 2005

The relative intensities of bands in a polarized Raman Lattice spectrum of p‐chloroaniline are interpreted in terms of the oriented gas model. Among different reasons for deviations from this model the vibronic intensity enhancement of B1g and B3g lattice bands has been found to be the most important one.
Raman spectroscopic study of MoO3/γ‐Al2O3 and CoO(or NiO)‐MoO3/γ‐Al2O3 oxide catalysts prepared by different methods
Authors: Agudo A. López , Gil F. J. , Calleja J. M. , Fernández V.
Published: May 2005

Raman spectroscopy has been used to characterize various MoO3/γ‐Al2O3 and CoO (or NiO)‐MoO3/γ‐Al2O3 catalysts containing 12 wt% MoO3 and 3 wt% CoO (or NiO) prepared by different methods. No significant differences between samples prepared by the wet impregnation and the pore volume method could be observed in molybdena‐supported catalysts; in these samples the majority of Mo is present as isolated distorted MoO42− tetrahedra due probably to a low coverage of the alumina surface (SBET=240 m2 g−1). Addition of NiO to the molybdena‐supported catalysts seems to cause only a slight increase in the distortion and interaction between MoO42− species. In contrast, CoO addition to the molybdena‐supported catalysts changes considerably the spectra features, suggesting that the Mo species are highly distorted, presumably in different surroundings on the alumina surface, due to the strong interaction of Co with Mo species. However, simultaneous impregnation of both MoO3 and CoO or NiO results in a more regular arrangement of Mo species and an increase in formation of polymeric Mo species, particularly with Co‐containing catalyst, where a relative higher degree of polymeric aggregation may occur.
Spectra and structure of gallium compounds: 8—Vibrational studies of trimethylgallane‐dimethylether and trimethylgallane‐dimethylether‐d6
Authors: Odom J. D. , Wasacz F. M. , Sullivan J. F. , Durig J. R.
Published: May 2005

The infrared (4000–80 cm−1) and Raman (3500–10 cm−1) spectra of (CH3)3GaO(CH3)2 and (CH3)3GaO(CD3)2 have been recorded for the solid state at 77 K. The Raman spectra of the liquids have also been recorded and depolarization values measured. The spectra have been interpreted in detail on the basis of Cs molecular symmetry. The valence force field model has been utilized in calculating the frequencies and potential energy distribution for the heavy atom skeleton. Considerable coupling has been observed among the OC2 bending motions and the GaC3 bending modes. The GaO stretch could not be assigned to a particular low frequency band, but this motion contributed significantly to four different bands ranging in frequency from 279 to 148 cm−1. The calculated force constants for the adducts are compared to those previously reported for the Lewis base moiety and the differences are shown to be consistent with structural changes expected upon adduct formation.
Kinetics of hydrogen‐deuterium exchange and kinetic isotope effects in inosine‐5′‐ monophosphate and inosine‐3′5′‐ monophosphate determined by laser Raman spectroscopy
Authors: Ferreira Susan A. , Thomas G. J.
Published: May 2005

The rates (kH) of deuterium exchange of 8‐CH groups, as well as the rates (kD) of protium exchange of 8‐CD groups in 5′‐IMP and cIMP, were measured by laser Raman spectrophotometry over the temperature range 30–80°C. The kH, or ‘forward’ rates, were determined from exchange in D2O solutions, while the kD, or ‘reverse’ rates, were determined from exchange in H2O solutions of the nucleotides. The hypoxanthine nucleotides were found to exchange with rates intermediate between those of corresponding adenine and guanine nucleotides, reported previously. The values obtained for the rate constants as a function of temperature (k=A exp (‐Ea/RT)) yield the following Arrhenius activation energies and frequency factors. For 5′‐IMP: EaH=25.5±0.6 kcal mol−1, AH=2.61×1015h−1; EaD=24.9±0.6 kcal mol−1, AD=4.32×1014h−1. For cIMP: EaH=22.2±0.6 kcal mol−1, AH=2.52×1013h−1; EaD=21.4±0.6 kcal mol−1, AD=3.93×1012h−1. The lower activation energy for cIMP accounts for its more rapid exchange vis‐à‐vis 5′‐IMP, confirming the trend observed also for adenine and guanine nucleotides. Moreover, as in the cases of adenine and guanine isomers, the differential exchange between cyclic and 5′‐nucleotides of hypoxanthine is large at lower temperatures and small at higher temperatures. These results confirm that exchange at 8‐C is influenced by the ribosyl phosphate group. The present data also provide evidence of small kinetic isotope effects in the 8‐C exchange reactions. For 5′‐IMP, kH/kD≈2.5, and for cIMP, kH/kD≈1.7. The isotope effects of 5′‐IMP and cIMP are close to the values observed for guanine nucleotides. Finally, Raman vibrational spectra of four isotopic modifications of the hypoxanthine nucleotides are compared to provide specific assignments of the Raman bands to vibrations of the purine skeleton and its exocyclic substituents.
Raman studies of reorientational relaxation of cyclohexane in the liquid state
Authors: Bien T. , Döge G.
Published: May 2005

Reorientational correlation functions have been obtained from the analysis of the totally symmetric vibrations ν4, ν5 and ν2 of liquid cyclohexane. For the interpretation of the data, the Kubo line shape theory was assumed to be valid. The most reliable results were obtained from the ν4 vibration and indicated that reorientational relaxation occurs close to the Debye limit of rotational diffusion. The data are compared with NMR results given in the literature. The effects of rotational‐vibrational coupling are discussed.
Raman spectral investigation of the cadmium thiocyanate complexes in solutions and solid
Authors: Antié‐Jovanovié A. , Jeremié M. , Long D. A.
Published: May 2005

Raman intensity measurements have been made of cadmium thiocyanate aqueous solutions containing various ratios of total cadmium to total thioeyanate. Both Job and mole‐ratio methods indicated existence of a distinct complex species with a cadmium to thiocyanate ratio from 1 to 4. All average ligand number values obtained from three different series of experiments lie on the same curve, meaning that only mononuclear species are formed. Four overall stability constants have been calculated. The spectra are consistent with mononuclear complexes in solution, some having SCN− attached to the metal through the sulphur, others through the nitrogen. A band observed at 2132 cm−1 was assigned to the Cd(SCN)+ complex while bands observed at 2102 and 784 cm−1 were attributed to higher members of the stepwise Cd(NCS)n2−n series. The spectra of solid Cd(SCN)2 were in accord with a bridged thiocyanate structure. Assignments were supported by x‐ray structural studies.
Characteristic Raman bands for Azo and hydrazone structures
Authors: Jacques P.
Published: May 2005

Raman spectra of two hydroxy azoic model compounds: 3,5‐dimethoxy‐4‐hydroxyazobenzene and 2,6‐dimethoxy‐4‐hydroxyazobenzene are compared. These compounds exist as the pure azo and pure hydrazone forms respectively, thus allowing the assignment of numerous Raman Bands characteristic of each tautomer. The usefulness of Raman spectroscopy for investigating azo‐hydrazone tautomerism is illustrated by a study of 2‐hydroxy‐5‐methyl‐azobenzene which is clearly proved to exist entirely in the azo form.
Vibrational analysis of peptides, polypeptides and proteins. XII—fermi resonance analysis of the unperturbed ND stretching fundamental in polypeptides
Authors: Krimm S. , Dwivedi Anil M.
Published: May 2005

We have obtained the spectrum of β‐poly(L‐alanine‐ND), and find three bands in the ND stretching region. By comparison with Fermi resonance analyses of deuterated derivatives of polyglycine I as well as with α‐poly(L‐alanine‐ND), we conclude that a three‐level Fermi resonance is involved in the β polypeptide, and that the unperturbed ND stretch fundamental occurs near 2428 cm−1.
Raman studies of L‐histidine and related compounds in aqueous solutions
Authors: Tasumi Mitsuo , Harada Issei , Takamatsu Tadahisa , Takahashi Seizo
Published: May 2005

The Raman spectra of L‐histidine, L‐histidine‐ 13C (labelled at C2 of the imidazole ring) and related compounds, namely, imidazole, 4‐methylimidazole, N‐acetyl‐L‐histidine methylamide, were observed in H2O and D2O solutions at various pH and pD values. A strong Raman band at around 1410 cm−1 was found for these compounds in acidic D2O solutions, and it was assigned to a mode characteristic of the N‐deuterated imidazolium ring (Im+) in which the N1C2N3 symmetric stretching and ND bending vibrations are mixed. It is concluded that this band would be useful as a probe for studying the ionization states of histidine residues in proteins.
Alkene‐halogen complexes studied by matrix isolation vibrational spectroscopy
Authors: Holroyd S. , Barnes A. J. , Suzuki S. , Orville‐Thomas W. J.
Published: May 2005

Vibrational spectra of mixtures of chlorine, bromine or iodine with ethene or 2,3‐dimethylbut‐2‐ene (tetramethyl‐ethene) in low‐temperature argon or nitrogen matrices are reported. The shifts observed for the halogen and CC stretching modes of the 1:1 alkene‐halogen complexes are related to the structure of the complexes.
A polarized infrared and Raman spectroscopic study of the electrooptic crystal m‐nitroaniline. 2—lattice vibrations
Authors: Szostak M. M.
Published: May 2005

The polarized Raman spectra of meta‐nitroaniline single crystals in the 10–150 cm−1 region as well as the far‐infrared spectra of the (010) platelets in the 20–200 cm−1 region have been measured and assignments of all expected bands have been proposed on the basis of the observed polarizations. To estimate the influence of the electrooptical properties of the crystal on the lattice spectra, the relative intensities of librational bands have been calculated from the oriented gas model, and observed discrepancies have been discussed. Comparisons with the spectra of the isomeric crystal p‐nitroaniline and of a similar non‐centrosymmetric crystal m‐chloronitrobenzene have been made.
The effect of inhomogeneous broadening on the absorption spectra and excitation profiles of resonance Raman and coherent anti‐stokes Raman scattering of polyatomic molecules
Authors: Lukashin A. V. , Frank‐Kamenetskii M. D.
Published: May 2005

A uniform treatment of the effect of inhomogeneous broadening on the absorption spectra and the excitation profiles of resonance Raman scattering and coherent anti‐Stokes Raman scattering is presented. For the case of Gaussian distribution of molecular energy values general expressions are obtained which are valid for arbitrary values of homogeneous and inhomogeneous broadening parameters. Just as for resonance Raman scattering excitation profiles, the coherent anti‐Stokes Raman scattering excitation profiles are quite sensitive to the mechanism of vibronic line broadening. The simple relation between resonance Raman scattering and coherent anti‐Stokes Raman scattering excitation profiles is shown to be valid only if the effect of inhomogeneous broadening is negligible. We suggest that this fact should be used for experimental estimation of the impact of inhomogeneous broadening. We discuss the possibility of using absorption data as well as resonance Raman scattering and coherent anti‐Stokes Raman scattering excitation profiles for testing the adequacy of the original model of vibronic theory.
Magnetic resonance‐Raman optical activity of ferrocytochrome c theory and experiment
Authors: Barron L. D. , Meehan C. , Vrbancich J.
Published: May 2005

The theory of magnetic resonance Raman optical activity in metal porphyrins is developed. Irreducible tensor methods are used to calculate the transition polarizabilities (involving both symmetric and antisymmetric contributions) which are formulated in terms of a vibronic development of the Raman transition tensors. The circular intensity difference for the vibrations of symmetry species A1, A2, B1 and B2 is explicitly evaluated for excitation within the 0–0 and 0–1 visible absorption bands. Polarized, depolarized and unpolarized magnetic resonance Raman optical activity spectra of ferrocytochrome c within the 0–0 and 0–1 bands are presented. Good qualitative agreement is found between theory and experiment.
A Raman spectroscopic temperature study of NH3+ torsional motion as related to hydrogen bonding in the L‐alanine crystal
Authors: Forss S.
Published: May 2005

A Raman study of the NH3+ torsional mode in the amino acid L‐alanine has been performed. The temperature dependence of this mode has been followed in the temperature region 110–350 K. The activation energy for NH3+ reorientation obtained from a linewidth vs temperature investigation, Ea = 3100±400 cm−1, is in excellent agreement with corresponding NMR results, thus demonstrating that Raman spectroscopy can serve as a complementary method to NMR in obtaining torsional barrier heights. Based on an X‐ray investigation, crystal and hydrogen bond parameters have been calculated as a function of temperature. The increase of the NH3+ torsional barrier on going to lower temperatures is essentially attributed to the shortening of one specific hydrogen bond. The detection of the NH3+ torsional hot transition is important for the determination of the shape of the lower portion of the NH3+ torsional potential. The sixfold term V6 of the potential used, three‐plus sixfold, is thus very sensitive to the frequency difference between the NH3+ torsional fundamental and hot band. The optimum frequency fit gives, however, too large a value for the barrier height V3. The reason for this is interpreted as arising from the severe distortion of the hydrogen bonds at large torsional angles. The results presented here support recent findings that a revision of the dynamic picture of the hydrogen bonds in L‐alanine crystal, as reported in two earlier papers, is needed.
Laser Raman and infrared spectra of di‐potassium tartrate hemi‐hydrate
Authors: Srivastava G. P. , Mohan S. , Jain Y. S.
Published: May 2005

An analysis of the Raman and infrared spectra of di‐potassium tartrate hemi‐hydrate (DKT), K2C4H4O6·½H2O, is reported. It has been inferred that the C4H4O ion and H2O molecule in a DKT crystal occupy points of C1 site symmetry. Various units of C4H4O ion/(H2O molecule) located at crystallographically distinguishable positions in this crystal do not appear to be different in their structure or the force fields governing their vibrational dynamics.
Raman spectrum of NH4ReO4 at high pressure
Authors: Klug D. D. , Sim P. G. , Brown R. J. C.
Published: May 2005

The pressure dependences at room temperature of the translational lattice modes and of the ν2 and ν4 internal bending modes of the ReO ion in solid NH4ReO4 are reported. There is no evidence of any phase transition up to a pressure of 15 kilobar. The pressure coefficients of the translational modes are 2.0 cm−1 GPa−1 and 3.0 cm−1 GPa−1 for the Bg and Eg modes respectively. The pressure coefficients of the bending modes are 1.0 cm−1 GPa−1 and 5.4 cm−1 GPa−1 for the Bg and Ag components of ν2, and 4.1 cm−1 for the overlapped Bg and Eg components of ν4.

The symmetry assignments of the low frequency lines in the spectrum were checked by means of polarized Raman spectra of a single crystal. The previous assignments are correct.
Activité Raman et Infrarouge des Cristaux Piezo Electriques BeSO4·4 H2O et BeSO4·4 D2O. 1–Vibrations Principales et Structure
Authors: Pigenet Claude
Published: May 2005

Les cristaux piezo‐élecriques BeSO4·4H2O ont été étudiés par diffusion Raman (4000 à 4 cm1) et spectroscopie infrarouge (4000 à 30 cm−1). Les modes normaux (sans les modes longitudinaux) ont été observés et attribués. Les modes relatifs aux groupements tétraédriques Be(H2O)4, ce qui est démontré par la substitution du deutérium, nous ont permis de calculer des constantes de force F,(BeOH) = 3.21 modyn A−1 et F α/r2(H2O−BeOH2) = 0.285 modyn A−1. Les modes internes des molécules d'eau et les modes de basse fréquence ont été reliés à la structure qui comporte deux liaisons hydrogène.
Resonance Raman spectra of methotrexate
Authors: Seng G. , Bolard J. , Chinsky L. , Turpin P. Y.
Published: May 2005

Resonance Raman spectra of methotrexate, using 257 nm excitation, gives new information on its pteridine moiety.
Spectre de Vibration et Vibrations Normales de I'Acide Pivalique
Authors: Longueville W. , Fontaine H. , Vergoten G.
Published: May 2005

L'acide pivalique (TMAA) se présente sous forme de dimères par double liaison hydrogéne. Un calcul en coordonnées normales est mené pour les quatre isotopes d0, d1, d9 et d10. L'affinement conduit à 45 constantes de force et à la description détaillée de l'ensemble des mouvements. Une visualisation est donnée pour certains mouvements caractéristiques (notamment du cycle) et plus particulièrement en basse fréquence (torsions). Les valeurs des barrières de potentiel sont données pour les torsions des groupements méthyl et t‐butyl.
Vibrational assignment of the sn‐1 and sn‐2 chain carbonyl stretching modes of membrane phospholipids
Authors: Levin Ira W. , Mushayakarara Ernest , Bittman Robert
Published: May 2005

Since the carbonyl stretching modes of membrane phospholipids reflect molecular perturbations and reorganizations at the bilayer interface region, a definitive assignment is desired of the vibrations associated with the carbonyl transitions at either the sn‐1 or sn‐2 lipid chain position. Ether glycerol phospholipids containing one alkyl ether chain and one acyl chain, with the carbonyl group in either the sn‐1 or sn‐2 chain, provide lipid systems for establishing these assignments. rac‐1‐0‐Hexadecyl‐2‐palmitoyl‐sn ‐glycero‐3‐phosphorylcholine yields a carbonyl stretching mode at 1716 cm−1, while the carbonyl mode for 1‐palmitoyl‐2‐0‐hexadecyl‐sn ‐glycero‐3‐phosphorylcholine shifts to 1737 cm−1, By eliminating the gauche bond at the α‐carbon position of the sn‐2 acyl chain in 1‐0‐hexadecyl‐2‐acetoyl‐sn‐glycero‐3‐phosphorylcholine, the lower frequency carbonyl fundamental reverts to a higher frequency (1739 cm−1) characteristic of a nearly trans conformation about the C2C1 bond in the ester linkage.
Low frequency vibrational study and reorientational motions in M(CO)3(η6C6H6) M = Cr, Mo, W
Authors: Chhor K. , Lucazeau G.
Published: May 2005

Raman and infrared spectra (5‐2000 cm−1) of Cr(CO)3(η6‐C6H6), Mo(CO)3 (η6‐C6H6) and W (CO)3 (η6‐C6H6) and of the deuterated derivatives (d6) of the Cr and Mo complexes have been recorded in the 5‐300 K temperature range. The low frequency region has been extensively studled. New modes are identified and a new assignment in this region is proposed. The temperature dependence of the low frequency spectra is discussed in connection with recent quasielastic neutron scattering results. Broadenings of the Raman bands are interpreted in terms of anharmonicity and vibrational dephasing connected with large amplitude motions associated with a potential barrier of 4.7 kcal mol−1, A qualitatlve representation of the potential driving the torsional motion is proposed and it is pointed out that the intermolecular potential plays a dominant role. 2π/6 ring jumps involving an activation energy of 3.9 kcal mol−1, as deduced from neutron scattering in Cr(CO)3(η6‐C6H6), occur, but the proportion of molecules in the state of jump is only 0.3% at 300 K and therefore the rate of dynamic disorder is too low to induce an order‐disorder phase transition. This result is consistent with our calorimetric measurements.
Precision Raman investigation of the ν1 mode of vibration of SO, WO and MoO in aqueous solutions of different concentrations
Authors: Dean K. J. , Wilkinson G. R.
Published: May 2005

The ν1 vibrational Raman modes of the anions SO, WO and MoO have been studied in aqueous solution with great precision, and the effect of different alkali metal cations (Li+, Na+, K+, Rb+ and Cs+) carefully recorded as a function of concentration. The results show that the symmetric vibrational frequency of the anions is dependent on both the concentration and on the cation present in the solution. Precise values of the anion ν1 frequencies were found at infinite dilution by extrapolation. These frequencies are: 980.75±0.1 cm−1 for SO, 931.1±0.1 cm−1 for WO and 986.1±0.1 cm−1 for MoO. When the alkali metal cations Li+ or Na+ were present in the solution, the anion ν1 frequency was shifted to a higher value than the infinite dilution frequency, whereas, when K+, Rb+ or Cs+ were present in the solution, the anion ν1 frequency was decreased. The frequency shifts were also found to depend linearly on the square root of the solution concentration. The results also indicate that in ionic aqueous solutions the water molecule behaves as though it has a radius of 1.15±0.01 Å and a polarizability of 0.39±0.01 Å3. An empirical relation between cation volume and polarizability has also been demonstrated.
Raman intensity and conjugation: 6—a Raman study of non‐planarity in substituted styrenes, biphenyls and stilbenes
Authors: Schmid E. D. , Topsom R. D.
Published: May 2005

A study of the Raman intensities of ν8 mode of benzene in series of styrene, biphenyl and stilbene hydrocarbons is reported. It is shown that, after correction for the resonance Raman effect, the intensities can be related to the degree of planarity of the molecules via a previously derived relationship between the intensity and the length of the conjugated system.
The hyper Raman spectra of some chloro‐ and bromo‐methanes and some group IV tetrachlorides
Authors: Dines T. J. , French M. J. , Hall R. J. B. , Long D. A.
Published: May 2005

The hyper Rayleigh and hyper Raman spectra of the following Group IV halides are reported: the liquids CCl4, CHCl3, CH2Cl2, CHBr3, CH2Br2, CH3Br, SiCl4, GeCl4 and SnCl4 and CBr4 in solution in CCl4. Relative hyper Rayleigh and hyper Raman intensities and depolarization ratios have been measured. These are discussed and the intensities compared with those observed in Raman and infrared spectra.
Normal‐coordinate analysis of retinal isomers and assignments of Raman and infrared bands
Authors: Saito Shigeki , Tasumi Mitsuo
Published: May 2005

Normal‐coordinate calculations have been performed for the all‐trans, 9‐cis, 11‐cis and 13‐cis isomers of retinal using a model structure in which the β‐ionone ring was replaced with a simplified structure. Most of the Raman and infrared bands observed from these isomers in the solid state are assigned on the basis of the results of calculation. The vibrational characteristics of each isomer are discussed.
Raman spectra and vibrational dephasing of methylacetylene
Authors: Kalasinsky V. F. , Little T. S.
Published: May 2005

The Raman spectra of gaseous and liquid methylacetylene have been recorded. The spectrum of the gas provides new data for verifying the vibrational assignments of certain A1 and E fundamentals. Some of the vibrations exhibit hot bands whose origins have been determined on the basis of their Raman intensities. The isotropic scattering for the three fundamentals in the liquid state was studied as a function of temperature. The hot band structure in the liquid state was modeled by using curve‐fitting procedures and the assignments made for the gas phase. The isotropic bandwidths for the fundamentals were observed to increase with decreasing temperature, and the broadening is consistent with the existence of a weak hydrogen bond in pure methylacetylene.
Pulsed laser induced vibrational resonance Raman scattering of chlorophyll a dimers
Authors: de Wilton A. , Haley L. V. , Koningstein J. A.
Published: May 2005

The pulsed laser induced Raman spectrum of dry chlorophyll a (Chl a) in hexane is reported. This sample is excited with a wavelength which is in resonance with an absorption band of the Chl a dimer at 432 nm. The observed resonance Raman excitation profile for several Raman bands shows that two electronic origins of the dimer are located at 434.1 and 435.4 nm and these are assigned to a pair of pseudo exciton levels. Features of this excitation profile are used to discuss the observed Raman spectra.
Raman and infrared spectra of spermidine and spermine and their hydrochlorides and phosphates as a basis for the study of the interactions between polyamines and nucleic acids
Authors: Bertoluzza A. , Fagnano C. , Finelli P. , Morelli M. A. , Simoni R. , Tosi R.
Published: May 2005

The Raman and infrared spectra of the polyamines spermidine and spermine and of their corresponding hydrochlorides and phosphates have been studied. These systems can be regarded as models of the molecular interactions between polyamines and nucleic acids, and the observed spectra are discussed in relation to this. Medium strong and strong NHCl and NHO hydrogen bonds are present in both the polyamine hydrochlorides and phosphates and the proton is predominantly located on the nitrogen atom. In the case of the phosphates, the Raman spectra indicate the formation of HPO groups, which can also interact among themselves by strong OHO hydrogen bonds.
Single crystal Raman spectra of magnesium and zinc perchlorate hexahydrates
Authors: Patel M. B. , Agarwal Anshu , Bist H. D.
Published: May 2005

Raman spectra of Mg(ClO4)2·6H2O and Zn(ClO4)2·6H2O single crystals have been recorded in the region 4000–20 cm−1 using an Ar+ laser as a source of excitation. The polarization behaviour of the Raman lines under different crystal orientations is reported. It is shown that the water molecules lie almost in a plane perpendicular to the crystal c‐axis.