bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antisymmetric light scattering of molecules with non‐degenerate electronic state
Authors: Baranova N. B. , Ya. Zel'dovich B. 
Published: May 2005

AbstractAntisymmetric light scattering of molecules with a non‐degenerate ground electronic state is discussed. Scattering of this type appears for a rotating molecule, but only when account is taken of (a) the dispersion of the polarizability and (b) the Coriolis force acting on the electrons. An expression is derived for the antisymmetric components of the scattering tensor α, which relates them to the tensor of the Faraday effect for a molecule with fixed nuclei and to the frequency derivative of the polarizability tensor, ∂\documentclass{article}\pagestyle{empty}\begin{document}$ {\rm{\hat \alpha }} $\end{document}/∂ω. Generally, the sum of both contributions yields αant ∼ Ω ∂α/∂ω, where Ω is the angular velocity of rotation of the molecule. The possibilities of experimental observation of the predicted effects are discussed.
The pure rotational Raman spectrum of SeO3
Authors: Brassington N. J. , Edwards H. G. M. , Long D. A. , Skinner M. 
Published: May 2005

AbstractThe pure rotational Raman spectrum of selenium trioxide monomer in the vapour phase at 410 K has been obtained and analysed for the first time. The following rotational constants and bond lengths were obtained:

This is the first spectroscopic determination of r0 in SeO3. The precision of r0 is significantly greater than the value of ra = 169±1 pm obtained from an earlier electron diffraction study.
High resolution Raman spectroscopy of gases with laser sources. XIII—the pure rotational spectra of 1,3,5,7‐cyclooctatetraene and 1,5‐cyclooctadiene
Authors: Thomas P. M. , Weber A. 
Published: May 2005

AbstractThe pure rotational Raman spectra of 1,3,5,7‐cyclooctatetraene (C8H8) and 1,5‐cyclooctadiene (C8H12) vapor at pressures of 4 and 2 torr, respectively were photographed under high resolution. The 4765 Å, 4880 Å and 5145 Å radiations of a single mode argon ion laser were used to generate the spectra. The molecular constants found from the analysis of the spectra are, for C8H8: B = 0.090392(15) cm−1, DJ = 1.34(10) × 10−8 cm−1 and, for C8H12: B = ½(A + B) = 0.090345(110) cm−1, DJ = 7.12(1.80) × 10−10, cm−1, where the errors are five standard deviations. These constants are averages over the ground state, the low‐lying vibrational states which are sufficiently populated at room temperature, as well as over the possible conformers concurrently present in the sample.
Polarized Raman spectra and intermolecular potential of α‐glycine‐C‐d2 and DL‐alanine‐α,β‐d4 crystals
Authors: Machida Katsunosuke , Kagayama Akira , Saito Yutaka 
Published: May 2005

AbstractPolarized Raman spectra of α‐glycine‐C‐d2 and DL‐alanine‐α,β‐d4 single crystals have been measured. Large factor group splittings due to the non‐bonded atom–atom interaction were observed for the CD2 bending mode of glycine‐C‐d2 and the CD3 asymmetric deformation and the CD3 torsional modes of DL‐alanine‐α,β‐d4. These factor group splittings and their change on N‐deuteration were explained fairly well by a normal coordinate analysis with an intermolecular potential of the exp‐6 type for the non‐bonded atom–atom interaction for the H…︁H, C…︁H, C…︁C and O…︁H(C) pairs. Good agreement was obtained between the observed and the calculated lattice frequencies on addition of the N…︁O non‐bonded interaction potential, the hydrogen bond stretching terms and the Coulomb interaction terms to the intermolecular potential.
Raman study on p‐nitroaniline: Molecular structure in the molten phase
Authors: Harrand M. 
Published: May 2005

AbstractThe Raman spectrum of pure liquid para‐nitroaniline (p‐NA) was studied between 150 and 220°C, and compared with those of the crystal and solutions. The 1270–1350 cm−1 region is the most significant. The ν line, very weak for the solid, becomes intense in the spectrum of molten p‐NA. Except for one case, all the depolarization factors are smaller than 0.75. We then assumed that, as in the cyrstal, the molecules are gauche in the pure liquid and that the conjugation state is slightly modified, the NO2 group being more localized. In the spectra of the solutions the ν lines are the strongest.
Spectres Raman et Transition de Phase des Cristaux de (ND4)2Cu(OD2)2Cl4
Authors: Poulet H. , Mathieu J. P. 
Published: May 2005

AbstractThe changes in the Raman spectra of single crystals of (ND4)2Cu(OD2)2Cl4 with temperature are indicative of an order–disorder transition, in contradistinction with the results of neutron diffraction. A space‐group deduced for the low temperature phase from a pseudo‐spin model is in agreement with the spectral results.
Lattice vibration spectra. XXII—infrared and Raman spectra of strontium chloride dihydrate, SrCl2·2H2O and SrCl2·2(H, D)2O
Authors: Lutz H. D. , Pobitschka W. , Christian H. , Becker R.‐A. 
Published: May 2005

AbstractThe infrared absorption and Raman spectra of SrCl2·2H2O powder as well as SrCl2·2D2O, and partially deuterated and isotopically dilute samples, have been recorded in the range from 30 to 4000 cm−1 at 95 and 295 K and analysed with regard to the strongly asymmetric force field in the H2O molecules. This is shown by an unusually large splitting of the OH and OD stretching fundamentals of the HDO molecules: 3426 and 3243 cm−1 and 2534 and 2408 cm−1 respectively at 95 K. Uncoupled OD stretching frequencies of SrCl2·6H2O and SrCl2·H2O are also presented. In SrCl2·2H2O both a relatively strong and a weak hydrogen bond to chloride ions are present; these are essentially straight.The spectra of SrCl2·2H2O exhibit the following characteristics: (1) no intramolecular coupling of the OH stretching vibrations; (2) very large Fermi resonance of νOH and 2δ; (3) the same high intensity of H2O twisting librations in the infrared spectra as for wagging and rocking modes; (4) splitting of the librational fundamentals of the HDO molecules, as large as 100 cm−1, caused by different structural arrangements of the H and D atoms in the asymmetric H2O molecules; and (5) strong intermolecular coupling of bending and librational fundamentals, which results in correlation splittings up to 75 cm−1. Possibilities of assigning the librational modes of H2O molecules which are in an asymmetric force field are discussed.
Raman spectra of lead chloride single crystals
Authors: Mendes‐Filho J. , Melo F. E. , Moreira J. E. 
Published: May 2005

AbstractRaman spectra of lead chloride single crystals have been measured at several temperatures, up to near the melting point. An assignment of the eighteen Raman‐active modes is made, based on low temperature polarized spectra. Analysis of the high temperature spectra shows that some Raman peaks can be related to a disordered chlorine sublattice. A comparison is made with the spectra of superionic compounds, where one sublattice can be considered as molten.
Etude par Spectrométrie Raman de Changements de Phase dans le Cristal de 4,4′‐Dichlorobenzophénone
Authors: Peretti P. , Ranson P. 
Published: May 2005

AbstractLow frequency vibrations of single crystal 4,4′‐dichlorobenzophenone (DCBP) have been determined by Raman spectroscopy and an analysis of the spectra is presented. In the temperature range 160–190 K two phase changes occur, a feature that is common to many organic molecular crystals and is quite likely due to conformational changes in individual molecules. These changes do not appear to alter the molecular symmetry, C2, or the space group C of the unit cell.
Etude par Effet Raman de la Transition de Phase α‐β du Sulfate de Potassium
Authors: Poulet H. , Mathieu J. P. 
Published: May 2005

AbstractThe α‐β phase transition of a K2SO4 single crystal has been studied by means of Raman scattering. The temperature variation of the spectra is accounted for by a model in which the order parameter is a pseudo‐spin variable. Above the transition temperature, several Raman lines persist, allowing some external modes to be attributed.
Pollutant trapping studies. 1—Resonance and spontaneous Raman spectra of the decomposition products of nitrogen dioxide on oxide surfaces
Authors: Cooney Ralph P. , Tsai Peter 
Published: May 2005

AbstractThe products of the surface decomposition of NO2/N2O4 on zeolites X and A and γ‐alumina have been investigated using Raman spectroscopy. On the zeolite surfaces results indicate that a self‐ionization surface reaction occurs to generate nitrate (NO3−) and nitrosonium (NO+) ions. The extent of self‐ionization of NO2/N2O4 appears to be far greater for the zeolitic absorbed phase than for the liquid phase. The nitrate appears to be held on cation sites while the nitrosonium ion is associated with the zeolitic oxide framework. Two different nitrate species form on zeolite A while only one nitrate species was detected on zeolite X. In the zeolite systems the spectra of adsorbed NO+ were resonance enhanced using shorter wavelength exciting lines while the nitrate spectra were conventional (spontaneous) Raman spectra. On γ‐alumina the products of the surface decomposition of NO2/N2O4 consist of three distinct types of surface nitrate with NO+ not being detected.
Interprétation des Profils d'Excitation Obtenus par Raman de Résonance des Modes de Vibration de la Diéthylcyanine
Authors: Rayez J. C. , Forel M. T. , Mejean T. 
Published: May 2005

AbstractThe excitation profiles of several vibrational Raman bands of diethylcyanine are examined where the exictation is applied to the first electronic transition. In order to analyse these profiles, firstly, a study of the electronic spectrum is carried out: the symmetry of the first electronic state is determined from an experimental approach (polarization of vibrational and electronic spectra) and from a theoretical approach (Hartree‐Fock semiempirical calculations); secondly, the vibration excitation profile located at 1368 cm −1 is analysed. The parameters of this vibration (1368 cm−1) and the mechanism of the scattering are obtained with the help of Raman and absorption spectra. A comparison between the scattered intensity and the 1368 cm−1 vibration intensity allows the studies of excitation profiles of the other vibrations.
Soft mode analysis on the lead germanate system
Authors: Hisano Kumao , Toda Kohji 
Published: May 2005

AbstractThe ferroelectric soft mode in the single crystals of the lead germanate system with silicon doping has been analysed by using the following three response functions χ(ω): (1) χ(ω)−1 = ω − ω2 − iγω, (2) χ(ω)−1 = ω − ω2 − ω2 − iγ2 and (3) χ(ω)−1 = ω − ω2 − iδ2ωτ(1 + ω2τ2)−1. The least squares fitting to the observed spectra showed that the response function of type (3) proposed by Yacoby et al. gave the satisfactory results to the soft mode theory with τ−1 ≈ 30 cm−1. The temperature dependence of the soft mode frequency and the mode strength has the Curie–Weiss form close to the Curie temperature. The increase of the silicon impurity lowers the soft mode frequency, while the effects on the line width are small. The soft mode frequency seems to be mainly influenced by the change of the short range harmonic force due to the silicon doping. The Curie temperature estimated from the soft mode frequency is consistent with that obtained from the dielectric measurements.
Inelastic light scattering in the presence of uniaxial stresses
Authors: Anastassakis Evangelos 
Published: May 2005

AbstractWhen a crystal is subject to a uniaxial stress, the Raman spectrum of various phonons may exhibit changes in the scattering intensity and also shifts of the frequencies and splittings of the degeneracies of the optical phonons. Valuable information can be obtained from such studies regarding the electronic band structure, the scattering mechanism, and the elastic and lattice‐dynamical properties of the material. The basic theoretical and experimental facts related to such effects are briefly reviewed in this contribution. Other possibilities are also discussed which demonstrate the usefulness of a uniaxial stress as a controlled perturbation in the study of crystalline matter by use of light scattering techniques.
Electronic Raman scattering in intermediate valence compounds
Authors: Gonçalves da C. E. T. , Nicola J. H. 
Published: May 2005

AbstractWe discuss electronic Raman scattering (ERS) in intermediate valence compounds. ERS is a unique tool to probe directly the charge fluctuations of the 4f electrons in these compounds. We calculate the Raman scattering cross‐section and present a quantitative estimate which suggests that the effect should be observable. We hope that these results will stimulate experimental interest.
Phase matching in coherent anti‐stokes Raman scattering
Authors: Chandra S. , Compaan A. , Wiener‐Avnear E. 
Published: May 2005

AbstractGeneralized phase matching conditions for the four‐wave mixing process of coherent anti‐Stokes Raman scattering (CARS) is examined. The use of three incident laser beams leads to better spectral and angular separation of the CARS signal than is possible in standard two beam CARS experiments. Furthermore, large background reduction is shown possible through the use of three frequencies. Special attention is paid to the universal phase matching geometry where two of the laser beams counterpropagate (COPCARS). Experimental results obtained with the COPCARS are presented. The technique is especially useful for studying small frequency shifts such as those associated with rotational Raman, Brillouin and Rayleigh wing scatterings.
A note on two‐phonon coherent anti‐stokes Raman scattering
Authors: Shen Y. R. 
Published: May 2005

AbstractDifference‐frequency mixing of two pump waves can in principle excite two coherent phonon waves via the parametric process. Only when the phonon excitation is small can the nonlinear susceptibility of two‐phonon coherent anti‐Stokes Raman scattering be described as proportional to the product of two Raman tensors.
Inelastic light emission from spherical particles and cylindrical fibers
Authors: Chang R. K. , Owen J. F. , Barber P. W. , Messinger B. J. , Benner R. E. 
Published: May 2005

AbstractThe inelastic light‐scattering properties of molecules embedded in small dielectric spheres and cylinders are presented. The angular distribution of inelastically scattered radiation is shown to differ from that of elastically scattered radiation from the same dielectric particle. Furthermore, the inelastic emission spectra from the embedded molecules exhibit additional peaks which are not present for the same molecules embedded in a much larger dielectric object. The angular distribution, which is a complicated function of the size, shape and refractive index of the host dielectric particle and the internal molecular distribution, contains information needed to deduce the concentrations of the embedded molecules, as well as to characterize the morphology of the dielectric particle. The emission spectra contain the natural mode resonances of the particle in addition to the usual bulk‐observed spectral characteristics of the embedded molecules. Consequently, both angular and spectral distributions are important in the interpretation of inelastic scattering (spontaneous Raman or fluorescence) from molecules embedded in or coated on dielectric particles.
Raman intensities of gas phase methyl chloride and deuterated derivatives, force constants and bond polarizability parameters
Authors: Orza J. M. , Domingo C. , Escribano R. , Montero S. 
Published: May 2005

AbstractThe absolute Raman intensities of all fundamental bands of CH3Cl, CD3Cl, CH2DCl and CHD2Cl have been measured in the gas phase, with an estimated accuracy of ∼ 10%. Using these data, and the most recently published vibration‐rotation data on these molecules, a refinement of the potential function has been carried out, and the results compared to the previous force field for methyl chloride. The derivatives of the molecular polarizability with respect to the symmetry coordinates have also been calculated, and an analysis has been performed of these magnitudes in terms of the bond polarizability theory.
Resonance Raman studies of transition metal peroxo complexes: 5—The oxygen carrier cobalt(II)‐salen and its μ‐peroxo complexes, [(L)(salen)Co]2O2; L = DMSO, py, DMF, pyO and no L
Authors: Hester R. E. , Nour E. M. 
Published: May 2005

AbstractResonance Raman spectra of the species [Co(salen)], [Co(salen)]2 and [Co(salen)(py)] were obtained both from the solids and from CHCl3 solutions. These spectra show a large number of bands in the 100–1750 cm−1 region which are assigned to vibrational modes of the salen ring. Oxygenated complexes having the general form μ‐peroxo‐[Co(salen)(L)]2O2, with ligand L being DMSO, py, DMF, pyO or no L and occupying the axial position trans to the dioxygen, gave resonance Raman spectra with many bands throughout the region 100–1750 cm−1. The ν(CoO) and ν (OO) wavenumbers in these complexes have been assigned by means of oxygen‐18 substitution. Force constants for the OO and COO bonds in the DMF complex have the values 380 and 247 N m−1, respectively. The effect of changing the ligand L on the observed wave numbers is interpreted in terms of both σ and π‐donor effects through the metal. Band intensity excitation profiles demonstrate that the O22− → Co3+ CT transition occurs at ˜370±10 nm for the complexes containing ligands L and at 580 nm for the complex with no L. Resonance function plots of Raman band intensities are interpreted in terms of the relative values of the OO bond orders which are shown to vary with the ligand L as follows: py>pyO>DMF>DMSO. This order is, however, at variance with that based on the ν (OO) wavenumbers.
Variable temperature and pressure study of the Raman spectrum of five phases of HgI2
Authors: Khilji M. Y. , Sherman W. F. , Stadtmuller A. , Wilkinson G. R. 
Published: May 2005

AbstractRaman spectra of red and yellow forms of HgI2 have been recorded as a function of temperature and pressure. Temperatures between 77 and 570 K and pressures up to 14 khar have been used to investigate the vibrational modes of four (and possibly five) phases of this material. No evidence could be found from the Raman spectrum to support the suggestion that a thermal anomaly within the stability range of the red form indicates a III to IV transition. Clear differentiation between the yellow high temperature and high pressure phases has been shown, and the phase boundary (YHP→YHT) located. A previously unreported Raman spectrum of an orange phase is shown, and a modified phase diagram is presented.
Laser Raman spectroscopy of biomolecules: 15—Conformational study of partially reduced, fully reduced and cyanogen bromide treated ribonuclease a
Authors: Lord Richard C. , Relyea Noël M. 
Published: May 2005

AbstractReduction of one disulfide bond in bovine pancreatic ribonuclease A, which leaves the enzyme with nearly unimpaired biological activity, makes barely perceptible changes in the aqueous Raman spectrum. Reduction of all four disulfide bonds, which inactivates the enzyme, produces serious conformational changes. The spectrum shows a substantial decrease in α‐helical content and conversion of all tyrosines to a weakly hydrogen‐bonded form. Cleavage of the peptide chain by cyanogen bromide at the three sites of methionine residues (13, 29–30 and 79) makes little alteration in the α‐helical content but reduces the proportion of the β‐pleated sheet. This structural change is attributed mainly to the chain breaking at residue 79, which occurs in the center of the β‐network.
The radial transition of tetrahydrofuran
Authors: Sont W. N. , Wieser H. 
Published: May 2005

AbstractA weak sequence of lines in the Raman spectrum of tetrahydrofuran vapour around 270 cm−1 has been observed for the first time and is assigned to combination transitions between the pseudorotational‐radial states of the five‐membered ring. With the aid of these lines an interpretation for the complex infrared band in the same region is suggested. A suitable Hamiltonian is applied to the pseudorotation energy levels in the ground and the first excited radial state.
Resonance Raman spectra of transient free radicals using stopped flow multichannel and rapid scan methods
Authors: Merlin J. C. , Lorriaux J.‐L. , Hester R. E. 
Published: May 2005

AbstractChemical oxidations of 1,4‐dimethoxybenzene (DMOB) and diazabicyclooctane (DABCO) in solution result in the generation of short‐lived free radical cations which have strong visible absorptions. These have been used for the excitation of resonance‐enhanced Raman spectra. The DMOB+˙ radicals were produced in a stopped‐flow apparatus linked with an optical multichannel Raman instrument. The DABCO+˙ species was produced by rapid mixing and its spectrum determined by rapid scanning of a conventional spectrometer. Both kinetic data and vibrational spectra are produced by these methods.
Spectra and structure of organogermanes: 21—Infrared and Raman spectra, and vibrational assignment of (CH3)3GeNNN and Normal coordinate calculations of (CH3)3GeNNN, (CH3)3GeNCO and (CH3)3GeNCS
Authors: Durig J. R. , Jalilian M. R. , Sullivan J. F. , Turner J. B. 
Published: May 2005

AbstractThe Raman spectra of gaseous, liquid and solid trimethylgermylazide, (CH3)3GeNNN, and the infrared spectra of the gas and solid have been recorded (20–3200 cm−1). Assignment of the fundamentals, based on their depolarization values and group frequencies, is given and discussed. A normal coordinate calculation has been carried out utilizing a modified simple valence force field. The extent of vibrational coupling has been determined. It is believed that the main force constants should be transferable to other substituted trimethylgermanium compounds and, thus, transferability is demonstrated by some normal coordinate calculations for trimethylgermylisocyanate and trimethylgermylisothiocyanate. The bonding in these pseudohalogens is discussed and it is shown that the appropriate resonance structures can account for the linearity of the GeNCS moiety and the non‐linearity of the GeNCO and GeNNN moieties.
Raman spectroscopic investigations of the acid‐base forms of dithizone
Authors: Pemberton Jeanne E. , Buck Richard P. 
Published: May 2005

AbstractRaman spectra of three forms of dithizone are presented. Significant structural changes are indicated in the Raman spectra when a proton is added or lost from neutral dithizone (H2Dz) to form the corresponding conjugate acid of dithizone (H3Dz+) and the dithizone anion (HDz−), respectively. These spectral changes are correlated with the structures previously proposed for these species.
Isotopic hydrogen exchange in the dinucleoside monophosphate IpI
Authors: Thomas G. J. , Ferreira S. A. 
Published: May 2005

AbstractEach of the hypoxauthine residues of the dinucleoside monophosphate, inosylyl(3′→5′)inosine (IpI), manifests the same rate of deuterium exchange of the proton at the 8‐C ring position, as measured by Raman spectrophotometry. In the temperature interval 30–80°C and at neutral pD, the exchange rate constants yield Arrhenius parameters (Ea = 22.4±0.6 kcal mol−1; A = 2.13 × 1013 h−1) that are identical to values obtained on inosine‐3′:5′‐monophosphate (cIMP), but different from those of inosine‐5′‐monophosphate (5′‐IMP) which exchanges more slowly. The results confirm that nucleotides containing the monovalent phosphate anion, exchange more rapidly than those containing the divalent phosphate anion, and suggest further that base stacking in IpI does not greatly retard the speed of 8‐CH exchange of either of the hypoxanthine rings.