bluuebunny/crossref_metadata_2025_split huggingface dataset:
Raman and infrared spectra of the 7‐cisand di‐cisisomers of retinal
Authors: Koyama Yasushi , Mukal Yumiko , Umemura Junzo , Ito Masayoshi , Tsukida Kiyoshi 
Published: May 2005

AbstractThe Raman and infrared spectra of the 7‐cis, 9‐cis, 11‐cis, 9‐cis, 13‐cisand 11‐cis, 13‐cisisomers of retinal have been recorded for the first time. The spectra of the all‐trans, 9‐cis, 11‐cisand 13‐cisisomers were also recorded for comparison. The isomers were isolated from a photoisomerization mixture of the all‐transisomer and their configurations were identified by means of1H NMR or Raman spectroscopy. The Raman spectra of the isomers in CCl4solution were recorded using a flow method, the 457.9 nm line of an Ar+laser and a Raman spectrometer equipped with a multichannel detector; their infrared spectra were recorded by using an FT‐IR spectrophotometer. Comparison of the Raman spectra of the mono‐cisisomers revealed key bands which, discriminate between unmethylated‐cis(7‐cisand 11‐cis) and methylated‐cis(9‐cisand 13‐cis) configurations. The key bands were related to local vibrations around the particularcisdouble bond. Unmethylated‐cisconfigurations show (1) a unique band around 1280‐1270 cm−1due to a coupled mode ofA1type (with reference to the local symmetryC2νof thecis‐CCHCHC group) consisting of the two CH in‐plane bendings and the CC stretching, (2) a stronger band at 969 cm−1ascribable to anA2‐type coupled mode consisting of the two CH out‐of‐plane waggings and the CC torsion and (3) a unique band at 563 cm−1, tentatively related to anA‐type coupled mode consisting of the CCC and CCC deformations. Methylated‐cisconfigurations show a stronger Raman band around 880 cm−1due to CMe stretchings. Raman bands characteristic of eachcisconfiguration (7‐cis, 9‐cis, 11‐cisor 13‐cis) also are discussed.
The low‐frequency Raman spectrum of trigonal (NH4)2 TiF6
Authors: Jenkins T. E. 
Published: May 2005

AbstractThe Raman spectrum of trigonal (NH4)2 TiF6 between room temperature and 10 K has been measured in the lattice region of the spectrum. All the four modes predicted by group theory have been observed and tentative assignments are proposed. No phase transition has been observed down to the lowest temperatures.
Raman study of vivianite
Authors: Piriou B. , Poullen J. F. 
Published: May 2005

AbstractA single crystal of vivianite, Fe3(PO4)2·8H2O, has been investigated at room temperature using Raman spectroscopy. Using the site symmetry method, we have identified the internal modes of the PO4 group. For the stretching modes we have observed: ν1(Ag)=950.5 cm−1. ν3(Ag)=990.0 cm−1, ν3(Ag)=1052.9 cm−1 and ν3(Bg)=1018 cm−1. The modes involving the motion of the iron atoms and their neighbourhood have also been identified.
Observations of structural resonances in the Raman spectra of optically levitated dielectric microspheres
Authors: Thurn R. , Kiefer W. 
Published: May 2005

AbstractApplying the technique of optical levitation by radiation pressure, it was possible to record Raman spectra from single microspheres of glass. Sharp intensity peaks are observed which are not present for a bulk sample of the glass. These peaks are shown to correspond to the natural resonant modes of the dielectric spher, and a good correlation is found between experimental and theoretically predicted spectra. The latter were calculated by making use of the Mie‐Debye theory.
Vibrational spectra of adenine and deuterium‐substituted analogues
Authors: Majoube Michel 
Published: May 2005

AbstractNew Raman and IR spectra have been recorded for adenine and its analogues substituted with deuterium on the nitrogen atoms, on the carbon at position 8 and on both. The bands observed have been assigned on the basis of experimental data and a normal coordinate analysis. The latter was carried out by means of a Urey‐Bradley force field comparable to that already established for guanine. Assignments are discussed in the light of observed and calculated frequencies and isotopic shifts.
Correction of the low‐frequency Raman spectra of gaseous formic and Acetic Acids to PDS Spectra
Authors: Bertie John E. , Eysel Hans H. , Permann Delmar N. S. , Kalantar Daniel H. 
Published: May 2005

AbstractThe low‐frequency Raman spectra of gaseous formic and acetic acids are corrected from counts per second to the square of the polarizability derivative with respect to the normal coordinate. The acetic acid peak at 98.9 cm−1 is shifted to 106 cm−1 by this correction, necessitating minor reassignments. The intense, broad, 'Rayleigh Line' is greatly reduced by this correction, to reveal scattering by pure rotational motion.
Resonance Raman spectroscopy of alkyl nitroxyl radicals
Authors: Bennett John E. , Grossman William E. L. , Hester Ronald E. , Killough Patrick M. 
Published: May 2005

AbstractResonance enhancement of the NO stretching Raman bands has been observed from dilute solutions (10−3‐10−2 mol dm−3) of some alkyl nitroxyl radicals by excitation into their ultraviolet absorption band (λmax ≈︁ 240 nm). Excitation at 248 nm was produced by a line‐narrowed, pulsed KrF excimer laser. Three overtone bands, which were observed for di‐tert‐butylnitroxyl, showed a small anharmonic contribution, xeνe = 8.8 cm−1.
Raman spectrum of gaseous phosphaethyne (HCP)
Authors: Kalasinsky V. F. , Pechsiri S. 
Published: May 2005

AbstractThe Raman spectrum of gaseous phosphaethyne (HCP) has been recorded, and the CH and CP stretching vibrations (ν1 and ν3) have been observed at 3218 and 1277 cm−1, respectively. These frequencies compare very favorably with those previously determined from IR and UV‐visible spectra. The sample is stable for short periods of time under the required experimental conditions, and the vibrational data are discussed in terms of the stability and reactivity of HCP.
Raman spectra and structures of the high‐ and low‐temperature phases in the two‐dimensional layer‐type compound (CH3CH2NH3)2SnCl6
Authors: Ben Ghozlen M. H. , Daoud A. , Mlik Y. , Poulet H. , Le Postollec M. , Toupry N. 
Published: May 2005

AbstractPolarized Raman spectra of oriented single crystals of (CH3CH2NH3)2SnCl6 measured over the temperature range 15–300 K have been used to investigate the mechanism of the structural transition at 125 K. A detailed study of some of the external modes and of the internal modes of both the SnCl62− and CH3CH2NH3+ ions in the high‐ and low‐temperature phases has enabled the structure of the disordered high‐temperature phase to be confirmed and suggestions for the structure of the low‐temperature phase to be proposed.
The analysis of unresolved Raman excitation profiles. 2—Totally Symmetric Fundamentals and Overtones of Some Azo Dyes
Authors: Cataliotti R. S. , Murgia S. M. , Paliani G. , Poletti A. , Zgierski M. Z. 
Published: May 2005

AbstractExcitation profiles of fundamentals of 4‐nitro‐4′‐diethylaminoazobenzene and 4‐nitro‐6‐cyano‐4′‐(N‐cyanoethyl‐N‐ethylamino)azobenzene reported in the preceding paper are interpreted quantitatively with multi‐mode, three electronic states calculations of Raman intensities. It is demonstrated that the visible absorption spectrum of these azo dyes consists of two overlapping electronic manifolds of nearly equal intensity but with different geometries. Vibrational displacement parameters are determined for five most active totally symmetric vibrations in each dye. The interpretation is supported by observed overtone and combination band intensities. Evidence is presented indicating that inhomogeneous broadening and pre‐resonance scattering from higher excited states play an important role in shaping excitation profiles in the visible region of the spectra.
Raman studies of phase transitions in Mg(ClO4)2·6H2O crystal
Authors: Agarwal Anshu , Patel M. B. , Bist H. D. 
Published: May 2005

AbstractRaman spectra of Mg(ClO4)2·6H2O single crystal in different polarizations in the temperature range 350–110 K are presented. Three phase transitions were found at 325, 272 and 225 K. The transition at 272 K is associated with the rotation of crystallographic a and b axes with respect to the space‐fixed coordinate axes X and Y in the ab plane. The transition at 325 K occurs as a result of reorientation of the ClO4− ion and that at 225 K as a result of the tumbling motion of the aquo complex.
Analysis of two‐phonon resonances in and Raman spectroscopy of ammonium chloride
Authors: Anikiev A. A. , Umarov B. S. , Scott J. F. 
Published: May 2005

AbstractUsing a model calculation of the unperturbed two‐phonon density of states for the frequency region encompassing the 2ν4 overtone of NH4Cl, together with the quantum field Green function approach of Ruvalds and Zawadowski, both the shape of the perturbed two‐phonon band in the Raman spectra and the detalled spectral evolution of the polariton spectra in this frequency regime as a function of wave vector q have been calculated. The calculation, which does not require a two‐phonon bound state, is in good agreement with experiment.
Measurement of stress in diamond anvils with micro‐Raman spectroscopy
Authors: Sharma Shiv K. , Mao H. K. , Bell P. M. , Xu J. A. 
Published: May 2005

AbstractMicro‐Raman spectroscopy has been used to measure first‐order Raman spectra from selected volumes in diamonds under pressure in a high‐pressure diamond‐anvil cell in both the 180° and 135° scattering geometries. The high‐frequency component of the diamond line at the diamond‐sample interface is found to shift linearly with pressure and exhibits a pressure coefficient of 0.237 cm−1 kbar−1. This shift of the diamond line could be used for pressure determination. The Raman spectra from selected volumes of the diamond anvil at various depths provide useful information about stress distribution in the anvil.
Instrumental advances in Raman optical activity
Authors: Reza Oboodi M. , Davies Mark A. , Gunnia Uma , Blackburn Marlana B. , Diem Max 
Published: May 2005

AbstractDesign features of a computer controlled, diode array detector equipped spectrometer for the acquisition of Raman optical activity (ROA) data are presented. This instrument utilizes an artifact reducing dual lens light collection system, and a novel approach to synchronize the light modulation and the detection electronics. ROA spectra, collected at full optical apertures, and without a polarization analyzer in the scattered light, are reported and compared to depolarized published data.
Vibrational study of phase transitions in CH3NH3NO3 and CH3ND3NO3
Authors: Mylrajan M. , Srinivasan T. K. K. 
Published: May 2005

AbstractRaman and infrared spectra (10–5000 cm−1) of single crystals and polycrystalline samples of CH3NH3NO3 and of its ND3 deuterated derivative were investigated in the temperature range 30–400 K. A systematic temperature dependence study of the frequencies and band widths was performed. The results show the existence of three phases. Assignments of most of the bands observed are proposed. Raman spectra of single crystal CH3NH3NO3 in the internal and lattice region are interpreted based on a D2h16 structure and relative polarization data. A thermal hysteresis characteristic of the first order was observed in the phase II⇌phase I transition. Raman and infrared spectral features of phase I indicate this to be a plastic phase, in which cations and anions exhibit isotropic reorientational motion. The spectral changes that occur in the phase II → phase III transition suggest freezing out of thermal motion and reveal only minor structural changes in phase III compared with phase II.
Raman excitation profiles from pigments in vivo
Authors: Wagner W.‐D. 
Published: May 2005

AbstractRaman excitation profiles (REPs) for bands of carotenoid and chlorophyll b (Chl b) from whole cells of green algae at low temperatures are presented. In addition to preventing thermal destruction of the samples during long‐term irradiation, the use of a double channel surface scanning technique allowed the recording of the Raman spectrum of a non‐resonating substance such as acetone suitable as an intensity reference at the same time. The measured REPs are compared with the absorption spectrum of whole cells at low temperatures.
Vibrational spectroscopic studies of the ferroelectric LiRbSO4
Authors: Chary B. Raghunatha , Bhat H. L. , Chandrasekhar P. , Narayanan P. S. 
Published: May 2005

AbstractLithium rubidium sulphate, LiRbSO4 (LRS), undergoes a sequence of four phase transitions at 166, 185, 202 and 204°C. The phase between 202 and 204°C is incommensurate. Polarized phonon Raman spectra in the frequency region of 50–1200 cm−1 are presented to identify the external and internal vibrational modes at room temperature. The internal mode frequencies of the sulphate ions are presented in the temperature region from −150 to 230°C covering all the phase transitions. The total integrated areas of the ν1, ν2 and ν4 modes show an anomalous increase across the phase transitions. The frequencies of the symmetric stretching (ν1) and symmetric bending (ν2) modes do not show any changes at the phase transitions, but the width of the ν2 mode shows changes across the phase transitions. A small increase in the linewidth of the ν2 mode observed in the incommensurate phase is attributed to the influence of the incommensurate modulation wave. A DSC thermogram showed endothermic peaks during heating at all the phase transitions. The IR spectrum recorded at room temperature showed the expected Au and Bu internal modes.
Raman spectroscopic investigations on the chromium(VI) equilibria part 2—species present, influence of ionic strength and CrO42−Cr2O72− equilibrium constant
Authors: Michel G. , Cahay R. 
Published: May 2005

AbstractIn addition to CrO42− and Cr2O72−, species such as H2CrO4, HCrO4− and HCr2O72− have been considered to exist in Cr(VI) equilibria in aqueous solution. The Raman spectra of dilute solutions of Cr(VI) at different pH have confirmed the non‐existence of the last three species in a Cr(VI) concentration range between 0.1 M and the lower detection limit of concentration (ca 0.003 M). The proposed equilibrium, 2CrO42− +2H+⇌Cr2O72− +H2O, seems to be the only one existing between pH 1 and 11. A quantitative Raman study of the influence of ionic strength on the corresponding apparent formation constant β′22 led us to the determination of the equilibrium constant at zero ionic strength, namely log β22=14.85±0.04 at 25°C. In more acidic aqueous Cr(VI) solutions, up to 12M in HNO3, preliminary investigations corroborated the presence of the trichromate and tetrachromate species.
Spectra and structure of organophosphorus compounds. XXV—Raman and infrared spectra and conformational stability of ethyldimethylphosphine
Authors: Durig J. R. , Hizer T. J. 
Published: May 2005

AbstractThe Raman (10–3500 cm−1) and infrared (50–3500 cm−1) spectra have been recorded for gaseous and solid ethyldimethylphosphine, CH3CH2P(CH3)2. Additionally, the Raman spectrum of the liquid has been recorded and qualitative depolarization values have been obtained. From the fact that several distinct Raman lines disappear on going from the fluid phases to the solid state, it is concluded that the molecule exists as a mixture of the gauche and trans conformers in the fluid phase with the gauche conformer being more stable and the only one present in the spectrum of the solid. From a temperature study of the Raman spectrum of the liquid, the enthalpy difference between the gauche and trans conformers was determined to be 134 ± 32 cm−1 (383 ± 92 cal mol−1). Relying on group frequencies and relative intensities of the infrared and Raman bands, and in some cases infrared band contours, a complete vibrational assignment is proposed for the gauche conformer. The assignment is supported by a normal coordinate calculation which was carried out utilizing a modified valence force field to obtain the frequencies of the normal modes and the potential energy distribution. The CH3‐P torsions have been observed at 208 and 185 cm−1 in the gas phase and from these frequencies the periodic barriers to internal rotation have been calculated to be 905 ± 95 cm−1 (2.56 kcal mol−1). The CH3‐C torsion was also observed in the gas phase at 217 cm−1 from which a periodic barrier of 1134 cm−1 (3.22 kcal mol−1) was calculated. The asymmetric torsional mode has been observed for the gauche conformer in both the infrared and Raman spectra of the gas at 91 cm−1 with evidence of ‘hot bands’ at lower frequencies. All of these results are compared with corresponding quantities for several other organophosphines.
Spectres de Vibration de l'Acide Furanne 3,4‐dicarboxylique et de Ses Sels de Potassium en Solution Aqueuse
Authors: Cassanas G. , Fabrègue E. , Bardet L. 
Published: May 2005

AbstractL'analyse des spectres Raman et infrarouge de l'acide furanne 3,4‐dicarboxylique et de ses sels de potassium montre que les groupements carboxyliques et carboxylates des composés sont hors du plan furannique. La liaison H‐intramoléculaire présente dans l'acide et le sel acide de potassium à l'état cristallin est assez forte pour persister en solution aqueuse.
The Raman spectrum of [15N]ammonium perrhenate
Authors: Park Y. S. , Shurvell H. F. , Brown R. J. C. 
Published: May 2005

Abstract15NH4ReO4 was synthesized and the Raman spectrum recorded at various temperatures between 10 and 300 K. 15N isotopic shifts of both internal and external modes of the ammonium ion relative to 14NH4ReO4 were observed. The temperature dependence of the external modes was studied. The librational lattice mode associated with the ammonium ion disappeared above about 180 K. At this temperature anomalies were observed in the temperature dependence of the perrhenate ion lattice modes.
Raman spectra ofcis‐transisomers of retinal homologues. Key bands of unmethylatedcisconfigurations and of all‐transparts of mono‐cisisomers
Authors: Mukai Yumiko , Koyama Yasushi , Ito Masayoshi , Tsukida Kiyoshi 
Published: May 2005

AbstractRaman spectra have been recorded for thecis‐transisomers of retinal homologues. They include the all‐trans, 9‐cis, 11‐cis, and 13‐cisisomers of retinylideneacetaldehyde (C22aldehyde), which have a longer polyene chain than retinal (C20aldeyhde), and the all‐trans, 7‐cisand9‐cisisomers of β‐ionylidenecrotonaldehyde (C17aldehyde) and β‐ionylideneacetaldehyde (C15aldehyde), which have a shorter chain. The homologues were prepared by the stepwise elongation of the conjugated chain. Thecisisomers were isolated by means of HPLC from a photoisomerization mixture of the all‐transisomer, and the configuration of each isomer was determined by1H NMR. The Raman spectra were recorded for flowing CCl4solutions under pre‐resonant conditions by using the 514.5 nm (C22aldehyde) or 457.9 nm (C17andC15aldehydes) line of an Ar+laser. Comparison of the spectra confirmed the key bands for the unmethylatedcisconfigurations (7‐ and 11‐cis), distinguishing them from the methylatedcisconfigurations (9‐ and 13‐cis), which were reported in a previous paper. It revealed also key bands for the all‐transparts of mono‐cisisomers, i.e. the β‐ionone side and the carbonyl side.
Vibrational spectra of tetrabromophosphonium (PBr4+) salts of some tetrabromate anions (MBr4−)
Authors: Shamir Jacob , Schneider Shlomo , van der Veken Benjamin J. 
Published: May 2005

AbstractComplete Raman and IR spectra were recorded for tetrabromophosphonium salts of tetrabromo‐borate, ‐aluminate, ‐gallate and ‐indate. The compounds were prepared by precipitation from non‐aqueous solvents in which the reactants were dissolved and reacted. Their vibrational spectra are interpreted on the basis of these complexes being of ionic structure of the general formula [PBr4]+[MBr4]−, both ions being tetrahedral with Td symmetry. All the expected fundamentals have been observed and assigned.
Surface‐enhanced Raman scattering of benzenethiol in silver sol
Authors: Joo Tai Ha , Kim Myung Soo , Kim Kwan 
Published: May 2005

AbstractThe surface‐enhanced Raman scattering of benzenethiol was investigated in a silver sol. It was found that benzenethiol was chemisorbed dissociatively on the silver surface by rupture of its SH bond and the benzenethiolate formed on adsorption was bound to silver via its sulphur atom. Using the electromagnetic surface selection rule, the orientation of the benzene ring with respect to the surface plane could not be determined conclusively. However, it seemed likely that benzenethiol was adsorbed face‐on to the silver surface.
Raman microspectroscopic determination of the methyl centralite (N, N′‐dimethyl‐N, N′‐diphenylurea) concentration profile in a nitrocellulose extruded mono‐perforated small arms propellant
Authors: Louden J. D. , Kelly J. , Phillipson J. 
Published: May 2005

AbstractA Raman microspectroscopic method for the determination of the concentration profile of a deterrent (methyl centralite) diffused into an extruded single base mono‐perforated small arms propellant (nitrocellulose) is presented. Preliminary results indicate a level concentration part way into the propellant from the external surface with an abrupt drop‐off in concentration, whereas from the internal surface an exponential concentration profile is obtained. These results indicate the possibility of two different diffusion mechanisms operating from the external and internal surfaces.
Raman study of glassy aqueous solutions of magnesium salts: MgCl2, Mg(NO3)2, MgSO4 and Mg(ClO4)2
Authors: Kanno H. , Hiraishi J. 
Published: May 2005

AbstractRaman spectra were obtained for aqueous solutions of MgCl2, Mg(NO3)2, MgSO4 and Mg(ClO4)2 in both liquid and glassy states. Spectral changes associated with the transition from the liquid to the glassy state were studied for the Raman OH stretching spectra, and the restricted translational Raman bands of the low‐frequency Raman spectra of the glassy solutions were characterized. It is shown that the spectral features and peak frequencies are greatly dependent on the chemical natures of the anions.
Three‐body‐like spectral behavior near the ν2 mode of supracritical fluid CO2
Authors: Hacura A. , Yoon J. H. , Baglin F. G. 
Published: May 2005

AbstractPrevious workers, involved in both experimental and theoretical light‐scattering studies of liquid and very dense fluid linear triatomic systems, have shown that owing to the presence of the large dipole polarizability anisotropy, molecules such as CO2 or CS2 show much weaker three body spectral cancellation effects when compared with spherical or near spherical scatterers. We now report a very prominent three‐body‐like spectral cancellation effect on the high‐frequency wing of the Raman dipole forbidden ν2 signal from supracritical CO2. We also indicate the correlation of the three‐body cancellations with number density and depolarization properties of the systems studied.
Raman study of n‐nonadecane and n‐heneicosane mixtures in the solid state
Authors: Maissara M. , Devaure J. 
Published: May 2005

AbstractThe Raman spectra of two mixtures of n‐ncnadecane and n‐heneicosane in the solid phase were recorded and compared with those of the pure compounds. In their low‐temperature phases,gauchedefects are observed in contrast to the pure compounds: the defects are not only GTn−4forms but also TGTn−5, and even kinks if heneicosane predominates in the mixture. In the high‐temperature phase, the same defects are observed but their quantity is significantly greater. A comparison between the experimental spectra and the spectra calculated from those of pure alkanes shows moregauchedefects in the mixtures.
Hyper‐Raman spectra of K2SnCl6 crystals
Authors: Morioka Y. , Nakagawa I. 
Published: May 2005

AbstractThe hyper‐Raman spectra of K2SnCl6 crystals were measured for various scattering geometries at ambient temperature. The F2u deformation mode of [SnCl6]2−, which is inactive in infrared and Raman spectra but hyper‐Raman active, was observed at 112 cm−1. The TO and LO frequencies of an F1u species are in good agreement with those obtained in a previous study of the far‐infrared reflection spectrum. A lattice dynamics analysis of the optically active crystal vibrations based on a rigid ion model explains the observed frequencies of all optical modes satisfactorily.