bluuebunny/crossref_metadata_2025 huggingface dataset:
Light scattering by polaritons in LiIO3
Authors: Kulevsky L. A. , Polivanov Yu. N. , Poluektov S. N.
Published: May 2005

The results obtained on near forward Raman scattering in LiIO3 by a photographic method are presented. The possibility of observation of the polariton dispersion over the range of the polariton wave vectors up to k = 0 cm−1, resulting from the directional dispersion of the magnitude of wave vector of the incident photons in the crystal is demonstrated. The dispersions of the ordinary and extraordinary refractive indices in this crystal from 2.5 to 10 μ by near‐forward scattering from the upperbranch polaritons are obtained. Our experimental investigations show the intensity dip for polariton frequencies near 1010 cm−1 which is due to lattice‐induced dispersion in the nonlinear susceptibility. Our results indicate that the intensity dip for polariton frequencies around 1600 cm−1, which was observed earlier by Gialorenzi and Tang results from Fermi‐resonance of polaritons with second order phonon lines.
Raman and infrared spectra of solid glyoxal‐d1 and glyoxal‐d2
Authors: Cole A. R. H. , Durig J. R.
Published: May 2005

The Raman spectra of solid glyoxal‐d1 and glyoxal‐d2 have been recorded at −190°C from 100 to 3000 cm−1. Fundamental frequencies of glyoxal‐d2 were observed at 2169, 1709, 1131, 944, 908 and 543 cm−1 and assigned as the CD stretching, CO stretching, CD rocking, CC stretching, CD wagging and CCO bending modes respectively. The infrared spectra of the solids have been recorded from 90 to 4000 cm−1. For C2D2O2 this gives the other six fundamentals at 2177, 1685, 1022, 643, 343 and 174 cm−1. The rule of mutual exclusion holds rigorously showing that the molecule has a centrosymmetric structure in the crystal and that the site is Ci (1). The Raman and infrared spectra of glyoxal‐d1 show many coincidences, confirming the breakdown of the rule of mutual exclusion when the center of symmetry is lost on partial deuteration. Fundamentals are assigned at 2882, 2161, 1720, 1699, 1352, 1116, 1005, 981, 710, 548, 357 and 193 cm−1. The frequency shifts upon solidification are discussed.
Anomalous isotope effect on Raman linewidths in KH2AsO4 and KD2AsO4 crystals
Authors: Laulicht I. , Ofek R.
Published: May 2005

Experiment on Raman scattering in KH2AsO4 and KD2AsO4 single crystals in the temperature range of 50–300 K has shown an anomalous isotope effect on the linewidths of a few A1 modes in the 200–900 cm−1 region. The widths in the deuterated crystal are narrowed by a factor of two to four depending on the line and temperature. The behaviour of the proton relaxation time has been obtained as a function of temperature and found to be very similar to those obtained by Lowendes et. al. from the spectral feature of the soft mode. A drastic decrease in the linewidths by a factor of three occurs at the ferroelectric phase transition.
Assignment of the CH stretching vibrational frequencies in the Raman spectra of lipids
Authors: Faiman Rosalind , Larsson Kåre
Published: May 2005

A Raman spectroscopic study of several substituted lipids lacking a methyl end group has been carried out in order to assign the vibrational CH stretching modes, all of which arise from the methylene group vibrations. Polarization measurements on the melt and cubic liquid crystalline phase show that the peak in the region of 2885±5 cm−1 is rather weakly polarized in the liquid and liquid crystalline phases, whereas the peak at 2850 cm−1 is rather strongly polarized. Thus it is concluded that the 2850 cm−1 peak arises mainly from the methylene symmetric stretching modes and the 2885±5 cm−1 peak arises mainly from the methylene antisymmetric stretching modes. The band at about 2930 cm−1 is assigned to a symmetric methylene stretching vibration. The implications in the interpretation of chain mobility and chain conformation are discussed.
Ring puckering Raman transitions of trimethylene sulfide and several deuterated analogs
Authors: Wieser H. , Kydd R. A.
Published: May 2005

The Raman spectra of the vapors of several deuterated analogs of trimethylene sulfide in the ring puckering region are reported. Several puckering energy level separations unavailable from the far‐infrared spectra are deduced and compared to values calculated with a quadratic‐quartic potential function. The “best fittingo” potential constants and hence the inversion barriers computed with the new data are virtually the same as those reported previously. For the perdeutero compound one far‐infrared assignment was corrected to fit the Raman data and new values for the potential constants and the barrier were calculated.
On the Raman spectra of solid natural α‐glycine and solid 15N‐substituted α‐glycine
Authors: Stenback Hans
Published: May 2005

Data on the Raman spectra of natural α‐Glycine and 15N‐substituted α‐Glycine are presented together with details of a computer calculation of the normal vibrations. Assignments are made and compared with previous assignments based on IR measurements.
Raman spectrum and vibrational assignments for tricyclo(3.3.0.02,6) octane
Authors: Baglin Frank G. , Fickes Garry N.
Published: May 2005

The vibrational assignments for the liquid phase of tricyclo(3.3.0.02,6)octane (TCO) are herein presented. Special emphasis was placed upon identification of polarized lines with respect to Fermiresonance interactions. The rigidity of the molecule is discussed.
A Raman spectroscopic study of a vibration‐vibration near resonant energy transfer mechanism in liquid toluene‐d5
Authors: Baglin Frank G. , Whang C. M.
Published: May 2005

The polarized signals from the methyl group stretching coordinate of toluene‐d5 have been analyzed by the time correlation technique. Based upon the polarized signal correlation function of the 2922 cm−1 signal and the presence of Fermi resonance in the molecule, mechanistic interpretations of a vibrational internal conversion process are offered.
Optimierung einer Raman‐Küvette für durchsichtige Proben
Authors: Pilz W. , Kriegsmann H.
Published: May 2005

Für viele Streuexperimente an durchsichtigen Substanzen Substanzen (speziell 90°‐Streuung) ist es notwendig, die gesamte Anordung, die aus laserstrahl, Kürvette, Kondensor und Abbildungslinse besteht, zu optimieren. Es wird theoretisch und auch in einer praktischen Näherung nachgewiesen, daß der beste Wert des Energieflusses von der Brennweite des Kondensors abhängt, wenn die Laser‐ und Monochromator‐Parameter fest vorgegeben sind. Die optimale Vergrößerung des Leuchtfadens ist für alle erforderlichen Auflösungen und verschiedene Laser konstant. In Erweiterung der ergebnise anderer Autoren [1–4] fanden wir bei unseren Untersuchungen des Leuchtfaden‐Durchmessers, daß der Einfluß der Beugung vernachlässigt werden kann, wenn der Laserstrahi nicht auf die TEM00‐Mode beschränkt ist.
Raman spectroscopic studies of the various phases of crystalline ammonium fluosilicate (NH4)2 SiF6
Authors: Poulet H. , Mathieu J. P.
Published: May 2005

Raman spectra of oriented single crystals of (NH4)2SiF6 are reported for the temperature range 440–20 K. The trigonal phase stable below 278 K undergoes a transition at 38.6 K. The changes in the spectra show that the symmetry does not remain trigonal, but give evidence for a lower symmetry.
Effet de la Liaison Hydrogène sur la Raie Raman ν(CH) de Composés Acétyléniques
Authors: Binet C. , Romanet R.
Published: May 2005

The Raman intensity of the ν(CH) band of 1,5‐hexadiyne has been determined for different states of association; autoassociation of 1,5‐hexadiyne has been comparatively studied by Raman and infrared spectroscopy. The integrated Raman intensity of the ν(CH) band is independant of the state of association within the error limits (⋍10%).
Étude des Effets de Solvant sur l'Intensité de la Raie Raman ν(CC) de l'Octyne‐4 et de l'Octyne‐1: Effets de la Liaison Hydrogene
Authors: Binet C. , Romanet R.
Published: May 2005

From study of the ν(CC) Raman band of 4‐octyne (a proton acceptor) is is shown that, whenever the solvent is respectively a poor or a good proton donor, the formation of the hydrogen bond increases or decreases the integrated intensity of the band comparatively to pure liquid. From study of the ν(CC) Raman band of 1‐octyne (an electron acceptor) it appears two groups of electron donor solvents: (i) solvents whose effect is compatible with solvent — cage model, (ii) solvents for which the intensity of the ν(CC) band depends of ionization potential, the result suggests a charge‐transfer model.
Stokes and anti‐stokes scattering of light by low‐frequency polaritons in LiIO3
Authors: Kulevsky L. A. , Polivanov YU. N. , Poluektov S. N.
Published: May 2005

Results are presented on near‐forward Raman scattering from low‐frequency polaritons in LiIO3 obtained by the photographic method using an iodine filter for attenuation of the laser light before it enters a spectrograph. Our experiment shows that the value of dielectric transition strength of the 238 cm−1 phonon mode measured by Otaguro et al. must be corrected. The clamped dielectric constant (ϵz = 5.9) was determined from polariton measurements at frequencies below the lowest transverse mode. This value is compared with those published elsewhere.
Raman spectra of orthorhombic M2SeO4 (M = K, Rb, Cs) single crystals
Authors: Ti S. S. , Kettle S. F. A. , Ra Ø.
Published: May 2005

The single crystal Raman spectra of orthorhombic K2SeO4, Rb2SeO4 and Cs2SeO4 are reported. Whilst the internal modes experimentally observed are in accord with the factor group prediction, fewer external modes than the predicted are observed.
Spectra and structure of phosphorus‐boron compounds. XV:vibrational studies of substituted P ‐ Hexamethylcyclotriborophosphanes
Authors: Durig J. R. , Sens M. A. , Kalasinsky V. F. , Odom J. D.
Published: May 2005

The infrared spectra (3500−30 cm−1) of solid hexa‐substituted P‐hexamethylcyclotriborophosphanes [(CH3)2PBX2]3 where X = F, Cl, Br, I and CH3 and some corresponding B‐monosubstituted and disubstituted species have been recorded. The Raman spectra (3500−10 cm−1) of the corresponding solids have also been investigated. The vibrational spectra of the hexa‐substituted compounds could best be interpreted on the basis of C3ν molecular symmetry. The observed intermolecular vibrations for these solids indicate little factor group effects. The vibrational spectra of the corresponding B‐monosubstituted compounds were very similar to those for the parent molecules with the addition of three ‘new’ B‐X motions. The molecular symmetries are discussed in relation to a recent nuclear magnetic resonance study.
Structure and conformation of polyriboadenylic acid
Authors: Scovell William M.
Published: May 2005

The Raman spectra of 1.5% polyriboadenylic acid in 0.2 M malonic acid at 15°C and pH 7.2, 5.7 and 5.2 are reported and discussed. Four regions of the spectrum reveal particular aspects of the structure and/or the conformational character of the double‐stranded helix, poly(rA+).
On the force field of cyclopropane
Authors: Robins J. R. , Daunt S. J. , Shurvell H. F.
Published: May 2005

Recent data obtained from gas phase Raman spectra of C3H6 and C3D6 has been used to refine the force field of cyclopropane. Values are reported for the interaction constants involving CH2 group vibrations.
Raman spectroscopic studies of chloroprene polymers
Authors: Coleman M. M. , Painter P. C. , Koenig J. L.
Published: May 2005

The Raman spectra of predominantly trans ‐ 1,4‐polychloroprenes are presented. Spectra were recorded of polymers prepared by free radical emulsion techniques in the temperature range −20 to +40°C in both the solid state and in CS2 solution. Spectral changes characteristic of the crystalline and amorphous regions of the polymers have been identified. Measurements of the relative broadness of the 1007 cm−1 Raman line, which is associated with the C‐C stretching frequency in the main chain, have been made and correlated with the amorphous content of the polymer. Extrapolations of these results indicates that polymers prepared in the range 50–60°C should be completely amorphous elastomeric materials.
Laser Raman spectroscopy of biomolecules. X‐frequency and intensity of the phosphodiester stretching vibrations of cyclic nucleotides
Authors: Forrest G. , Lord R. C.
Published: May 2005

Phosphate frequencies for eight nucleoside 3′,5′‐ and four nucleoside 2′, 3′‐cyclic monophosphates have been determined by Raman and infrared spectroscopy based on comparisons with modified cyclic nucleotides and model cyclic phosphates. To a first approximation the symmetric diester stretching frequency, νs(OPO), is determined by the OPO bond angle. However, substitution on the phosphate ring also affects the frequency and intensity of νs(OPO). These results are discussed in terms of the use of νs(OPO) to determine the degree of backbone order in polynucleotides.
Rotation‐vibrational Raman spectra of gaseous allene‐1,1‐d2
Authors: Hegelund Flemming
Published: May 2005

Several rotation‐vibrational bands of gaseous allene‐1,1‐d2 have been studied by Raman spectroscopy and a number of molecular constants are obtained including the ground state constants A0 B̄0 = 2.9520 ± 0.0019 cm−1 and DK = (3.3 ± 0.6) × 105 cm−1. A reassignment of the CD‐stretching vibrations ν5 and ν12 is proposed.
Liaison Hydrogène en Phase Liquide et Spectrométrie Raman II–Amines Primaires et Secondaires
Authors: Perchard C. , Perchard J. P.
Published: May 2005

Structure, intensity and depolarization ratio of NH or NH2 Raman bands of some primary and secondary amines have been studied in pure liquid state at different temperatures and in dilute CCl4 solutions. The depolarization ratio and scattering activity, as in the case of alcohols previously studied, increase with self association. It confirms the change of the XH bond polarizability derivatives with hydrogen bond formation.
Matrix isolation Raman spectra of FeCl3 and Fe2Cl6
Authors: Givan A. , Loewenschuss A.
Published: May 2005

Distinct Raman spectra of FeCl3 and Fe2Cl6 trapped in solid krypton at 20 K are reported. The spectrum of the monomer consisting of four bands at 460.2 cm1, 363 cm−1, 113.8 cm−1 and 68.7 cm−1 is interpreted in terms of a pyramical C3v molecule. The assignment of these frequencies to ν3, ν1, ν4 and ν2, respectively, as well as the assumption of a non‐planar geometry, differ from a previous infrared study. Force constants calculations and isotope effects support this conclusion. Third‐law thermodynamic functions are calculated. The D2h centrosymmetric geometry of the dimer is confirmed, bond stretching modes assigned and stretching force constants calculated.
Vibrational spectra and normal mode calculations of p‐toluidine and p‐nitrotoluene molecules
Authors: Abasbegović N. , Colombo L. , Bleckmann P.
Published: May 2005

Raman and infrared spectroscopic studies of p‐toluidine and p‐nitrotoluene molecules have been performed. In normal mode calculations, the force field has been constructed by the local interaction approximation.
Laser Raman spectra of the complex PtCI3 (9‐methyladeninium)
Authors: Theophanides T. , Berjot M. , Bernard L.
Published: May 2005

The complex PtCI3 (9‐methyladeninium) has been prepared in acidic media and its laser Raman spectrum has been recorded. The spectrum shows small but interesting changes in the vibrations of 9‐methyladenine upon platinum complexation. A comparison of the laser Raman spectra of the free and protonated 9‐methyladenine with that of the complex indicates that platinum coordlnation at N‐7 produces small shift and important perturhathfons of the band intensities of the parine ring vibrations. This result is in agreement with the crystal structure data, which show small local electronic effects when platinum coordinates at N‐7.
Low frequency Raman bands and space symmetries in sym‐tetrachlorobenzene
Authors: Lin C. T. , Pessine F. B. T. , Srivastava R. , Katiyar R. S.
Published: May 2005

The external Raman active vibrational modes for sym‐tetrachlorobenzene single crystals have been recorded at different low temperatures. Accurate temperature dependent Raman measurements on frequencies and on relative intensities show that tetrachlorobenzene suffers a phase transition at T0 = 160 ± 5 K. Group theoretical Correlation indicates that if the low temperature phase of tetrachlorobvenzene (α phase) is P1 symmetry, then one should observe nine lattice modes in the Raman spectrum; likewise, one should observe only six modes if the space symmetry of the β phase tetrachlorobenzene is P1. The fact that we do not see more than six external Raman peaks at lower temperatures suggests that the low temperature phase symmetry should be P1 for tetrachlorobenzene.
A laser Raman spectroscopic study of the product formed in the reaction of phosphoryl chloride with N,N‐dimethylformamide and with N,N‐dimethylbenzamide
Authors: Scheuermann W. , McGillivray G. , White J.
Published: May 2005

The Raman spectra of POCl3, HCONMe2, PhCONMe2 and reaction mixtures of POCl3 and HCONMe2, and POCl3 and PhCONMe2 have been recorded in an attempt to establish the nature of the reaction products. Assignments for most of the bands observed in the spectra of the reaction product are given. The spectra were compared with the spectra of the products of the reaction between HCONMe2 and SOCl2. Several arguments could be advanced which indicated that the only product (RP1) formed in the reaction of POCl3 with HCONMe2 was \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm HCOPOCl}_{\rm 2} \mathop {\rm N}\limits^{\rm + } {\rm Me}_{\rm 2} {\rm Cl}^ - $\end{document} rather than \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm HCCI}\mathop {\rm N}\limits^{\rm + } {\rm Me}_2 {\rm OPOCl}_2^ - $\end{document}. The observed accidental degeneracy of the amide I band at 1668 cm−1 in RP1 and the imine band at 1665 cm−1 in \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm HCCI}_{\rm 2} \mathop {\rm N}\limits^{\rm + } {\rm Me}_{\rm 2} {\rm Cl}^ - $\end{document} showed that the usefulness of the amide I and imine bands as characteristic bands is restricted.
Raman spectra and lattice vibrations in single crystals of potassium acid phthalate
Authors: Krishnamurthy N. , Soots V.
Published: May 2005

Raman scattering from single crystals of potassium acid phthalate has been observed with the 4880 Å and 5145 Å excitations of an argon ion laser. The room temperature Raman spectra, recorded with a Jarrel‐Ash spectrometer, in the region 0–300 cm−1, exhibit broad bands which are attributed to the translatory and rotatory types of lattice vibrations of the potassium and acid phthalate ions in the crystal. Experiments were carried out at 77 K using a Spex double monochromator and the Raman scattering in the second‐order of the gratings were observed. The result was a splitting of the several broad bands into their components. Assignments of these low frequency Raman spectra, consistent with the crystal structure and the group theoretical predictions is given. Variations in intensities of some of the spectra due to crystal orientation are also observed and briefly discussed.
Raman spectra and phase transition of ammonium uranyl nitrate
Authors: Caville C.
Published: May 2005

Raman spectra of single crystals of NH4UO2(NO3)3 are recorded for the temperature range 293–6 K. In various orientations the room temperature spectra are similar to the corresponding isomorphous rubidium and caesium salts. As the crystal is cooled the changes in the Raman spectra indicate a phase transition due to an ordering of the ammonium ions.
Raman spectra from adsorbed iodine species on an unroughened platinum electrode surface
Authors: Cooney R. P. , Hendra P. J. , Fleischmann M.
Published: May 2005

Raman spectra are reported of potential dependent surface species on an unroughened platinum electrode in 1.0 M H2SO4, 10−3 M KI. The results obtained using signal‐averaging and ‘line imaging’ of the laser are contrasted with previously reported spectra obtained using platinized high‐surface‐area electrodes and ‘spot imaging’ of the laser. Spectra are interpreted in term of ‘crystal‐like’ and ‘gas‐like’ I2 and adsorbed I−3 on the surface of the platinum electrode.
Resonance Raman spectrum of β‐carotene
Authors: Sufrà S. , Dellepiane G. , Masetti G. , Zerbi G.
Published: May 2005

Resonance Raman spectra for β‐carotene in carbon disulphide at room temperature have been measured. The experimental absorption spectrum and excitation profiles were analysed using a three‐dimensional model involving several molecular parameters related to the excited state's structure. These parameters are quite different from those reported previously in the literature. A possible explanation for this discrepancy is proposed.
Spectres de Vibration et Structure de l'Octamethylcyclotetrasilazane [(CH3)2SiNH]4 dans les Etats Gazeux, Liquide et Cristallin
Authors: Imbenotte M. , Palavit G. , Legrand Ep. , Huvenne J. P. , Vergoten Et G.
Published: May 2005

Infrared and Raman spectra of octamethylcyclotetrasilazane [(CH3)2SiNH]4 are reported for the compound in the gaseous and liquid states and for solutions in CCl4. 21 Raman bands have been observed for the first time. They are assigned on the basis of group frequencies. Their temperature dependence does not reveal any favoured conformation. Raman spectra of both polycrystalline powders and single crystals are well explained if the existence of chair and boat forms is assumed, according to X‐ray results.
Excited state (excitation) interactions in polyene aggregates. Resonance Raman and absorption spectroscopic evidence
Authors: Salares V. R. , Young N. M. , Carey P. R. , Bernstein H. J.
Published: May 2005

The carotenoids astaxanthin, lutein and zeaxanthin form high molecular weight aggregates in aqueous solvent systems. The absorption spectra of the aggregates, compared to those of the monomer molecules, show significant bandwidth narrowing and blue shifts of 600–800 Å. The resonance Raman spectra of these aggregated polyenes are anomalous in that ν CC occurs near 1518 cm−1 whereas a well‐established νCC vs 1/λmax correlation predicts that νCC should be near 1560 cm−1. The Raman and absorption data together demonstrate that strong excited state interactions are taking place and these results illustrate the utility of the resonance Raman technique for recognizing excited state perturbations. Raman excitation profiles (the variation of Raman intensity with wavelength) on aggregated astaxanthin and low temperature (−100 °C) absorption spectra on aggregates of astaxanthin and lutein establish that a pronounced change in vibronic structure occurs upon aggregation. In contrast to astaxanthin or lutein monomers whose electronic absorption spectra are made up of 0–0, 0–1, 0–2,… transitions, only the 0–0 transition is seen in the aggregates. The results are explained in terms of the molecular exciton model.
Solved and unsolved problems in the Raman spectrum of S in KI single crystals
Authors: Holzer W. , Racine S. , Cipriani J.
Published: May 2005

The orientational dynamics is studied by the Raman spectrum of the ground state molecules S and is found to be isotope selective. The Raman spectrum of S molecules in the excited state 2Πu and in another tentatively assigned state is presented.
High‐pressure variable temperature Raman studies on hexamethyl benzene crystals
Authors: Bodenheimer J. S. , Sherman W. F. , Wilkinson G. R.
Published: May 2005

The Raman spectra of hexamethyl benzene and HMB‐d18 have been recorded as a function of temperature between 4 K and 400 K and as a function of pressure up to 8kbar. In the low‐frequency region, librational and torsional modes have been distinguished. The spectra indicate a phase transition to a high‐pressure phase IV. The polarized infrared spectra of single crystals have also been observed at different temperatures.
Diffusion Raman des Acides Pivalique Hydrogéné et Déutérie en Phase Liquide et en Solution
Authors: Longueville W. , Fontaine H.
Published: May 2005

Raman spectra have been recorded for d0, d1 and d9 pivalic acids and pivalic anhydride in the liquid phase and in solution in CCl4. A complete assignment of the bands is proposed and discussed specially in relation to dimerization and eventual breaking of dimers. The potential energy for hindered rotation of the CH3 groups is calculated.
Configurational equilibria of trihalogeno complexes of mercury (II) in amide solvents
Authors: Waters D. N. , Kantarci Z. , Rahman Nazmun N.
Published: May 2005

Solutions containing the ions HgCl or HgBr in N,N′‐diethylformamide, N,N′‐dimethylacetamide, N,N′‐diethylacetamide and hexamethylphosphoramide give Raman spectra indicative of the presence of two structurally distinct forms of these ions in equilibrium. These are interpreted as being configurational isomers HgX (unsolvated, of D3h symmetry) and SHgX (having one coordinated solvent molecule and possessing essentially C3ν symmetry), respectively.
Second order Raman spectrum of rutile TiO2
Authors: Nicola J. H. , Brunharoto C. A. , Abramovich M. , Conçalves da Silva C. E. T.
Published: May 2005

Data are presented on the second order Raman spectrum of rutile TiO2 for various scattering geometries, at room and liquid N2 temperatures. The results of a standard critical point analysis (i) allow the most important addition processes at low energies to be identified, (ii) indicate the importance of matrix element effects, and (iii) cannot account for a peak at 172 cm−1 for the Y (xy) X geometry.
Laser Raman inelastic light scattering investigations of hyaluronic acid primary and secondary structure
Authors: Barrett T. W. , Peticolas W. L.
Published: May 2005

The solvent‐subtracted Raman spectrum of hyaluronic acid is reported. The spectrum is unchanged by (i) variations in the pH of the solution 6.0–8.5, when buffered at constant ionic strength 0.1, and (ii) changes in temperature 10–50°C.

As rheological, flow birefringence, and linear dichroism studies of hyaluronate solutions indicate a large and abrupt structural transition across the physiological pH range 7.0–7.5, the negative finding reported here is of considerable interest in contrast with those previous studies. When considering the polysaccharides in general, as precise rheological, flow birefringence and linear dichroism data are only available for hyaluronic acid, the present finding is of interest for hyaluronic acid considered as a model polysaccharide system exhibiting elasticity.

The result reported here is discussed within the context of, on the one hand, the possible limitations of the Raman technique which is a probe of g‐state vibrational modes and, on the other hand, the possible extension of the Raman technique to probing oriented (stressed) samples. As a previous study demonstrated a small limiting birefringence but a large limiting extinction angle with minimum change in monomer anisotropy for these solutions, the suggestion is favored that the abrupt structural transition across the physiological pH range previously reported is due to long‐range Van der Waals interactions.
Spectres Raman de Résonance de Dérivés Parasubstitués de l' Azobenzène
Authors: Lorriaux J. L. , Merlin J. C. , Dupaix A. , Thomas E. W.
Published: May 2005

Resonance Raman spectra of twenty parasubstituted azobenzene derivatives are compared, enabling a more complete assignment of bands to be made. Since all the spectra are rather similar, the various ring substituents are not resonance Raman active, and all the observed bands can be assigned to vibrational modes of the aromatic rings and to the azo group itself. Frequency shifts in the PhN stretching region are opposite to those expected based on delocalization along the PhNNPh moiety. From the complexity of band pattern around the NN stretching region and from the above described frequency shifts, several types of vibrational coupling are evident. On the basis of the band assignments, some useful conclusions can be reached for interpreting the observed spectral changes when azobenzene derivatives are used as chromophore probes in biochemical system studies.
Raman and infrared spectra of potassium nitrilosulphonate dihydrate, K3N(SO3)3 · 2H2O, and its 15N derivative: A normal coordinate analysis of the ion, N(SO3)
Authors: Hall John R. , Johnson Robert A. , Shurvell Herbert F.
Published: May 2005

The infrared and Raman spectra (4000–50 cm−1) of polycrystalline K3N(SO3)3·2H2O have been recorded at 77K. Spectra of the 15N derivative, the anhydrous salt, an aqueous solution of the soluble sodium salt and K3N(SO3)3·2D2O have also been recorded. A normal coordinate analysis was applied to predict the 14N/15N isotopic frequency shifts. The potential energy distribution indicated extensive mixing of the normal modes. The NS symmetric stretch is predicted to occur at 276 cm−1 (kNS = 3.1 mdynes Å−1) and a Raman band at 293 cm−1 in the solid state spectrum is assigned to this mode. NS antisymmetric stretching occurs at 912 and 887 cm−1 (888 and 861 cm−1 for 15N). The 14NS3 out‐of‐plane bending mode is mixed with NSO bending in features observed at 872 and 165 cm−1. The SO3 groups show characteristic group frequencies.
Resonance Raman spectra of insoluble monolayers spread on a water surface
Authors: Takenaka Tohru , Fukuzaki Hiroko
Published: May 2005

Resonance Raman spectra of insoluble (or spread) monolayers of cetyl orange on a water surface have been obtained by the use of a total reflection method previously proposed. The spectra of the monolayers resemble that of solid cetyl orange rather than that of the chloroform solution, suggesting that the structure of cetyl orange in the monolayer is similar to that in the solid state. From polarization measurements of the spectra, the molecular orientation in the monolayers has been examined at various surface pressures. The molecules in the insoluble monolayers show a higher orientation with respect to the vertical axis as compared with those in soluble (or adsorbed) monolayers. The degree of molecular orientation rises with an increase in surface pressure of the monolayers but decreases considerably upon collapse.
Resonance Raman spectra of sulfophthalein dyes in aqueous solutions
Authors: Machida Katsunosuke , Lee Hohi , Uno Toyozo
Published: May 2005

Resonance Raman spectra of nine sulfophthalein dyes have been measured in aqueous solutions at various pH values between 4.0 and 11.0. Raman band assignments have been carried out by referring to the spectra of related compounds and the band shifts of Phenol Red on deuteration of the two phenol rings. The phenolsulfophthalein dyes have been ascertained to exist as a pure quinoid form in the weakly acidic solution, while in the alkaline solution they exist as a resonance hybrid of the quinoid and phenolate structures.
Determination by Raman spectroscopy of the solvation number of the chloride ion in liquid hydrogen chloride
Authors: Desbat B. , Huong P. V.
Published: May 2005

Solutions of various concentrations of tetramethylammonium chloride and trimethylammonium chloride in liquid hydrogen chloride have been examined by Raman spectroscopy and the solvation number of Cl− anions in these solutions determined. It was found for solutions up to 3 mol I−1 of (CH3)4N+Cl− in liquid HCl, that the Cl− anions are solvated by six HCl molecules, while trimethylammonium chloride exists in the form of ion pairs solvated by five HCl molecules, (CH3)3N+H ⃛Cl−, 5HCl.
The presence of graphitic carbon in thin films of magnesium oxide as detected by surface Raman spectroscopy
Authors: Brown N. M. D. , Nelson W. J. , Cook B. , Louden J. D.
Published: May 2005

Here is reported for the first time using surface laser Raman spectroscopy the presence of graphitic carbon in thin films (50–100 Å thick) of inagnesium oxide grown directly on magnesium metal by both thermal and d.c. plasma oxidation. The two characteristic and identifying bands are located at 1330 and 1615 cm−1.
Raman and infrared study on the effects of dimethylsulphoxide (DMSO) on water structure
Authors: Bertoluzza A. , Bonora S. , Battaglia M. A. , Monti P.
Published: May 2005

Raman and infrared spectra of liquid dimethylsulphoxide (DMSO) and DMSO‐water mixtures in a wide range of concentrations are reported and discussed. It is found that changes in the vibrational spectra can be related to a gradual insertion of water molecules in the cluster structure of liquid DMSO. In the more dilute aqueous solutions a gradual lowering of the νs=0 stretching frequency is observed and this can be related to the cooperative character of DMSO–water interactions. The interpretation of the spectra is in agreement with the capacity of DMSO for ‘breaking’ the structure of water in the more concentrated aqueous solutions and ‘enhancing’ it in very dilute solutions.
Vibrational study of phase transitions in (NH3(CH2)3NH3)MnCl4
Authors: Sourisseau C. , Lucazeau G.
Published: May 2005

Infrared and Raman spectra (10–4000 cm−1) of single crystals and of polycrstalline samples of (NH3(CH2)3NH3)MnCl4 and of its ND3 deuterated derivative have been investigated in the 10–400 K temperature range. An assignment of most of the observed bands is proposed. The first‐order phase transitions at 306 K and 336 K have been characterized. The spectra of the room temperature phase (III) and of the high temperature phase (I) differ mainly in the broadness of the bands and it is concluded that their structures can be similar. A strong perturbation of the chlorine lattice is observed at 306 K and 100 K. A systematic temperature dependence study (10–300 K) of the frequencies, ν, and half‐widths, Δν, of the low frequency Raman bands has been performed; it has been concluded that at about 110 K a large proportion of NH3 groups are jumping and that the activation energy, E0 ≃ 1.0 kcal mol−1, extracted from the curves Δν = f(T), is of the same order of magnitude as the potential barrier, V6 = 1.2 kcal mol−1, calculated from the torsional frequency of NH (329 cm−1) or of ND (245 cm−1). The NH3 torsional motions coupled with librations of alkylene chains are believed to be responsible for disorder observed among most of the modes. The low temperature spectra have been interpreted assuming D2h factor group and Z = 2 (i.e. the same as at room temperature) and they can be interpreted as if the sample was ordered, suggesting the possible existence of an ordered low temperature phase IV.
Raman spectral study of NbCl5 in chloroaluminate melts
Authors: Huglen R. , Mamantov G. , Smith G. P. , Begun G. M.
Published: May 2005

The Raman spectra of NbCl5 dissolved in AlCl3–NaCl and AlCl3–KCl melten and molten Al2Cl6 have been examined as a function of melt composition, temperature, and NbCl5 concentration. The results are compared with previously published data. The binary AlCl3–NbCl5 system at ∼200°C contains noninteracting NbCl5, Nb2Cl10 and Al2Cl6 molecules. The complexes formed when NbCl5 is dissolved in AlCl3–MCl (MNa and K) melts depend on acidity and temperature: NbCl is present only in very basic melts; NbCl5 is stable in basic and acidic melts; Nb2Cl10 is found only in acidic melts. High temperature favors formation of NbCl5 while low temperature stabilizes Nb2Cl10.
Raman study of phase transition and dynamic structure of solid CCl4
Authors: Ebisuzaki Y.
Published: May 2005

A high pressure Raman study of CCl4 II and CCl4 III and the changes in the Raman activity at the II–III phase transition at 300 K are reported. The spectrum of CCl4 II is characterized by low intensity lattice bands and by the presence of sidebands on both the low and high energy side of the internal modes, ν2 and ν4. The sideband structure becomes Raman inactive and the lattice bands increase in intensity at the II–III phase transition; however, the major lattice peaks appear to be Raman active in both phases. It appears that there are some orientationally disordered molecules in CCl4 II. On the other hand, CCl4 III is an ordered phase.
Light scattering from phonons and magnons in CoCl2 · 2H2O
Authors: Helms C. A. , Scott J. F. , Toms D. J.
Published: May 2005

A light scattering study of cobalt chloride dihydrate is reported. Emphasis is placed upon phonon–magnon interactions in the antiferromagnetic phase. Data taken at T = 1.6 K and magnetic fields from 0 to 5 T confirm the conclusion of Schneider and Weitzel that the ferrimagnetic–antiferromagnetic phase transition is first‐order and that a large hysteresis is observable at temperatures below 4.2 K.
Magnetoelastic waves and a group‐theoretical determination of selection rules for magnon—phonon interactions and two‐magnon Raman scattering in FeCl2 · 2H2O and CoCl2 · 2H2O
Authors: Cracknell A. P.
Published: May 2005

In this paper we deduce selection rules for magnon–phonon coupling at k0 and for lines of symmetry passing through k0 for the antiferromagnetic materials FeCl2 · 2H2O and CoCl2 · 2H2O. The results are tabulated. We also determine the symmetries of two‐magnon states in these materials and deduce selection rules for the Raman activity of these states. It is found that all the two‐magnon states are Raman active in each material, although there are some restrictions on the polarizations.
Spectres Raman des Modes Transverses et Longitudinaux à 293 K et 83 K et Spectres de Réflexion Infrarouge à 293 K et 83 K et Spectres de Réflexion Infrarouge à 293 K d'un Monocristal de Phosphite de Lithium, LiH2PO3
Authors: Beys Louis , Hillaire Paul , Cadène Michel
Published: May 2005

The Raman spectra of oriented single crystals of 7LiH2PO3 and 6LiH2PO3 at 293 K and 83 K are reported and compared. 6Li/7Li substitution was used to identify the translational modes of the lithium atoms. Bands with a lithium isotopic shift of 3–6% are observed in the 300–500 cm−1 region. The spectra of the 6LiH2PO3 single crystal indicate a coupling between the lithium vibrations and the deformation modes δ(PO3) of the HPO2OH− ion. Assignments are proposed for internal modes of the crystal. Polarized infrared reflection spectra at 293 K and longitudinal Raman spectra at 293 K and 83 K in the 400–2500 cm−1 region are reported for 7LiH2PO3 single crystal. An analysis in terms of Drude oscillators leads to a better understanding of the dielectric properties of the monocrystal and also to the determination of the dispersion parameters of the transverse and longitudinal optical modes. The values obtained for the longitudinal frequencies and for the oscillator strengths in Raman scattering and infrared reflection are in good agreement.
Pollutant trapping studies. 2—Spontaneous and resonance Raman studies of the surface reaction of sulphur dioxide on zeolites
Authors: Tsai Peter , Cooney Ralph P.
Published: May 2005

Raman spectra of SO2 adsorbed on zeolites X, Y and A are reported together with a normal coordinate analysis of the various spectra of the adsorbed molecuar SO2. The data indicate that crystal‐like SO2 is adsorbed on cation sites II and III of the zeolitic oxide framework. Internal SO2 force constants quantifying adsorbate distortion are developed and compared with the frequency difference parameter,Δ(ν3–ν1). Raman spectral data also indicate the formation of several decomposition products of SO2, generated by surface reactions, which may include S, S2, S4, SxO, SO and SO. Of these the lines attributed to S, S2, S4 and SxO exhibit resonance enhancement.
Etude des Spectres de Diffusion Raman Et d'Absorption Infrarouge des Cyanures de Sodium et de Potassium En Phase II et Phase III
Authors: Fontaine D.
Published: May 2005

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

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

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

The rotational‐vibrational Raman Spectrum of the v2 band of H14N3 has been measured. The results of the analysis of the observed wavenumbers are v0 = 2140.308(4) cm−1, ΔB = −0.00312(1) cm−1 and ΔDj = −7(5)×10−9 cm−1. The Q‐branches of the hot band transitions v5→v2+v5 and v6→v2+v6 have been determined to be at 2129.3(1) cm−1.
Caractérisation des Phases dans le Polyéthylène par Effet Raman
Authors: Luu Dang Vinh , Cambon Louis , Lapeyre Claude
Published: May 2005

Research on the Raman spectrum shows that the features of the different phases of which semi‐crystalline polyethylene is composed can be obtained through bending vibrations of δ (CH2).
Intensities of some vibrational bands in the pre‐resonance Raman spectra of quinoxaline, phthalazine and pyridazine
Authors: Aminzadeh A. , Fawcett V. , Long D. A.
Published: May 2005

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

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

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

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

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

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

Calibrated coherent anti‐Stokes Raman (CARS) spectra have been recorded for the resolved Q branches of the vibrational fundamentals and first hot bands of 14N2, 14N15N and 15N2 at a temperature of 1200 K. The spectra show a convolved linewidth of 0.13 cm−1, and have been used to derive new values of spectroscopic constants, for the species observed, with specific reference to the position of the Q branch lines where J > 20 for v = 1–0, and J = 0–30 for v = 2–1. The critical overlap region of the fundamental and the hot band may now be computer simulated with confidence, which should be of considerable help in combustor thermometry using CARS.