bluuebunny/crossref_metadata_2025 huggingface dataset:
Raman linewidth study of molecular interactions in mixtures of hexafluorobenzene with benzene and with mesitylene
Authors: Tanabe Kazutoshi , Hiraishi Jiro
Published: May 2005

Raman linewidths have been measured at room temperature for the 560 cm−1 band of hexafluorobenzene, for the 991 cm−1 band of benzene, and for the 576 cm−1 band of mesitylene, in the pure liquids and in binary solutions. Linewidths have also been measured for the 799 cm−1 band of cyclohexane as a reference. Rotational diffusion constants for the tumbling motion of the molecular planes have been evaluated from the Raman linewidths. Experimental diffusion constants are compared with theoretical values calculated on the basis of the semi‐slip rotational diffusion model. Effects of molecular interactions of hexafluorobenzene with benzene or mesitylene on the rotational motion of molecules in solution are discussed.
The ν5 Raman band of CH3CD3
Authors: Jensen Per , Brodersen Svend
Published: May 2005

The ν5 Raman band of CH3CD3 was photographed with a resolution of about 0.4 cm−1 and analysed by an iterative method, in which the peak wavenumbers of the observed and computed contours are compared directly. Precise values for ν0 and ΔB were obtained, whereas it only could be shown that ΔA is an order of magnitude smaller than ΔB. Some basic problems of the method of analysis are discussed.
Vibrational relaxation in liquids with intermolecular dipole potentials of the order of kT: A Raman study of the CO‐stretching vibration band of liquid methyl ethyl ketone
Authors: Scheibe Doris
Published: May 2005

The Raman band of the CO‐stretching vibration of methyl ethyl ketone has been recorded in the temperature range 233 K to 343 K, and also at 293 K in various solvents at various concentrations. This polarized Raman band shows asymmetry and a non‐coincidence of the iso‐ and anisotropic frequency maxima which cannot be explained in the usual treatment using the Kubo line shape theory. So, on the basis of former work, a simple theoretical approach to the behaviour of various band shape parameters in terms of dipole interactions has been worked out in the frequency domain. This allows us to interpret, at least qualitatively, the variation of band shape parameters under different conditions.
Raman spectral studies of aqueous solutions of non‐electrolytes: Dimethylsulfoxide, acetone and acetonitrile
Authors: Singh Surjit , Krueger Peter J.
Published: May 2005

Raman spectra of aqueous solutions of dimethylsulfoxide, dimethylsulfoxide‐d6, acetone and acetonitrile are reported in the OH stretching region, and in the stretching regions of the functional groups of these solutes. Raman intensities and frequency shifts of these bands show definite trends with varying concentrations of the solutions. The results obtained are discussed in terms of the mixture model of water, and they are compared with results obtained from Raman spectral studies of aqueous electrolytes. It is proposed that water structure breaking and the formation of solute‐solvent complexes when organic solutes are added to water can account for these results.
A study of the torsional modes in ethylammonium chloride, bromide and iodide as a function of temperature
Authors: Ratcliffe C. I. , Sherman W. F. , Wilkinson G. R.
Published: May 2005

Raman spectra of the torsional and lattice modes in single crystals of the chloride, bromide and iodide salts of the ethylammonium ion, C2H5NH, have been obtained over the range between liquid nitrogen and room temperatures. Corresponding infrared spectra of the torsional modes of the salts in caesium halide discs have also been obtained at the two temperature extremes. In general the modes all show an apparently linear decrease in frequency with increasing temperature. The torsions show relatively large splittings between their Raman and infrared components, due to interactions between adjacent rotors in the lattice. A two‐rotor model has been applied to attempt to quantify the principal threefold barriers to rotation and the interaction potential constants for both the NH and CH3 rotors. The torsional frequencies and barriers reflect the changing effects from one salt to another, of hydrogen bonding and steric forces in the lattice.
Detection of the Raman active T2g mode in Cdln2S4 by Fourier transform spectroscopy
Authors: Joshi N. V.
Published: May 2005

The Raman active T2g mode was observed in the optical absorption spectrum obtained by the Fourier transform spectroscopic technique in an undoped single crystal of Cdln2S4. This was activated owing to the partially inverse spinel structure of Cdln2S4. It is quite possible that infrared modes can also be activated for the Raman process and hence data obtained with Raman spectroscopy should be re‐examined.
Infrared and Raman spectroscopic studies of KHSO4 crystals
Authors: Dey B. , Jain Y. S. , Verma A. L.
Published: May 2005

The Raman spectra of KHSO4 single crystals in different geometries have been investigated in the 10–4000 cm−1 range at 300 K, 150 K and 120 K. The infrared spectra of polycrystalline KHSO4 have also been measured. An interpretation of these results consistent with the crystal structure and other information on this system is presented.
Etude Spectroscopique Infrarouge et Raman d'Alcools β‐Cyclopropylidéniques
Authors: Guiliano M. , Mille G. , Chouteau J. , Léandri G. , Méou A.
Published: May 2005

L'examen comparatif des spectres infrarouges et Raman d'une série d'alcools β‐cyclopropylidéniques et de certains de leurs homologues deutériés permet de proposer une attribution des principales vibrations fondamentales. Les résultats montrent qu'il existe des bandes de vibration pouvant être utilisées pour caractériser la classe d'alcool, le groupement cyclopropylidénique et le degré de substitution en position −2 et −3.
Raman studies of pressure‐induced frequency shifts in d0‐ and d8‐naphthalene
Authors: Backer M. , Häfner W. , Kiefer W.
Published: May 2005

The influence of hydrostatic pressure on lattice vibrations in single‐crystals of d0‐ and d8‐naphthalene has been measured by observations of their first‐order Raman scattering spectra at pressures in the range 0‐8.5 kbar. Measurements were performed at room temperature for both the external and the internal vibrations. Mode Grüneisen parameters γi in the range 3‐4.5 and 0.004‐0.25 have been derived for external and internal modes, respectively.
Raman spectroscopic study of Streptomyces subtilisin inhibitor
Authors: Harada I. , Takeuchi H. , Tasumi M. , Tsuji T. , Kainosho M.
Published: May 2005

Raman spectra of Streptomyces subtilisin inhibitor (SSI) in H2O and D2O solutions were observed for the first time. Information obtained regarding the conformations of polypeptide backbone, disulphide bridge and methionyl side chain was largely consistent with the results derived from other methods. As for the microenvironments of the three tyrosyl residues, the Raman spectrum suggested that none of these residues were involved in a specific interresidue interaction as proposed by nuclear magnetic resonance study for Tyr‐93. The Raman spectrum was shown to be useful for studying the binding of the sulphate ion to SSI.
Strength of vibronic coupling between excited electronic states estimated using Raman spectroscopy
Authors: Bree A. , Zwarich R. , Taliani C.
Published: May 2005

The magnitudes of vibronic coupling matrix elements are estimated from the analyses of the pre‐resonant Raman excitation profile for several b3g fundamentals of biphenyl. The 1158 and 1464 cm−1 modes have profiles with about the same shape, and the value of αy2 appears to be derived from in‐phase contributions from two pairs of highly excited electronic states. The matrix elements have reasonable values that range from 170 to 450 cm−1. For the 612 cm−1 mode, αy2 is probably made up of two major contributions which have opposite sign, and the magnitudes of the couplings are large (about 700 cm−1).
Raman spectroscopic investigations of the CrO/Cr2O equilibrium in aqueous solution
Authors: Michel G. , Machiroux R.
Published: May 2005

With the intention of doing a study of the CrO/Cr2O equilibrium in aqueous solution, we have carefully re‐examined the Raman spectra of CrO, Cr2O and ClCrO. Diluting stepwise an aqueous solution of CrO ion we have showed the non‐existence of the HCrO species which was previously considered to exist in such systems. By studying the effect of pH on the Raman spectra we calculated the constant for the equilibrium: 2 CrO + 2H+ ⇌ Cr2O + H2O to be log β22=13.77±0.02 (20°C and KNO3 0.8 M). Using this value of the constant, we were able to establish the distribution diagram of the CrO and Cr2O species versus pH.
The Raman spectrum of solid tribromofluoromethane
Authors: Shurvell H. F. , James D. W.
Published: May 2005

Raman spectra of polycrystalline films of CFBr3 have been recorded at 77 K. A spectrum of the liquid at room temperature has also been recorded and depolarization ratios of the fundamentals measured. Splittings have been observed for all fundamentals and the external mode region contains at least five bands. An orthorhombic crystal structure together with LO‐TO components of the degenerate CBr3 stretching mode ν4 are suggested to account for the observed splittings.
Raman spectra of the transplutonium orthophosphates and trimetaphosphates
Authors: Hobart D. E. , Begun G. M. , Haire R. G. , Hellwege H. E.
Published: May 2005

Raman spectra have been obtained from multimicrogram samples of crystalline transplutonium (americium through einsteinium) orthophosphates. Spectra were also obtained for americium, curium, and californium trimetaphosphates. Assignments of the major Raman bands and confirmation of the compounds' stoichiometry were made by comparison with spectra obtained in previous studies on the lanthanide phosphates. The variation of transplutonium orthophosphate vibrational frequencies as a function of atomic number was found to be smaller in magnitude than that established for the lanthanide orthophosphates.
UV‐excited resonance Raman spectra of methyl orange and its complex with cetyltrimethylammonium bromide
Authors: Lee Hohi , Machida Katsunosuke , Kuwae Akio , Harada Issei
Published: May 2005

Resonance Raman spectra of methyl organge and its ring‐deuterated and 15N‐azo derivatives were measured with the excitation line at 350.7 nm of a Kr+ laser, and the spectral changes on the complex formation between the dye and cetyltrimethylammonium bromide were studied. In the presence, as well as the absence, of the surfactant, the UV‐excited resonance Raman spectrum of each isotope of methyl orange is appreciably different from the corresponding spectrum excited with the Ar+ 488.0 nm line. The UV‐excited spectrum of the pure aqueous solution of the dye is attributed to the non‐hydrated monomeric species of the dye anion responsible for the absorption band around 420 nm. The spectral pattern between 1500 and 1300 cm−1 of the mixed solution of the dye and the surfactant changes in two steps on increase of the surfactant concentration in accordance with the change of the absorption spectrum in the UV‐visible region due to the formation of micelles. The UV‐excited resonance Raman spectra of a cidic solutions of the isotopic methyl orange zwitterions were also meaured. By combining the data relating to the effect of pH and the concentration of the surfactant, the NN stretching frequency in the Raman spectrum was shown to be correlated closely with the π‐π* transition frequency in the absorption spectrum.
Carp haemoglobin iron‐imidazole linkage and subunit equivalence; evidence from resonance Raman spectroscopy of deoxy‐ and nitrosyl forms
Authors: Walters Marc A. , Spiro Thomas G. , Scholler D. M. , Hoffman B. H.
Published: May 2005

Nitrosyl hemoglobin (Hb) from carp shows a resonance Raman spectrum characteristic of 6‐coordinate (NO) heme. Switching the quaternary structure from R to T by addition of insitol hexaphosphate (IHP) at pH 5.8 does not produce a 5‐coordinate spectrum, as it does for human Hb. Only intensity changes are seen for bands at ∼490, 387 and 357 cm−1, indicating a subtle alteration in the porphyrin‐protein interaction. In carp deoxy Hb, IHP addition produced a shift of the Fe‐ImH (ImH = imidazole) stretching mode, from 223 to 214 cm−1. The band remained symmetrical, indicating essential equivalence of the subunits. This is in contrast to human deoxy Hb for which the R‐T shift in the Fe‐ImH frequency is much greater in the α than the β chains. In carp Hb all the Fe‐ImH bonds appear to be weakened in the T state, but to an extent insufficient to induce rupture upon binding NO.
A single crystal Raman spectroscopic study on p‐chloroaniline
Authors: Steger E. , Garbe S. , Klosowski J.
Published: May 2005

A single crystal of p‐chloroaniline was prepared, and aligned optically. The intensities observed from the different tensor elements of the unit cell were compared with the expected intensity distributions from the molecular vibrations, transformed into the unit cell. For the 13 vibrations of species a1 (and an additional Fermi resonance band) intensity distributions were found which are in accord with these symmetry considerations and with the atomic displacements in all the different vibrations. Some assignments of other symmetry species are also considered.
Vibrational spectra and force constants for trans‐sodium hyponitrite
Authors: Chen L.‐H. , Laane J.
Published: May 2005

Laser Raman spectra of trans‐sodium hyponitrite (Na2N2O2) as a solid and in aqueous solution have been recorded, together with its infrared spectrum. Polarization data for the aqueous solution Raman spectra were also determined for the first time. The results confirm the trans structure of the hyponitrite ion and also have led to a new vibrational assignment. Force constant calculations have been carried out and these accurately predict the observed frequency shifts upon isotopic substitution. The potential energy distributions were also determined and these provide a useful picture of the coupling of the vibrational modes.
Resonance Raman spectra (5800–40 cm−1) of All‐transand 15‐cisisomers of β‐carotene in the solid state and in solution. Measurements with various laser lines from ultraviolet to red
Authors: Saito Shigeki , Tasumi Mitsuo , Eugster Conrad H.
Published: May 2005

The Raman spectra (5800–40 cm−1) of the all‐transand 15‐cisisomers of β‐carotene were observed in the solid state at 77 K and in cyclohexane solutions using laser lines of various wavelengths for excitation. The Raman spectra of the solid samples exhibited not only the well known strong bands but also a great number of sharp bands (mostly weak in intensity) which could not be observed or were observed broadly in solutions at room temperature. The molecules of both isomers in solution seem to have structures slightly different (‘relaxed’) from those in the solid state. All the bands in the region of 5800–1800 cm−1were satisfactorily accounted for as overtones or combination tones of relatively strong fundamentals. Rough excitation profiles and depolarization degrees measured for cyclohexane solutions gave information on the mechanism of resonance enhancement. The polarized bands of the all‐transisomer at 1597 and 1525 cm−1are both resonant with the1Bu←1Agabsorption around 480 nm. In addition, the 1597 cm−1band is resonant with the 21Bu←1Agabsorption around 275 nm. The polarized bands at 1597, 1533, 1194, 1156 and 1004 cm−1of the 15‐cisisomer are resonant with the ‘cis‐peak’ around 340 nm as well as with the1B1←1A1absorption around 475 nm. The polarized bands at 1241, 1052 and 953 cm−1of the 15‐cisisomer are characteristic of this isomer, but these are only slightly resonant with the ‘cis‐peak’. The intensity of the depolarized band at 1564 cm−1of the 15‐cisisomer is enhanced by the vibronic interaction between the excited1Aand1B1states.
Normal‐coordinate analysis of β‐carotene isomers and assignments of the Raman and infrared bands
Authors: Saito Shigeki , Tasumi Mitsuo
Published: May 2005

Normal‐coordinate calculations were performed for the all‐trans, 7‐cis, 9‐cis, 13‐cis, 15‐cis, 9, 13‐di‐cis, 9,13′‐di‐cis, 9,15‐di‐cisand 13,15‐di‐cisisomers of β‐carotene. The Raman and infrared bands of the all‐transand 15‐cisisomers in the solid state were assigned on the basis of the results of the normal‐coordinate calculations. The Raman excitation profiles of the main Raman bands of the above two isomers in cyclohexane solution reported previously were satisfactorily correlated with the calculated vibrational modes and the molecular structures in the excited electronic states. The Raman bands of the 7‐cis, 9‐cis, 13‐cis, 9,13‐di‐cis, 9,13′‐di‐cis, 9,15‐di‐cisand 13,15‐di‐cisisomers were assigned. The vibrational modes assigned to the Raman bands characteristic of thecisisomers were analysed in detail.
Raman scattering from phonons in MnCO3
Authors: Komura H. , Akiyama H. , Fukaya M. , Ishikawa K.
Published: May 2005

Measurements of Raman scattering from the vibronic origin in MnCO3 (rhodochrosite) are reported. The observed five Raman lines (184, 289, 719, 1086 and 1415 cm−1) are identified with and classified into the relevant phonon modes. Those lines show the theoretically expected polarization characteristics.
Phospholipid—protein molecular interactions in relation to immunological processes: 1—Raman spectroscopic and calorimetric studies of phospholipidpolyglycine molecular interactions in model membranes
Authors: Bertoluzza A. , Bonora S. , Fini G. , Morelli M. A. , Simoni R.
Published: May 2005

Dipalmitoylphosphatidylcholine (DPPC)‐polyglycine and dimyristoylphosphatidylcholine (DMPC)‐polyglycine systems have been studied by Raman spectroscopy and differential scanning calorimetry. The results of both techniques indicate that the interactions are confined to the lipid‐water interface. Some penetration is observed in DMPC systems. The presence of cholesterol does not change the surface character of the interaction of the lipids with polyglycine molecules. Because of the similarity of the behaviour of the two lipids, DMPC can be used instead of DPPC in studies with artificial membranes. DMPC has the advantage of a lower Tm. Since lipid‐water interactions define the conformational state of extrinsic proteins and consequently their biological behaviour, these surface interactions could be a first approach to an understanding of the mechanism of processes such as the immunological response.
High‐temperature infrared and Raman spectra of aluminium chloride dimer and monomer in the vapour phase
Authors: Tomita T. , Sjøgren C. E. , Klaeboe P. , Papatheodorou G. N. , Rytter E.
Published: May 2005

The infrared spectra of aluminium chloride vapour (Al2Cl6 and AlCl3) including AlCl6 and AlCl6 at 473–843 K were measured in the region 700–50 cm−1 with an evacuable Fourier transform spectrometer by transmission and emission techniques. Evacuable cells of nickel were employed having windows of type IIa diamond and sealed with gold O‐rings. Raman spectra of Al2Cl6 vapour at ca 500 K and of AlCl3 at 1075 K with pressures from 0.3 to 10 atm were recorded, polarization measurements were carried out and additional spectra of the 35Cl and 37Cl compounds were obtained. The dimer spectra were interpreted in terms of D2h symmetry. All the nine Raman‐active and seven of the infrared‐active dimer fundamentals were assigned. The IR active mode ν10(B1u), expected below 40 cm−1, and the inactive mode ν5(Au) were left unassigned. The monomer spectra were interpreted in terms of D3h symmetry and all four fundamentals were assigned. A dimer force field, involving 12 independent force constants, was derived. The calculated frequencies were fitted with a least‐squares programme to 30 observed fundamentals of AlCl6 and AlCl6 and 14 additional isotopic shifts transferred from previous matrix isolation spectra. A complete force field for the monomer was derived, using the four observed fundamentals and seven isotopic shifts transferred from previously reported matrix isolation spectra.
Self‐association of dimethyl sulphoxide and its dipolar interactions with water: Raman spectral studies
Authors: Sastry M. I. S. , Singh Surjit
Published: May 2005

Raman spectra of solutions of dimethyl sulphoxide (DMSO) in carbon tetrachloride (CCl4) and water are reported for both parallel and perpendicular polarizations in the SO stretching region. The various bands obtained were subjected to Gaussian band fittings. It was observed that the bands for solutions in CCl4 may be fitted satisfactorily by considering four components and those for solutions in water may be fitted by considering five components. It is inferred that the band at ca 1070 cm−1 observed in the spectra of DMSO in CCl4 belongs to the SO stretching mode of free DMSO, whereas the two bands observed at ca 1058 cm−1 and ca 1040 cm−1 belong to out‐of‐phase and in‐phase SO stretchings of the cyclic dimer. The low‐frequency band at ca 1025 cm−1 is assigned to linear dimer/higher polymers. Aqueous solutions of DMSO show an additional band at ca 1010 cm−1 due to DMSO hydrogen‐bonded with water.
A divided‐disc method for the measurement of the intensity of resonance Raman bands of solid samples
Authors: Machida Katsunosuke , Tsukamoto Ikuko
Published: May 2005

A method utilizing divided KBr discs has been developed for estimating the relative intensities of the resonance Raman bands of different samples in the solid state. The relationship between the band intensity and the sample concentration in the disc is described on the basis of the Kubelka‐Munk theory of diffuse reflection. The utility of the method was checked by using crystalline methyl orange and potassium sulphate as the sample and reference materials, respectively. By comparing the measured and calculated intensities, the Raman scattering coefficient of the NN stretching band of methyl orange at 1420 cm−1 was estimated to be 440±90 times as large as that of the 984 cm−1 band of potassium sulphate.
The CH3 asymmetric stretchings of p‐halogenotoluenes
Authors: Kanesaka Isao , Satozaki Yoshiko , Kiyokawa Yoshinobu , Kawai Klyoyasu
Published: May 2005

The vibrational spectra of p‐halogenotoluenes and o‐fluorotoluene in the region of the CH3 asymmetric stretchings are reported. The observed bands at 2997, 2987, 2975 and 2945 cm−1 at 77 K in p‐fluorotoluene are asslgned to the B2, A1, A2 and B1 modes, respectively, on the basis of the C20 symmetry. Two Raman bands at 2971 and 2945 cm−1 at 77 K in p‐chlorotoluene are assigned to the B2 and B1 modes, respectively, where the former in the liquid state is a polarized band and is assigned also to the A1 mode. This is also true for p‐bromotoluene.
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

The 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

The 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

A 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

Applying 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

New 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

The 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

Resonance 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

The 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

Polarized 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

Excitation 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

Raman 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

Using 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

Micro‐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

Design 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

Raman 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

Raman 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

Lithium 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

In 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

The 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

L'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

15NH4ReO4 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

Raman 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

Complete 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

The 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

A 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

Raman 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

Previous 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

The 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

The 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.
Raman study of the ν(CO) mode of ethyl trifluoroacetate in solution. Reorientational and vibrational relaxation
Authors: Hernanz A. , Troitiño D.
Published: May 2005

The reorientational and vibrational correlation functions of the carbonyl stretching mode of ethyl trifluoroacetate have been determined from its infrared and Raman band shapes in solution in hexane, CCl4, CS2 and CHCl3. Reorientational motion is less hindered in hexane and CCl4 than in CS2 or CHCl3. Kubo and Rothschild's and Oxtoby's stochastic theories have been applied to describe the experimental correlation functions. An intermediate modulation regime is observed in the solvents used. The fastest modulation corresponds to CS2. Fisher and Laubereau's isolated binary collision model for vibrational dephasing does not account for the observed vibrational widths.