bluuebunny/crossref_metadata_2025_split huggingface dataset:
Raman spectroscopy of cyclohexanethiol adsorbed on a silver surface
Authors: Kwon Cheol Kee , Kim Myung Soo , Kim Kwan 
Published: May 2005

AbstractThe surface‐enhanced Raman scattering of cyclohexanethiol was investigated in a silver sol. Cyclohexanethiol was found to adsorb dissociatively after losing its thiol proton and adsorption was found to occur via its sulphur atom. Both the equatorial and axial chair conformers were found to exist on the surface at low surface coverage. However, at full monolayer coverage, the equatorial chair was the sole conformation of the adsorbed thiolate. An improved vibrational assignment for the molecule has been made.
Preparation and spectroscopic properties of chlorocarbonylfluorocarbonyl disulphide, ClC(O)SSC(O)F
Authors: Védova C. O. Della 
Published: May 2005

AbstractChlorocarbony fluorocarbonyl disulphide, CIC(O)SSC(O)F, was prepared from bis(fluorocarbonyl) disulphide and BCI3. IR data of the vapour, liquid and matrix‐isolated CIC(O)SSC(O)F at low temperature together with the Raman spectrum of the liquid suggest the existence of a more abundant non‐planar conformer with symmetry C1 in both the vapour and liquid phases. For all but the torsional modes of this conformer wavenumbers are reported. However, the valence force constants were calculated by a semi‐empirical method. The study was complemented with the characterization of the compound by 19F NMR and mass spectra.
Resonance Raman scattering in azo dyes
Authors: Cataliotti R. S. , Morresi A. , Paliani G. , Zgierski M. Z. 
Published: May 2005

AbstractResonance Raman excitation profiles of some azo dyes were studies and interpreted in terms of a model that treats vibratious as displaced harmonic oscilators. It is shown that the visible absorption spectrum is formed by two overlapping electronic transitions of a mixed charge‐transfer and nπ* character.
Lattice dynamics and intermolecular forces in P4Se3 derived from the Raman spectra
Authors: Bougeard Daniel 
Published: May 2005

AbstractThe Raman‐active lattice modes of crystalline P4Se3 at room temperature have been calculated in the rigid–body approximation by using estimated atom‐atom potentials for the Se atoms. The agreement is satisfactory and reveals several types of couplings of the different degrees of freedom. The calculated lattice energy is of the correct order of magnitude. The potentials obtained show characteristic features which correlate with the presence of short SeSe distances in the crystal.
IR and polarized Raman spectra of K4P4O12Te(OH)62D2O
Authors: Mathew Xavier , Nayar V. U. 
Published: May 2005

AbstractIR and Raman spectra of K4P4O12Te(OH)62D2O and K4P4O12Te(OH)62H2O have been recorded and analysed. The P4O12 modes are assigned on the basis of characteristic vibrations of the POP and PO2 groups. The P4O4 ion has C2h symmetry and the P4O12 and TeO6 groups coexist in this compound. Two crystallographically distinct water molecules exist in K4P4O12Te(OH)62H2O. The water molecules form strong hydrogen bonds.
Resonance Raman spectrum of phenolphthalein in alkaline solution and vibrational spectra of the pure compound and its potassium salts
Authors: Chattopadhyay S. , Kastha G. S. , Nandy S. K. , Brahma S. K. 
Published: May 2005

AbstractRaman and infrared spectra of phenolphthalein and its white and pink potassium salts together with the resonance Raman spectrum of the parent compound in alkaline solution were studied. From careful comparison of the spectra, the observed frequencies were assigned to appropriate vibrational modes and from these assignments frequencies originating from vibrations of hybridized bonds in the resonating molecular forms of phenolphthalein, believed to be present in alkaline solution were identified. It was shown that such resonating forms are present in the pink but not the white potassium salt. The spectral data also indicate that the vibrations of the carboxylate ion group do not take part in the resonance Raman phenomenon.
Temperature and pressure study of vibrational relaxation in liquid benzene
Authors: Wrzalik R. , Nikiel L. , Bródka A. 
Published: May 2005

AbstractThe isotropic Raman spectra of monodeuterated benzene (C6H5D) in the region around 3000 cm−1 were studied at temperatures of 30, 60 and 90°C and pressures up to 2 kbar. In this frequency region we observed two overlapping bands (ν1 and ν12), and hence an additional broadening process, the energy relaxation to other modes, gives a contribution to the band widths. The changes in frequencies and band widths are interpreted in terms of the Schweizer and Chandler theory.
Surface‐enhanced Raman scattering of zinc tetrakis(4‐N‐methylpyridyl)porphyrin
Authors: Song Ok‐Keun , Yoon Min‐Joong , Kim Dongho 
Published: May 2005

AbstractThe surface‐enhanced Raman spectra of zinc tetrakis(4‐N‐methylpyridyl)porphyrin in silver sol using various excitation wavelengths are reported. On the basis of comparison of the patterns of the relative enhancement between SERS and normal Raman bands and using previous theoretical calculations, this molecule is found to be anchored on the silver surface with ‘flat‐on’ geometry. Generally, out‐of‐plane porphyrin and pyridyl modes are relatively strongly enhanced relative to the in‐plane porphyrin skeletal modes in SERS as compared with normal Raman spectra. The mode assignment for this molecule was attempted based on the enhancement pattern of Raman modes depending on the geometry of the adsorbed molecule and the mode character. The selective enhancement of some modes would be helpful in the vibrational mode assignments of porphyrins having peripheral phenyl groups.
Fourier transform Raman spectroscopy of illicit drugs
Authors: Hodges C. M. , Hendra P. J. , Willis H. A. , Farley T. 
Published: May 2005

AbstractFourier transform (FT) Raman spectroscopy was investigated as a means of characterizing pure amphetamine sulphate, cocaine hydrochloride, heroin and diluted (‘cut’) samples of these drugs at drug concentrations down to 5%. The pure compounds give spectra that are excellent for rapid identification, as do samples cut with sorbitol. Some cutting agents are fluorescent, however, and identification then presents difficulties. The major advantage of FT Raman spectroscopy over other techniques for the testing of illicit drugs is that no sample preparation is needed. The test is very fast (3 min), and after examination the sample can be completely recovered in the same form as that in which it was received, so that it can, if required, be submitted to other test procedures.
Effect of temperature on the fermi resonance and the resonance intermolecular coupling in the Raman spectra of liquid water
Authors: Sokołowska Anna 
Published: May 2005

AbstractThe temperature dependence of the isotropic and anisotropic Raman components for the H2O and D2O stretching vibrations has been studied. The results of resolution of the isotropic component into three constituents and the anisotropic into four constituents are compared with the values calculated by the perturbation method for a superposition of the Fermi and intermolecular coupling resonances. The experimental results were found to agree qualitatively with the predicted values.
Raman and far‐infrared spectra of crystalline formaldehyde, H2CO and D2CO
Authors: Weng S. X. , Anderson A. , Torrie B. H. 
Published: May 2005

AbstractRaman and far‐infrared spectra of crystalline formaldehyde and its fully deuterated analogue have been recorded over the frequency range 25–350 cm−1 and at temperatures of 80 and 20 K; 16 Raman and 8 far‐infrared lattice peaks have been resolved. Isotopic frequency shifts together with inertia and intensity arguments are used to assign the peaks. Raman spectra of the internal vibrational modes of solid formaldehyde are also presented, with several crystal field splittings observed. The results are consistent with a group theoretical analysis based on the molecular and crystal symmetries.
Electronic and pre‐resonance Raman spectra of the anion [VO(C3H2O4)2]2−
Authors: Baran Enrique J. , Jubert Alicia H. , Rocha Adriana L. 
Published: May 2005

AbstractA study of the Raman, pre‐resonance Raman and electronic spectra of the [VO(C3H2O4)2]2− anion was performed. The excitation profiles of the vibrational modes that show pre‐resonance on excitation with laser lines within the electronic bands in the visible region are reported. On this basis, the VOmalon. vibrations could be unambiguously assigned and stronger experimental support is provided for the origin of some of the electronic transitions.
Raman spectrum of Cu(NO3)2 · N2O4
Authors: Givan A. , Loewenschuss A. 
Published: May 2005

AbstractThe Raman spectrum of the coordination compound Cu(NO3)2 · N2O4 is reported. X‐ray diffraction studies showed its lattice to be composed of layers of polymeric [Cu(NO3)3]− anions (in which the Cu—nitrate bonds are bridging) and of discrete charge‐balancing NO+ cations, whereas infrared results indicated the presence of discrete covalent N2O4 molecules in the lattice, and some interaction of Cu atoms with the NO+ units. Raman spectra of this highly hygroscopic and deeply coloured compound are in accord with the structural conclusions of the x‐ray diffraction work.
Resonance raman spectrum of sirohydrochlorin in desulfoviridin from Desulfovibrio gigas
Authors: Lai K. K. , Yue Kwok To 
Published: May 2005

AbstractResonance Raman spectra with excitations in the Soret region are reported for desulfoviridin, the sulfite reductase from Desulfovibrio gigas. Desulfoviridin contains sirohydrochlorin, a hydroporphyrin of the type isobacteriochlorin. The typical spectrum shows a large number of bands, with the prominent v4* mode at 1336 cm−1. Using perturbation and group theories, we were able to develop some conceptual understanding of the in‐plane vibration modes of isobacteriochlorin. This has enabled us to arrive at the tentative conclusion that the sirohydrochlorin prosthetic groups in desulfoviridin are not coupled to any metal ion(s).
Linewidths in the pure rotational Raman spectra of hydrogen chloride and carbon monoxide and of nitrogen and carbon monoxide perturbed by hydrogen chloride
Authors: Edwards H. G. M. , Long D. A. , Sherwood G. 
Published: May 2005

AbstractPressure‐broadening coefficients, σp, have been determined for self‐broadening of pure rotational Raman lines of carbon monoxide and for pure rotational Raman lines of hydrogen chloride, and carbon monoxide and nitrogen perturbed by hydrogen chloride at 293 K. The results are discussed and compared with calculated and experimental σp values in the literature.
Spectra and structure of organophosphorus compounds XXXVIII—Raman and infrared spectra, vibrational assignment, conformational stability and normal coordinate analysis for ethylphosphonic dichloride
Authors: Durig J. R. , James C. G. , Hizer T. J. 
Published: May 2005

AbstractThe Raman (3500‐10 cm−1) and infrared (3500‐50 cm−1) spectra of solid CH3CH2P(O)Cl2 and CD3CD2P(O)Cl2 and the infrared spectra of the gases were recorded. Additionally, the Raman spectra of the liquids were measured and qualitative depolarization ratios were obtained. Since several distinct Raman lines disappear from the spectra on going from the fluid to the solid states, it is concluded that the molecule exists as a mixture of trans and gauche conformers. A variable‐temperature study of the Raman spectrum of the liquid yielded an enthalpy difference between the conformers of 72 ± 10 cm−1 (206 ± 27 cal mol−1). The trans conformer is the more stable form in the liquid, and the only one present in the solid. On the basis of band intensities, group frequencies and depolarization values, a complete vibrational assignment is proposed for the trans conformer. This assignment is supported by a normal coordinate analysis utilizing a modified valence force field. These results are compared with those from some similar molecules.
Polarized Raman and infrared spectra of (NH3)2(CH2)2HXO4 (X =P, As)
Authors: Philip Daizy , Aruldhas G. 
Published: May 2005

AbstractPolarized Raman and IR spectra of (NH3)2(CH2)2HPO4 and (NH3)2(CH2)2 HAsO4 have been recorded and analysed. Crystal field effects are found to be stronger in the phosphate than in the arsenate and the symmetry of the anion is reduced from C3v to C1. In the arsenate the ethylenediammonium groups are identical whereas in the phosphate they are crystallographically different. The effects of strong vibrational coupling between PO(H) stretching and POH out‐of‐plane bending modes are observed in the phosphate. It is found that the HAsO has a greater angular distortion.
Normal‐coordinate treatment of a nucleic base pair model in its crystalline state: 1‐Methylcytosine–9‐ethylguanine
Authors: Lagant P. , Vergoten G. , Derreumaux P. , Dhennin R. 
Published: May 2005

AbstractA normal‐mode analysis of a nucleic base pair model, 1‐methylcytosine–9‐ethylguanine in the crystal state was performed in order to analyse the degree of participation of the intra‐ or intermolecular hydrogen bonds in the vibrational modes. The base pair model compound crystallizes in the P1 space group (triclinic system with two molecules per unit cell); 125 adjacent cells were necessary to take into account the intramolecular hydrogen bonds. A General Valence Force Field was derived from previous studies on nucleosides. Comparison with experimental vibrational studies allows a good assignment of the observed bands. Mixing of the intra‐ and intermolecular hydrogen bond vibrational modes with the internal modes is observed over a large range of frequencies.
Solvent‐dependent vibrational relaxation studies in polar liquid
Authors: Purkayastha Anusree , Das Radhendu , Kumar Kamal 
Published: May 2005

AbstractIsotropic Raman line broadening studies were carried out for the CO stretching mode of vibration in N,N‐dimethylformamide and cyclohexanone molecules in solution. The broadening for the Raman band is explained on the basis of hydrodynamic, multipole‐multipole, induction and dispersion forces. The intercept on the linear graph [Γiso vs f(ρ, η, n)] is explained on the basis of induction forces and multipole interactions for dipolar and non‐dipolar solvents.
Theory of resonance Raman scattering by molecules subject to twisting with an application to ethylene
Authors: Siebrand Willem , Zgierski Marek Z. 
Published: May 2005

AbstractModel calculations are reported on molecules such as ethylene that twist on electronic excitation. Resonance Raman spectra and excitation profiles are calculated for several pairs of torsional potentials. For a 90° twist, the resonance Raman spectra show double‐quantum torsional progressions that tend to be very long for resonance in the region of strong absorption. The Raman excitation profiles of the torsional‐mode bands resemble the absorption spectrum in that most of the intensity is found in the region of near‐vertical transitions, where the upper‐state torsional levels change from vibrational to rotational. This picture remains valid if the upper state has minima at angles other than 90° relative to the ground‐state minimum, provided that the point group symmetry of the molecule is not lower than D2 at these points; this is the case for ethylene. If, however, the minimum corresponds to a lower point group, as for asymmetrically substituted ethylenes, Raman transitions involving an odd number of quanta become allowed. For very small angles of twist (≲ 15°) such systems resemble displaced harmonic oscillators. These results are compared with recently reported resonance Raman spectra in the UV absorption region of ethylene where both π→π* and Rydberg transitions are active. The analysis suggests a new potential for torsion in the first Rydberg state.
Infrared, Raman and ultraviolet spectra and normal coordinate analysis of chlorocarbonyl isocyanate
Authors: Ulic S. E. , Della Védova C. O. , Aymonino P. J. 
Published: May 2005

AbstractIR data from gaseous and matrix‐isolated chlorocarbonyl isocyanate and Raman data from the liquid were obtained. The observed features agree with the existence, proved by electron diffraction, of at least two conformers due to rotational isomerism around the CN bond. Some force constants were calculated for the planar trans (anti) conformer.
Temperature dependence of line width of SO42− modes in the Raman spectra of ammonium sulphate
Authors: Bajpai P. K. , Jain Y. S. , Bist H. D. 
Published: May 2005

AbstractThe temperature dependence of the Raman line width of the ν1 and ν2 modes of the SO ion in ammonium sulphate was investigated. A sudden change in the full width at half maximum intensity (FWHM) of both bands is observed at the ferroelectric transition point of the crystal. The results are explained in terms of the coupling between phonons originating from these modes and NH4+ ion pseudo‐spins. The results obtained from pseudospin–phonon coupling formulations agree satisfactorily with the experimental results. The coupling also accounts for the temperature dependence of spontaneous polarization.
Electronic, vibrational and resonance Raman spectra of the layered semiconducting compound NbS3
Authors: Sourisseau C. , Cavagnat R. , Fouassier M. , Maraval P. 
Published: May 2005

AbstractThe electronic (900–250 nm), infrared and Raman (600–10 cm−1) spectra of polycrystalline samples of NbS3 were investigated. A complete vibrational assignment is proposed and the band wavenumbers are compared for NbS3 and the related ZrS3 and NbS2Cl2. All the assignments have been checked by a complete valence force field calculation including intrachain, interchain and interlayer contributions. The potential energy distributions and mean square vibrational amplitudes so calculated and the values of force constants are in agreement with the two‐dimensional character of the lattice dynamics in NbS3.In addition, an extensive resonance Raman study has been performed using various exciting radiations in the visible (676.4–457.9 nm) and near‐UV regions (363.8 and 351.1 nm). The experimental unresolved Raman excitation profiles in the contour of two low‐energy electronic transitions (λmax≈︁ 600 and 560 nm) exhibit interesting interference and exact resonance effects depending on the nature of the vibration. Taking account of multi‐state interference phenomena and inhomogeneous broadening effects, these profiles compare well with the computed ones on the assumption of weakly displaced oscillators. This allows conclusions to be drawn about the scattering mechanisms and the nature of the first electronic excited states.
Vibrational spectra of the organometallic estrogen‐receptor marker [3‐O‐(3‐hydroxypropyl)‐17β‐estradiol]‐α‐tricarbonylchromium(0) and related compounds
Authors: Butler Ian S. , Dicaire François , Cordier Christine , Top Siden , Vessieres Anne , Jaouen Gerard , Guy Herve 
Published: May 2005

AbstractThe IR, micro‐Raman and Fourier transform (FT) Raman spectra of 3‐O‐(3‐hydroxypropyl)‐17β‐estradiol and the two (α and β) diastereomers, produced by coordination of a Cr(CO)3 moiety to the arene A ring of the steroid, are presented. The three compounds exhibit spectra typical of arene hormonal steroids and the α‐ and β‐diastereomers can be readily distinguished from one another, especially by their FT‐Raman spectra in the CO stretching region which, unlike the corresponding micro‐Raman data, are not significantly masked by the presence of strong fluorescence backgrounds. This distinction is important since the α‐diastereomer is a useful IR estrogen‐receptor marker, whereas the β‐diastereomer is not.
Raman and infrared spectra of D‐ribose and D‐ribose 5‐phosphate
Authors: Carmona P. , Molina M. 
Published: May 2005

AbstractRaman and infrared spectra were examined for D‐ribose, O‐deuterated D‐ribose, [1 – 13C]‐D‐ribose [2‐ 13C]‐D‐ribose and D‐ribose 5‐phosphate as crystalline powders and in aqueous solution. The vibrational modes are assigned on the basis of isotopic frequency shifts, depolarization ratios and relative intensities. The data are of value in testing previous assignments, some of them being revised and discussed in terms of their use in determining the structure of the ribose residue in nucleotides.
Vibrational spectra and normal coordinate analysis of some diethyl tertiary amides
Authors: Sudarshan R. , Rao G. Ramana , Chalapathi V. V. 
Published: May 2005

AbstractThe Raman and infrared spectra of N,N‐diethylformamide, N,N‐diethylacetamide, N,N‐diethylchloroacetamide and N,N‐diethylpropionamide were measured. Raman polarization measurements were also made. A normal coordinate analysis was carried out for N,N‐diethylformamide, N,N‐diethylacetamide and N,N‐diethylchloroacetamide using a 63‐parameter modified valence force field. The force constants were refined in an overlay least‐squares technique using vibrational frequencies of the molecules to obtain a converged set of meaningful force constants. The reliability of the force constants so obtained was tested by making a zero‐order calculation for N,N‐diethylpropionamide. The potential energy distributions and eigenvectors calculated in the process were used to make unambiguous vibrational assignments.
Raman and far‐infrared spectra of crystalline chloroiodomethane
Authors: Torrie B. H. , Prystupa D. A. , Clark J. , Taylor S. , Wong Y. W. 
Published: May 2005

AbstractThe lattice vibrations and internal modes of polycrystalline CH2ClI and CD2ClI have been studied as a function of temperature using Raman and far‐infrared spectroscopy. Both isotopic forms have four phases; one is plastic, one is partially ordered and the other two are fully ordered. Some aspects of the structures are discussed.
Saturation effects on ultraviolet resonance Raman intensities: Excimer/YAG laser comparison and aromatic amino acid cross‐sections
Authors: Su Chang , Wang Yang , Spiro Thomas G. 
Published: May 2005

AbstractSubstantial saturation effects are noted for resonance Raman (RR) bands of the aromatic residues in cytochrome c (excited at 230 nm) with an H2 Raman‐shifted YAG or a frequency‐doubled excimer‐pumped dye laser. At a given average power, saturation is much lower for excimer than for YAG excitation because of the longer pulse and higher repetition rate of the excimer laser. The signal quality at low average power is significantly higher for the excimer‐excited spectra. Ultraviolet RR cross‐sections have been redetermined for aqueous phenylalanine, tyrosine and tryptophan at a series of wavelengths from 240 to 192 nm. The excimer laser was used at 209 nm and longer wavelengths, and in addition deconvolution techniques were applied to better define the individual RR bands. These improvements led to quantitative changes in the cross‐section values from those reported previously, but the interpretation of the excitation profiles in terms of excited‐state properties of the aromatic residues remains unchanged.
Raman intensities of lattice vibrations in the 2,2′‐bipyridine crystal
Authors: Muniz‐Miranda M. , Cardini G. , Castellucci E. 
Published: May 2005

AbstractThe intensity of the Raman external phonons of the 2,2′‐bipyridine crystal were calculated using a published method. Two different models were used in the calculation, the oriented gas model and the local field model for polarizability. The eigenvectors used in the oriented gas model were either those of the rigid body lattice dynamics phonon energy calculation or those of the complete dynamic approach in which the mixing of the external modes with the internal torsional mode was taken into account. The molecular polarizability was obtained from the fitting of the experimental intensity of the powder spectrum starting from the polarizability of biphenyl. The overall agreement between calculated and experimental intensities of the Raman spectra corresponding to the scattering tensor elements referred to the optical indicatrix principal axes was satisfactory for all the models. A smaller standard deviation was obtained using the local field model for polarizability. This model gave better results if the interactions were split over two centres, corresponding to each of the two pyridine moieties.