bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence of quantum‐size effect and electron–phonon interactions in resonance Raman scattering spectra of semiconductor nanocrystals
Authors: Baranov A. V. , Bobovich Ya. S. , Petrov V. I. 
Published: May 2005

AbstractRaman spectra of II–VI semiconductor nanocrystals embedded in silicate glass matrices with near‐resonance and resonance excitation in the range of electron transitions between size‐quantized energy levels were studied. It is shown that only the transitions with angular momentum l = 0, 2 contribute to the resonance Raman enhancement. The influence of the electron–phonon interaction on the Raman excitation profiles of the LO phonons and elastic vibrations of nanocrystals is analysed. The effect of the matrix on the intensities and frequencies of the low‐frequency Raman (LFR) bands and the possibilities of determining the particle size determination using LFR spectra are discussed.
Evaluation of Raman spectra of solutions with predominantly ionic metal–oxygen interactions
Authors: Bengtsson L. A. , Brooker M. H. 
Published: May 2005

AbstractThe assignment of infrared and Raman bands in the low‐wavenumber (0–500 cm−1) region of molten salts and glasses is complicated by the difference in the selection rules for infrared and Raman activity. Assignments are presented for several molten and glassy nitrates for infrared‐active (antisymmetric metal–oxygen motions) and Raman‐active (symmetrical metal–oxygen motions) vibration modes. Bands associated with monomolecular reorientational motion of the polarizability anisotropy (Raman) and dipole moment (infrared) may also contribute intensity in the 0–200 cm−1 region. A Raman band at about 500 cm−1 which was detected previously in solutions of lithium nitrate in molten (K, Na)NO3 has been reassigned to the glass of the container wall.
Inter‐ and intramolecular force constants of some trihalides of the fifth group in the gas, liquid and solid
Authors: Kondyurin Alexey , Byelousova Nadezhda , Byelousova Sofia , Kozulin Alexander 
Published: May 2005

AbstractThe Raman spectra of trihalides of the Fifth Group, BiCl3, AsCl3, AsBr3, SbBr3 and PCl3, in the gas, liquid and solid were obtained. A normal coordinate analysis was performed. The intermolecular force constants were calculated from variations of the intramolecular force constants of the molecule during the phase transition. The half‐periods of librations in the liquid and lattice frequencies in the crystal were calculated and the lattice spectrum of the crystal was interpreted. It is shown that for a heavy central atom the calculation of intermolecular force constants may be performed in the approximation of a diagonal potential energy matrix. For a light central atom such an approximation may be used only for estimates. In this case the use of a complete potential energy matrix of a molecule is necessary for an accurate calculation.
High‐pressure Raman study of liquid and crystalline CHF2Cl and CHF3
Authors: Wu Y. H. , Onomichi M. , Sasaki S. , Shimizu H. 
Published: May 2005

AbstractHigh‐pressure Raman spectra of liquid and crystalline CHF2Cl and CHF3 were measured up to pressures of 15 and 10 GPa, respectively, at 300 K in a gasketed diamond‐anvil cell. The liquid–solid phase transition pressures were determined to be 3.49 GPa for CHF2Cl and 2.46 GPa for CHF3. For both CHF2Cl and CHF3, the wavenumbers of the CH stretching mode ν1 increased rapidly with increasing pressure, and this behaviour was investigated by the theory of reasonance hybrid of the covalent‐bonded and ionic‐bonded structures.
Laser‐induced anisotropy and depolarization ratios
Authors: Dawson Don F. , Koningstein J. A. 
Published: May 2005

AbstractMonobeam transmission and resonance Raman (RR) experiments were used to study the excited state Sm ← S3(B) spectra and the depolarization ratios, ρn, of the ν2(Cβ–Cβ), A1g, \documentclass{article}\pagestyle{empty}\begin{document}$ \Delta \mathop \nu \limits^ - = 1558{\rm cm}^{ - {\rm 1}} $\end{document}, and δ(pyr), A1g, \documentclass{article}\pagestyle{empty}\begin{document}$ \Delta \mathop \nu \limits^ - = 1643{\rm cm}^{ - {\rm 1}} $\end{document} RR peaks of meso‐tetrakis(N‐methyl‐4‐pyridyl)porphine, H2TMpyP(4), in phosphate buffer (pH 7) at an excitation of λ1 = 422 nm (\documentclass{article}\pagestyle{empty}\begin{document}$ \Delta \mathop {\nu _1 }\limits^ - = 23697{\rm cm}^{ - {\rm 1}} $\end{document}) as a function of pump intensity, I1 (mW), over the range of I1 = 0–5 mW. Three factors, ground state depletion, induced anisotropic density distribution of the ground stage, n1G, and the anisotropic polarized excited‐state absorption effect, are discussed to explain the behaviour of ρn versus I1 for these two peaks. In addition, scattering tensors and experimentally determined depolarization ratios for the \documentclass{article}\pagestyle{empty}\begin{document}$ \Delta \mathop \nu \limits^ - = 1558{\rm cm}^{ - {\rm 1}} $\end{document} and \documentclass{article}\pagestyle{empty}\begin{document}$ \Delta \mathop \nu \limits^ - = 1643{\rm cm}^{ - {\rm 1}} $\end{document} RR peaks of H2TMpyP(4) at excitations of λ1 = 422, 476.5 and 514.5 nm (\documentclass{article}\pagestyle{empty}\begin{document}$ \Delta \mathop \nu \limits^ - = 23697,{\rm 20986 and 19436 cm}^{ - {\rm 1}} $\end{document}, respectively) are presented. The results seem to imply that a > b, and could be interpreted as the presence of x‐ and y‐splitting of the Soret B band.
Vibrational spectra and structure of perchlorinated metal‐free phthalocyanine and lutetium bisphthalocyanine
Authors: Gobernado‐Mitre I. , Klassen B. , Aroca R. , DeSaja J. A. 
Published: May 2005

AbstractThe infrared and Raman spectra of perchlorinated phthalocyanine (Pc), H2PcCl16, LuPc2Cl32 and the unsymmetrical LuPc2Cl16 are reported. The vibrational data set also include SERRS and the far‐infrared spectra between 100 and 400 cm−1. The vibrational assignment of characteristic wavenumbers was supported by a semi‐empirical calculation using the PM3 Hamiltonian. The H2Pc molecule was used as a reference in the PM3 vibrational calculations. The effect of the chlorine substituents on the optical spectra of the phthalocyanine ring is examined.
Process analysis of electroless nickel deposition baths by Raman spectroscopy
Authors: Gantner E. , Beck M. , Müller H. G. , Steinert D. , Ache H. J. 
Published: May 2005

AbstractIn a test experiment carried out in a small compact electroless plating facility, the concentrations of hypophosphite and phosphite in a nickel deposition bath of the Kanigen type were monitored on‐line with a dispersive Raman spectrometer. From the results, which agreed with off‐line Fourier transform (FT) IR data within ca. 10%, the molar amounts of nickel, hypophosphite and phosphite consumed and formed were calculated and compared with the stoichiometry of the nickel plating process adopted. In addition, nickel bath samples were also measured with an FT Raman spectrometer to compare the performances of both Raman techniques with a view to their application to aqueous solutions.
Contribution of Raman spectroscopy to art and history
Authors: Coupry Claude , Lautié Alain , Revault Madeleine , Dufilho Jérôme 
Published: May 2005

AbstractBlue pigments used by a 19th century French artist were analysed by Raman microspectrometry. The results are discussed in relation to the painting materials available at that time. This study is connected with an artistic study of the drawings, and allows the artistic and technical aspects of the work of this painter to be compared.
An approach to stone and fresco lichen biodeterioration through Fourier transform Raman microscopic investigation of thallus—substratum encrustations
Authors: Edwards H. G. M. , Edwards K. A. E. , Farwell D. W. , Lewis I. R. , Seaward M. R. D. 
Published: May 2005

AbstractThe Fourier transform Raman spectra of thallus‐substratum interfaces of Xanthoria parietina growing in situ on sandstone and gypsum were obtained for the first time. The presence of small amounts of calcium oxalate in thallus‐substratum interfaces was confirmed spectroscopically and evidence for biodeterioration via lichen metabolic by‐products was also noted. Although the oxalate determined spectroscopically was in good agreement with the results from thermogravimetric measurements there was also spectroscopic evidence for incorporation of stone particles into the lichen encrustation. Comparisons are made with Raman spectroscopic studies of the thalli of the high oxalate‐producing lichen Dirina massiliensis forma sorediata. The Raman spectra Ochrolechia parella growing in association with Xanthoria parietina on maritime sandstone were also recorded and the spatial discrimination of the techniques for these high and low oxalate‐producing lichens was demonstrated.
Non‐traditional methods for obtaining glasses for coatings: A raman and infrared vibrational study
Authors: Bertoluzza A. , Morelli M. A. , Tinti A. , Vasina M. 
Published: May 2005

AbstractSynthetic methods which provide alternatives to the oxide melting method for the preparation of inorganic glasses are described. These methods were monitored by Raman spectroscopy. The transformation products involved in two main synthetic methods, the ‘sol–gel’ method illustrated here for obtaining glassy SiO2 and the ‘polymeric’ route used for the first time in the preparation of calcium phosphate glasses (CaO.P2O5, calcium metaphosphate; xCaO.P2O5, calcium oligophosphates, where x ≤ 1.6) are characterized and discussed using their Raman spectra. These alternative methods allow vitreous materials to be prepared at moderate temperatures. They can therefore be important in the field of biomaterials for coating metal implants with bioactive glasses and ceramics. The melting method (for glasses) and the plasma spray technique (for ceramics) frequently induce changes of stoichiometry in the coating and also activation of the support material, metal or alloy, resulting in a lack of biocompatibility.
Use of a rapid scanning stigmatic Raman imaging spectrograph in the industrial environment
Authors: Williams K. P. J. , Pitt G. D. , Smith B. J. E. , Whitley A. , Batchelder D. N. , Hayward I. P. 
Published: May 2005

AbstractRaman spectroscopy is steadily growing in importance in the industrial analytical laboratory. The nature of the equipment, its ease of use and its cost are making the method more acceptable to non‐experts. This paper illustrates the capabilities of a recent commercialized Raman system which fulfils the criteria of ease of use, speed and low cost. The system is designed for Raman microscopy and uses a single spectrograph and CCD detector. The combination provides confocal microscopy, high throughput and optimum sensitivity, to the extent that it only requires the use of a low‐powered laser to provide high‐quality spectral data. The additional feature of direct Raman imaging is seen as being beneficial in the industrial environment in that it provides spatial information over large surface areas quickly and without the need for excessive amounts of data processing. The performance of the instrument is illustrated with applications taken from the industrial environment.
Structural characterization of heterocyclic polymer networks by low‐frequency Raman scattering
Authors: Novikov V. N. , Shebanin A. P. , Azarenkov V. P. , Baibak A. V. , Kramarenko Yu. V. , Privalko V. P. 
Published: May 2005

AbstractGlassy, heterocyclic copolymers of an epoxy oligomer and hexamethylene diisocyanate were characterized by low‐frequency Raman scattering spectra at room temperature. The experimental data were treated according to the formalism of the theory of inelastic light scattering from fractons to derive structural information in the scale range below 10 nm. The samples studied were shown to behave essentially fractal‐like in the range of characteristic scales (on an order‐of‐magnitude basis) spanning roughly the chain persistence length (ca. 0.7 nm) as a lower structural limit and the network mesh size (ca. 3 nm) as an upper structural limit.
Raman intensity of lattice vibrations in BaCl2 · 2H2O. Many‐body treatment
Authors: Kanesaka Isao , Matsuda Toshiyuki , Niwa Yukie 
Published: May 2005

AbstractPolarized Raman spectra of BaCl2 · 2H2O and their assignments are reported. The Raman intensity was analysed by means of the pair approximation and the many‐body interaction among induced dipoles. It was found that the many‐body treatment is more quantitative than the pair approximation, although the agreement between the observed and calculated polarized spectra is still incomplete. The difference between the two methods is discussed.
Low‐frequency vibrational spectra of spirocyclic bis(ethane‐1,2‐dithiolato[2‐]‐S,S′‐tin(IV)) and its pyridine and related complexes
Authors: Shamir J. , Starostin P. , Peruzzo V. 
Published: May 2005

AbstractThe Raman and infrared spectra of the tetracoordinated SnS4 compound spirocyclic bis(ethane‐1,2‐dithiolato[2‐]‐S,S'‐tin(IV)) (1) and its related hexacoordinated SnS4L2 complexes with pyridine (2), 2‐(2‐pyridyl)ethylamine (3) and 3‐aminopyrazole (4) were recorded and interpreted. The skeletal vibrations of SnS4 and SnS4N2 were asigned and are discussed. The tetrahedral SnS4 core in 1, which has essentially Td symmetry changes into a square planar with D4h symmetry when coordinating to the N‐donor ligands (2, 3 and 4). This change in structure and symmetry also causes the Sn‐S vibrations to change both in number and wavenumber.
Stimulated Raman and CARS spectroscopy of ν1 and 2ν2 (A1) bands of 12CF4
Authors: Tabyaoui A. , Lavorel B. , Saint‐Loup R. , Rotger M. 
Published: May 2005

AbstractTwo experimental coherent Raman techniques, stimulated Raman and coherent anti‐Stokes Raman spectroscopy (CARS), were employed to study the Raman spectrum of CF4 in the 900 cm−1 region. The stimulated Raman and CARS spectra of the ν1 band of CF4 were recorded at high resolution. The analysis of these spectra enabled some spectroscopic constants of this band to be refined and higher order constants to be determined for the first time. The first high‐resolution CARS spectrum of the 2ν2 (A1) harmonic band is also presented. The rotational transitions of this band up to J = 40 were assigned and the first set of spectroscopic constants for this sub‐level were determined. These results improve our knowledge about the Raman‐allowed vibrational bands of CF4.
New possibilities of overlapping Raman band resolution by methods of CARS spectroscopy
Authors: Fishman A. I. , Mironov S. F. 
Published: May 2005

AbstractNew possibilities for the resolution of Raman bands, provided by polarization‐sensitive CARS in combination with a phase‐mismatching technique, are presented. The use of this combination of techniques allows one to achieve the most informative spectra and resolve the complex structure of inhomogeneously broadened contours. The variation of the resonant/non‐resonant ratio using a phase‐mismatching technique and the special possibilities of polarization CARS spectroscopy in lineshape formation are used. The results of an investigation of a cyclohexane and naphthalene mixture and ofn‐pentane by polarization CARS in combination with a phase‐mismatching technique are presented.
Raman spectra of H2S along the liquid–vapour coexistence curve
Authors: Salmoun Farida , Dubessy Jean , Garrabos Yves , Marsault‐Herail Françoise 
Published: May 2005

AbstractThe ν1 isotropic Raman spectrum of H2S was studied in the dilute gas phase and in the gas and liquid phases along the saturation line (282 ≤ T ≤ Tc = 373.4 K). The temperature and density dependence of the hand shift was analysed assuming a strong resonant transfer due to dipolar interactions. A significant rotational contribution prevents a precise study of the vibrational effects on the asymmetric profile observed at ρ < ρc. A striking critical inhomogeneous broadening is observed as the critical point is approached. Some new results on the v2 isotropic and anisotropic bands of liquid H2S are also presented.
On the difficulty of attributing a fractal signature to low‐frequency Raman spectra of polymers in solution
Authors: Papin R. , Rousseau M. , Durand D. , Nicolai T. 
Published: May 2005

AbstractMeasurements of the low‐frequency Raman spectra (LFRS) (below 100 cm−1) of poly(methyl methacrylates) in solution are reported. The reduced intensity exhibits a power law dependence on the frequency at any concentration and at any conversion rate of the polymerization reaction. Even monomeric liquids such as toluene and methyl methacrylate show such a power law behaviour. The results are compared with recent theories on low‐frequency Raman scattering from fractal structures and suggest that a more careful interpretation of LFRS is needed.
High‐pressure Raman spectra of 3‐methyl‐4‐nitropyridine N‐oxide crystal and pressure‐induced phase transitions
Authors: Zhang Delong , Lan Guoxiang , Hu Shifen , Wang Huafu , Zheng Jimin 
Published: May 2005

AbstractRaman spectra of a 3‐methyl‐4‐nitropyridine N‐oxide crystal were investigated as a function of pressure in a diamond‐anvil cell up to 93 kbar at room temperature. The crystal shows successive reversible phase transitions at 8, 20 and 60 kbar. Above 60 kbar, all of the external Raman peaks and most of the internal peaks were found to vanish, and this is interpreted as due to polymerization or a crystalline‐to‐amorphous phase transition. On decreasing the pressure, this amorphous state persists to about 20 kbar, and then the spectrum can be recovered completely on decreasing the pressure continuously to ambient, Zallen and Slade's vibrational scaling law was successfully checked.
Fourier transform Raman study of glass‐fibre‐reinforced poly(ethylene terephthalate)
Authors: Quintanilla L. , Rodríguez‐Cabello J. C. , Pastor J. M. 
Published: May 2005

AbstractFT‐Raman spectroscopy has been proved as a useful tool to form the quantitative study of conformational changes in glass‐fibre‐reinforced annealed poly(ethylene terephthalate) (PET). Based on composite Raman bands directly related to the ethylene glycol fragment in the trans and gauche conformations, it was observed that glass‐fibre‐reinforced PET exhibits the same two‐phase conformational model as the isolated matrix. In contrast to the matrix, annealing thermal treatment of the composite does not seem to affect the composite microstructure since the isomer contents remain constant with annealing temperature. Thus, the microstructure is mainly determined by the fabrication process and its effect is similar to that observed in an annealed matrix at the highest temperatures. Therefore, the disordered trans isomer content can be considered negligible in the composite. In contrast to the spectroscopic results, the crystallinity values of the composite obtained by differential scanning calorimetry (DSC) only tend to coincide with those of the annealed matrix at temperatures above 150°C, and below this temperature they are always lower. A comparison between the results obtained by FT‐Raman and DSC techniques seems to indicate an improvement in the fibre–matrix interface in which an interfacial structure with a low degree of perfection changes to more perfect crystals.
Effects of vinyl substitutions on resonance Raman spectra of (bacterio)chlorophylls
Authors: Feiler Ute , Mattioli Tony A. , Katheder Ingrid , Scheer Hugo , Lutz Marc , Robert Bruno 
Published: May 2005

AbstractSoret resonance and Qy preresonance Raman spectra are reported and compared for a series of (bacterio)chlorophylls. Chlorophyll a, 2‐acetylchlorophyll a, bacteriochlorophyll a and 2‐vinylbacteriochlorophyll a were studied in the non‐protic solvent tetrahydrofuran. These experiments were designed to identify Raman bands corresponding to the stretching mode(s) of the vinyl group at the C‐2 position of ring I of chlorophyll a and 2‐vinylbacteriochlorophyll a, and to ascertain whether additional bands corresponding to Ca Cm and/or Cb Cb vibrations could be observed in the 1615–1660 cm−1 region. Raman spectra of chlorophyll a and 2‐vinylbacteriochlorophyll a exhibit a 1625 cm−1 band, which is absent from the Raman spectra of 2‐acetylchlorophyll a and bacteriochlorophyll a. It is assigned to the vC2a C2b mode of the vinyl group. No other band can be definitively assigned to any mode predominantly arising from vinyl motions. The acetyl‐containing molecules 2‐acetylchlorophyll a and bacteriochlorophyll a give rise to a ca. 1070 cm−1 band, which appears to be related to the presence of the acetyl substituent. The 1615–1660 cm−1 region of the Raman spectra of all four derivatives did not contain any additional band which could be ascribed to modes involving the vCa Cm and/or νCb Cb coordinates.
Raman study of saturated ZnBr2(CdBr2)CH3CNH2O solutions in the CN stretching region
Authors: Astinov V. H. , Stoev M. D. 
Published: May 2005

AbstractRaman spectroscopy was used to study the complexation in saturated ZnBr2(CdBr2)CH3CNH2O solutions at 25°C within the CN stretching region. Using the Fourier deconvolution procedure for spectral contours, the formation of the complex (CH3CN)Zn2+ in saturated and unsaturated (0.2 mole fraction CH3CN) solutions of the system ZnBr2CH3CNH2O was studied. The Fermi resonance interaction between 2253 and 2290 cm−1 determines opposite directions of the combination band shift for the two systems. The differences in complexation of Zn2+ and Cd2+ in the mixed solvent are discussed on the basis of the preferred cation solvation by the solvent molecules.
Surface‐enhanced Raman spectra of langmuir–blodgett monolayers of (hexadecamethyltetralino) porphyrazines
Authors: Souto J. , Aroca R. , Desaja J. A. 
Published: May 2005

AbstractLangmuir monolayers of metal‐free tetra(1,1,4,4‐tetramethyl‐6,7‐tetralino) porphyrazine (HDMTLPH2) and its copper complex (HDMTLPCu) were formed on a water subphase. The surface pressure‐area isotherms were measured and the floating monolayers were transferred to various substrates. The spectra of Langmuir‐Blodgett (LB) films deposited on metal surfaces were studied. Surface‐enhanced Raman spectra of a single LB monolayer of HDMTLPH2 and HDMTLPCu deposited on rough surfaces (silver‐coated tin spheres and island films of silver and gold) are reported. Reflection absorption Fourier transform IR spectra of LB films on smooth silver are also presented. The spectroscopic characterization includes the UV‐visible spectra of multilayer films on glass slides, solutions and the bulk materials. Characteristic vibrational wavenumbers are listed and used to discuss molecular orientation in the LB assemblies.
Pre‐resonance Raman effect of solid‐state phenothiazine
Authors: de Faria D. L. A. , Santos P. S. 
Published: May 2005

AbstractThe band intensities of Raman spectrum of PTZ in the solid state show a clear dependence on the laser excitation wavelength. Such a behaviour, not observed when the spectrum is obtained from PTZ in solution, indicates that in the crystal the molecular. orbital of the compound is perturbed to some extent. The PTZ · SO2 complex in solution presents the same pre‐resonahce pattern as does solid PTZ, suggesting that the same PTZ orbital is involved in both cases. The most enhanced PTZ modes are those ascribed to the aromatic ring vibrations, indicating an interaction through the π molecular orbitals; it is proposed that PTZ acts as a π‐donor toward SO2 on the basis of the pre‐resonance pattern of the Raman spectrum of PTZ · SO2.