摘要:

AbstractThe transform method has been used to investigate the CARS excitation profiles (CEPs) of a highly fluorescent cyanine dye including linear non‐Condon sources of scattering. It is demonstrated that the calculated predictions of the CEPs are in good agreement with the experimental data of the CARS excitation profile of the dye. The observed values of the linear non‐Condon activity parameters,Ca, of three vibrational modes of 3,3′‐diethylthiacar‐bocyanine bromide were as large as 0.3. This suggests that linear non‐Condon electronic transition moments are important in the investigation of CEPs of c

ISSN:0377-0486    

DOI:10.1002/jrs.1250180602

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractIn situRaman spectroscopic studies of the electrochemical reduction of carbon dioxide at lead‐impregnated PTFE‐bonded carbon gas diffusion electrodes are reported. Polarization of the electrode surface resulted in the appearance of two weak bands at 2824 and 2915 cm−1. These do not correspond to the wavenumber shifts expected for free formic acid, but they are thought to arise from the presence of a ‘free’ formate ion and the formic acid perturbed at the electrode surface, respectively. Spectral changes observed at lower wavenumber shifts on polarization of the electrodes are interpreted in terms of the reduction of lead oxid

ISSN:0377-0486    

DOI:10.1002/jrs.1250180603

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe full resonance Raman spectra of cobalt(II) and cobalt(I) phthalocyanine are presented. By comparison with the Raman spectra of similar compounds, it has been possible to assign many of the bands. The resonance Raman spectrum of cobalt(II) phthalocyanine was replaced by that of cobalt(I) phthalocyanine when a PTFE‐bonded carbon gas diffusion electrode impregnated with a small amount of cobalt(II) phthalocyanine was maintained at a potential of −1.80 V, the gas side of the electrode being exposed to a carbon dioxide atmosphere. These results indicate that cobalt(I) phthalocyanine is a reactive intermediate in the electrochemical reduction of carbon dioxide to carbon monoxide at cobalt(II) phthalocyanine‐impregnated elect

ISSN:0377-0486    

DOI:10.1002/jrs.1250180604

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractA method for the quantitative determination of the laser beam deflection on passage through an electro‐optic modulator is presented. The hardware used to determine simultaneously the beam polarization parameters and deflections is described, and a procedure for minimizing these deflections is outlined. Examples of artifacts caused by the motion of the laser beam in the observation of Raman optical activity are presente

ISSN:0377-0486    

DOI:10.1002/jrs.1250180605

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe Raman spectra of polycrystalline samples of the metavanadates MIIV2O6(with M = Ca, Cd, Cu and Mg), belonging to the brannerite structural type, have been recorded. A general assignment, supported by comparisons with known vibrational properties of other oxovanadium species, is proposed. The compounds only give poorly defined IR spectra, which are not useful for the analysis of the vibrational behaviour.

ISSN:0377-0486    

DOI:10.1002/jrs.1250180606

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe SERS spectra of acrylamide and polyacrylamide adsorbed on the surface of silver colloid particles are reported. The SERS spectrum of acrylamide is interpreted as indicating that polymerization takes place on silver colloid surfaces. Evidence supporting this conclusion includes the fact that the CH2stretching vibrations of acrylamide adsorbed on the silver colloid surfaces are at 2926 and 2972 cm−1, which correspond exactly to those of polyacrylamide, and are greatly different from those at 3050 and 3115 cm−1observed for acrylamide in aqueous solution. Another possible indication of polymerization is the band at 1164 cm−1, which can be assigned to a polymer skeletal vibration.Although acrylamide is polymerized on the silver colloid surfaces, the SERS spectra of polyacrylamide polymerized before adsorption and acrylamide polymerized on the colloid surface are very different from each other. This observation is attributed to the different surface geometry of these two polymers, and the possible contibution of non‐polymerized species in the SERS spectrum of acr

ISSN:0377-0486    

DOI:10.1002/jrs.1250180607

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe Raman (3500–10 cm−1) and infrared (3500–50 cm−1) spectra of solid ethylphosphonothioic dichloride, CH3CH2P(S)Cl2, and its deuteriated analog, CD3CH2P(S)Cl2, have been recorded. 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 liquid phase to the solid state, it is concluded that the molecule exists as a mixture of thetransandgaucheconformers in the liquid phase with thegaucheconformer being the more stable form and the only one present in the solid Gtate. A variable temperature study of the Raman spectrum of the liquid did not yield an enthalpy difference between the conformers. Relying mainly on group frequencies and relative intensities of the infrared and Raman bands, a complete vibrational assignment is proposed for thegaucheconformer. This 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. All of these results are compared with corresponding quantities for several other organopho

ISSN:0377-0486    

DOI:10.1002/jrs.1250180608

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

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

ISSN:0377-0486    

DOI:10.1002/jrs.1250180609

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractTemperature‐dependent Raman spectra of oriented single crystals of [N(CH3)4]2CoCl4are reported. An assignment of the observed Raman bands has been made and it was found that the N(CH3)4+and CoCl42−groups occupy sites ofCssymmetry in the lattice at room temperature. However, because of rapid reorientation, the CoCl42−groups retain an effective tetrahedral symmetry. The prototypic to incommensurate to commensurate phase transitions are associated with the orientational dynamics of the CoCl4tetrahedra. The monoclinic to orthorhombic super lattice phase transition at 122 K in [N(CH3)4]2CoCl4is triggered by the distortion of the N(CH3)4+groups in the la

ISSN:0377-0486    

DOI:10.1002/jrs.1250180610

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractModel calculations of coherent Raman spectra under resonance pumping conditions for polyatomic molecules have been carried out. The influence of the resonance background, which originates from the ‘extra’ resonance term of the resonance vibronic transitionS0S1, is demonstrated. According to the calculations, the coherent anti‐Stokes Raman scattering (CARS) spectra for ωa= 2ωp−ωsare slightly changed when the resonance background is taken into account. The background contribution to the coherent Stokes Raman scattering (CSRS) for ωs= 2ωp−ωais higher. It is shown that a line reshaping associated with the concentration changes contains information about the relaxation parameters of the molecules, especially about the

ISSN:0377-0486    

DOI:10.1002/jrs.1250180611

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY