摘要:

AbstractThe micro‐Raman spectra of eight ferrocene derivatives [CpFeCp′; Cp; Cp = η5−C5H5, Cp′= η5−C5H4R where R = C(O)Me, C(O)Ph, C(O)CH2Ph, etc.] and three (η6‐C6H5R)Cr(CO)3complexes have been recorded for the solids at room temperature in order to demonstrate the applicability of this new spectroscopic technique to organometallic complexes. Much lower laser powers than are normally used for Raman measurements have proved possible (0.5–3 mW at the samples) because of the high collection efficiency of the microscope optics and the multiscanning capability of the spectrometer. Raman spectra can now be obtained for materials earlier thought to be too unstable to survive the long periods of continuous laser irradiation necessary. Some vibrational assignments are proposed for the organometallic co

ISSN:0377-0486    

DOI:10.1002/jrs.1250180102

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe Raman spectrum of chlorocyclohexane has been recorded as a function of temperature from −40 to +110 °C and the conformational enthalpy for the equatorial to axial equilibrium was determined as 1.10±0.13 kJ mol−1for ΔH ea0. Changes in the Raman spectrum as a function of pressure up to 5.6 kbar have been interpreted in terms of a shift in the conformational equilibrium to favour the axial form at high pressure. The associated conformational volume change has been calculated as 2.33±0.27

ISSN:0377-0486    

DOI:10.1002/jrs.1250180103

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe vibrational energy deposited in a liquid by stimulated Raman gain was detected using the thermal lens scheme. The technique was demonstrated using benzene and toluene, with a frequency doubled Q‐switched Nd–YAG laser and a tunable dye laser. The rise time of the thermal lens signal was recorded with the object of obtaining information on vibrational to translational energy transfer proces

ISSN:0377-0486    

DOI:10.1002/jrs.1250180104

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe Raman spectra of aqueous mixtures of glutathione (GSH) and methylmercury(II) were obtained at various [GSH]/[CH3Hg(II)] ratios and pH conditions. The results show that the favored step in the complexation of these species is through the substitution of the proton on the thiol group of GSH by a CH3Hg+ion. Coordination of a second methylmercury ion on to the sulfur atom is also believed to occur extensively in acidic solutions, giving the charged complex GS(HgCH3)2+. The decrease in the concentration of this species with increasing pH is partly compensated for by complexation through substitution of a proton on the protonated amino group of GSH, a process which is favored in basic solutions. A factor analysis, based on Raman spectra of various mixtures studied under different pH conditions, has shown that these three types of complexation accounts for nearly all of the interactions which take place between glutathione and methylmercury.

ISSN:0377-0486    

DOI:10.1002/jrs.1250180105

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe resonance Raman effect in solid Na5[Cu(HIO6)2].16H2O at room temperature was investigated and the experimental excitation profiles were obtained. From the analysis of the overtone progression of the ν1(A1g) mode, corresponding to the IO symmetric stretching vibration, theX11anharmonicity constant was determined. The dependence of the Raman intensities on the scattered frequency is briefly discuss

ISSN:0377-0486    

DOI:10.1002/jrs.1250180106

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 (3500−20 cm−1) spectra of CH3PF2BH3and CH3PF2BD3were recorded for the gaseous and solid states. Additionally, the Raman spectrum of the liquid was recorded and qualitative depolarization values were measured. All the fundamental modes except the two internal rotations were assigned utilizing band contours, depolarization values, isotopic shifts and group frequencies. A normal coordinate calculation was carried out utilizing a modified valence force field to calculate the frequencies and the potential energy distributions. The observation of five Raman lines in the spectrum of the solid, and the observation of the doubling of several of the intramolecular fundamentals, indicate that there are at least two molecules per primitive cell. These results are compared with similar quantities in some corresponding mo

ISSN:0377-0486    

DOI:10.1002/jrs.1250180107

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe intensities of the Raman lines of anthracene in solution and in the pure crystal at room temperature have been measured using several excitation frequencies (ν0) in the pre‐resonance region. The data were used to derive molecular scattering elements αiiat each νofor a number ofagfundamentals. While the values of αxxand αyyare constant over the restricted range of excitation used, αzzshows an enhancement as νomoves towards resonance with the first absorption system (I). Overlap factors were determined from the fluorescence spectrum of anthracene in a biphenyl matrix, and these values were used to calculate the contribution αzz(I) due to scattering off the first excited electronic state. Working beyond the oriented‐gas assumption improved the fit between calculated and observed enhancement. There is a measurable background contribution to αzzdue to scattering off higher excited states and this has an opposite algebraic sign from αzz(I) for allagfundamentals except possibly for the

ISSN:0377-0486    

DOI:10.1002/jrs.1250180108

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe effect of temperature on the peak positions, the isotropic and reorientational band widths and the depolarization ratios of the Raman bands for the totally symmetric vibrations of CHCl3, CH2Cl2, CH2Br2, CH3Br, CH3I and CD3I has been measured in the liquid state. The isotropic band width for a CX stretching vibration decreases with increasing temperature for molecule with only one CX bond, whereas it increases for a molecule with two or three equivalent CX bonds. The isotropic band width for the deformation vibrations decreases with increase in temperature. For all the bands, the depolarization ratios depend only slightly on temper

ISSN:0377-0486    

DOI:10.1002/jrs.1250180109

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractTwo samples of solid all‐trans‐β‐carotene which differed in their degrees of crystallinity were studied using visible absorption and resonance Raman spectroscopy.The absorption spectrum of a commercial crystalline β‐carotene sample revealed two bands at 18 450 and 20 040 cm−1which were not present in the absorption spectrum of a prepared amorphous sample. Instead, the spectrum of the amorphous material showed a band at 19 268 cm−1which is in a position approximately half way between the 18 450 and 20 040 cm−1bands. From these observations these two latter bands are assigned to the Davydov components of the crystalline β‐carotene.The resonance Raman spectrum of crystalline all‐trans‐β‐carotene revealed several frequencies for the backbone CC stretching mode, νcc, as the laser excitation wavelength was varied. This frequency was observed to vary between 1516 and 1525 cm−1. The amorphous carotene sample also exhibited a wavelength‐dependent Raman spectrum where νccranged from 1516 to 1522 cm−1initially. On further exposure to laser radiation (30–60 min) at 514.5 nm, the range increased to an upper limit of 1525 cm−1, which was attributed to a photochemical product formed in both the crystalline and amorphous samples. The wavelength‐dependent νccfrequency of these carotene samples is interpreted as being due to resonance‐enhanced Raman bands of β‐carotene molecules with different effective double bond chain lengths origina

ISSN:0377-0486    

DOI:10.1002/jrs.1250180110

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY

摘要:

AbstractThe 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 su

ISSN:0377-0486    

DOI:10.1002/jrs.1250180111

出版商:John Wiley&Sons, Ltd.    

年代:1987

数据来源: WILEY