摘要:

AbstractThe vibrational spectrum of the benzophenone molecule has been studied using Raman spectroscopic techniques. The assignment of the observed bands has been supported by a normal mode calculation. Special attention has been paid to the interpretation of the low‐frequency mode

ISSN:0377-0486    

DOI:10.1002/jrs.1250110302

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractInteractions of cobalt(III) ion with adenosine‐5′‐triphosphate in the presence of 1,10‐phenanthroline and superoxide were studied by laser Raman spectroscopy. Striking intensity enhancement of two adenine ring vibrations at 734 and 1430 cm−1was observed upon formation of the complex Co(III)‐(phen)‐ATP‐O2−. The effect could be abolished by addition of cyanide ion to replace the superoxide ion. The spectral features were interpreted as indicating a direct binding of Co(III) to the C6‐NH2group of adenine. The interaction between Co(III) and 1,10‐phenanthroline was manifested in the frequency and intensity changes near 436 and 1064 cm−1. Raman intensities at 734, 1312, 1055 and 1430 cm−1were measured as a function of laser exciting wavelength. The gradual changes in Raman excitation profiles of ATP lines from 647.1 nm to 457.9 nm indicated the preresonance effect with a charge transfer transition between adenine and Co(III), which may lie between 300 and 400 nm as evidenced by the more dramatic enhancement of these lines

ISSN:0377-0486    

DOI:10.1002/jrs.1250110303

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe Raman spectra of the three solid phases of methyl ammonium chloride and its deuterated analogues have been measured and compared with IR results available in the literature. The static and correlation field splitting of the internal modes have been studied by the use of isotopic solid solutions. The methyl‐ammonium ions are found to be orientationally ordered in both γ‐ and β‐MAC. Evidence of at least local orientational order in α‐MAC is given. Spectra of the partly ammonium and methyl deuterated analogues show that the ammonium group is distorted in the low temperature phases, having approximatelyCssymmetry in γ‐MAC andC1symmetry in β‐MAC, and that the methyl group is slightly di

ISSN:0377-0486    

DOI:10.1002/jrs.1250110304

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractThe Raman spectra (50–3500 cm−1) have been recorded for gaseous, liquid and solid trimethylgallium. The infrared spectra (40–4000 cm−1) have also been recorded for trimethylgallium in the vapor and crystalline states. A complete vibrational assignment is proposed and the out‐of‐plane, GaC3deformation is assigned to an infrared band observed at 150 cm−1in the spectrum of the vapor. The vibrational spectrum of the solid is very simple which indicates that the molecule remains monomeric. Only one lattice mode was observed in the far infrared spectrum and none in the Raman spectrum. The spectrum of the solid can best be interpreted on the basis of C3site symmetry with either one or two molecules per unit cell. Normal coordinate calculations for the skeletal modes have been carried out utilizing a four atom

ISSN:0377-0486    

DOI:10.1002/jrs.1250110305

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractPure thiophene and furan isotropic Raman bandprofiles (corresponding to different A1totally symmetric bands) are investigated in function of temperature in the liquid and plastic phases. The vibrational band widths and correlation functions are derived. The results are interpreted by means of phenomenological models describing the bandwidths (Fischer and Laubereau, Oxtoby) and by means of Kubo‐Rothschild's model as regards the correlation functions. It is shown that other vibrational relaxation origins than dephasing processes must be considered in order to explain the whole experimental results. In particular, we point out the possible existence of intermolecular energy transfers which would the more easily occur as they take place between nearer vibrational level

ISSN:0377-0486    

DOI:10.1002/jrs.1250110306

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractRaman spectroscopy was used in structural studies of solution‐phase RhBr63−anions. The observed spectra are consistent with an octahedral ground‐state structure. Polarization measurements of the ν1(A1g) and ν2(Eg) vibrational modes support the contention of cubic symmetry. The degree of polarization of these lines is independent of laser wavelength, not unlike observations of otherd6hexahalide complexes. No resonance enhancement is observed with eitherT1gorT2gelectronic transitions in the visible spectral region. Rather it is believed that the Raman transitions obtain intensity by way of virtual excitation of the allowedT1uelectronic transition in the near‐ultraviolet portion of the

ISSN:0377-0486    

DOI:10.1002/jrs.1250110307

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractRaman and infrared spectra (10–400 cm−1) of Ni(C5H5)2, Fe(C5H5)2and of their perdeuterated derivatives (d10) have been recorded in the 30–300 K temperature range. A new assignment for some internal modes is proposed. The temperature dependence of the low frequency spectra (10–200 cm−1) and quasi‐elastic neutron scattering results are discussed in terms of dynamical disorder coming from molecular conformational fluctuations. The elastic incoherent structure factor (EISF) measured from neutron scattering on Ni(C5H5)2is compatible with 2π/5 ring jumps involving an activation energy of 1.5 kcal mol−1, while Raman band broadenings are interpreted in terms of large amplitude torsional motions associated with an activation energy of about 0.5 kcal mol−1. A qualitative representation of the potential driving the torsional motion is proposed and it is pointed out that the intermolecular potential plays an important role. Finally, although the conformational fluctuations can be responsible for the pretransitional effects, they take part only for 15% of the enthalpy variations in the phase transit

ISSN:0377-0486    

DOI:10.1002/jrs.1250110308

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractRaman active torsion‐libration fundamentals and overtones have been observed in crystals of N2H6Cl2and N2H6Br2. The temperature dependences of these modes have been followed between liquid nitrogen and room temperatures in the case of the chloride. Potential barriers to rotation have been calculated and compared with NMR activation energies to gain insight into the relationship between the two kinds of result. The external barrier for NH3+reorientation and the internal barrier for N2H62+have been found to be 3597 and 709 cm−1respectively for the chloride at 73 K, and 3066 and 676 cm−1respectively for the bromide at 92 K. The chloride results clearly show that the barriers are slightly temperature dependent. It is concluded that the NMR activation energy for NH3+reorientation must also have a temperature dependence which is probably of the formEa=Ea′ ‐CT. The discrepancies between the two types of results have been tentatively interpreted in terms of small sixfold contributions to

ISSN:0377-0486    

DOI:10.1002/jrs.1250110309

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractRaman spectra of a single crystal of C2H5NH3Br have been obtained at several pressures up to 10 kbar, to observe, in particular, the behaviour of the two torsional modes. Several bands show dramatic pressure shifts. The CH3torsion shows the largest shift of all (1.918±0.039 cm−1kbar−1), in striking contrast to the NH3+torsion which does not shift with pressure. Threefold barriers to rotation, and their pressure dependence, have been calculated from the torsional frequencies. An explanation of the observed behaviour has been sought in terms of hard and soft regions in the lattice s

ISSN:0377-0486    

DOI:10.1002/jrs.1250110310

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY

摘要:

AbstractResonance Raman spectra of azobenzene and some hydroxyazobenzene derivatives, in strong acid solution (HCI 6 M), are analysed. All the observed bands between 900 and 1700 cm−1can be assigned to vibrational modes of the aromatic rings and the azo group, and give evidence for atransazo type structure both for azobenzene and theparasubstituted hydroxyazobenzene derivatives studied. Resonance Raman spectra of six substituted 2‐(4′‐ hydroxyphenylazo)‐benzoic acid derivatives in strong acid solutions are investigated. The spectral features are rather different from the above studied hydroxyazobenzene derivatives, but can be explained on the basis of an azo type structure. A strong perturbation effect on the NN stretching mode is demonstrated using deuterium substitution. From the complexity of frequency shifts obtained on deuterium substitution, vibrational coupling between NH bending and many other vibrational modes is evident. A tentative assignment of the observed resonance Raman bands

ISSN:0377-0486    

DOI:10.1002/jrs.1250110311

出版商:John Wiley&Sons, Ltd.    

年代:1981

数据来源: WILEY