摘要:

AbstractThe Raman spectra of oriented single crystals of Copper (II) sulphate and selenate at 290 K and 150 K are reported and compared. Assignments are proposed for numerous internal modes of the crystals. Raman scattering tensors are calculated for the normal modes of (SO4)2−and (SeO4)2−and compared with experimental results. The structure and the part played by ligands (SO4)2−and (SeO4)2−in these crystals are stated precisely. The molecular complexes Cu(H2O)4and Cu(D2O)4are characterized by the assignment of their vibrational freq

ISSN:0377-0486    

DOI:10.1002/jrs.1250050202

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe resonance Raman spectrum of a Ti(IV)H2O2complex in acidic (H2SO4) aqueous solution is shown to consist of bands at 623, 1236 and 1852 cm−1. Excitation with three different lines of an argon ion laser showed the higher two Raman bands to be overtones of the 623 cm−1fundamental, this arising from the symmetric TiO stretching mode, ν2, of a TiO2species with C2νsymmetry. No ν(O  O) resonance enhancement was observed. Depolarization data and Raman intensity – molar absorbtivity relationships a

ISSN:0377-0486    

DOI:10.1002/jrs.1250050203

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractThe relative intensities of the resonance‐enhanced Raman bands and the solvent effect on these intensities were quantitatively studied for 1,1,4,4‐tetrachloro‐1,3‐butadiene. The results were interpreted on the basis of the normal coordinate treatment in combination with Albrecht's theory of Raman intensities. The vibrational structure of the electronic absorption band was interpreted simultaneously. Information on the molecular structure and normal modes of vibrations in the electronic excited state was obtained. The importance of the normal coordinate treatment in the analysis of the resonance Raman spectra is emp

ISSN:0377-0486    

DOI:10.1002/jrs.1250050204

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractResonance Raman excitation profiles have been obtained for several non‐totally symmetric fundamentals (A2gandB2gorB2gofD4hsymmetry) of Ni(II)‐porphin and some of their overtones in the region of the β absorption band using Ar and Kr ion laser exciting lines. Simulation calculations have been carried out for the observed profiles on the basis of Albrecht's formulation, and thereby vibronic coupling constants between theBandQstates have been evalu

ISSN:0377-0486    

DOI:10.1002/jrs.1250050205

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractEstimates are given for the process by which thes–dexchange interaction may contribute to the Raman scattering due to the magnon–spin flip of the conduction electron processes in antiferromagnetic semiconductors. It is shown that for the typical values of thes–dexchange interaction integral, i.e. 0.01–0.1 eV, the extinction coefficient can be larger by two orders of magnitude than that in ferromagnetic semiconductors. The value of the extinction coefficient in antiferromagnetic semiconductors is found to be 10−9–10−11cm−1sr−1. It is also shown that the change of the value of an absorbed energy in an external magnetic field allows us to determine the gyromagnetic factor for the con

ISSN:0377-0486    

DOI:10.1002/jrs.1250050206

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractFür viele Streuexperimente an durchsichtigen Substanzen Substanzen (speziell 90°‐Streuung) ist es notwendig, die gesamte Anordung, die aus laserstrahl, Kürvette, Kondensor und Abbildungslinse besteht, zu optimieren. Es wird theoretisch und auch in einer praktischen Näherung nachgewiesen, daß der beste Wert des Energieflusses von der Brennweite des Kondensors abhängt, wenn die Laser‐ und Monochromator‐Parameter fest vorgegeben sind. Die optimale Vergrößerung des Leuchtfadens ist für alle erforderlichen Auflösungen und verschiedene Laser konstant. In Erweiterung der ergebnise anderer Autoren [1–4] fanden wir bei unseren Untersuchungen des Leuchtfaden‐Durchmessers, daß der Einfluß der Beugung vernachlässigt werden kann, wenn der Laserstrahi nicht auf die TEM

ISSN:0377-0486    

DOI:10.1002/jrs.1250050207

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractOrder‐disorder phenomena in binary oxides with fluorite‐related structures were studied by Raman spectroscopy.Raman spectra of disordered phases show broad bands, defects leading to selection rule breakdown. For well‐ordered structures, the scattering active modes observed are those allowed by crystal symmetry. Broadening of Raman peaks occurs when order defects are present: antiphase boundaries, distribution of different cations on equivalent crystallographic posi

ISSN:0377-0486    

DOI:10.1002/jrs.1250050208

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractVibronic coupling of the Herzberg‐Teller type is discussed as a possible source of the depolarization dispersion of a fundamental line of a totally symmetric vibration in resonance Raman scattering (RRS). Two cases are discussed separately. The first case concerns RRS from an electronic state that borrows part of its intensity from a non‐overlapping electronic state of different symmetry. In this case the depolarization ratio of the fundamental line for right angle scattering linearly polarized light can vary between the limits 1/8 and 3/4. The second case arises when part of the intensity is borrowed from an electronic state of the same symmetry but with a transition moment non‐parallel to that of the resonant state. Such a situation can occur in molecules with a symmetry corresponding to one of the following point groups:C1,Ci,C2,Cs,C1h,C2h,S2. In this situation the depolarization ratio ρlcan vary between the limits 1/8 and. In both cases the amplitude of the variations of ρldepends on the damping constant. In the second case the value of the displacement parameter of a totally symmetric mode has a major influence on the range of change of ρl. Both cases show prominent resonance‐antiresonance coincidences between depolarization dispersions and excitation profiles, which has been previously predicted for non‐totally symmetric modes, and for molecular dimers. It is pointed out that the depolarization ratio in the preresonance region is very sensitive to vibronic coupling and can serve as a probe of s

ISSN:0377-0486    

DOI:10.1002/jrs.1250050209

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

摘要:

AbstractRaman spectra of oriented single crystals of (NH4)2SiF6are reported for the temperature range 440–20 K. The trigonal phase stable below 278 K undergoes a transition at 38.6 K. The changes in the spectra show that the symmetry does not remain trigonal, but give evidence for a lower symmetr

ISSN:0377-0486    

DOI:10.1002/jrs.1250050210

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY

ISSN:0377-0486    

DOI:10.1002/jrs.1250050201

出版商:John Wiley&Sons, Ltd.    

年代:1976

数据来源: WILEY