摘要:

This paper reviewsab initioinvestigations of the Renner-Teller effect in a number of triatomic molecules. The potential surfaces for nuclear motion are calculated using the MRD-CI method. The calculation of vibronic energy levels and wave functions is performed using a simple matrix method for solution of the corresponding Schrodinger equation. In this approach the potential and the kinetic energy operators are expanded in polynomial series in the bending coordinate and the hamiltonian is diagonalized in a basis consisting of products of the electronic wave functions (or their linear combinations) calculated in the Born-Oppenheimer approximation with eigenfunctions of a two-dimensional harmonic oscillator. The method allows for the treatment of large-amplitude bending vibrations and an accurate consideration of non-adiabatic effects. In the second part of this paper the effect of various approximations, as well as some interesting technical details of calculations are discussed. In the third and fourth parts of this review, a summary of results of various calculations is given. A systematic study of dihydrides of the atoms belonging to the first two rows of the Periodic Table allows the recognition of some general trends concerning the equilibrium structure and shapes of the corresponding potential surfaces. A comparison with available experimental data shows that the results ofab initiocalculations permit a reliable representation of observed spectra. Further, the structure of yet unknown spectra can be predicted.

ISSN:0144-235X    

DOI:10.1080/01442358509353356

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Qualitative aspects of semiempirical energy band calculations are surveyed with the purpose of highlighting the key features of the electronic structures of some insulators, semiconductors and metallic systems. The nodal structure of the electronic orbitals is stressed as the common underlying theme in such effects as: the Peierls distortions of metallic systems; the changing electron counts (due to charge transfer or different d-electron counts); the high-pressure transformations of solids. The range of applicability of semiempirical non-self-consistent band theories is assessed. The discussion is illustrated by several examples.

ISSN:0144-235X    

DOI:10.1080/01442358509353357

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

This report lists atoms and free radicals in the gas phase which are of interest for environmental and flame chemistry and have been detected directly. The detection methods which have been used are discussed with respect to their range of application, specificity and sensitivity. In table 1, detection methods for the five atoms of group IV (C, Si, Ge, Sn, Pb) and about 60 radicals containing at least one atom of group IV are summarized

ISSN:0144-235X    

DOI:10.1080/01442358509353358

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Physics of Amorphous Materials. By S. R. ELLIOTT. (Longman, 1984.) [Pp. 432.] £25-00. ISBN 0582446368.

ISSN:0144-235X    

DOI:10.1080/01442358509353359

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor