ISSN:
0020-7608
Keywords:
electron correlations
;
charge fluctuations
;
correlation strength
;
chemical bonds
;
first-row homonuclear diatomic molecules
;
Chemistry
;
Theoretical, Physical and Computational Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
We investigate, by means of ab initio calculations, the strength of electron correlations within covalent bonds: the first-row homonuclear diatomics serve as test cases. As an appropriate measure of the correlation strength, we introduce the reduction of the mean-square deviations of the electronic charges in localized orbitals forming a bond. A recently developed population analysis in terms of local operators derived from localized molecular orbitals is thereby used. The correlation-strength parameter depends only weakly on dynamical correlations as test calculations demonstrate. Therefore, the full-valence complete active space self-consistent field (CASSCF) approximation is applied in order to study the changes in the correlation strength with changing bond length for different types of bonds. A number of simple rules emerge from this discussion. In addition, we show that charge fluctuations are not only a reliable measure of intrabond correlation effects, but also can be used to monitor intraatomic quasi-degeneracy effects as well as the interdependence within multiple bonds. © 1998 John Wiley & Sons, Inc. Int J Quant Chem 67: 157-173, 1998
Additional Material:
12 Ill.
Type of Medium:
Electronic Resource
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