Original scientific paper

The Applicability of Point-Charge Approximations to the Calculation of Molecular Expectation Values

Michael Grodzicki ; I. Institut fur theoretische Physik der Universitat Hamburg, Jungiusstrasse 9, D-2000 Hamburg 36, West-Germany

Abstract

The recently developed self-consistent charge Xa (SCC- Xa)
method has been utilised to investigate various types of point-
charge approximations to molecular expectation values. In the first'
A A
part observables of the structure m1 (r) r' Y L (r) and a1 (r) r -'-1 Y L (r),
respectively, are analysed yielding the conclusion that, in general,
only certain matrix elements can be treated by point-charge approximations,
namely the two-center crystal-field integrals and
the three-center integrals. The results are then a calculation of the total valence energies as a function of bond
distances, and it turns out that the SCC-Xo. method is able to
reproduce equilibrium geometries with deviations of less than 100/o
provided all matrix elements are evaluated in an exa'Ct way, while
all investigated types of point-charge approximations fail in predicting
geometries.

Keywords

Hrčak ID:

194077

URI

https://hrcak.srce.hr/194077

Publication date:

14.1.1985.

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