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The reliability of the point charge model representing intermolecular effects in ab initio calculations

✍ Scribed by Péter Surján; János G. Ángyán

Publisher
Elsevier Science
Year
1994
Tongue
English
Weight
667 KB
Volume
225
Category
Article
ISSN
0009-2614

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✦ Synopsis

The reliability of modeling ions or polar molecules by point charges is investigated from the point of view of possible nonphysical variational distortions of the molecular wavefunction. Mathematical and observable-based criteria are given to monitor the extent of variational distortions. A model system of two Ha molecules and a cation is studied, allowing investigation of large basis sets. The unphysical distortion, which tends to be worse as the basis set increases, is already observed in split-shell quality bases, if sensitive parameters (e.g. van der Waals distances) are investigated. It has a negligible influence on less sensitive molecular properties, such as the total electron density, even in large basis sets.

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