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A simple treatment of intermolecular interactions: Synthesis of ab initio calculations and combination rules
Author(s) -
Hoinkis J.,
Ahlrichs R.,
Böhm H.J.
Publication year - 1983
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560230306
Subject(s) - intermolecular force , coulomb , chemistry , ab initio , computational chemistry , molecule , charge (physics) , ab initio quantum chemistry methods , intermolecular interaction , chemical physics , atomic physics , physics , quantum mechanics , organic chemistry , electron
A new technique for a simple and efficient treatment of intermolecular interactions is proposed and tested. The method is based on an approximation of the first order SCF term E SCF (1) which is the most structured contribution to the total interaction. E SCF (1) is represented by a site–site potential V of (exp, 1/ R )‐type, which accounts for the exchange plus penetration and the long range Coulomb forces (by means of a point charge model). The individual contributions to V are obtained by means of combination rules from corresponding site parameters of interacting molecules. The site parameters are consequently molecular and not intermolecular properties and can conveniently be determined by probing a molecule with appropriate test particles. Site parameters are reported for He, Ne, Ar, N 2 , CO, CO 2 , CS 2 , and HCl. Comprisons show close agreement of V with E SCF (1)which in turn is close to Δ E SCF if polarization and charge transfer effects are small.