A THEORETICAL STUDY OF MOLECULAR INTERACTION-A PSEUDOPOTENTIAL VALENCE-ELECTRON-ONLY AB INITIO CALCULATION WITH ENERGY DECOMPOSITION

A method of valence-electron-only ab initio calculation with energy decomposition is presented. In this soheme the part of valence-electron-only ab initio calculation is based on the method of the Barthelat's three-parameter atomic pseudopotential, and the part of energy decomposition is based on the analysis proposed by Morokuma and coworkers. Trial calculations for molecular complexes (H_2O)_2, (HF)_2, and FCl-NH_3 are carried out with this method. The results of these computations are in good agreement with those obtained from Morokuma's original method in which all electron ab imtio is used. This indicates that the pseudopotential energy decomposition soheme proposed in this paper is able to provide a result of interaction energy and its components and charge components comparable to that from ab initio treatment, while the computation was simplified.