Determination of pair potentials from ab-initio simulations

Alexander Lyubartsev and Aatto Laaksonen

Chem. Phys. Lett., v.325, pp.15-21

Abstract

We present a novel approach to construct pairwise site-site intermolecular interaction potentials from the results of ab initio quantum mechanical modeling to be used in classical molecular simulations. In the present application we, as a first step, have carried out ab initio Car-Parrinello molecular dynamics simulations of liquid water to calculate the radial distribution functions (RDF) between all the pairs of nuclei. Second step involves use of the Inverse Monte Carlo method, recently developed by us [Phys. Rev. E, 52, 3730 (1995)], to construct a full set of site-site interaction potentials from the ab initio RDFs. The resulting three-site SPC-like water model, which reproduces the liquid structure obtained in the Car-Parrinello MD simulations, can be used as a potential function in classical molecular simulations. We have also found that there exist no pair potential for a rigid three-site water model which exactly satisfy the experimental water's RDFs

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Alexander Lyubartsev
Last modified: Wed Jan 10 17:42:02 MET 2001