Quantum chemical calculation of intermolecular interaction potentials, mainly of van-der-Waals type

Abstract

After a discussion of the differences between chemical and intermolecular interaction and a discussion of the asymptotic 1/R expansion from the viewpoint of new theoretical work, the calculation of van der Waals constants based on natural states of the interacting systems is outlined. For finite distances the problems that arise with perturbational and variational approaches are discussed. The appropriate choice of the variational ansatz is derived with particular attention to the coupling of intra- and inter-subsystem correlation effects. Finally some practical calculations are reviewed.