Damped dispersion interaction energies for He-H2, Ne-H2, and Ar-H2.

Abstract

The van der Waals interaction energy between two closed-shell systems can be approximated as the sum of the Hartree-Fock (HF) and dispersion interaction energies. The dispersion energy is given as a power series in ${R}^{\mathrm{\ensuremath{-}}n}$ when the interaction potential is expanded in the multipole operators of the asymptotic systems. This series is convergent only if the overlap of the systems is explicitly considered. This paper will describe the calculation of the induced-dipole--induced-dipole dispersion interaction including the anisotropic damping due to charge overlap. The He-${\mathrm{H}}_{2}$, Ne-${\mathrm{H}}_{2}$, and Ar-${\mathrm{H}}_{2}$ systems were considered and the van der Waals potentials were constructed with use of available HF interaction potentials.