Perturbation calculations of rare-gas potentials near the van der Waals minimum

A perturbation method used previously to calculate rare-gas potentials for He2 and Ne2 is modified to handle the many contributions to the Coulomb and exchange energy for heavier atoms. The procedure involves a transformation to an equivalent orbital basis and the neglect of all except the largest overlap contributions to the energy. Potentials are obtained for homo- and heteronuclear pairs for the atoms He, Ne and Ar, and the results are compared with the best empirical potentials.