A new single-center perturbation theory for the treatment of simple hydrides

The perturbation expansion of Hartree-Fock potential energy surfaces of simple hydrides in a single-center scale 1/Z-expansion is carried out using diagrammatic methods. Diagrams having the topological structure of third-order diagrams are summed to all orders using an integral equation technique. The resulting one-electron wavefunction is used to generate a resummed perturbation series correct through fourth order.