Perturbation theory and Padé approximants for a hydrogen atom in an electric field

Abstract

The behaviour of a coulomb system perturbed by (i) a radial electric field and (ii) an axial electric field is studied. In both cases the perturbation series for the energy is calculated to high order using the hypervirial method and shown to be divergent. Padé approximants to these series are found to be convergent and to yield the correct eigenvalues.