The effect of anisotropy on a hydrogenic Hamiltonian in an electric field

Abstract
The effect of an electric field on an anisotropic hydrogen-like Hamiltonian is studied by means of a variational calculation and the Stark coefficient is found as a function of the direction of the electric field and of the degree of anisotropy. A partial extension of the results to high fields is suggested. A comparison is made with predictions from a spherically averaged Hamiltonian. The paper also includes some previously unpublished results for the anisotropic ground state when the energy surfaces are oblate.