On exact analytical solutions for the few-particle Schrödinger equation. I. A perturbation study

Abstract

As the first stage in a project aimed at finding exact bound-state solutions for the few-particle Schrödinger equation, some restricted two-and three- body systems are treated by Rayleigh–Schrödinger perturbation theory. Formal solutions for the perturbation equations are obtained by using standard techniques for solving differential equations. Particular attention is given to justifying the various boundary conditions, since the same conditions apply to formal solutions of the eigenvalue equations. It is shown that boundary conditions designed to preserve the Hermitian character of the Hamiltonian are sufficient to determine all parameters in the formal solutions. The procedure is demonstrated by application to a hydrogen atom perturbed by stationary point charges. Results are given for the ground and some excited states.