The generating equations of Rayleigh—Schrödinger perturbation theory

Abstract

A set of non-linear equations is given which solves the stationary Schrödinger equation in terms of a known subproblem. An iterative solution of the equations yields the degenerate version of Rayleigh—Schrödinger perturbation theory, but other approximation schemes, as well as a purely numerical solution, are possible. As an illustration the Stark effect of the planar rigid rotator is discussed.