Perturbation Theory of Constraints: Application to a Lithium Hydride Calculation

Abstract

The perturbation theory of the constrained variational method is applied to a calculation on the lithium hydride molecule by Browne and Matsen. The changes in various properties on constraining the expectation values of force and virial operators to vanish are calculated. It is shown that the perturbation series converge very rapidly, so that only the leading terms are required. However, in this particular case the imposition of the constraints has a negligible effect on the calculated properties.