Ground State of the Helium-Hydride Ion

Abstract

The variational method developed by James and Coolidge was applied to the ground state of (He H)+, extending the earlier work of Coulson and Duncanson and of Toh. Several terms not considered previously in the power series expansion of the wave function in elliptic coordinates were found to be very effective in increasing the binding energy. Calculations with a 20-term wave function gave an equilibrium internuclear separation of 1.432 a0 and a fundamental frequency of 3600 cm−1. A 23-term wave function established 1.68 ev as the lower limit for the corrected dissociation energy.