Application of Configuration Interaction to the 23S State of Helium. II

Abstract

The configuration interaction method is applied to the nonrelativistic 2³S state of the helium atom. It is shown, by variationally adjusting the effective charges of the angular configurations, that no radial readjustment occurs for this state. The final set of 80 configurations then gives an energy of —2.1752259 a.u., recovering 27% of the energy difference between our best previous configuration‐interaction value and the extrapolated value of Pekeris. A discussion is then given concerning the relative merit of the configuration interaction method and suggestions given for its future application to the 2³S state of the two‐electron system.