The configuration interaction method is applied to the nonrelativistic 23Sstate 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 mdash;2.1752259 a.u., recovering 27 of the energy difference between our best previous configurationhyphen;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 23Sstate of the twohyphen;electron system.
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