COMPONENTS OF ELECTRON CORRELATION WITHIN A CI-DESCRIPTION OF HE(2P(2)-P-3)-LIKE IONS

Energetically acceptable configuration-interaction (CI) wavefunctions for the He(2p(2 3)P)-like ions are used in their natural expansion for m to analyse the separate angular and radial components of electron co rrelation. Angular Coulomb holes, one- and two-particle radial holes, and several related expectation quantities are calculated for these do ubly excited systems when 1 less than or equal to Z less than or equal to 4. By employing renormalized truncations of each natural expansion , the structure and shape of the holes and the magnitude and convergen ce of the various expectation values can be assessed. The quality of t he orbital-based CI wavefunctions is judged by comparing the present f indings with those derived previously from elaborate explicitly correl ated (EC) functions. For Z greater than or equal to 2, the agreement i s impressive. When Z = 1, the natural-expansion truncations highlight the causes of the differences between the CI and EC results. Moreover, of particular interest for each system, the truncations emphasize the relative importance of specific configurations within the wavefunctio n and also reveal their influence on the radial and angular properties as Z increases. Finally, comparisons are made between the doubly exci ted states and the ground states in terms of several statistical corre lation coefficients.