ANGULAR AND RADIAL CORRELATION IN DOUBLY-EXCITED SYSTEMS WHEN 1-LESS-THAN-OR-EQUAL-TO-Z-LESS-THAN-OR-EQUAL-TO-4 - THE 2P(2) P-3 STATE

The angular and radial components of electron correlation have each be en examined in detail for the discrete 2p2 3P States of H-, He, Li+ an d Be2+. These doubly excited sytems were described by highly accurate explicitly correlated wavefunctions. The analysis involved the use of angular Coulomb holes, changes in the one- and two-particle radial den sity distributions and several angular and radial expectation values. Additionally, various statistical cor-relation coefficients were used which emphasized, in tum, angular and radial correlation properties in different regions of the two-particle density. The angular holes and related properties showed a clearly defined inverse-Z effect for He an d the positive ions. This trend was not repeated for the radial curves . However, the radial densities did reveal a distinct 'in-out' correla tion effect-similar in character to the split-shell behaviour for the ground state. By comparison with the findings for Z greater-than-or-eq ual-to 2, the angular and radial correlation effects for H- were alway s exceedingly large, thus setting it apart from the other systems. For He, the angular hole for the comparatively slow moving 2p2 3P electro ns was found to be over 50% deeper than that for the ground state and about six times the depth of a 1s2p 3P hole. The statistical correlati on coefficients highlighted a steady growth, with Z, in the relative i mportance of angular correlation. Nevertheless, for each system, these coefficients indicated that the radial effect was the prevailing infl uence on the two-particle probability distribution.