CONFIGURATION-INTERACTION STUDY OF THE DIFFERENTIAL CORRELATION ENERGIES AMONG THE LOWEST S-2, D-2, AND P-2(0) STATES OF CA+

In order to analyze the differential correlation energies among the lo west S-2(4s(1)), D-2(3d(1)), and P-2(o)(4p(1)) states of Ca+, configur ation-interaction calculations have been carried out for the three sta tes. The results reveal that the D-2 State has a larger core-valence c orrelation energy by 0.66 and 0.91 eV and a smaller core-core correlat ion energy by 0.38 and 0.39 eV than the 2S and P-2(o) states, respecti vely. Based on an analysis of the computed correlation energies in ter ms of contributions by various excitation types, the differential core -cole correlation energy is interpreted as the difference in the contr ibution from the 3p(2)-->dd' excitation between the D-2 State and the others. The 3s intrashell correlation energies as well as the 3s-3p in tershell correlation energies are uniformly equal among the three stat es.