RELATIVISTIC MANY-BODY CALCULATIONS OF ENERGIES OF N = 3 STATES FOR THE BORON ISOELECTRONIC SEQUENCE, Z = 6-30

Energies of the 2s(2)(S-1)3l, 2s2p(P-1)3l, 2s2p(P-3)3l, 2p(2)(P-3)3l, 2p(2)(D-1)3l, and 2p(2)(S-1)3l states, with l = s, p, and d, for B-lik e ions with nuclear charges Z in the range 6-30 are determined to seco nd order in relativistic many-body perturbation theory starting from a frozen-core Dirac-Fock basis. These perturbation theory calculations include the first- and second-order diagram contributions from the Cou lomb and Breit operators for diagonal and nondiagonal matrix elements. Corrections for the frequency dependence of the Breit interaction are taken into account in lowest order. The Lamb-shift correction to the energies is also included in lowest order. Contributions of the three- electron interaction are compared with contributions of the one- and t wo-electron interactions. Comparisons are made with other theoretical calculations and with experimental data. We obtain excellent agreement for term splitting, even for low-Z ions. (C) 1998 Academic Press.