RELATIVISTIC MANY-BODY CALCULATIONS OF ENERGIES OF N = 3 STATES FOR BORON-LIKE SODIUM

Energies of 2s(2)3l, 2s2p(P-1)3l, 2s2p(P-3)3l and 2p(2)3l states (with I = s, p, d) for B-like Na are calculated. These perturbation-theory calculations make use of a frozen-core relativistic Hartree-Fock basis sets. The calculations include Coulomb and Breit contributions from f irst- and second-order diagrams for both diagonal and non-diagonal mat rix elements. Corrections for the frequency-dependent Breit interactio n are taken into account in lowest order and corrections for the Lamb shift are also included. Contributions from three-electron diagrams ar e compared with those from one-and two-electron diagrams. Comparisons are made with available experimental data; we find good agreement in m ost cases with experimental term-splitting values in ions with small n uclear charge.