Relativistic many-body calculations of energies for core-excited states in sodiumlike ions

Energies of ${2s}^2{2p}^5{3l3l}^{\prime }$ and ${2s2p}^6{3l3l}^{\prime }$ states for sodiumlike ions with $Z=14\mathrm{}–100$ are evaluated to second order in relativistic many-body perturbation theory starting from a neonlike Dirac-Fock potential. Second-order Coulomb and Breit interactions are included. Correction for the frequency dependence of the Breit interaction is taken into account in the lowest order. The Lamb shift correction to energies is also included in the lowest order. Intrinsic particle-particle-hole contributions to energies are found to be 20–30 % of the sum of one- and two-body contributions. Comparisons are made with available experimental data. These calculations are presented as a theoretical benchmark for comparison with experiment and theory.