Relativistic many-body calculations of energies for core-excited states   in sodiumlike ions
  Energies of (2s2 2p5 3l3l') and (2s 2p6 3l3l') states for sodiumlike ions with Z =14--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 lowest order. The Lamb shift correction to energies is also included in 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. 
U.I. Safronova, W. R. Johnson, M.S. Safronova, and J. R. Albritton