Relativistic configuration-interaction calculation of energy levels of   core-excited states in lithium-like ions: argon through krypton
  Large-scale relativistic configuration-interaction calculation of energy levels of core-excited states of lithium-like ions is presented. Quantum electrodynamic, nuclear recoil, and frequency-dependent Breit corrections are included in the calculation. The approach is consistently applied for calculating all $n=2$ core-excited states for all lithium-like ions starting from argon ($Z = 18$) and ending with krypton ($Z = 36$). The results obtained are supplemented with systematical estimations of calculation errors and omitted effects. 
V. A. Yerokhin and A. Surzhykov
physics.atom-ph