Calculation of quasidegenerate energy levels of two-electron ions

Abstract

Accurate QED calculations of the interelectron interaction corrections for the $(1s2p){2}^{1}{P}_{1}$ and $(1s2p){2}^{3}{P}_{1}$ two-electron configurations for ions with nuclear charge numbers $10\ensuremath{\leqslant}Z\ensuremath{\leqslant}92$ are performed within the line profile approach. Total energies of these configurations are evaluated. Employing the fully relativistic treatment based on the $j\ensuremath{-}j$ coupling scheme these energy levels become quasidegenerate in the region $Z\ensuremath{\leqslant}40$. To treat such states within the framework of QED we utilize the line profile approach. The calculations are performed within the Coulomb gauge.