Binding energies of the $1s^2\,2s\,2p\, ^3P_{0,2}$ states of berylliumlike xenon

Abstract

Binding energies of the $^3P_0$ and $^3P_2$ levels of the $1s^2\,2s\,2p$ electron configuration in berylliumlike xenon are rigorously evaluated using ab initio QED approach. All relevant one- and many-electron QED contributions are accounted for up to the second order of the perturbation theory. The interelectronic-interaction effects of the third and higher orders are considered within the Breit approximation. Nuclear recoil effect is taken into account as well. In addition, we study all possible levels of the configuration $1s^2\,2s\,2p$, namely $^1P_1$ and $^3P_{0,1,2}$, by means of the configuration-interaction Dirac-Fock-Sturm method in berylliumlike neon, iron, and xenon. In this case the QED effects are treated approximately within the model QED approach. The obtained theoretical predictions are compared with the results of previous relativistic calculations and high-precision measurements.