Calculation of quasi-degenerate energy levels of two-electron ions

Accurate QED calculations of the interelectron interaction corrections for the $(1s2p)2 {}^1 P_1$, $(1s2p)2 {}^3 P_1$ two-electron configurations for ions with nuclear charge numbers $10\le Z \le 92$ are performed within the line profile approach. Total energies of these configurations are evaluated. Employing the fully relativistic treatment based on the {$j$--$j$} coupling scheme these energy levels become quasi-degenerate in the region $Z\le 40$. To treat such states within the framework of QED we utilize the line profile approach. The calculations are performed within the Coulomb gauge.Comment: 22 pages, 11 figure

Excited states of the helium-antihydrogen system

Potential energy curves for excited leptonic states of the helium-antihydrogen system are calculated within Ritz' variational approach. An explicitly correlated ansatz for the leptonic wave function is employed describing accurately the motion of the leptons (two electrons and positron) in the field of the helium nucleus and of the antiproton with arbitrary orbital angular momentum projection $\Lambda$ onto the internuclear axis. Results for $\Lambda$=0, 1 and 30 are presented. For quasibound states with large values of $\Lambda$ and rotational quantum numbers $J>\Lambda$ no annihilation and rearrangement decay channels occur, i. e. they are metastable

Asymmetry of the natural line profile for the hydrogen atom

The asymmetry of the natural line profile for transitions in hydrogen-like atoms is evaluated within a QED framework. For the Lyman-alpha $1s-2p$ absorption transition in neutral hydrogen this asymmetry results in an additional energy shift of 2.929856 Hz. For the $2s_{1/2}-2p_{3/2}$ transition it amounts to -1.512674 Hz. As a new feature this correction turns out to be process dependent. The quoted numbers refer to the Compton-scattering process.Comment: RevTex, 7 Latex pages, 1 figur