QED calculations of the $n=2$ to $n=1$ x-ray transition energies in middle-$Z$ heliumlike ions

TL;DR

This paper presents high-precision QED calculations of x-ray transition energies in heliumlike ions of various elements, combining rigorous quantum electrodynamics with correlation effects, and compares results with existing data.

Contribution

The study introduces a comprehensive ab initio QED approach for calculating x-ray transition energies in heliumlike ions, including higher-order correlation effects.

Findings

Calculated transition energies agree with experimental data within uncertainties.

Provided detailed binding energies for n=1 and n=2 states.

Enhanced accuracy over previous theoretical evaluations.

Abstract

Ab initio QED calculations of the four x-ray transitions from the $L$ to $K$ shell in heliumlike argon, titanium, iron, copper, and krypton are performed. The binding energies for all the $n=1$ and $n=2$ states are evaluated as well. The calculation approach combines the rigorous QED treatment in the first two orders of the perturbation theory constructed within the extended Furry picture with the third- and higher-order correlation effects evaluated in the Breit approximation. The obtained results are compared with the previous evaluations and available experimental data.