# Breit and QED contributions in atomic structure calculations of tungsten ions

## TL;DR

This paper compares different computational codes and methods for calculating atomic structures of tungsten ions, focusing on Breit and QED effects, to improve the accuracy of spectroscopic data interpretation.

## Contribution

It evaluates various approaches to include Breit and QED corrections in atomic calculations across multiple tungsten ion cases, highlighting their impact and uncertainties.

## Key findings

- Breit and QED effects significantly influence tungsten ion spectra.
- Different computational codes show consistent results within uncertainties.
- Electron correlation effects are comparable to Breit and QED contributions.

## Abstract

The FAC, GRASP2K, and MCDFGME codes are compared in three case study of radiative transitions occurring in tungsten ions: (i) Ni1 and Ni2 lines in Ni-like tungsten, (ii) $3p_{3/2}{-}3p_{1/2}$ fine splitting in Cl-like tungsten, and (iii) $K\alpha_{1}$ and $K\alpha_{2}$ lines in W VIII. Various approaches to including the Breit interaction term and QED corrections in atomic calculations are examined. Electron correlation effects are also investigated and compared to the Breit and QED contributions. The data presented here may be used to estimate theoretical uncertainties relevant to interpretation of high-resolution spectroscopic data.