R-matrix electron-impact excitation data for the H- and He-like ions with Z=6-30

TL;DR

This paper provides a comprehensive set of electron-impact excitation data for H-like and He-like ions with atomic numbers 6 to 30, improving plasma diagnostics for astrophysical X-ray spectra.

Contribution

It introduces systematic R-matrix calculations for these ions, offering more accurate data than existing plasma codes and literature, aiding high-resolution X-ray spectroscopy.

Findings

New excitation data show differences with existing plasma codes.

Data are relevant for current and future X-ray spectrometers.

Improved atomic data enhances plasma diagnostic accuracy.

Abstract

Plasma models built on extensive atomic data are essential to interpreting the observed cosmic spectra. H-like Lyman series and He-like triplets observable in the X-ray band are powerful diagnostic lines to measure the physical properties of various types of astrophysical plasmas. Electron-impact excitation is a fundamental atomic process for the formation of H-like and He-like key diagnostic lines. Electron-impact excitation data adopted by the widely used plasma codes (AtomDB, CHIANTI, and SPEX) do not necessarily agree with each other. Here we present a systematic calculation of electron-impact excitation data of H-like and He-like ions with the atomic number Z=6-30 (i.e., C to Zn). Radiation damped R-matrix intermediate coupling frame transformation calculation was performed for each ion with configurations up to $n=6$. We compare the present work with the above three plasma codes and literature to assess the quality of the new data, which are relevant for current and future high-resolution X-ray spectrometers.