R-matrix Electron-impact Excitation Data for the H- and He-like Ions with Z = 6−30

Abstract

Abstract Plasma models built on extensive atomic data are essential to interpreting 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). A 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 the literature to assess the quality of the new data, which are relevant for current and future high-resolution X-ray spectrometers.