Frequently Used References For Atomic Data In X-ray Spectroscopy

Abstract

Accurate atomic physics reference data are a crucial requirement for analysis and interpretation of observed spectra, even more so for observations with high spectral resolution. This document provides a curated list of atomic physics references frequently used for plasma diagnostics in X-ray spectroscopy, outside of comprehensive plasma models that typically come with their own underlying atomic databases. The list includes references to physical constants, laboratory benchmarks, transition energies, position and line shapes of neutral fluorescence lines, radiative branching ratios, and commonly used notation for prominent transitions. Quick-look tables for transition energies in H-, He-, and Li-like ions and line positions and shapes for fluorescence lines in neutrals. The main focus is on K-shell transitions. For the H- and He-like tables, we cite state-of-the art calculations that we consider currently the best available reference energies, which are considered high accuracy and thus typically used for energy scale calibration in laboratory measurements. Omissions in these tables are due to the lack of availability in the chosen references, and are not a statement about the relevance of these lines. Due to their complex and highly source-dependent line shape, the atomic data for neutrals is of lower accuracy than that for the highly charged ions, and the best reference data for these line shapes typically consist of empirical models derived from very high-resolution laboratory measurements. The table for neutrals provided here is consistent with the reference used for the energy gain scale calibration of XRISM/Resolve. This document is meant to serve as a resource to help find relevant references and conveniently formatted overview tables. When making use of the information found in these papers, credit should be given to their original authors by citing the appropriate references.