K-shell photoionization of Nickel ions using R-matrix

TL;DR

This paper provides detailed R-matrix calculations of K-shell photoionization cross sections for nickel ions, including relativistic effects and damping, crucial for modeling photoionized plasmas.

Contribution

It offers the first comprehensive set of level- and term-resolved cross sections for nickel ions across multiple ionization stages, incorporating relativistic corrections and damping effects.

Findings

Damping effects smooth the K-edge profiles.

Relativistic corrections significantly impact cross sections.

Data aids in modeling photoionized plasma features.

Abstract

We present R-matrix calculations of photoabsorption and photoionization cross sections across the K edge of the Li-like to Ca-like ions stages of Ni. Level-resolved, Breit-Pauli calculations were performed for the Li-like to Na-like stages. Term-resolved calculations, which include the mass-velocity and Darwin relativistic corrections, were performed for the Mg-like to Ca-like ion stages. This data set is extended up to Fe-like Ni using the distorted wave approximation as implemented by AUTOSTRUCTURE. The R-matrix calculations include the effects of radiative and Auger dampings by means of an optical potential. The damping processes affect the absorption resonances converging to the K thresholds causing them to display symmetric profiles of constant width that smear the otherwise sharp edge at the K-shell photoionization threshold. These data are important for the modeling of features found in photoionized plasmas.