Intermediate-coupling collision strengths for fine-structure transitions betweenSandPlevels andSandDlevels in highly charged He-like ions

Abstract

A method for obtaining scaled collision strengths $Z^2\Omega$ for highly charged ions in terms of scaled results for hydrogenic ions with $Z=\infty$ is modified by a perturbation theory approach to include the major relativistic corrections. The results are then expected to provide useful estimates for ions with $Z$ in the range $3N\lesssim Z\lesssim 50$, where $N$ is the number of bound electrons per ion. Cases in which the modified approach simplifies are considered and numerical results are given for intermediate-coupling fine-structure transitions in highly charged He-like ions involving transitions between $S$ and $P$ levels and between $S$ and $D$ levels with $n\le 5$ for six or more energies. Some comparison is made with previous results of Jones.