R-matrix electron-impact excitation data for the Li-like iso-electronic sequence including Auger and radiation damping^⋆

G. Y. Liang and N. R. Badnell

Department of PhysicsUniversity of Strathclyde, Glasgow, G4 0NG, UK
e-mail: guiyun.liang@strath.ac.uk

Received: 28 December 2010
Accepted: 27 January 2011

Abstract

We present results for the electron-impact excitation of all Li-like ions from Be⁺ to Kr³³⁺ which we obtained using the radiation- and Auger-damped intermediate-coupling frame transformation R-matrix approach. We have included both valence- and core-electron excitations up to the 1s²5l and 1s2l4l′ levels, respectively. A detailed comparison of the target structure and collision data has been made for four specific ions (O⁵⁺, Ar¹⁵⁺, Fe²³⁺ and Kr³³⁺) spanning the sequence so as to assess the accuracy for the entire sequence. Effective collision strengths (Υs) are presented at temperatures ranging from 2 × 10²(z + 1)² K to 2 × 10⁶(z + 1)² K (where z is the residual charge of the ions, i.e. Z − 3). Detailed comparisons for the Υs are made with the results of previous calculations for several ions which span the sequence. The radiation and Auger damping effects were explored for core-excitations along the iso-electronic sequence. Furthermore, we examined the iso-electronic trends of effective collision strengths as a function of temperature.