Electron-impact excitation of highly charged berylliumlike ions with inclusion of configuration mixing

Abstract

Electron-impact scaled collisions strengths $Z^2\Omega$ for a large number of transitions involving configuration-mixed initial and/or final states are obtained for berylliumlike ions in the limit $Z\to \infty$. These results are compared with the corresponding non-configuration-mixed results. It is found that the effect of configuration mixing is usually small (≲30%) and nearly independent of impact electron energy, but in a very few cases it is large, resulting in a change in $\Omega$ by about a factor of 2. The results are expected to be of interest for applications to high-temperature plasmas containing moderately heavy elements.