Abstract
The authors report a sequence of configuration interaction calculations of the oscillator strength for the 2s22p5 2Po-2s2p6 2Se transition in Ne II and Mg IV. They obtain 0.096+or-0.005 for Ne II, which is 25% larger than the experimental values, and 0.089+or-0.005 for Mg IV. The good agreement between some previous calculations and experiment for Ne II was due to the neglect of external correlation in the earlier work. They have also calculated oscillator strengths for the 2s22p5-2s22p43s 2Pe, 2De and 2Se transitions in Ne II, obtaining 0.11, 0.063 and 0.0058 respectively. The experimental values for the 2Po-2s22p43s 2Se line are almost a factor of two larger than theory.