Radiative transitions in Ne II and Mg IV

The authors report a sequence of configuration interaction calculations of the oscillator strength for the 2s 2 2p 5 2 P o -2s2p 6 2 S e 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 2s 2 2p 5 -2s 2 2p 4 3s 2 P e , 2 D e and 2 S e transitions in Ne II, obtaining 0.11, 0.063 and 0.0058 respectively. The experimental values for the 2 P o -2s 2 2p 4 3s 2 S e line are almost a factor of two larger than theory.