Electron excitation of the 1s²2s²2p⁵²Po3/2-²Po1/2transition and analysis of the 1s²2s2p⁶nl resonances for Ne II and Mg IV

The author has calculated collision strengths for electron excitation of the 1s 2 2s 2 2p 5 2 P o 3/2 - 2 P o 1/2 transition in Ne II and Mg IV using the R-matrix method. The author has included the 1s 2 2s 2 2p 5 2 P o and 1s 2 2s2p 6 2 S e states, which were represented by sophisticated configuration interaction wavefunctions. Reactance matrices were obtained in LS coupling and transformed using JAJOM to give the fine-structure collision strengths. These have been averaged over a Maxwellian electron velocity distribution to give the effective collision strengths, which we have fitted as analytic functions of temperature between 0 and 40000 K. To estimate the accuracy of the results the author has calculated the positions and widths for the lower members of the 1s 2 2s2p 6 ns and 1s 2 2s2p 6 np resonance series. The results are in good agreement with experiment and with previous theory for both Ne II and Mg IV.