Electron collisional excitation in F-like selenium

Abstract

Electron collisional excitation of the low-lying 1$s^2$2$s^2$2$p^5$ and 1$s^2$2s2$p^6$ states of F-like selenium to the singly excited M-shell states is studied using a relativistic distorted-wave model and multiconfigurational relativistic Hartree-Fock bound states. Results are presented for all 2-3 transitions from the low-lying 2$s^2$2$p^5$ ${}_{}{}^2{}_{}{}^{}\mathrm{P}_{3/2}^{}{}_{}{}^{}$ and ${}_{}{}^2{}_{}{}^{}\mathrm{P}_{1/2}^{}{}_{}{}^{}$ levels, and also the 2s2$p^6$ ${}_{}{}^2{}_{}{}^{}\mathrm{S}_{1/2}^{}{}_{}{}^{}$ level. We find a number of strong dipole-allowed 2p-3d cross sections with peak values near threshold in excess of ${10}^{\mathrm{-}20}$ ${\mathrm{cm}}^2$, and derive Gaunt factors which are in good agreement with values used in the literature (0.15–0.20) for most strong transitions.