Electron-impact ionization ofW27+

Abstract

Electron-impact ionization cross sections for ${\mathrm{W}}^{27+}$ are calculated using a semirelativistic configuration-average distorted-wave (CADW) method. Calculations for direct ionization, excitation autoionization, and branching ratios are compared with recent calculations by Jonauskas et al. [Phys. Rev. A 91, 012715 (2015)], who used fully relativistic subconfiguration-average distorted-wave (SCADW) and level-to-level distorted-wave (LLDW) methods. Reasonable agreement is found between the CADW and the recent LLDW calculations for direct ionization of the $4l(l=0\char21{}1,3)$ subshells, but not the $4d$ subshell, and between the CADW and recent SCADW-LLDW calculations for excitation autoionization of the $4l(l=0\char21{}2)$ subshells. Reasonable agreement is also found between the CADW and the recent SCADW calculations, including branching ratios, but both differ from the recent LLDW calculations. Additional CADW calculations are made for excitation autoionization, including branching ratios involving the important $3l(l=1\char21{}2)$ subshells, not examined by Jonauskas et al. [Phys. Rev. A 91, 012715 (2015)].