Electron-impact ionization of Al$^{2+}$ and Al

Electron-impact ionization cross sections are calculated for Al$^{2+}$ and Al. The non-perturbative R-Matrix with PseudoStates (RMPS) method was used to calculate the direct ionization of the 3s and 2p subshells and the indirect ionization of the 2p subshell for Al$^{2+}$ in a single, comprehensive calculation. This model agrees well with the experimental measurement of Thomason and Peart [1]. For Al, the RMPS and time-dependent close coupling methods are used to calculate cross sections for incident energies ranging from 5 to 30 eV. The non-perturbative close-coupling methods are found to be substantially lower than the perturbative distorted-wave cross sections due to electron correlation effects in both the direct ionization and indirect excitation-autoioniozation contributions. In addition, the close-coupling cross sections are found to be in good agreement with experiment [2]. \\[4pt] [1] J. W. Thomason and B. Peart J Phys B {\bf 31} L 201 (1998)\\[0pt] [2] R. S. Freund et al Phys. Rev. A {\bf 41} 3575 (1990)