Electron-impact single ionization of Mg andAl+

Abstract

Theory and experiment are compared for the electron-impact single ionization of Mg and ${\text{Al}}^{+}$. Nonperturbative $R$ matrix with pseudostates (RMPS) and time-dependent close-coupling (TDCC) calculations have been carried out that exhibit large reductions from perturbative distorted-wave results of 38% for Mg and 20% for ${\text{Al}}^{+}$. Experimental single-ionization data available for Mg and ${\text{Al}}^{+}$ are in reasonable accord with distorted-wave data and lie substantially above the new theoretical results. Rate coefficients, necessary for the collisional-radiative modeling of Mg and Al plasmas were generated from the RMPS ionization cross sections. In the collisional-ionization region near the ionization threshold, the resulting rates were found to be up to two times lower for Mg and three times lower for ${\text{Al}}^{+}$ than the rates generated from experimental data.