Ionisation of Mg+, Ca+ and Sr+ due to electron impact

Electron impact ionisation cross sections for Mg(+), Ca(+) and Sr(+) have been calculated in the binary encounter approximation. The contributions of the excitation-autoionisation process have been included in the present work. Hartree-Fock velocity distributions for the bound electrons have been used throughout the calculations. The present calculations give a good account of the experimental observations.