H

H+ impact single and He2+ impact single and double electron capture cross sections of magnesium atoms have been calculated in the modified binary encounter approximation (BEA). The accurate expressions of ion impact $\sigma _{\Delta {E}}$ (cross section for energy transfer $\Delta E$) and Hartree-Fock momentum distributions of the target electrons have been used throughout the calculations. On the basis of the present work it is concluded that inner shell captures by H+ and He2+ ions incident on magnesium atoms contribute partly to single electron capture and partly to transfer ionization cross sections. The calculated He2+ impact double electron capture cross sections of magnesium are in reasonably good agreement with the experimental observations. This indicates the success of the present theoretical approach in study of charge transfer cross sections of atoms as indirect mechanisms do not interfere with double electron capture processes in this case