Single and double ionization ofH2byHe2+

Cross sections for the nondissociative single ionization and double ionization of ${\mathrm{H}}_2$ by ${\mathrm{He}}^{2+}$ projectiles in the range of 125–750 keV/amu are reported. The results are compared to impact-parameter calculations and to measurements with ${\mathrm{He}}^{+}$ projectiles. The direct double-collision process is found to be the important contributor to double ionization in this range of energies. The single-ionization cross section, when compared to proton bombardment, does not scale as ${\mathit{Z}}^2$.