Modified over-barrier model for ionization cross sections of atomic hydrogen by multiply charged ions

The impact ionization of atomic hydrogen in collisions with H+, He2+, Li2,3+Li2,3+, C2,3,4,5,6+C2,3,4,5,6+, N2,3,4,5+N2,3,4,5+, O2,3,4,5,6+O2,3,4,5,6+, and Ar3,4,5,6+Ar3,4,5,6+ ions has been studied by the modified over-barrier model at low-to-intermediate velocities. Compared with the calculated results of the classical trajectory Monte Carlo (CTMC) method and the unitarized-distorted-wave approximation (UDWA), this model satisfactorily reproduces the experimentally obtained velocity dependence of the absolute ionization cross sections at intermediate impact velocities.