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+, C-2,C-3,C-4,C-5,C-6+, N-2,N-3,N-4,N-5+,N- O-2,O-3,O-4,O-5,O-6+, and Ar-3,Ar-4,Ar-5,Ar-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. (c) 2007 Elsevier B.V. All rights reserved.