In this paper a complete scheme for calculating ionization cross sections for molecular targets is given, and for the first time the cross sections for the e++H2 to e++e-+H2+ processes are calculated in the energy region 30-200 eV using the CPT model. The results show some conformity with recent experimental data.

A formulation for calculating the distorted-wave Born approximation cross sections for both atomic and molecular ionizations using the partial-wave-expansion method is introduced. The ionization cross sections of molecular and atomic hydrogen target with positron impact are calculated in the intermediate collision velocity region with this formulation. The results are compared to the updated experiment data. This comparison has offered an alternative evaluation for the present model of ionization process.PACS number (s): 34.50.Fa, 34.50.Gb, 34.90.+q Measurements of the positron-impact ionization of molecular hydrogen and atomic hydrogen have been reported by Raith and co-workers [1,2] in recent years. The theoretical treatments with respect of atomic hydrogen target include the quantum-mechanical calculations of