The effect of target representation in positron-impact ionization of molecular hydrogen

Ionization cross sections for positron collisions with hydrogen molecules have been calculated using a two-center molecular representation. The results are compared with our previous work which used sphericaly averaged H₂ wavefunctions as well as with existing experimental results. The use of a two-centre wave function for the molecular target, either of the Heitler–London type or a Gaussian representation, produces results which lie between the two most recent sets of experimental data. We find that our CPE4 model produces results in better agreement with experiment over the whole energy range than our CPE model.