Positron-impact ionization of molecular hydrogen

Two ionization models containing realistic descriptions of the final state of the system, but employing only plane and Coulomb waves, are applied to positron ionization of molecular hydrogen. In addition, spherically averaged H2 wavefunctions are used to simplify the complexity of the molecular geometry. The theoretical cross sections are compared with the measurements of Fromme et al and Moxom et al. The agreement between the experiment of Moxom et al and the CPE model with a reasonably accurate H2 representation is similar to the agreement shown by Campeanu et al for positron ionization of noble gases. These results suggest that relatively accurate spherical representations of the molecular wavefunction can be used successfully in distorted-wave calculations of positron-impact ionization of molecular targets. (author)