The ratioR i for nondissociative ionization of molecular hydrogen by antiproton/proton impact

The theoretical ratioRi of antiproton/proton cross sections for nondissociative ionization of hydrogen molecule has been obtained as a function of the impact energyE in the range 30⩽E⩽2500 KeV lab. The required cross sections were computed in the close-coupling formulation of the semiclassical impact parameter theory using a simple one-active electron model for the molecular target. The ratioRi is important for the analysis of the recent experimental data of Andersen et al. on antiproton scattering and the understanding of the collisional mechanisms in the KeV range.