Single-electron ionisation of helium by anti-proton and proton impact

Abstract

Single-electron ionisation of He by 200 keV and 500 keV anti-proton and proton impact is studied. Single differential cross sections as a function of the energy and angle of the ejected electron and total cross sections are calculated with the continuum distorted-wave-eikonal initial-state model. Present results are compared with calculations performed with the classical trajectory Monte Carlo method and with experimental data for proton impact. A very good agreement is obtained with experiments and predicted differences between anti-proton and proton results are confirmed but of smaller magnitude.