Double electron excitation of helium by charged particle impact

A four-body classical trajectory Monte Carlo method is applied in the study of double electron (2s2, 2s2p and 2p2) excitation of helium by charged particle impact. The calculations are based on the independent particle model. As projectiles we consider protons and antiprotons with energies between 0.25 and 5 MeV. The state selective total cross sections are calculated as a function of the impact energy and compared with experimental and theoretical data.