Abstract
The classical trajectory Monte Carlo method (CTMC) has been used to calculate doubly differential ionised-electron cross sections for the impact of He2+ and H+ on He at collision energies of 50 and 100 keV amu-1. The results exhibit the capture to the continuum peak and agree in both shape and magnitude with experimental data. The dependence of the cross sections on the projectile charge ZP is analysed and it is found to be very asymmetric with regard to the capture to the continuum peak. This behaviour is in agreement with very recent experimental data. Large deviations from the Z2P scaling predicted by first-order theories are found at large ejection angles.