Momentum spectroscopy of electrons lost by light projectiles in collisionswith neon targets - art. no. 022714

Absolute doubly differential electron-loss cross sections were measured for H-0, H-2(+), D-0, D-2(+), He-0, and He+ on neon at 0.1 and 0.5 MeV/amu in order to investigate the velocity dependence and any projectile dependence of the electron spectra. An additional measurement of target ionization in 0.1 MeV/amu Ne-0+He collisions in comparison with electron loss from 0.1 Me V/amu He-0+Ne was aimed at testing the method of "inverse kinematics" for a collision system where the electron angular distribution is dominated by a distinct Ramsauer-Townsend minimum. The measured absolute singly different ial cross sections, transformed to the neon frame of reference, agree well over the whole angular range (0 degrees-180 degrees), thereby establishing this as a useful method when high-energy beams of a particular projectile a re not readily available. Calculations using both the on-shell and off-shel l version of the electron impact approximation show that the quasielastic s cattering theory is rather poor at such low collision velocities, but never theless reveal the importance of doubly inelastic processes in the case of both He-0 and He+ ionization. Satisfactory agreement between theory and exp eriment was obtained at the higher velocity. The H-2(+) and D-2(+) results show evidence of molecular effects.