W. Wu et al., EXPERIMENTAL SEPARATION OF ELECTRON-ELECTRON AND ELECTRON-NUCLEAR CONTRIBUTIONS TO IONIZATION OF FAST HYDROGENLIKE IONS COLLIDING WITH HE, Physical review letters, 72(20), 1994, pp. 3170-3173
Recoil momentum spectroscopy has been used to distinguish experimental
ly between contributions to the ionization of hydrogenlike O and F pro
jectiles from interactions with the electrons and with the nucleus of
a target He atom. The electron-electron contribution is separated from
the nuclear one in the final momentum space of the recoil He ion, and
is found to produce much smaller recoil momenta, both transverse and
longitudinal, than the nuclear process. The relative contributions of
the two mechanisms are consistent with theoretical expectations.