Energy and Angular Distribution of Electrons Ejected from Helium by Fast Protons and Electrons: Theory and Experiment

A comprehensive study of the angular and energy distributions of electrons ejected in collisions of fast electrons and protons with He is presented. New experimental results for 300-keV, 1-MeV, and 5-MeV proton impact are reported along with theoretical results for 2-keV electron impact and 100-keV, 300-keV, 1-MeV, and 5-MeV proton impact. The theoretical results, based upon Born approximation with Hartree-Slater initial discrete and final continuum wave functions, show excellent agreement with experimental electron-impact results. Serious discrepancies are found between theory and experiment in the angular distribution of ejected electrons for forward angles for 100- and 300-keV proton impact; the discrepancies decrease markedly for 1-MeV proton impact and are absent for 5-MeV protons. The agreement between theory and experiment for intermediate and backward angles of electron ejection, on the other hand, is uniformly good for all proton impact energies. The reasons for this behavior in terms of a charge-exchange process to a continuum state contributing to electron ejection at forward angles is discussed, and the energy dependence of the data is shown to be consistent with this explanation

Conductivity mechanism probed by ion transmission through nanocapillaries during the discharging process

L

Electron emission from metals induced by highly charged ions: effect of depht distribution of electron excitation on the emission properties

info:eu-repo/semantics/nonPublishe

Electron emission from below the surface induced by highly charged ions: effect of depth distribution of electron excitation

info:eu-repo/semantics/nonPublishe

Fragmentation of H2O molecules following the interaction with slow, highly charged Ne ions

International audienceWe measured the energy and angular distribution of fragment ions from collisions of 2–90 keV Neq+ ions (q = 1, 3, 5, 7 and 9) with H2O molecules. A strong dependence on the charge state of the incident ion was observed. The results are interpreted within the framework of a Coulomb explosion model. Deviations from this model in the energy and angular distribution of recoil ions are attributed to post-collision effects by the electric field of the projectile. Absolute cross sections for ion production were measured and found to be consistent with the cross sections calculated using the classical over-barrier model