The electron impact ionization of one- and two-electron atoms and ions close to the ionization threshold

Abstract

We present triple differential cross-sections for the electron impact ionization of hydrogen and helium in energy sharing coplanar constant Θ12 = 180° and coplanar energy sharing perpendicular plane geometries at impact energies of a few eV's above ionization threshold. We investigate the role of incident channel effects in determining the shape of the cross-section. We present cross-sections in the same geometries for the isoelectronic sequence of hydrogenic and helium-like ions with nuclear charges up to Z = 10.