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Abstract

We have examined the fully differential cross section (FDCS) for single ionization of helium by a 2 MeV amu-1 C6+ ion. The FDCS is presented for a variety of momentum transfers and ejected electron energies. The theoretical model we use, labelled 3DW-EIS (three-body distorted wave—eikonal initial state), treats the collision as a three-body problem (projectile, active electron, residual ion). In the final state, each two-particle pair is treated exactly and the initial state is an eikonal state which contains the proper asymptotic forms of the projectile–target ion and projectile–electron interactions. Most importantly, the final state of the ejected electron is treated as a distorted wave calculated numerically from the static Hartree–Fock potential for the ion. Our theoretical results are compared with both absolute experimental measurements and previous theoretical calculations. It is shown that the 3DW-EIS results are in good agreement with experiment for all cases except large momentum transfer and low ejected-electron energies.