The total cross section and the single-differential cross section in energy for the ionization of the ground-state helium atom by electron impact have been calculated in distorted-wave approximations. The optical potential, or self-energy of the single-particle Green’s function, was used to investigate effects of electron correlations in the initial state. Our results are compared with the results of experiments and other calculations.

• Received 25 May 1989

DOI:https://doi.org/10.1103/PhysRevA.41.3624