摘要
Single differential and total cross sections of the electron-impact ionization of the hydrogen atom are calculated numerically in the two-potential distorted-wave approximation for excess energies from 0 to 1 eV. Partial-wave contributions to the cross sections are also investigated. The near-threshold cross section is parametrized by the power gamma and the proportionality constant a 0 for models with various asymptotic charges, and the dependence of a 0 on the asymptotic charge is studied. The validity range of the threshold power law is also discussed. © 1994 IOP Publishing Ltd.