Optical-potential study of electron-hydrogen scattering at intermediate energies.

Abstract

Electron-hydrogen scattering is studied in the range of incident energies from 12 to 100 eV. The equations resulting from a six-state close-coupling expansion are supplemented by an optical potential to represent contributions from states not explicitly considered. The optical potential is evaluated through the use of a pseudostate expansion. Solutions are obtained by a linear algebraic integral equation method. Results are presented for elastic scattering and total cross sections for initial 1s, 2s, and 2p states. All 1s\ensuremath{\rightarrow}n=2, 1s\ensuremath{\rightarrow}n=3, and n=2\ensuremath{\rightarrow}n=3 excitation cross sections are computed. Particular attention is given to obtaining convergence of sums with respect to the total angular momenta. Analytic formulas are given for the energy dependence of the cross sections from least-squares fits. Effective collision strengths are determined by averaging over a thermal distribution of incident electron energies.