THE TOTAL CROSS-SECTION FOR ELECTRON-SCATTERING BY ATOMIC-HYDROGEN

The authors attempt to construct an accurate total cross section for e --H(1s) scattering in the intermediate energy range from 1.0 to 3.7 Ryd by adding together the best cross sections for elastic scattering, bound-state excitation and ionization that are presently available. For elastic scattering and n=2 excitation they have used the theoretical cross sections arising from intermediate energy R-matrix (IERM) calculations, for n=3 excitation experimental results have been implemented, while for excitation to n=4 and above an extrapolation procedure has been employed. For the ionization component the experimental cross section has been adopted. The constructed total cross section is found to be in very good agreement with the IERM theoretical total cross section obtained by applying the optical theorem to their elastic scattering amplitude. In addition, the authors have examined the accuracy with which the ionization cross section might be extracted from the total cross sections given the available knowledge about bound-state excitation cross sections.