Infinite-Channel Close-Coupling Theory in the Second Born Approximation. I. Charge Polarization in the Elastic Electron Scattering from H and He

One of the oldest methods suggested for treating the effect of charge polarization on elastic scattering is revived by the use of certain physically reasonable assumptions, and is shown to lead to results, in the limit of small scattering angles and high incident energies, which are in quantitative agreement with experimental and theoretical expectations. The theory is worked out in detail for one- and two-electron atoms, and the extension to more complex systems is also discussed. The effect of charge polarization on the elastic differential cross section for 500-eV incident electrons on He is calculated and compared with the experimental results of Bromberg and the theoretical results of LaBahn and Callaway. The agreement is good over the angular range $0°\le \theta <6\mathrm{}°$ if exchange scattering contributions are included.