The use of second order potentials in the theory of the scattering of charged particles by atoms. IV. Electron scattering of helium atoms

Abstract
For pt. III see abstr. A83212 of 1972. The method of paper I (see abstr. A24375 of 1972) is applied to the scattering by helium atoms of electrons between 50 and 1000 eV, and results are presented for elastic scattering and the 21S and 21P excitation. It is found that the inclusion of second order potential terms leads to cross sections which are in significantly better agreement with the experimental data than those of previous calculations.