Excitation cross sections ofe−+He→e−+He(3P1,4P1)and the polarization of the 5016-Å helium line resulting frome−−Hescattering in Glauber theory

Abstract

The recently derived generating function $I_p({\lambda }_1,{\lambda }_2;q)$ in the Glauber amplitude for $2{}_{}{}^1{}_{}{}^{}P$ excitation of He by electron impact is used to evaluate the cross sections for the $3{}_{}{}^1{}_{}{}^{}P$ and $4{}_{}{}^1{}_{}{}^{}P$ excitations of He by electron impact with incident energies from 50 to 1000 eV. Comparison is made with the Bethe approximation, the Born approximation, and the classical theory of Gryzinski. The theoretical results for the total excitation cross sections are in reasonable agreement with the experimental data. The positions of the peak values for the total cross section for both cases are found to be around 100 eV, which are consistent with the existing experimental findings. The $n^{-3\mathrm{}}$ rule is also briefly discussed. The polarization fraction of the 5016-Å helium line emitted in $e^{-}+\mathrm{He}$ collisions is also calculated in the Glauber approximation. The theoretical results for the polarization fraction are in reasonable agreement with the existing experimental data in the energy range $50<\mathrm{}{E}_a<1000\mathrm{}$ eV.