Excitation in electron−metastable helium collisions

The 21,3P, 31,3S, 31,3P, 31,3D and 41,3P excitations arising from e−He(21,3S) collisions are examined by application of the Born and of the Vainshtein, Presnyakov, and Sobel’man approximations. Total excitation cross sections are calculated for the above transitions for electron impact energy E up to 500 eV. Contrary to expectation, excitation to the 31,3D and 31,3S states dominate the 31,3P and 41,3P excitations except at incident energies above 100 eV.