ELECTRON-IMPACT EXCITATION FROM METASTABLE HELIUM - 2 S-1,S-3-]N (1,3)L (L=0, 1, 2 N=2, ... ,INFINITY)

Integral cross sections for electron-impact excitation from the helium 2 S-3 and 2 S-1 metastable excited states, to all energetically highe r S, P, and D excited states, are reported from threshold to 200 eV, T hese cross sections have been obtained using the distorted-wave approx imation. and are compared to other experimental and theoretical result s. Special attention is paid to obtaining an adequate representation f or the wave functions of the n S-1 excited states (n = 2, 3, and 4). T he total integral electronic excitation cross sections from each of th ese metastable states, summed over rr for fixed L of the final state, and then summed over L, are also reported. These results are combined with other cross-section data to obtain the total inelastic integral c ross section for inelastic electron scattering from each of these two helium metastable states.