Calculation of electron scattering from the metastable states of helium

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Abstract
We present the first application of the CCC method to electron scattering from the metastable 23,1S states of helium at energies of 35.2, 40 and 50 eV relative to the ground state. Due to unitarity of the close-coupling formalism the reliability of the e-He(23,1S) results may be tested not only by comparison with available e-He(23,1S) experimental data, but also by comparing with the e-He(11S) results arising from the same calculation with appropriate experiments. In the case of electron-impact ionization of He(23S), we find that the CCC results are in quantitative agreement with the ionization spin asymmetries, but are almost a factor of two lower than the total ionization cross section measurements. However, the corresponding total ionization cross sections from the ground state are also in quantitative agreement with experiment. Agreement with available differential cross section measurements is only fair.