Electron-impact excitation of n < 2 levels of helium at intermediate energies

Five-state close-coupling equations for electron-helium scattering are solved in the energy region from 30 to 100 eV. Integral and differential cross sections for excitation of the ground state to the n < 2 states 2 3S, 2 1S, 2 3P0, and 2 1P0 are presented. Calculated shapes of differential cross sections versus angle for various energies are in fair agreement with measurements, but the magnitudes of the cross sections are overestimated. Allowance for coupling between 2 3S and 2 3P0 brings calculated differential cross sections into good quantitative agreement with experiment