Effect of Nonspherical Distorting Potentials in a First-Order Distorted-Wave Calculation

The first-order distorted-wave approximation (DWB1) has proved to be one of the most successful approaches for the theoretical calculation of electron-atom scattering. It is now evident that one must perform multistate close-coupling calculations or second-order perturbation calculations to improve significantly upon the DWB1, but these calculations require enormous computational efforts. Consequently, it is of interest to investigate the possibility of improving the standard DWB1. One such possibility that has not been investigated for electron-atom scattering is the use of realistic nonspherical distorting potentials. In this paper, the DWB1 formalism is presented for nonspherical distorting potentials, and the effects of such a potential are investigated for electron-impact excitation of the 2p state of hydrogen.