Asymptotically-correct distorted-wave calculations for low-energy electron-impact ionization of helium

Recently, inclusion of the final-state electron-electron interaction in the distorted-wave Born approximation was accomplished. The three-body distorted-wave Born approximation (3DWBA) includes the short-range static electron-target interactions for both initial-and final-state wavefunctions that satisfy the correct asymptotic boundary condition. It was shown that the 3DWBA gives a good description of ionization in coplanar asymmetric geometry for the intermediate-energy range (incident-electron energies from 5 to 20 times the ionization energy). Here we apply the theory to low-energy collisions (2 to 5 times the ionization energy).