Asymptoticaljy-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 (jdwba) includes the short-range static electron-target interactions for both initial- and Bnal-state wavefunctions that satisfy the correct asymptotic boundary condition. It was shown that the jdwba gives a good description of ionization in coplanar asymmetric geometry for the intcrmediate-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).