In a previous paper [Bhatia and Temkin, Phys. Rev. A $64,$ 032709-1 (2001)], electron-hydrogen S-wave scattering phase shifts were calculated using the optical potential approach. This method is now extended to the singlet and triplet electron-${\mathrm{He}}^{+}$ scattering in the elastic region. Phase shifts are calculated using Hylleraas-type correlation functions with up to 95 terms. Results are rigorous lower bounds to the exact phase shifts.

• Received 9 August 2002

DOI:https://doi.org/10.1103/PhysRevA.66.064702