Confined Variational Calculations Of Low-Energy Electron-Helium Scattering

The S-, P-, and D-wave elastic scattering of electrons by atomic helium with the scattering energy between 0.136 and 16.463 eV is studied using the confined variational method. Our calculated phase shifts improve the best published results by at least one order of magnitude. The finite nuclear mass effect on the S-wave phase shift at very low scattering energy between 0.022 and 0.067 eV is investigated, and the accurate S-wave scattering length is determined to be 1.1723a(0,) where a(0) is the Bohr radius. The results reported here can serve as a benchmark for other theoretical and experimental studies.