Elastic scattering of electrons by hydrogen and helium atoms

Abstract

A recently developed theory of electron scattering by complex atoms based upon the R matrix method, is used to calculate the elastic scattering of electrons by hydrogen and helium atoms. Phase shifts for e--H scattering are obtained in the static approximation and also allowing for the atomic polarizability using the pseudo-state method. Phase shifts for e--He scattering are obtained using both a Hartree-Fock and a correlated target wavefunction. A discussion is given of why a low energy e--He resonance does not occur in the latter approximation and why probably one does not exist. Finally, the dependence of the phase shift on the number of basis states included in the expansion of the total wavefunction is discussed and a pseudo-potential method is introduced to obtain rapid convergence.