The elastic scattering of electrons from inert gases. I. Helium

The R-matrix calculations of O'Malley et al. (1979) are simplified and extended to the intermediate impact energy range in which the He ground-state wavefunction is coupled with a 1 P pseudo-state to include the full static dipole polarisability. Phaseshifts, differential, integrated and momentum transfer cross sections for electrons elastically scattered from helium are reported for the impact energy range of 5 to 200 eV. At low energies the present calculation essentially reproduces the results of O'Malley et al. (1979) for 5<or=E<or=16.5 eV. At intermediate energies good agreement between the present calculations and the most recent measurements is observed.