Calculation of Total Cross Section for Positron Scattering on Helium

Total scattering cross sections for positron scattering on helium are calculated at intermediate energies and compared with experimental measurements. The method used is the coupled-channels-optical method with an ab initio complex polarization potential, which takes all channels into account. Calculated results show that the ionization continuum and positronium formation rearrangment channels are very important parts in total scattering cross section of positron-helium collision.