Theoretical Calculation of Differential Cross Section for e+-Ar and e--Ar Elastic Scattering

The differential cross sections for e--Ar and e+-Ar elastic scattering are calculated by relativistic partial wave expansion method. In the processes an incident particle (electron or positron) is treated as moving relativistically in an effective central potential. For electron-atom scattering, the effective potential is calculated by relativistic self-consistent-field (SCF) method with the Slater local exchange approximation. For the positron scattering, the effective potential is the electrostatic potential determined by the ground-state electron charge density calculated by the SCF method. For atomic target polarization due to the incident charge particle(electron or positron), the effect is treated approximately by adding a static polarization potential to the SCF potentials. The calculated results show that the polarization effect is very important for the low energy positron-atom scattering.