New approaches to the quantum-mechanical treatment of charge polarization in intermediate-energy electron scattering

Two new approaches to the inclusion of target charge-polarization effects in electron-scattering calculations are presented and tested. The first approach is an energy-dependent polarization potential based on an r-6 nonadiabatic correction to the adiabatic polarization potential. The second approach is a matrix effective potential which includes the nonadiabatic dynamics of the polarization effect at all r. The two approaches are tested by comparing them to accurate phase shifts and differential cross sections for electron-helium scattering for impact energies 12-- 400 eV