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 $r^{-6\mathrm{}}$ 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.