Dispersion-equation approach to obtaining complex optical potentials for electron scattering

The absorption part of a local optical potential for electron-He scattering is obtained from an energy-dependent polarization potential by numerically solving the dispersion relation relating the real and imaginary parts of the optical potential. The resulting optical model, with no empirical parameters, yields reasonably accurate total scattering cross sections for elastic plus inelastic scattering at impact energies in the 30–100 eV range.