TEST OF LOCAL MODEL POTENTIALS FOR POSITRON SCATTERING FROM RARE-GASES

We report calculations of differential and integral cross sections for positron (e+) scattering from He, Ne, Ar, Kr, and Xe rare gases. An o ptical-potential approach is employed in which the repulsive Coulombic interaction is calculated exactly at the Hartree-Fock level and the a ttractive polarization and correlation effects are included via a mode l potential determined from the use of a local density-functional theo ry (DFT). These model calculations are further compared with the resul ts from two other local potentials, one based on determining the short -range correlation energy, E(C), for a positron in an homogeneous elec tron gas and the other from the correlation-polarization potential of an electron interacting with a free-electron gas. We found that the pr esent DFT-based, correlation-polarization treatment is fairly simple t o implement computationally and appears to be the most accurate of all the models examined here. Our results are in fact compared with recen t measurements of differential and integral cross sections for positro n scattering with rare gases and are found to be remarkably close to b oth sets of experiments.