Close-coupling approach to positron scattering from potassium

Abstract
Close-coupling cross sections are calculated for e+-K scattering in the energy range 4-50 eV using two-, four- and five-state close-coupling expansions. Model potential wavefunctions are used for the target states. The total cross section is in good agreement with experimental results which exist for the energy range 7.9 -98.5 eV. The authors have also performed a two-state close-coupling calculation using numerical frozen-core Hartree-Fock wavefunctions. The total cross section calculated with these wavefunctions is larger by between 16 and 28% than that calculated with model potential wavefunctions. This indicates that valence-core correlation as well as the distortion of the core has a substantial effect on the scattering results.