Elastic and inelastic scattering of electrons from potassium

We have examined elastic and inelastic scattering of electrons from potassium. For the case of elastic scattering, we have compared potential scattering theory and perturbation theory. If one wishes to use the potential scattering approach, it is shown that both the non-local effects of polarization and absorption must be properly modelled to get accurate elastic differential cross sections. The second-order distorted wave results For elastic scattering and excitation of the (4p) 2 P and (5p) 2 P states are compared with existing experimental data and a very recent close coupling calculation for energies between 7 and 100 eV.