A generalized Kohn-Sham theory for low-energy electron scattering by atoms including relativistic effects

Abstract

As has been shown in a recent study by one of the authors (L. F.), it is possible to cast the total energy E of an N-electron system in a form such that the equations to be obeyed by the one-particle states used in the CI-expansions of the N-electron function attain the Kohn-Sham form if E is required to be stationary against variation of Ψ. Hence, these Kohn-Sham-type equations apply to the ground state as well as to excited states, of which the (N + 1)-electron problem of electron scattering by atoms represents a special case. Once the calculational procedure is fixed, the new scheme is parameter-free and has been used to calculate elastic differential cross sections, scattering-induced electron polarization, and T- and U-parameters. In a previous study the scheme has successfully been applied to noble gases. The results presented here refer to open-shell as well as closed-shell target atoms like Na, K, Hg, Pb, and Bi. In either case we obtain good agreement with respective experiments for impact energies above 5 eV.