On electronic interactions in the free-electron model including exchange

Abstract

We have investigated the concept of electronic screening from the standpoint of achieving a uniform and consistent interpretation for the purpose of providing a technique for dealing, in first approximation at least, with the effects of electronic interactions while retaining the relative simplicity of the one-electron picture and, in particular, the plane-wave approximation to the Hartree-Fock solutions. Our study has led us to conjecture that a consistent interpretation of the screening term may be found in its use as a variational function along the lines of the calculation by Macke. Also, we have been led to hypothesize the existence of a uniform screening function to be employed in the calculations using plane-wave determinants of all off-diagonal Coulomb matrix elements occurring in probability coefficients of wave expansions or in transition probabilities