Comments on the Dielectric Function of Toigo and Woodruff

Abstract

The approximation to the electron-gas dielectric function recently proposed by Toigo and Woodruff is examined and found to differ from the known Hartree-Fock result in the limit of zero frequency and large wave number. It is shown that Toigo and Woodruff erred in evaluating this limit; the correct expression for it is obtained and two incorrect conclusions drawn from the erroneous result are corrected.