Importance of Pauli-principle restrictions for accurate numerical evaluation of the exchange-only screening function

Abstract

It is shown how the Pauli-principle restrictions eliminate the need for a Cauchy principal-part interpretation of the integral representation for the wave-vector-dependent exchange contribution to the static screening function of an electron gas. This modified expression is accurately evaluated, removing the anomalous behavior obtained by Antoniewicz and Kleinman, while confirming their conclusion regarding the coefficient of the gradient expansion for exchange-only density-functional theory.