Simple model of the static exchange-correlation kernel of a uniform electron gas with long-range electron-electron interaction

TL;DR

This paper proposes a simple, approximate static exchange-correlation kernel for a uniform electron gas with long-range Coulomb interaction, useful for improving density functional theory calculations by separating long- and short-range effects.

Contribution

It introduces a new approximate kernel that interpolates between known asymptotic behaviors and incorporates G0W0 data, enhancing correlation models in electronic structure methods.

Findings

Kernel accurately interpolates between small and large wave vectors.

More local than traditional Coulombic kernel, suitable for DFT approximations.

Potential to improve adiabatic connection fluctuation-dissipation methods.

Abstract

A simple approximate expression in real and reciprocal spaces is given for the static exchange-correlation kernel of a uniform electron gas interacting with the long-range part only of the Coulomb interaction. This expression interpolates between the exact asymptotic behaviors of this kernel at small and large wave vectors which in turn requires, among other thing, information from the momentum distribution of the uniform electron gas with the same interaction that have been calculated in the G0W0 approximation. This exchange-correlation kernel as well as its complement analogue associated to the short-range part of the Coulomb interaction are more local than the Coulombic exchange-correlation kernel and constitute potential ingredients in approximations for recent adiabatic connection fluctuation-dissipation and/or density functional theory approaches of the electronic correlation problem based on a separate treatment of long-range and short-range interaction effects.