An improved exchange-correlation potential for polarizability and dissociation in DFT

TL;DR

This paper introduces a new exchange-correlation potential in density functional theory that improves the modeling of polarizabilities and dissociation processes, especially in electric fields, by focusing on the scalar part of the VK response potential.

Contribution

It presents a novel scalar response potential that enhances ground-state property predictions and dissociation behavior in DFT calculations.

Findings

Improved polarizability predictions for H2 chain.

Correct dissociation of open-shell fragments in electric fields.

Better ground-state properties over traditional functionals.

Abstract

We propose a novel approach to the problem of polarizabilities and dissociation in electric fields from the static limit of the Vignale-Kohn (VK) functional. We consider the response to the purely scalar part of the VK response potential.This potential has ground-state properties that notably improve over the full VK response density and over usual (semi-)local functionals. The correct qualitative behavior of our potentials means that it is expected to work well for polarizabilities in cases such as the H$_2$ chain, and it will also correctly dissociate open-shell fragments in a field.