Response potential in the strong-interaction limit of DFT: Analysis and comparison with the coupling-constant average

TL;DR

This paper investigates the response potential in the strong-interaction limit of density functional theory, analyzing its features and comparing it with the coupling-constant averaged response potential across different molecular systems.

Contribution

It provides a detailed analysis of the response potential in the strong-coupling limit and introduces a simple model to derive exact properties, revealing key features of the Kohn-Sham potential.

Findings

Response potential exhibits a second peak near the most electronegative atom.

Strong-coupling limit response potential differs significantly from the averaged response potential.

A simple 1D model captures essential features of the exact response potential.

Abstract

Using the formalism of the conditional amplitude, we study the response part of the exchange-correlation potential in the strong-coupling limit of density functional theory, analysing its peculiar features and comparing it with the response potential averaged over the coupling constant for small atoms and for the hydrogen molecule. We also use a simple one-dimensional model of a stretched heteronuclear molecule to derive exact properties of the response potential in the strong-coupling limit. The simplicity of the model allows us to unveil relevant features also of the exact Kohn-Sham potential and its different components, namely the appearance of a second peak in the correlation kinetic potential on the side of the most electronegative atom.