A multiconfigurational hybrid density-functional theory

TL;DR

This paper introduces a multiconfigurational hybrid density-functional theory that combines multiconfiguration self-consistent-field methods with density-functional approximations, effectively capturing static correlation effects better than traditional methods.

Contribution

It presents a new multiconfigurational hybrid density-functional approach that extends hybrid approximations by incorporating static correlation through a linear decomposition of electron-electron interaction.

Findings

A good bbbb value of 0.25 for bb improves results.

The method enhances accuracy for systems with strong static correlation.

Test cases include ozone reactions and diatomic molecule dissociation.

Abstract

We propose a multiconfigurational hybrid density-functional theory which rigorously combines a multiconfiguration self-consistent-field calculation with a density-functional approximation based on a linear decomposition of the electron-electron interaction. This gives a straightforward extension of the usual hybrid approximations by essentially adding a fraction \lambda of exact static correlation in addition to the fraction \lambda of exact exchange. Test calculations on the cycloaddition reactions of ozone with ethylene or acetylene and the dissociation of diatomic molecules with the Perdew-Burke-Ernzerhof (PBE) and Becke-Lee-Yang-Parr (BLYP) density functionals show that a good value of \lambda is 0.25, as in the usual hybrid approximations. The results suggest that the proposed multiconfigurational hybrid approximations can improve over usual density-functional calculations for situations with strong static correlation effects.