A Guide to Molecular Properties from the Bethe-Salpeter Equation

TL;DR

This paper reviews how the GW-BSE method, originally used for excitation spectra, can be extended as a general framework for calculating various molecular properties, offering a cost-effective alternative to traditional methods.

Contribution

It summarizes recent theoretical and practical developments in applying GW-BSE beyond excitation energies, providing guidelines for future applications in chemistry and materials science.

Findings

GW-BSE accurately describes charge-transfer and Rydberg excitations.

Recent advances extend GW-BSE to broader molecular properties.

Guidelines facilitate collaboration with experimentalists.

Abstract

The Bethe-Salpeter equation (BSE) combined with the Green's function GW method has successfully transformed into a robust computational tool to describe light-matter interactions and excitation spectra for molecules, solids, and materials from first principles. Thanks to its ability to accurately describe charge-transfer and Rydberg excitations, the GW-BSE already forms an established and cost-efficient alternative to time-dependent density functional theory. This raises the question whether the GW-BSE approach can become a more general framework for molecular properties beyond excitation energies. In this mini-review, we recapitulate recent endeavors along this point in terms of both theoretical and practical developments for quantum chemistry, physical chemistry, and related fields. In doing so, we provide guidelines for current applications to chemical challenges in collaboration with experimentalists as well as to future developments to extended the GW-BSE toolkit.