The GW compendium: A practical guide to theoretical photoemission spectroscopy

TL;DR

This paper provides a comprehensive, practical overview of the GW approximation in theoretical photoemission spectroscopy, covering its formal foundations, computational choices, and applications for newcomers and experts alike.

Contribution

It offers detailed guidance on performing GW calculations, discusses recent applications, and explores methods beyond conventional GW, serving as a practical resource for researchers in the field.

Findings

GW provides accurate charged excitation energies

Successful application to molecules and surfaces

Discussion of methods beyond standard GW

Abstract

The GW approximation in electronic structure theory has become a widespread tool for predicting electronic excitations in chemical compounds and materials. In the realm of theoretical spectroscopy, the GW method provides access to charged excitations as measured in direct or inverse photoemission spectroscopy. The number of GW calculations in the past two decades has exploded with increased computing power and modern codes. The success of GW can be attributed to many factors: favorable scaling with respect to system size, a formal interpretation for charged excitation energies, the importance of dynamical screening in real systems, and its practical combination with other theories. In this review, we provide an overview of these formal and practical considerations. We expand, in detail, on the choices presented to the scientist performing GW calculations for the first time. We also give an introduction to the many-body theory behind GW, a review of modern applications like molecules and surfaces, and a perspective on methods which go beyond conventional GW calculations. This review addresses chemists, physicists and material scientists with an interest in theoretical spectroscopy. It is intended for newcomers to GW calculations but can also serve as an alternative perspective for experts and an up-to-date source of computational techniques.