Comparing self-consistent GW and vertex corrected G0W0 (G0W0{\Gamma}) accuracy for molecular ionization potentials

TL;DR

This study compares the accuracy of self-consistent GW and vertex corrected G0W0 methods for molecular ionization potentials, finding that self-consistent GW generally outperforms or matches vertex corrected approaches with more reliable predictions.

Contribution

The paper provides a comprehensive comparison of self-consistent GW and vertex corrected G0W0 methods, highlighting the advantages of self-consistent GW for molecular ionization potential predictions.

Findings

Self-consistent GW outperforms vertex corrected G0W0 in accuracy.

Vertex corrections increase computational cost without consistent accuracy gains.

Imaginary axis self-consistent GW with analytical continuation yields reliable IP spectra.

Abstract

We test the performance of self-consistent GW and several representative implementations of vertex corrected G0W0 (G0W0{\Gamma}). These approaches are tested on benchmark data sets covering full valence spectra (first ionization potentials and some inner valence shell excitations). For small molecules, when comparing against state of the art wave function techniques, our results show that performing full self-consistency in the GW scheme either systematically outperforms vertex corrected G0W0 or gives results of at least the same quality. Moreover, the G0W0{\Gamma} results in additional computational cost when compared to G0W0 or self-consistent GW and the G0W0{\Gamma} dependency on the starting mean-filed solution is frequently larger than the magnitude of the vertex correction. Consequently, for molecular systems self-consistent GW performed on imaginary axis and then followed by modern analytical continuation techniques offers a more reliable approach to make predictions of IP spectra.