biostudies-literatureTal ASNF | Swiss National Centre of Competence in Research Kidney Control of Homeostasis (NCCR Kidney.CH)SNF | Swiss National Centre of Competence in Research Kidney Control of Homeostasise2311472121https://www.ebi.ac.uk/biostudies/studies/S-EPMC10927489biostudies-literatureUnknown121(10)We demonstrate the importance of addressing the Γ vertex and thus going beyond the <i>GW</i> approximation for achieving the energy levels of liquid water in many-body perturbation theory. In particular, we consider an effective vertex function in both the polarizability and the self-energy, which does not produce any computational overhead compared with the <i>GW</i> approximation. We yield the band gap, the ionization potential, and the electron affinity in good agreement with experiment and with a hybrid functional description. The achieved electronic structure and dielectric screening further lead to a good description of the optical absorption spectrum, as obtained through the solution of the Bethe-Salpeter equation. In particular, the experimental peak position of the exciton is accurately reproduced.Proceedings of the National Academy of Sciences of the United States of AmericaAbsolute energy levels of liquid water from many-body perturbation theory with effective vertex corrections.PMC10927489200020-172524Pasquarello ABischoff TTal AfalseAbsolute energy levels of liquid water from many-body perturbation theory with effective vertex corrections.We demonstrate the importance of addressing the Γ vertex and thus going beyond the <i>GW</i> approximation for achieving the energy levels of liquid water in many-body perturbation theory. In particular, we consider an effective vertex function in both the polarizability and the self-energy, which does not produce any computational overhead compared with the <i>GW</i> approximation. We yield the band gap, the ionization potential, and the electron affinity in good agreement with experiment and with a hybrid functional description. The achieved electronic structure and dielectric screening further lead to a good description of the optical absorption spectrum, as obtained through the solution of the Bethe-Salpeter equation. In particular, the experimental peak position of the exciton is accurately reproduced.2024-01-01T00:00:00Z2024 Mar2025-04-26T21:21:05.861Z2025-04-06T16:45:16.216ZS-EPMC109274893842760410.1073/pnas.2311472121