2024-03-05 スイス連邦工科大学ローザンヌ校(EPFL)
Water molecules and electron density corresponding to the exciton state resulting from photon absorption. Credit: Krystian Tambur (background)/Alexey Tal (water molecules)
＜関連情報＞
- https://actu.epfl.ch/news/a-new-theoretical-development-clarifies-water-s-el/
- https://www.pnas.org/doi/10.1073/pnas.2311472121
有効頂点補正を用いた多体摂動論から、液体の水の絶対エネルギー準位を解明 Absolute energy levels of liquid water from many-body perturbation theory with effective vertex corrections
Alexey Tal, Thomas Bischoff, and Alfredo Pasquarello
Proceedings of the National Academy of Sciences Published:March 1, 2024
DOI:https://doi.org/10.1073/pnas.2311472121
Significance
The knowledge of the electronic structure of liquid water is essential for fundamental science and technology. However, state-of-the-art electronic-structure schemes have so far been unable to match experimental energy levels, by which severe ambiguities persist for the ionization potential and the electron affinity of liquid water. Here, it is shown that the consideration of a vertex function within many-body perturbation theory succeeds in producing photoemission and absorption spectra in excellent agreement with experiment on the absolute scale, overcoming this long standing issue.
Abstract
We demonstrate the importance of addressing the Γ vertex and thus going beyond the GW 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 GW 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.
