水の電子構造を解明する新たな理論的展開(A new theoretical development clarifies water’s electronic structure)

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2024-03-05 スイス連邦工科大学ローザンヌ校(EPFL)

水の電子構造を解明する新たな理論的展開(A new theoretical development clarifies water’s electronic structure)Water molecules and electron density corresponding to the exciton state resulting from photon absorption. Credit: Krystian Tambur (background)/Alexey Tal (water molecules)

水は重要であることは疑いようがありません。生命は水なしでは始まらず、今日も続いていません。地球の70%以上を覆う海洋だけでなく、環境においても重要な役割を果たしています。しかし、液体水は電子の微妙な特性を持ち、これまで化学、物理、技術の科学者たちを長く困惑させてきました。水の電子構造に関する最新の研究では、高度な計算手法が用いられ、水の電子特性が正確に理解され、これが光と他の物質との相互作用を理解するための重要な基盤となっています。

<関連情報>

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.

1701物理及び化学
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