Riera Marc, Lambros Eleftherios, Nguyen Thuong T, Götz Andreas W, Paesani Francesco
Department of Chemistry and Biochemistry , University of California , San Diego , La Jolla , California 92093 , USA.
San Diego Supercomputer Center , University of California , San Diego , La Jolla , California 92093 , USA.
Chem Sci. 2019 Jul 26;10(35):8211-8218. doi: 10.1039/c9sc03291f. eCollection 2019 Sep 21.
Despite its apparent simplicity, water displays unique behavior across the phase diagram which is strictly related to the ability of the water molecules to form dense, yet dynamic, hydrogen-bond networks that continually fluctuate in time and space. The competition between different local hydrogen-bonding environments has been hypothesized as a possible origin of the anomalous properties of liquid water. Through a systematic application of the many-body expansion of the total energy, we demonstrate that the local structure of liquid water at room temperature is determined by a delicate balance between two-body and three-body energies, which is further modulated by higher-order many-body effects. Besides providing fundamental insights into the structure of liquid water, this analysis also emphasizes that a correct representation of two-body and three-body energies requires sub-chemical accuracy that is nowadays only achieved by many-body models rigorously derived from the many-body expansion of the total energy, which thus hold great promise for shedding light on the molecular origin of the anomalous behavior of liquid water.
尽管水看似简单，但其在相图上展现出独特的行为，这与水分子形成密集但动态的氢键网络的能力密切相关，这些氢键网络在时间和空间上持续波动。不同局部氢键环境之间的竞争被认为是液态水异常性质的一个可能起源。通过系统应用总能量的多体展开，我们证明室温下液态水的局部结构由两体和三体能量之间的微妙平衡决定，这种平衡进一步受到高阶多体效应的调制。除了为液态水的结构提供基本见解外，该分析还强调，正确表示两体和三体能量需要亚化学精度，而目前只有通过从总能量的多体展开严格推导出来的多体模型才能实现，因此这些模型有望揭示液态水异常行为的分子起源。
