Liu Jinfeng, He Xiao, Zhang John Z H, Qi Lian-Wen
State Key Laboratory of Natural Medicines , Department of Basic Medicine and Clinical Pharmacy , China Pharmaceutical University , Nanjing , 210009 , China . Email:
School of Chemistry and Molecular Engineering , East China Normal University , Shanghai , 200062 , China.
Chem Sci. 2017 Dec 4;9(8):2065-2073. doi: 10.1039/c7sc04205a. eCollection 2018 Feb 28.
An accurate and efficient molecular dynamics (AIMD) simulation of liquid water was made possible using the fragment-based approach (J. F. Liu, X. He and J. Z. H. Zhang, , 2017, , 11931-11936). In this study, we advance the AIMD simulations using the fragment-based coupled cluster (CC) theory, more accurately revealing the structural and dynamical properties of liquid water under ambient conditions. The results show that the double-donor hydrogen-bond configurations in liquid water are nearly in balance with the single-donor configurations, with a slight bias towards the former. Our observation is in contrast to the traditional tetrahedral water structure. The hydrogen-bond switching dynamics in liquid water are very fast, with a hydrogen-bond life time of around 0.78 picoseconds, determined using AIMD simulation at the CCD/aug-cc-pVDZ level. This time scale is remarkably shorter than the ∼3.0 picoseconds that is commonly obtained from traditional nonpolarized force fields and density functional theory (DFT) based first-principles simulations. Additionally, the obtained radial distribution functions, triplet oxygen angular distribution, diffusion coefficient, and the dipole moment of the water molecule are uniformly in good agreement with the experimental observations. The current high-level AIMD simulation sheds light on the understanding of the structural and dynamical properties of liquid water.
使用基于片段的方法（J. F. Liu、X. He和J. Z. H. Zhang，《》，2017年，第11931 - 11936页）实现了对液态水的精确高效分子动力学（AIMD）模拟。在本研究中，我们利用基于片段的耦合簇（CC）理论推进了AIMD模拟，更准确地揭示了环境条件下液态水的结构和动力学性质。结果表明，液态水中双供体氢键构型与单供体构型近乎平衡，且略微偏向于前者。我们的观察结果与传统的四面体水结构相反。液态水中氢键切换动力学非常快，通过在CCD/aug - cc - pVDZ水平上的AIMD模拟确定，氢键寿命约为0.78皮秒。这个时间尺度明显短于传统非极化力场和基于密度泛函理论（DFT）的第一性原理模拟通常得到的约3.0皮秒。此外，所获得的径向分布函数、三重态氧角分布、扩散系数以及水分子的偶极矩均与实验观测结果一致。当前的高水平AIMD模拟有助于深入理解液态水的结构和动力学性质。
