Acta Chimica Sinica ›› 2020, Vol. 78 ›› Issue (6): 547-556.DOI: 10.6023/A20030054 Previous Articles     Next Articles

Article

应用极化水分子模型研究单分子层受限水的介电性质

范勤, 梁洪涛, 许贤祺, 吕松泰, 梁尊, 杨洋   

  1. 华东师范大学 物理与电子科学学院 凝聚态物理研究所 上海 200241
  • 收稿日期:2020-03-04 发布日期:2020-06-02
  • 通讯作者: 杨洋 E-mail:yyang@phy.ecnu.edu.cn
  • 基金资助:
    项目受国家自然科学基金(Nos.11504110,11874147)、中央高校基本科研业务费专项资金和华东师范大学公共创新服务平台(001)资助.

Study of the Dielectric Property of Monolayer Confined Water Using A Polarizable Model

Fan Qin, Liang Hongtao, Xu Xianqi, Lv Songtai, Liang Zun, Yang Yang   

  1. School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
  • Received:2020-03-04 Published:2020-06-02
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Nos. 11504110, 11874147), the Fundamental Research Funds for the Central Universities and East China Normal University Multifunctional Platform for Innovation (001).

The direct measurement of the dielectric properties of the confined water is exceedingly challenging, result in the lack of a quantitative understanding of its critical roles in electrochemistry, interfacial reactivity and transport thermodynamics. In this paper, we employ the equilibrium molecular dynamics simulation and the linear response theory-based analytical expressions for the local permittivity tensor, to calculate the static and dynamic dielectric response properties of the monolayer ice and water confined in the 0.65 nm size hydrophobic slab pore under 5×108 Pa lateral pressure and different temperatures. We carry out a detailed comparative study on the performance of predicting the confined structure and dielectric response properties between two well known water molecule models, i.e., constant dipole moment SPC/E model and polarizable SWM4-NDP water model. We have analyzed the probability distributions of the instantaneous SWM4-NDP water molecular dipole moments and calculated the static structure factor, radial dipole-dipole correlation function, static dielectric tensor, total dipole autocorrelation function and Debye relaxation time of each simulation system. For the first time, we found the novel variation of the water molecular polarities, in the monolayer confined liquid and solid phase of water, due to the extreme confinement condition. The performance in describing the structural properties are found comparable between the two water models, and the enhancement of the confinement weakens the advantage of the SWM4-NDP model in predicting the static dielectric property. However, in the prediction of the dynamic properties such as dielectric relaxation time, SWM4-NDP water model is superior to the SPC/E model. Therefore, we suggest that using SWM4-NDP model in the future investigation of the structural phase transition kinetics, ionic transportation and solvation kinetics would be the better choice. The current achievement of the fundamental insight and computational data could potentially facilitate the theoretical advancements in designing new devices of energy storage, sensor, and medicine delivery based on confined water systems.

Key words: confined water, square ice, polarizable water model, molecular dynamics, dielectric property