Interface dielectric constant of water at the surface of a spherical solute
Interface dielectric constant of water at the surface of a spherical solute
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球形溶质表面水的界面介电常数
DOI：
10.1016/j.molliq.2023.121400
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发表时间：
2023
影响因子：
6
通讯作者：
Matyushov, Dmitry V.
中科院分区：
文献类型：
--
作者：
Dinpajooh, Mohammadhasan;Matyushov, Dmitry V.
界面介电常数被用来量化极性响应的水界面的球形溶质。这个界面参数，受界面结构内约两个水化层，是从根本上不同于体介电常数（材料性能）。分子动力学模拟用于提取界面介电常数的波动关系相关的偶极矩的界面层与介质静电。对于探针离子，必须计算水合壳层偶极矩和静电势之间的互相关，而对于探针偶极子，需要壳层偶极矩和静电场之间的互相关。所有协议产生介电常数的水接口的非极性溶质显着低于散装值。我们分析的波动关系的协议，使用周期性边界条件与埃瓦尔德总和计算静电相互作用施加的校正。这些校正对于典型的模拟协议是无关紧要的。
Interface dielectric constant is used to quantify polar response of water interfacing a spherical solute. This interfacial parameter, affected by the interfacial structure within about two hydration layers, is fundamentally distinct from the bulk dielectric constant (a material property). Molecular dynamics simulations are used to extract the interface dielectric constant from fluctuation relations correlating the dipole moment of the interfacial layer with the medium electrostatics. For a probe ion, one has to calculate cross-correlations between the hydration shell dipole moment and the electrostatic potential, while cross-correlations between the shell dipole moment and the electrostatic field are required for a probe dipole. All protocols produce dielectric constants of water interfacing a nonpolar solute significantly below the bulk value. We analyze corrections imposed on the fluctuation relations by protocols using periodic boundary conditions with Ewald sums to compute electrostatic interactions. These corrections are insignificant for typical simulation protocols.