Computing the dielectric constant of liquid water at constant dielectric displacement
Computing the dielectric constant of liquid water at constant dielectric displacement
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DOI：
10.1103/physrevb.93.144201
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发表时间：
2015-10
影响因子：
3.7
通讯作者：
Chao Zhang;M. Sprik
中科院分区：
文献类型：
--
作者：
Chao Zhang;M. Sprik
液态水的静态介电常数的计算使用经典力场为基础的分子动力学模拟在固定的电位移$\mathbf{D}$。限制电位移的方法是Stengel、Spaldin和范德比尔特[Nat. Phys. 5，304（2009）]开发的常数$\mathbf{D}$方法的有限温度经典变体。也有一个修改这个计划强加固定值的宏观场$\mathbf{E}$。该方法适用于流行的SPC/E模型的液态水。我们比较了四种不同的估计的介电常数，两个从波动的极化在$\mathbf{D}=0$和$\mathbf{E}=0$和两个从有限的$\mathbf{D}$和$\mathbf{E}$的变化。据发现，所有四个估计同意时，适当收敛。然而，实现收敛的计算工作量各不相同，常数$\mathbf{D}$计算效率更高。我们将这种差异归因于纵向极化的弛豫时间比横向极化加速常数$\mathbf{D}$计算短得多。
The static dielectric constant of liquid water is computed using classical force field based molecular dynamics simulation at fixed electric displacement $\mathbf{D}$. The method to constrain the electric displacement is the finite-temperature classical variant of the constant $\mathbf{D}$ method developed by Stengel, Spaldin, and Vanderbilt [Nat. Phys. 5, 304 (2009)]. There is also a modification of this scheme imposing fixed values of the macroscopic field $\mathbf{E}$. The method is applied to the popular SPC/E model of liquid water. We compare four different estimates of the dielectric constant, two obtained from fluctuations of the polarization at $\mathbf{D}=0$ and $\mathbf{E}=0$ and two from the variation of polarization with finite $\mathbf{D}$ and $\mathbf{E}$. It is found that all four estimates agree when properly converged. The computational effort to achieve convergence varies, however, with constant $\mathbf{D}$ calculations being substantially more efficient. We attribute this difference to the much shorter relaxation time of longitudinal polarization compared to transverse polarization accelerating constant $\mathbf{D}$ calculations.