Properties of water along the liquid-vapor coexistence curve via molecular dynamics simulations using the polarizable TIP4P-QDP-LJ water model
Properties of water along the liquid-vapor coexistence curve via molecular dynamics simulations using the polarizable TIP4P-QDP-LJ water model
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DOI：
10.1063/1.3200869
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发表时间：
2009-08-28
影响因子：
4.4
通讯作者：
Patel, Sandeep
中科院分区：
文献类型：
--
作者：
Bauer, Brad A.;Patel, Sandeep
我们提出了 TIP4P-QDP 模型的扩展 TIP4P-QDP-LJ，旨在将排斥和色散非键相互作用的变化与极化率的变化耦合起来。极化率与相互作用的经典力场模型的色散分量密切相关，我们探索了明确结合这种联系对纯水沿液-气共存曲线的性质的影响。 TIP4P-QDP-LJ 模型经过参数化，可以再现 298 K 时的凝相液态水特性，它可以预测环境条件下的密度、汽化焓、自扩散常数和介电常数，其精度与 TIP4P-QDP 大致相同，但在再现液-气共存曲线方面显示出显着改进。 TIP4P-QDP-LJ预测的临界常数为T-c=623 K、rho(c)=0.351 g/cm(3)和P-c=250.9 atm，分别与T-c=647.1 K、rho(c)=0.322 g/cm(3)和P-c=218 atm的实验值吻合良好。应用比例因子校正（通过使用三项韦格纳展开将实验气液平衡数据拟合到直线直径定律而获得），模型预测临界常数（T-c=631 K 和 rho(c)=0.308 g/cm(3)）。汽化焓、自扩散常数、表面张力和介电常数对温度的依赖性再现了实验趋势。 We also explore the interfacial potential drop across the liquid-vapor interface for the temperatures studied.界面电位在较低温度 (300-450 K) 下表现出很小的温度依赖性，而在高温下则显着增强（指数）依赖性。当温度接近临界温度时，由界面势分解为偶极子和四极子贡献而产生的项显示单调接近零。这项研究的结果表明，自洽地处理经典水力场中相依赖的极化率与色散相互作用的耦合可能对于可极化水力场的扩展以再现沿着液-气共存包络线以及接近临界条件的特性具有重要作用。更重要的是，本研究证明了参数化为单状态点的水模型向其他热力学状态的相当显着的可转移性。建议进一步研究。
We present an extension of the TIP4P-QDP model, TIP4P-QDP-LJ, that is designed to couple changes in repulsive and dispersive nonbond interactions to changes in polarizability. Polarizability is intimately related to the dispersion component of classical force field models of interactions, and we explore the effect of incorporating this connection explicitly on properties along the liquid-vapor coexistence curve of pure water. Parametrized to reproduce condensed-phase liquid water properties at 298 K, the TIP4P-QDP-LJ model predicts density, enthalpy of vaporization, self-diffusion constant, and the dielectric constant at ambient conditions to about the same accuracy as TIP4P-QDP but shows remarkable improvement in reproducing the liquid-vapor coexistence curve. TIP4P-QDP-LJ predicts critical constants of T-c=623 K, rho(c)=0.351 g/cm(3), and P-c=250.9 atm, which are in good agreement with experimental values of T-c=647.1 K, rho(c)=0.322 g/cm(3), and P-c=218 atm, respectively. Applying a scaling factor correction (obtained by fitting the experimental vapor-liquid equilibrium data to the law of rectilinear diameters using a three-term Wegner expansion) the model predicts critical constants (T-c=631 K and rho(c)=0.308 g/cm(3)). Dependence of enthalpy of vaporization, self-diffusion constant, surface tension, and dielectric constant on temperature are shown to reproduce experimental trends. We also explore the interfacial potential drop across the liquid-vapor interface for the temperatures studied. The interfacial potential demonstrates little temperature dependence at lower temperatures (300-450 K) and significantly enhanced (exponential) dependence at elevated temperatures. Terms arising from the decomposition of the interfacial potential into dipole and quadrupole contributions are shown to monotonically approach zero as the temperature approaches the critical temperature. Results of this study suggest that self-consistently treating the coupling of phase-dependent polarizability with dispersion interactions in classical water force fields may be an important effect for the extension of polarizable water force fields to reproduce properties along the liquid-vapor coexistence envelope as well as near critical conditions. More importantly, the present study demonstrates the rather remarkable transferability of a water model parametrized to a single state point to other thermodynamic states. Further studies are recommended.