Piskulich Zeke A, Thompson Ward H
Department of Chemistry, University of Kansas, Lawrence, Kansas 66045, USA.
J Chem Phys. 2020 Feb 21;152(7):074505. doi: 10.1063/1.5139435.
There is strong interest in understanding the behavior of water in its supercooled state. While many of the qualitative trends of water dynamical properties in the supercooled regime are well understood, the connections between the structure and dynamics of room temperature and supercooled water have not been fully elucidated. Here, we show that the reorientational time scales and diffusion coefficients of supercooled water can be predicted from simulations of room temperature liquid water. Specifically, the derivatives of these dynamical time scales with respect to inverse temperature are directly calculated using the fluctuation theory applied to dynamics. These derivatives are used to predict the time scales and activation energies in the supercooled regime based on the temperature dependence in one of two forms: that based on the stability limit conjecture or assuming an equilibrium associated with a liquid-liquid phase transition. The results indicate that the retarded dynamics of supercooled water originate from structures and mechanisms that are present in the liquid under ambient conditions.
人们对理解过冷水状态下的水的行为有着浓厚兴趣。虽然过冷状态下水动力学性质的许多定性趋势已得到很好的理解，但室温下水与过冷水的结构和动力学之间的联系尚未完全阐明。在此，我们表明过冷水的重排时间尺度和扩散系数可以通过室温液态水的模拟来预测。具体而言，这些动力学时间尺度相对于逆温度的导数是使用应用于动力学的涨落理论直接计算得出的。这些导数用于基于两种形式之一的温度依赖性来预测过冷状态下的时间尺度和活化能：基于稳定性极限猜想的形式或假设与液 - 液相转变相关的平衡的形式。结果表明，过冷水的延迟动力学源于环境条件下液体中存在的结构和机制。
