Faculty of Physics, University of Vienna, A-1090 Vienna, Austria.
Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
J Chem Phys. 2023 Mar 28;158(12):124503. doi: 10.1063/5.0140814.
Despite the importance of ice nucleation, this process has been barely explored at negative pressures. Here, we study homogeneous ice nucleation in stretched water by means of molecular dynamics seeding simulations using the TIP4P/Ice model. We observe that the critical nucleus size, interfacial free energy, free energy barrier, and nucleation rate barely change between isobars from -2600 to 500 bars when they are represented as a function of supercooling. This allows us to identify universal empirical expressions for homogeneous ice nucleation in the pressure range from -2600 to 500 bars. We show that this universal behavior arises from the pressure dependence of the interfacial free energy, which we compute by means of the mold integration technique, finding a shallow minimum around -2000 bars. Likewise, we show that the change in the interfacial free energy with pressure is proportional to the excess entropy and the slope of the melting line, exhibiting in the latter a reentrant behavior also at the same negative pressure. Finally, we estimate the excess internal energy and the excess entropy of the ice Ih-water interface.
尽管冰核形成过程非常重要，但在负压条件下，该过程几乎没有得到研究。在这里，我们使用 TIP4P/Ice 模型通过分子动力学播种模拟研究了拉伸水中的均相冰核形成。我们观察到，在超冷度的函数关系中，当压力从-2600 到 500 巴时，临界核大小、界面自由能、自由能势垒和成核率几乎没有变化。这使我们能够在-2600 至 500 巴的压力范围内确定均相冰核形成的通用经验表达式。我们表明，这种普遍行为源于界面自由能随压力的变化，我们通过模具积分技术计算了界面自由能，在-2000 巴左右发现了一个浅的最小值。同样，我们表明，界面自由能随压力的变化与过剩熵和熔化线的斜率成正比，在后者中，同样的负压也表现出再入行为。最后，我们估计了冰 Ih-水界面的过剩内能和过剩熵。
