Espinosa J R, Sanz E, Valeriani C, Vega C
Departamento de Química Física, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
J Chem Phys. 2014 Nov 14;141(18):18C529. doi: 10.1063/1.4897524.
In this work, we evaluate by means of computer simulations the rate for ice homogeneous nucleation for several water models such as TIP4P, TIP4P/2005,TIP4P/ICE, and mW (following the same procedure as in Sanz et al. [J. Am. Chem. Soc. 135, 15008 (2013)]) in a broad temperature range. We estimate the ice-liquid interfacial free-energy, and conclude that for all water models γ decreases as the temperature decreases. Extrapolating our results to the melting temperature, we obtain a value of the interfacial free-energy between 25 and 32 mN/m in reasonable agreement with the reported experimental values. Moreover, we observe that the values of γ depend on the chosen water model and this is a key factor when numerically evaluating nucleation rates, given that the kinetic prefactor is quite similar for all water models with the exception of the mW (due to the absence of hydrogens). Somewhat surprisingly the estimates of the nucleation rates found in this work for TIP4P/2005 are slightly higher than those of the mW model, even though the former has explicit hydrogens. Our results suggest that it may be possible to observe in computer simulations spontaneous crystallization of TIP4P/2005 at about 60 K below the melting point.
在这项工作中，我们通过计算机模拟评估了几种水模型（如TIP4P、TIP4P/2005、TIP4P/ICE和mW，遵循与Sanz等人[《美国化学会志》135, 15008 (2013)]相同的程序）在很宽温度范围内的冰均匀成核速率。我们估算了冰 - 液界面自由能，并得出结论：对于所有水模型，γ都随温度降低而减小。将我们的结果外推至熔点温度，我们得到的界面自由能值在25至32 mN/m之间，与报道的实验值合理吻合。此外，我们观察到γ的值取决于所选的水模型，并且在数值评估成核速率时这是一个关键因素，因为除了mW（由于没有氢原子）之外，所有水模型的动力学前置因子都非常相似。有点令人惊讶的是，尽管TIP4P/2005有明确的氢原子，但这项工作中发现的TIP4P/2005的成核速率估计值略高于mW模型。我们的结果表明，在计算机模拟中有可能观察到TIP4P/2005在低于熔点约60 K时的自发结晶。
