On the time required to freeze water
On the time required to freeze water
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DOI：
10.1063/1.4965427
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发表时间：
2016-12-21
影响因子：
4.4
通讯作者：
Vega, C.
中科院分区：
文献类型：
--
作者：
Espinosa, J. R.;Navarro, C.;Vega, C.
通过使用播种技术的成核率在室内压力下的冰的形成将估计为TIP 4P/ICE模型使用更长的运行和更小的网格的温度比在以前的工作。将确定TIP 4P/ICE和水的mW模型的冰的生长速率。虽然TIP 4P/ICE和mW具有相似的熔点和熔化焓，但它们在冷冻动力学方面存在显著差异。由于mW具有较高的界面自由能，其成核速率低于TIP 4P/ICE。冰的成核率的实验结果是这两个模型的预测之间时，从播种技术，虽然更接近TIP 4P/ICE的预测。mW模型的冰的增长率比TIP 4P/ICE大四个数量级。Avrami的表达式是用来估计的成核和生长速率的值的结晶时间。对于mW的结晶时间的最小值被发现在熔点以下约85 K，其值约为几ns，与从强力模拟由摩尔和Molinero获得的结果一致。对于TIP 4P/ICE，在熔点以下约55 K处发现最小值，但其值约为10微秒。该值与避免冰的形成和获得玻璃相所需的最小冷却速率相容。对于有限尺寸的系统，将讨论从成核控制结晶到生长控制结晶的交叉。这种交叉可以解释由不同的实验组获得的J值之间的明显差异的温度低于230 K，并应被视为一个替代假设，以先前提出的两个：内部压力和/或表面冻结效应。TIP 4P/ICE模型在过冷水中的压缩性最大。弛豫时间远小于结晶时间在该最大值出现的温度下，因此该最大值是该模型的真实的热力学特征。在最小结晶时间的温度下，结晶时间仅比弛豫时间大两个数量级。由AIP出版社出版。
By using the seeding technique the nucleation rate for the formation of ice at room pressure will be estimated for the TIP4P/ICE model using longer runs and a smaller grid of temperatures than in the previous work. The growth rate of ice will be determined for TIP4P/ICE and for the mW model of water. Although TIP4P/ICE and mW have a similar melting point and melting enthalpy, they differ significantly in the dynamics of freezing. The nucleation rate of mW is lower than that of TIP4P/ICE due to its higher interfacial free energy. Experimental results for the nucleation rate of ice are between the predictions of these two models when obtained from the seeding technique, although closer to the predictions of TIP4P/ICE. The growth rate of ice for the mW model is four orders of magnitude larger than for TIP4P/ICE. Avrami's expression is used to estimate the crystallization time from the values of the nucleation and growth rates. For mW the minimum in the crystallization time is found at approximately 85 K below the melting point and its value is of about a few ns, in agreement with the results obtained from brute force simulations by Moore and Molinero. For the TIP4P/ICE the minimum is found at about 55 K below the melting point, but its value is about ten microseconds. This value is compatible with the minimum cooling rate required to avoid the formation of ice and obtaining a glass phase. The crossover from the nucleation controlled crystallization to the growth controlled crystallization will be discussed for systems of finite size. This crossover could explain the apparent discrepancy between the values of J obtained by different experimental groups for temperatures below 230 K and should be considered as an alternative hypothesis to the two previously suggested: internal pressure and/or surface freezing effects. A maximum in the compressibility was found for the TIP4P/ICE model in supercooled water. The relaxation time is much smaller than the crystallization time at the temperature at which this maximum occurs, so this maximum is a real thermodynamic feature of the model. At the temperature of minimum crystallization time, the crystallization time is larger than the relaxation time by just two orders of magnitude. Published by AIP Publishing.