Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom.
J Chem Phys. 2017 Feb 21;146(7):074701. doi: 10.1063/1.4975776.
We apply the capillary wave method, based on measurements of fluctuations in a ribbon-like interfacial geometry, to determine the solid-liquid interfacial free energy for both polytypes of ice I and the recently proposed ice 0 within a mono-atomic model of water. We discuss various choices for the molecular order parameter, which distinguishes solid from liquid, and demonstrate the influence of this choice on the interfacial stiffness. We quantify the influence of discretisation error when sampling the interfacial profile and the limits on accuracy imposed by the assumption of quasi one-dimensional geometry. The interfacial free energies of the two ice I polytypes are indistinguishable to within achievable statistical error and the small ambiguity which arises from the choice of order parameter. In the case of ice 0, we find that the large surface unit cell for low index interfaces constrains the width of the interfacial ribbon such that the accuracy of results is reduced. Nevertheless, we establish that the interfacial free energy of ice 0 at its melting temperature is similar to that of ice I under the same conditions. The rationality of a core-shell model for the nucleation of ice I within ice 0 is questioned within the context of our results.
我们应用基于带状界面几何形状波动测量的毛细波方法，来确定单原子水分子模型中两种冰 I 多型体和最近提出的冰 0 的固-液界面自由能。我们讨论了区分固-液的分子序参量的各种选择，并展示了这种选择对界面硬度的影响。我们量化了在界面轮廓取样时离散化误差的影响，以及准一维几何形状假设所施加的精度限制。两种冰 I 多型体的界面自由能在可实现的统计误差内是不可区分的，并且这种微小的差异源于序参量的选择。在冰 0 的情况下，我们发现低指数界面的大表面单位胞限制了界面带状的宽度，从而降低了结果的准确性。尽管如此，我们确定了在相同条件下冰 0 的界面自由能在其熔点时与冰 I 相似。在我们的结果背景下，对冰 0 中冰 I 形核的核壳模型的合理性提出了质疑。
