Abstract:

A microcosmic model of ice-water two-phase was constructed by molecular dynamics simulation method, and the variation of interface structure with temperature and interface structures was studied. The results show that when two phases reach equilibrium, there is a reversible dynamic transition between the disordered water molecules and the ordered ice crystals at interface, which results in the dynamics of the interface structure. The ice-water interface structure is largely dependent on temperature and crystal planes. At the same temperature, the interface thickness of primary prism and secondary prism is slightly thinner than that of the base plane, and the boundary is well-organized and three-dimensional network recombination of intermolecular hydrogen bonds exists. When the degree of supercooling increases, the interface structure tends to the ordered state of six-membered ring arrangement, and the number of disorder water molecules in the interface increases. The residence time of water molecules at the interface layer increases, and the probability of crystal plane growth increases.This article clarified the change law of the interface structure of ice-water system from the molecular scale, which has certain guiding significance for understanding the icing process and the development of ice control technology.

Key words: molecular simulation, interface of ice and water, dynamic structure, order parameters, icing

摘要：

为了探究结冰过程冰水界面结构的动态复杂性，利用分子动力学模拟方法构建微观的冰水两相共存模型，研究了冰水两相界面结构随温度和晶面的变化规律。结果表明，当冰水两相达到平衡时，冰水界面结构中存在无序水分子和有序冰晶结构的可逆动态转变，造成了界面结构的不均匀性。在改变环境温度和晶面类型时，冰水界面结构表现出不同的分布规律。在相同的温度下，一次棱柱面和二次棱柱面的界面层厚度比基面的略薄，而棱柱面水分子排列的有序性强，且存在分子间氢键的三维网络重组。当过冷度较大时，界面结构趋于六元环排列的有序状态，界面内无序水分子增多，同时水分子在界面层内的停留时间增长。从分子尺度上阐明了冰水体系界面结构的变化规律，对理解结冰过程和发展控冰技术具有一定的指导意义。

关键词: 分子模拟, 冰水界面, 动态结构, 序参量, 结冰