论文标题
通过水环境稳定AGI极地表面及其对冰形成的影响
Stabilization of AgI's polar surfaces by the aqueous environment, and its implications for ice formation
论文作者
论文摘要
碘化银是已知的最有效的无机冰核颗粒之一，这通常归因于其基础Ag-（0001）和I-（000-1）表面和冰之间的优异晶格匹配。但是，这种晶体终止是III型极性表面，因此，除非极性补偿机制占上风，否则其表面能与晶体大小相差。在这项模拟研究中，我们研究周围水性环境能够在多大程度上提供这种极性补偿。本身，我们发现纯水无法以物理合理的方式稳定AGI晶体，而移动式载体（例如溶解离子）至关重要。换句话说，必须将接近溶解的离子视为异质冰形成机制的组成部分。我们执行的模拟利用了仿真方法的最新进展，其中施加了适当的电气和电位移场。这项研究的一个有用的副产品是与此实现的常用Yeh-Berkowitz方法的直接比较。在这里，我们发现后者的幼稚应用会导致身体上不合理的结果，并极大地影响了接触层中水的结构。因此，我们预计这些结果对于在水性环境中研究极性/带电表面的人至关重要。
Silver iodide is one of the most potent inorganic ice nucleating particles known, a feature generally attributed to the excellent lattice match between its basal Ag-(0001) and I-(000-1) surfaces, and ice. This crystal termination, however, is a type-III polar surface, and its surface energy therefore diverges with crystal size unless a polarity compensation mechanism prevails. In this simulation study, we investigate to what extent the surrounding aqueous environment is able to provide such polarity compensation. On its own, we find that pure water is unable to stabilize the AgI crystal in a physically reasonable manner, and that mobile charge carriers such as dissolved ions, are essential. In other words, proximate dissolved ions must be considered an integral part of the heterogeneous ice formation mechanism. The simulations we perform utilize recent advances in simulation methodology in which appropriate electric and electric displacement fields are imposed. A useful by-product of this study is the direct comparison to the commonly used Yeh-Berkowitz method that this enables. Here we find that naive application of the latter leads to physically unreasonable results, and greatly influences the structure of water in the contact layer. We therefore expect these results to be of general importance to those studying polar/charged surfaces in aqueous environments.
