We examine ice crystallization from liquid water and from water vapor, focusing on the underlying physical processes that determine growth rates and structure formation. Ice crystal growth is largely controlled by a combination of molecular attachment kinetics on faceted surfaces and large-scale diffusion processes, yielding a remarkably rich phenomenology of solidification behaviors under different conditions. Layer nucleation plays an especially important role, with nucleation rates determined primarily by step energies on faceted ice/water and ice/vapor interfaces. The measured step energies depend strongly on temperature and other factors, and it appears promising that molecular dynamics simulations could soon be used in conjunction with experiments to better understand the energetics of these terrace steps. On larger scales, computational techniques have recently demonstrated the ability to accurately model the diffusion-limited growth of complex structures that are both faceted and branched. Together with proper boundary conditions determined by surface attachment kinetics, this opens a path to fully reproducing the variety of complex structures that commonly arise during ice crystal growth.

中文翻译：

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冰晶生长的物理动力学

我们研究了液态水和水蒸气中的冰结晶，重点关注决定生长速率和结构形成的潜在物理过程。冰晶生长在很大程度上受多面表面上的分子附着动力学和大规模扩散过程的组合控制，在不同条件下产生了非常丰富的凝固行为现象学。层成核起着特别重要的作用，成核速率主要由多面冰/水和冰/蒸汽界面上的阶跃能量决定。测得的阶跃能量很大程度上取决于温度和其他因素，而且分子动力学模拟很快可以与实验结合使用，以更好地了解这些阶跃的能量学，这似乎很有希望。在更大的尺度上，计算技术最近证明了精确模拟多面和分支复杂结构的扩散限制生长的能力。再加上由表面附着动力学确定的适当边界条件，这为完全再现冰晶生长过程中通常出现的各种复杂结构开辟了道路。