Niu Haiyang, Yang Yi Isaac, Parrinello Michele
Department of Chemistry and Applied Biosciences, ETH Zurich c/o USI Campus, Via Giuseppe Buffi 13, 6900 Lugano, Switzerland.
Facoltà di Informatica, Instituto di Scienze Computationali, and National Center for Computational Design and Discovery of Novel Materials MARVEL, Università della Svizzera Italiana, Via Giuseppe Buffi 13, 6900 Lugano, Switzerland.
Phys Rev Lett. 2019 Jun 21;122(24):245501. doi: 10.1103/PhysRevLett.122.245501.
Ice nucleation is a process of great relevance in physics, chemistry, technology, and environmental sciences; much theoretical effort has been devoted to its understanding, but it still remains a topic of intense research. We shed light on this phenomenon by performing atomistic based simulations. Using metadynamics and a carefully designed set of collective variables, reversible transitions between water and ice are able to be simulated. We find that water freezes into a stacking disordered structure with the all-atom transferable intermolecular potential with 4 points/ice (TIP4P/ice) model, and the features of the critical nucleus of nucleation at the microscopic level are revealed. We have also estimated the ice nucleation rates along with other nucleation parameters at different undercoolings. Our results are in agreement with recent experimental and other theoretical works, and they confirm that nucleation is preceded by a large increase in tetrahedrally coordinated water molecules.
冰核形成是一个在物理、化学、技术和环境科学中极具相关性的过程；人们在理解它方面投入了大量的理论研究工作，但它仍然是一个深入研究的课题。我们通过基于原子模拟来阐明这一现象。使用元动力学和精心设计的一组集体变量，能够模拟水和冰之间的可逆转变。我们发现，水在具有全原子可转移分子间势的4点/冰（TIP4P/ice）模型下冻结成堆积无序结构，并揭示了微观层面成核临界核的特征。我们还估计了不同过冷度下的冰核形成速率以及其他成核参数。我们的结果与最近的实验和其他理论研究一致，并且证实成核之前四面体配位水分子会大幅增加。
