Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X7, Canada.
J Chem Phys. 2011 Sep 28;135(12):124506. doi: 10.1063/1.3638046.
Crystallization and vitrification of tetrahedral liquids are important both from a fundamental and a technological point of view. Here, we study via extensive umbrella sampling Monte Carlo computer simulations the nucleation barriers for a simple model for tetrahedral patchy particles in the regime where open tetrahedral crystal structures (namely, cubic and hexagonal diamond and their stacking hybrids) are thermodynamically stable. We show that by changing the angular bond width, it is possible to move from a glass-forming model to a readily crystallizing model. From the shape of the barrier we infer the role of surface tension in the formation of the crystalline clusters. Studying the trends of the nucleation barriers with the temperature and the patch width, we are able to identify an optimal value of the patch size that leads to easy nucleation. Finally, we find that the nucleation barrier is the same, within our numerical precision, for both diamond crystals and for their stacking forms.
四面体液体的结晶和玻璃化在基础和技术方面都很重要。在这里，我们通过广泛的伞状采样蒙特卡罗计算机模拟研究了在热力学上稳定的开放四面体晶体结构（即立方和六方金刚石及其堆积杂化体）的情况下，用于四面体镶嵌粒子的简单模型的成核势垒。我们表明，通过改变角键宽度，可以将玻璃形成模型转变为易于结晶的模型。从势垒的形状，我们推断出表面张力在形成结晶簇中的作用。通过研究成核势垒随温度和镶嵌宽度的趋势，我们能够确定出导致易于成核的最佳镶嵌尺寸。最后，我们发现，在我们的数值精度内，对于金刚石晶体及其堆积形式，成核势垒是相同的。
