Chen Bin
Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803-1804, USA.
J Chem Phys. 2023 Aug 21;159(7). doi: 10.1063/5.0165492.
A lattice-based version of the aggregation-volume-bias Monte Carlo method that was introduced recently has allowed for the extension of the calculation of the nucleation free energies from liquid clusters to solid clusters. Here, it was used to calculate the nucleation free energies of both bcc and fcc clusters formed by Lennard-Jones particles. Under the simulation conditions considered in this study, a cross-over of the thermodynamic stability from the bcc to the fcc structure was observed directly from the free energy results. In addition, the free energies obtained for both types of clusters were used to extrapolate bulk phase information, including chemical potential and surface tension, which revealed that bcc clusters are favored due to the lower surface tension. These results corroborate a recent classical density functional theory study. This work also demonstrates that this approach can be used to predict the entire thermodynamic landscape (i.e., free energies for clusters of different structures and sizes, including an infinitely large cluster, which is the bulk phase), which is important to answer fundamental questions related to crystallization such as the origin of polymorphism.
最近引入的基于晶格的聚集体积偏差蒙特卡罗方法的一个版本，使得成核自由能的计算能够从液体团簇扩展到固体团簇。在此，它被用于计算由 Lennard-Jones 粒子形成的体心立方（bcc）和面心立方（fcc）团簇的成核自由能。在本研究考虑的模拟条件下，从自由能结果中直接观察到了从 bcc 结构到 fcc 结构的热力学稳定性的转变。此外，为这两种类型团簇获得的自由能被用于外推体相信息，包括化学势和表面张力，结果表明由于较低的表面张力，bcc 团簇更受青睐。这些结果证实了最近一项经典密度泛函理论研究。这项工作还表明，这种方法可用于预测整个热力学态势（即不同结构和尺寸团簇的自由能，包括无限大的团簇，即体相），这对于回答与结晶相关的基本问题（如多晶型的起源）很重要。
