Duncan Peter D, Masters Andrew J, Wilson Mark R
Department of Chemistry, University of Durham, South Road, Durham DH1 3LE, UK.
Phys Rev E Stat Nonlin Soft Matter Phys. 2011 Jul;84(1 Pt 1):011702. doi: 10.1103/PhysRevE.84.011702. Epub 2011 Jul 7.
The system of hard cut spheres (disk-shaped particles formed by symmetrically truncating the end caps of a sphere) exhibits an intriguing "cubatic" phase with cubic orientational symmetry. However, it is unclear whether this phase is metastable with respect to the columnar phase. We attempt to provide an answer to this question by carrying out free energy calculations by the expanded ensemble Monte Carlo method. We conclude that there may be a very small region of cubatic stability in the vicinity of the isotropic-cubatic phase transition, but that that transition would need to be determined more accurately to obtain a definitive answer. We also comment on the efficacy of the expanded ensemble method for these kinds of calculations.
硬截顶球体系统（通过对称截断球体的端盖形成的盘状粒子）呈现出一种具有立方取向对称性的有趣“立方相”。然而，目前尚不清楚该相相对于柱状相是否为亚稳相。我们试图通过扩展系综蒙特卡罗方法进行自由能计算来回答这个问题。我们得出结论，在各向同性 - 立方相转变附近可能存在一个非常小的立方稳定区域，但需要更精确地确定该转变才能得到明确答案。我们还对扩展系综方法在这类计算中的有效性进行了评论。
