Hefei National Laboratory for Physical Sciences at the Microscale, and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China.
J Chem Phys. 2011 Dec 28;135(24):244108. doi: 10.1063/1.3672237.
Using a two-center Lennard-Jones (2CLJ) model, the simplest anisotropic case, we investigated how anisotropy affects global minimum structures of clusters and obtained some interesting results. The anisotropy parameter, R, is defined as the ratio of the bond length of 2CLJ dimer to the LJ equilibrium pair separation, where a larger R value means higher anisotropy. For low R values, the structures resemble those of the Lennard-Jones atomic clusters. However, as the pairwise interaction becomes more anisotropic, the "magic numbers" change, and several novel cluster patterns emerge as particularly stable structures, and the global minima change from icosahedral, to polyicosahedral and to novel irregular structures. Moreover, increasing the anisotropy effectively softens the 2CLJ potential. Given the general importance of the LJ cluster as a simple model cluster, 2CLJ model can provide a straightforward and useful analysis of the effect of molecular shape on the structures of clusters.
利用双中心 Lennard-Jones（2CLJ）模型，这一最简单的各向异性情况，我们研究了各向异性如何影响团簇的全局最小结构，并得到了一些有趣的结果。各向异性参数 R 定义为 2CLJ 二聚体键长与 LJ 平衡对分离的比值，其中 R 值越大表示各向异性越高。对于低 R 值，结构类似于 Lennard-Jones 原子团簇。然而，随着成对相互作用变得更加各向异性，“幻数”发生变化，并且出现了一些新的团簇模式作为特别稳定的结构，全局最小值从二十面体变为多二十面体，再变为新颖的不规则结构。此外，增加各向异性会有效地软化 2CLJ 势能。鉴于 LJ 团簇作为简单模型团簇的普遍重要性，2CLJ 模型可以提供对分子形状对团簇结构影响的直接而有用的分析。
