Costales Aurora, Blanco M A, Francisco E, Pandey Ravindra, Martín Pendás A
Departamento de Química Física y Analítica, Facultad de Química, Universidad de Oviedo, 33006-Oviedo, Spain.
J Phys Chem B. 2005 Dec 29;109(51):24352-60. doi: 10.1021/jp055094j.
A global optimization of stoichiometric (AlN)(n) clusters (n = 1-25, 30, 35, ..., 95, 100) has been performed using the basin-hopping (BH) method and describing the interactions with simple and yet realistic interatomic potentials. The results for the smaller isomers agree with those of previous electronic structure calculations, thus validating the present scheme. The lowest-energy isomers found can be classified in three different categories according to their structural motifs: (i) small clusters (n = 2-5), with planar ring structures and 2-fold coordination, (ii) medium clusters (n = 6-40), where a competition between stacked rings and globular-like empty cages exists, and (iii) large clusters (n > 40), large enough to mix different elements of the previous stage. All the atoms in small and medium-sized clusters are in the surface, while large clusters start to display interior atoms. Large clusters display a competition between tetrahedral and octahedral-like features: the former lead to a lower energy interior in the cluster, while the latter allow for surface terminations with a lower energy. All of the properties studied present different regimes according to the above classification. It is of particular interest that the local properties of the interior atoms do converge to the bulk limit. The isomers with n = 6 and 12 are specially stable with respect to the gain or loss of AlN molecules.
已使用 Basin-hopping（BH）方法并结合简单且实际的原子间势来描述相互作用，对化学计量比的(AlN)(n)团簇（n = 1 - 25、30、35、……、95、100）进行了全局优化。较小异构体的结果与先前的电子结构计算结果一致，从而验证了本方案。根据其结构 motif，发现的最低能量异构体可分为三类：（i）小团簇（n = 2 - 5），具有平面环状结构和 2 重配位；（ii）中等团簇（n = 6 - 40），其中堆叠环和球状空笼之间存在竞争；（iii）大团簇（n > 40），大到足以混合前一阶段的不同元素。中小团簇中的所有原子都在表面，而大团簇开始出现内部原子。大团簇在四面体和八面体状特征之间存在竞争：前者导致团簇内部能量较低，而后者允许表面终止能量较低。根据上述分类，所研究的所有性质都呈现出不同的状态。特别有趣的是，内部原子的局部性质确实收敛到体相极限。n = 6 和 12 的异构体相对于 AlN 分子的得失特别稳定。
