锗团簇Ge_(65),Ge_(70),Ge_(75)的稳定结构及其电子结构性质

Stable structures of Ge_(65),Ge_(70),Ge_(75) and their electronic properties

将两种全局结构搜索方法(压缩液态法、遗传算法)与锗的紧束缚势模型相互结合,对Ge65,Ge70,Ge75的稳定结构进行了大规模的搜寻,提出能量较低的可能结构,然后进一步利用第一性原理方法对这些低能结构进行精确的优化计算,确定出了这三种尺寸团簇的基态结构.发现这三种团簇各具有两种稳定的并且能量相近的异构体:类球形和类椭球形,这与实验上报道的大尺寸团簇Gen(65≤n≤80)的结构特征相符合.简要地分析了这三种团簇基态结构的电子性质.

The low-lying candidates of Ge 65 , Ge 70 and Ge 75 are extensively investigated through combining the tight-binding potential of germanium with two kinds of global minima search strategies： compressing liquid and genetic algorithm. Then, we perform accurate ab initio calculations to optimize the atomic structures of these low-lying candidates and identify the ground state structures. Our calculations predict that there exist two kinds of stable isomers characterizing the sphere- and ellipsoid-like structural features for each sized cluster, and the two kinds of isomers are energetically competitive. This is consistent with the observation for the large sized clusters Ge n （65 ≤n ≤80） in experiment. Meanwhile, we also briefly analyze the electronic properties of these three kinds of clusters.