锗团簇Ge65, Ge70, Ge75的稳定结构及其电子结构性质

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Ge_n (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. 关键词： 锗团簇 紧束缚势 遗传算法 压缩液态法

Stable structures of Ge65, Ge70, Ge75 and their electronic properties

The low-lying candidates of Ge₆₅, Ge₇₀ and Ge₇₅ 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.
Keywords： germanium clusters tight-binding potential genetic algorithm compressing liquid