Al_n(n=2～7)团簇的结构和能级分布

Geometry and energy level of Al_n (n=2～7)

采用密度泛函B3LYP的方法研究了小原子团簇Al2～ 7的几何结构和能级分布 ,分析了随团簇原子数的增加 ,团簇的几何结构和费米能级的变化情况。研究结果表明 :Al2～ 7的团簇的几何结构在 5个原子以前为平面结构 ,而从六个原子开始为空间立体的稳定结构。电子壳层结构表明 ,在铝团簇中没有出现非常明显的象碱金属那样的稳定幻数结构。在Al2 ～Al7团簇中 ,能级结构呈现明显的分立特征 ,费米能级随着原子个数的增加而减小 ,到Al7时又有所增加 ,且团簇的能量间隙最小。

In this paper the geometry structure and energy level distribution of small clusters of Al 2～7 are investigated with Density Functional Theory(DFT). The changes of the geometry structure and energy level with the cluster sizes are analyzed in the study. Al 2～7 clusters with five atoms or less have a planar structure built from distorted equilateral triangles, which is the typical pattern of close packing in two dimensions. The clusters with six and seven atoms have three dimensional structures. The shell structure of electrons reveals that the magic number doesn't exist obviously in the Al n clusters as in the alkali metals. The energy levels are apparently incontinuous in the Al 2～7 clusters. The Fermi energy decreases with the increase of atom numbers until seven atoms and the enrgy interval in the Al 7 clusters is smallest.