Ga_(2n)(n=1～4)团簇自旋极化机理的密度泛函理论研究

利用基于密度泛函理论的第一性原理方法,在广义梯度近似(GGA)下对Ga_(2n)(n=1～4)团簇进行了几何结构优化和结合能计算,并对其电子结构及成键特性进行了分析.结果表明,Ga_2,Ga_4团簇的基态都是自旋极化态,Ga_6团簇的能量局域极小的八面体结构也具有自旋极化;这些团簇的最外层分子轨道的空间分布是对称的,最外层分子轨道之间的能量相差很小,最外层分子轨道的近简并引起了自旋极化;对称性较高的团簇容易形成近简并的最外层分子轨道.

Theoretical study for the electronic spin polarization of Ga2n(n=1~4) clusters

Density-functional theory with generalized gradient approximation for the exchange-correlation potential has been used to calculate the geometries structure and binding energy of Ga~(2n)(n=1～4)clusters. Their electronic structures and bond properties are analyzed. The calculated results show that the lowest energy structures of Ga_2 and Ga_4 clusters are spin polarized. The octahedral structure is a local energy minimum geometry of Ga_6 and it is spin polarized too. For these clusters, The spatial distribution of the outermost molecular orbitals are symmetrical and these orbitals are nearly degenerate in energy leading to spin polarization. Degenerate outermost molecular orbitals is more easily formed when cluster has higher symmetry.