氧化镁纳米管团簇电子结构的密度泛函研究

Electronic properties of MgO nanotube clusters studied with density functional theory

用密度泛函理论(DFT)的杂化密度泛函B3LYP方法在6-31G(d)基组水平上对MgO纳米管团簇的二元环双管、三元环、三元环双管三种构型共21个团簇进行优化,对各构型的平均结合能、能隙、平均原子电荷以及总电荷密度进行了理论研究.结果表明,平均结合能和配位数呈线性关系;随着纳米管的生长,团簇的稳定性增加,其中以三元环纳米管最为稳定;生长过程中发生原子间的电荷转移现象,预测出至无限长时的平均原子电荷分别为1.298,1.270,1.306;混合离子共价键始终存在于MgO纳米管团簇之中.

The averaged binding energy,energy gap,atomic charge and total charge density of the MgO nanotube clusters were calculated with B3LYP method at 6-31G（d） level. The calculations show that the everaged binding energy decreases approximately linearly with increasing coordination. The structural stability increases in company with length of MgO nanotube clusters,and the most stable structure is 3MR species. The charge transfer increases with length of MgO nanotube clusters,the averaged atomic charges of 2,3 and 3 converge to 1.298,1.270,1.306,respectively. Mixed covalent and ionic bonding property always exist in MgO nanoclusters.