Mg2Bn(n=4～9)团簇结构与性质的DFT研究

DFT study on the structure and properties of Mg_2B_n(n=4～9) clusters

用密度泛函理论(DFT)的B3LYP方法在6-31G*的基组水平上对Mg2Bn(n=4～9)团簇的各种可能的几何构型进行优化,得到了Mg2Bn(n=4～9)团簇的最稳定结构,并对其几何结构、振动光谱、电离能、能隙、电荷布局、成键特性等性质进行了计算.结果表明:Mg2Bn(n=4～9)团簇中大部分B原子为负电性且总是处在团簇的中心,Mg原子总是处在端位上并显正电性;随着n的增大,团簇最稳定结构逐渐由平面结构向立体结构转变;n=4、8时的结构相对较稳定.

Possible geometrical structures and relative stability of Mg2Bn（n=4～9） clusters are studied by using the hybrid density functional theory（B3LYP） with 6-31G^＊ basis sets.For the most stable isomers of Mg2Bn（n=4～9） clusters,the electronic structure,vibrational properties,ionization potential,HOMO-LUMO gap,charge properties and bond properties are analyzed.The calculated results show that there is a electronegative center with most of B atoms of cluster,the Mg atoms with positive charge are always located at apex of the cluster;The most stable isomers of Mg2Bn（n=4～9） clusters are changing gradually from planar structure to Three-Dimensional structure;and the clusters with n=4、8 are more stable than other clusters.