Mg_nLa (n=2-6)掺杂团簇的密度泛函研究

DFT study on the La-doped Mg_nLa (n=2-6) clusters

采用密度泛函(DFT)中的B3LYP方法,选择CEP-31g基组,优化并得到了MgnLa(n=2-6)小团簇的基态平衡结构,计算出了掺杂团簇的基态结构的平均键长、对称性、费米能级、能级间隙、束缚能、总能的二阶差分.结果表明,随着团簇原子数的增加,La原子更容易趋于团簇表面位置.与未掺杂Mg团簇相比,La原子多采用取代其稳定基态结构的一个Mg原子形成掺杂团簇的稳定结构.从有限的结果看,其中Mg3La和Mg6La的结构更为稳定.

The possible geometrical and electronic structures of small Mg n La （n=2-6） clusters have been optimized by using B3LYP method of density functional theory .The binding energies ,energy level dis-tribution ,energy gaps ,electron affinities ,dissociation energy and second difference in energy are calcu-lated and discussed .T he resulting geometries show that the La atom remains on the surface of clusters . In comparison with the pure Mg clusters ,the stable structures of Mgn La clusters form by substituting La for Mg of the stable pure Mg clusters .It is found that the Mg3 La and Mg6 La show the higher stabili-ty than the others.