钇小团簇的结构和电离势的计算

采用密度泛函DFT中的B3LYP方法，选择LANL2DZ双ζ基组，优化并得到了Y_n=(n=2—8)小团簇的基态平衡结构，同时计算出其电离势.结果表明，钇原子之间形成团簇最稳定的结构是倾向于平均配位数最大，其电离势没有“奇-偶”振荡或“幻数”效应，表明Y_n团簇光致电离开始主要发生在Y原子局域化的4d轨道上的电子而不是在5s上.对Tomasz提出的钇团簇电离势的解析式进行合理地修正，修正后电离势解析式的计算值与实验值更接近. 关键词： Y团簇 密度泛函 平衡几何结构 电离势

Calculation of ionization potential and geometry of small yttrium metal clusters

The equilibrium geometrical structures of ground state of small Y_n(n＝2—8) clusters are optimized by mean of density functional theory(DFT), and the ionization potentials are calculated. The results show that the most stable structures of clusters tend to maximize the average coordination number of Y atoms. The value of ionization potential shows uo magic number or odd-even alternations, this would imply that the threshold for photoionization occurs mainly from a localized 4d orbital rather than from a 5s orbital of Y clusters. It is the first time to come up with a modification of the analytical formula of calculating ionization potential of Y clusters proposed by Tomasz, and the new analytical formula is in better agreement with experiment.