Nbn（n=2-15）小团簇的第一性原理研究

摘要

【目的】研究纳米尺寸 Nbn 小团簇的结构演变过程,为进一步讨论 Nbn 小团簇的催化氧化性质提供参考。【方法】采用基于密度泛函理论(包括 PW91和 BLYP 函数)的第一性原理计算方法对 Nbn (n=2-15)小团簇的几何结构进行优化计算。【结果】随着原子数 n 的增加,Nbn (n=2-15)小团簇的结构及其特性具有明显的变化,平均每原子结合能(Binding Energy)随着原子数的增加呈递减趋势。【结论】Nbn (n=2-15)小团簇随尺寸变化具有明显的奇偶震荡性,n 为偶数时比 n 为奇数时的结构稳定,其中 Nb4、Nb6、Nb8、Nb10、Nb12小团簇结构较为稳定。%Objective]The structural properties of Nbn (n =2-15)clusters are analyzed and dis-cussed,which provides a reference for the catalytic oxidation of Nb clusters.[Methods]The first principle method based on density functional theory (including the PW91 and BLYP functions) is used to calculate the optimum structures of Nbn (n=2-15)clusters.[Results]With increasing the number n,Nbn (n=2-15)clusters obviously change in their structures and properties,and the average binding energy per atom increases as the number of atoms decreases.[Conclusion]An odd-even oscillation of Nbn (n =2-15)clusters energy has been observed.Furthermore,the Nbn clusters with even numbers are more stable than that with odd number structures.Among them,the Nb4 ,Nb 6 ,Nb8 ,Nb 1 0 ,Nb 1 2 clusters are more stable.