Mo_n(n=2～10)团簇结构和性质的密度泛函理论研究

Density functional theory study of the structures and electronic properties of Mo_n(n=2～10) clusters

采用密度泛函理论下的广义梯度近似(Generalized Gradient Approximation,GGA)方法对Mo_n(n=2～10)团簇的直线结构、平面结构和立体结构分别进行优化和分析.结果表明仅直线结构具有双原子对结合趋势,且偶数团簇比相邻奇数团簇稳定;平面结构中奇数原子团簇锯齿状较稳定,偶数原子团簇以多边形较稳定;立体结构在所有维度中最稳定.对团簇总磁矩的分析表明直线结构偶数团簇磁矩淬灭,奇数团簇具有较大的反磁矩;基态结构中仅Mo_3和Mo_8有2_(μB)的磁矩.基态结构的二阶能量差分、垂直电离势和能隙均表明Mo_5为幻数团簇,并分析了其热力学性质,对幻数团簇Mo_5的热力学性质分析表明,标准热力学函数随温度增加而增大.

Linear, planar and 3D structures of Mon（n=2-10） clusters were optimized by using density functional theory with generalized gradient approximation. The results showed that the linear structures have a strong tendency to form dimers and the even number clusters were more stable than their neighboring odd number clusters; in the planar structures, the odd number clusters were stable in zigzags and the even number clusters were stable in polygons; 3D structures were the most stable among all dimen- sions. Only Mo3 and Mo8 had 2μB magnetic moments in the ground state structures. According to the results of the second order deference of total energies, vertical ionization potential and energy gaps, the magic number of the Mon （n=2- 10） clusters was 5. Analyzed the thermodynamic properties of magic number cluster Mo5 showed that the standard thermodynamic functions increased with the temperatures increasing.