WnNim(n+m=8)团簇结构与电子性质的理论研究

采用密度泛函理论(DFT)中的B3LYP方法,在Lanl2dz基组水平上对W_nNi_m(n+m=8)团簇的各种可能构型进行了几何参数全优化,得到了它们的基态构型;并对基态构型的平均结合能、Wiberg键级(WBI)、磁学性质、NBO进行了分析,结果表明:团簇随着W原子数的增多,稳定性增强,n≥5时,结构中都含有纯钨团簇的结构基元;W-W键级高于W-Ni键和Ni-Ni键;W₅Ni₃,W₆Ni₂团簇发生了"磁矩猝灭"的现象;在W,Ni原子内部,轨道电荷发生了转移,产生了"轨道杂化"现象,W,Ni原子之间也发生了电荷转移形成了较强的化学键. 关键词： nNi_m(n+m=8)团簇')" href="#">W_nNi_m(n+m=8)团簇 几何结构 电子性质 密度泛函理论

Theoretical study on structural and electronic properties of WnNim(n+m=8) clusters

The possible equilibrium geometries of W_nNi_m(n+m=8) clusters are optimized by using the density functional theory at the B3LYP/LANL2DZ level. For the ground state structures, the average binding energy, the wiberg bond index(WBI), the magnetism and the natural bond orbital(NBO) method are analyzed. The calculated results show that with the increase of the W atom number, the cluster becomes more stable. The strength in WBI is in the following order: W-W>W-Ni>Ni-Ni. When n≥5, the W_nNi_m(n+m=8) clusters include the basic structure of W_n cluster. The magnetic moments of W_nNi_m(n+m=8) clusters are quenched at n=5 and 6.Inside W and Ni atoms, the hybrid phenomenon happens, owing to the charge transfer. And the charge transfer also occurs between W and Ni atoms, thereby forming a strong chemical bond between W and Ni.