Co2Bn (n = 1 - 8) 团簇几何结构的密度泛函理论研究
Geometries of the Co2Bn (n = 1 - 8) clusters: A density functional theory investigation

受到小型环状和管状的双金属掺杂硼团簇的启发，采用密度泛函理论，在B3LYP / 6-311 + G(d)水平下对Co2Bn (n = 1 - 8)团簇的几何结构、相关稳定性、电子性质和磁性进行了的研究．研究结果表明：当n ≤ 5时，团簇的最低能量结构为平面结构．当6 ≤ n ≤ 8时，团簇的最低能量结构为立体结构．对团簇的平均原子结合能、二阶差分能量、HOMO-LUMO能隙、垂直电子亲和能、垂直电离能和化学硬度分析结果表明，Co2B7具有幻数特征．对Co2Bn (n = 1 - 8)团簇的总磁矩计算表明其和团簇的自旋态有很强的关系，而且团簇的总磁矩主要由钴原子的3d轨道所贡献．
Inspired by the article of metal doped boron clusters with cyclic and tubular configurations, the geometric structures, relative stabilities, electronic and magnetic properties of Co2Bn clusters up to n = 8 were systematically investigated by using density functional theory at B3LYP / 6-311 + G (d) level. The results show that at n ≤ 5, the lowest energy structures of clusters adopt the flat structures. At 6 ≤ n ≤ 8, the lowest energy structures of Co2Bn clusters demonstrate the three-dimensional configuration. The binding energies per atom, the second-order differences of energies, HOMO - LUMO energy gaps, vertical electron affinities, vertical ionization potentials and chemical hardnesses of these clusters show that Co2B7 cluster has the characteristics of magic number. The calculations of the total magnetic moments for Co2Bn clusters (n = 1-8) clusters indicate that the magnetic moments are strongly related to the spin states. Furthermore, the magnetic moments of these clusters are mainly composed of 3d orbital contributions of cobalt atoms.