在UBP86/TZVP水平上计算了小镍团簇(Ni<,n>,n=2～6)的稳定基态结构并用自然键轨道(NBO)和分子中的原子量子理论(QTAIM)分析了这些团簇的电子结构.计算结果表明,Ni团簇基态结构具有较高自旋多重度.QTAIM分析表明镍团簇中Ni-Ni键均为金属键.除Ni<,2>团簇中Ni-Ni键为纯粹的σ键外,其他团簇中Ni-Ni键具有部分π键特征.提出了采用团簇的原子平均离域化指数(δ)来表示团簇的相对稳定性,平均离域化指数与团簇的平均结合能具有较好线性关系.%The ground state structures of small nickel clusters (Ni2-6 ) were investigated at the UBP86/TZVP level, and their electronic structures were analyzed by natural bond orbital (NBO) and quantum theory of atom-in-molecules (QTAIM). The computational results indicate that the ground state of the nickel cluster is a high-spin state. The Ni-Ni bond in the nickel clusters is predicted to be metallic bond by QTAIM. The Ni-Ni bond of Ni2 is pure r bond, while the Ni-Ni bond in the other clusters is π bond. The proposed atomic average electron delocalization index can be used to represent the relative stability of the clusters. The atomic average electron delocalization index has a good linear relationship with the average binding energy of the cluster.
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