Special stability of cationic MPb12+ clusters and superalkali character of neutral MPb12 clusters (M = B, Al, Ga, In, and Tl).
Special stability of cationic MPb12+ clusters and superalkali character of neutral MPb12 clusters (M = B, Al, Ga, In, and Tl).
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阳离子 MPb12 团簇的特殊稳定性和中性 MPb12 团簇（M = B、Al、Ga、In 和 Tl）的超碱性特性。
DOI：
10.1063/1.2189224
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Chia
中科院分区：
文献类型：
--
作者：
De;W. Tian;Wencai Lu;Chia
在密度泛函理论框架内研究了具有50个价电子的阳离子MPb12⁺团簇（M = B、Al、Ga、In和Tl）的电子结构和稳定性。结果表明，在B3LYP/cc - pVDZ(-PP)和BPW91/cc - pVDZ(-PP)理论水平下，具有二十面体（Iₕ）对称性的MPb12⁺结构在能量上是有利的，它们的高稳定性可能源于π子系统的闭壳层性质，该性质符合N(π)=1时的2(N(π + 1)²规则。此外，这五种团簇具有较大的核独立化学位移，反映了这些团簇共有的芳香性特征。通过对结合能以及最高占据分子轨道和最低未占据分子轨道能隙的研究比较，AlPb12⁺团簇比其他团簇具有更高的稳定性，这与最近在质谱中发现的Al掺杂Pbₙ⁺团簇中AlPb12⁺高度富集的结果一致。使用相同的方法搜索中性MPb12团簇的结构。计算表明，BPb12和GaPb12团簇最稳定的几何构型具有Iₕ对称性，AlPb12和InPb12团簇具有Tₕ对称性，TlPb12团簇具有C₅ᵥ对称性。此外，中性MPb12团簇的垂直电离势小于一些碱金属原子的垂直电离势，这表明中性MPb12团簇具有超碱金属特性。
The electronic structures and stabilities of cationic MPb12+ clusters (M = B, Al, Ga, In, and Tl) with 50 valence electrons are investigated within density functional theory. It is shown that, at the B3LYP/cc-pVDZ(-PP) and BPW91/cc-pVDZ(-PP) levels of theory, the structures of MPb12+ with icosahedra (I(h)) symmetry are energetically favorable, and their high stabilities may arise from the closed-shell nature of the pi subsystems which are subject to the 2(N(pi + 1)2 rule with N(pi = 1). In addition, the possessing of large nucleus-independent chemical shifts of the five kinds of clusters reflects the common aromatic character of these clusters. From the comparison of our studies on the binding energies and the highest occupied molecular orbital and the lowest unoccupied molecular orbital energy gaps, the cluster AlPb12+ has higher stability than the others and this is consistent with the recent mass-spectrometric discovery of Al-doped Pb(n)+ clusters, in which AlPb12+ is highly abundant. The same methods are used to search for the structures of the neutral MPb12 clusters. The calculations reveal that the most stable geometries of the BPb12 and GaPb12 clusters have I(h) symmetry, the AlPb12 and InPb12 clusters have T(h) symmetry, and the TlPb12 cluster has C5v symmetry. Furthermore, the vertical ionization potentials of the neutral MPb12 clusters are smaller than that of some alkali atoms, indicating that the neutral MPb12 clusters possess superalkali character.