Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
J Phys Chem A. 2010 Feb 11;114(5):2045-52. doi: 10.1021/jp908406h.
The electronic structure of Al(n)X (n = 1-6; X = As, Sb) clusters has been investigated using a synergistic approach combining negative ion photoelectron spectroscopy and first principles electronic structure calculations. It is shown that Al(3)X and Al(5)X exhibit enhanced energetic stability, as evidenced from calculated removal and embedding energies as well as chemical stability manifested through a large gap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). However, the stabilities of these species are derived from different mechanisms. Al(3)As and Al(3)Sb, with HOMO-LUMO gaps of 1.86 and 1.73 eV, respectively, are shown to have planar geometries where the p orbitals combine to form one pi and two sigma aromatic orbitals reminiscent of conventional all-metal aromatic species. Al(5)As and Al(5)Sb, with 20 valence electrons, possess a closed electronic shell (1s(2), 1p(6), 1d(10), 2s(2)) within a jellium framework and have HOMO-LUMO gaps of 1.12 and 1.17 eV, respectively.
使用结合负离子光电子能谱和第一性原理电子结构计算的协同方法，研究了 Al(n)X（n = 1-6；X = As、Sb）团簇的电子结构。结果表明，Al(3)X 和 Al(5)X 表现出增强的能量稳定性，这可以从计算的去除和嵌入能以及化学稳定性得到证明，其最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）之间存在较大的间隙。然而，这些物种的稳定性来自不同的机制。Al(3)As 和 Al(3)Sb 的 HOMO-LUMO 间隙分别为 1.86 和 1.73 eV，它们具有平面几何形状，其中 p 轨道结合形成一个 π 和两个 σ 芳香轨道，类似于传统的全金属芳香族物种。Al(5)As 和 Al(5)Sb 具有 20 个价电子，在类金属框架内具有封闭的电子壳（1s(2)、1p(6)、1d(10)、2s(2))，其 HOMO-LUMO 间隙分别为 1.12 和 1.17 eV。
