Origins of Stability in Mixed Bismuth−Indium Clusters

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• 作者：Ujjwal Gupta ; J. Ulises Reveles ; Joshua J. Melko ; Shiv N. Khanna ; A. W. Castleman ; Jr.
• 刊名：Journal of Physical Chemistry C
• 出版年：2010
• 出版时间：September 30, 2010
• 年：2010
• 卷：114
• 期：38
• 页码：15963-15972
• 全文大小：546K
• 年卷期：v.114,no.38(September 30, 2010)
• ISSN：1932-7455

文摘

The electronic structure and stability of neutral and negatively charged Bi_xIn_y (x = 1−4, y = 1−6) clusters are investigated through anionic photoelectron spectroscopy employing magnetic bottle and photoelectron velocity map imaging experiments. Experimental and theoretical adiabatic and vertical detachment energies of the anionic species containing up to 4 Bi and 4 In atoms are deduced from first principles calculations. Among the Bi_xIn_y series, many clusters are found to exhibit special stability in the mass spectra, exhibit a large gap between the highest occupied and lowest unoccupied molecular orbitals (HOMO−LUMO gap), and a large formation energy. This stability is rationalized by different mechanisms. Bi₂In⁻ is classified as a gas phase Zintl species despite only having three atoms, making it the smallest possible case. Bi₃In₂⁻, with 12 valence electrons and a closo structure in agreement with Wade’s rule, is similar to Bi₃Ga₂⁻, a gas phase Zintl analogue of Sn₅²⁻. Bi₄In⁻ and Bi₄In₂ are both found to follow Wade’s rule, indicating gas phase Zintl clusters. BiIn₃ is a cyclic planar molecule similar to BiGa₃ and BiAl₃, all-metal aromatic systems, and BiIn₅ is a 20 electron closed shell Jellium species. Additionally, an even−odd oscillation of the HOMO−LUMO gaps, formation energies, and adiabatic electron affinities are found correlating with the open-shell/closed-shell nature of the clusters.