Symmetry and electronic structure of noble-metal nanoparticles and the role of relativity -: art. no. 093401
Symmetry and electronic structure of noble-metal nanoparticles and the role of relativity -: art. no. 093401
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DOI：
10.1103/physrevlett.93.093401
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发表时间：
2004-08-27
影响因子：
8.6
通讯作者：
von Issendorff, B
中科院分区：
文献类型：
--
作者：
Häkkinen, H;Moseler, M;von Issendorff, B
本文报道了冷质量选择Cu-n（-）、Ag-n（-）和Au-n（-）（n=53-58）的高分辨紫外光电子能谱。观察到的电子态密度不是预期的简单电子壳层结构，而是受到电子-晶格相互作用的强烈影响。只有Cu-55（-）和Ag-55（-）表现出高度简并态。这是它们二十面体对称性的直接结果，正如密度泛函理论计算所证实的那样。相邻的尺寸表现出扰动的电子结构，因为它们是通过去除或添加原子到二十面体而形成的，因此具有较低的对称性。在相同尺寸范围内的金团簇显示出完全不同的光谱，几乎没有简并，这表明它们具有低得多的对称性结构。这种行为与金中强的相对论成键效应有关，如Au-55（-）的从头计算所证明的。
We present high resolution UV-photoelectron spectra of cold mass selected Cu-n(-), Ag-n(-), and Au-n(-) with n=53-58. The observed electron density of states is not the expected simple electron shell structure, but is strongly influenced by electron-lattice interactions. Only Cu-55(-) and Ag-55(-) exhibit highly degenerate states. This is a direct consequence of their icosahedral symmetry, as is confirmed by density functional theory calculations. Neighboring sizes exhibit perturbed electronic structures, as they are formed by removal or addition of atoms to the icosahedron and therefore have lower symmetries. Gold clusters in the same size range show completely different spectra with almost no degeneracy, which indicates that they have structures of much lower symmetry. This behavior is related to strong relativistic bonding effects in gold, as demonstrated by ab initio calculations for Au-55(-).