Pande Seema, Gong Xingao, Wang Lai-Sheng, Zeng Xiao Cheng
Department of Chemistry , University of Nebraska-Lincoln , Lincoln , Nebraska 68588 , United States.
Department of Physics, Key Laboratory for Computational Physical Science (Ministry of Education) , Fudan University , Shanghai 200433 , China.
J Phys Chem Lett. 2019 Apr 18;10(8):1820-1827. doi: 10.1021/acs.jpclett.9b00446. Epub 2019 Apr 2.
Among coinage metal nanoclusters with 55 atoms, only Ag and Cu are the geometric magic-number clusters, as both exhibit icosahedral symmetry. Au, however, exhibits much lower symmetry due largely to the strong relativistic bonding effect. In this study, we collect a much larger population (>10,000 isomers) of low-energy isomers of Au to Au by using the combined density-functional theory and basin-hopping global optimization method. We also include the spin-orbit effect in the density-functional theory computation to achieve simulated photoelectron spectra in quantitative fashion. Remarkably, we uncover that the Au core with the highest icosahedral ( I) symmetry emerges at the size of Au. Stability analysis suggests that Au with 58 valence electrons, an electronic magic number, is the relatively more stable cluster in the size range considered. Overall, in this size range we reveal a compromise between the trend toward having a perfect icosahedral 13-atom core and the strong relativistic bonding effect.
在含有55个原子的硬币金属纳米团簇中，只有银和铜是几何幻数团簇，因为它们都呈现二十面体对称性。然而，金的对称性要低得多，这主要是由于强烈的相对论键合效应。在本研究中，我们使用密度泛函理论和盆地跳跃全局优化方法相结合，收集了数量多得多（超过10000个异构体）的金到金的低能异构体。我们还在密度泛函理论计算中纳入了自旋轨道效应，以定量方式获得模拟光电子能谱。值得注意的是，我们发现具有最高二十面体（I）对称性的金核出现在金的尺寸处。稳定性分析表明，具有58个价电子（一个电子幻数）的金是所考虑尺寸范围内相对更稳定的团簇。总体而言，在这个尺寸范围内，我们揭示了朝着拥有完美的13原子二十面体核的趋势与强烈的相对论键合效应之间的一种折衷。
