Yu Wang, Bo Maolin, Huang Yongli, Wang Yan, Li Can, Sun Chang Q
Key Laboratory of Low-dimensional Materials and Application Technology (Ministry of Education), Hunan Provincial Key Laboratory of Thin Film Materials and Devices, and School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105 (China).
School of Information and Electronic Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China).
Chemphyschem. 2015 Jul 20;16(10):2159-64. doi: 10.1002/cphc.201500171. Epub 2015 Apr 27.
By using combination of bond-order-length-strength (BOLS) correlation, the tight-binding (TB) approach, and zone-selective photoelectron spectroscopy (ZPS), we were able to resolve local bond relaxation and the associated 4f7/2 core-level shift of Au atomic clusters, Au(100, 110, 111) skins, and Au foils exposed to ozone for different lengths of time. In addition to quantitative information, such as local bond length, bond energy, binding-energy density, and atomic cohesive energy, the results confirm our predictions that bond-order deficiency shortens and stiffens the bond between undercoordinated atoms, which results in local densification and quantum entrapment of bonding electrons. The entrapment perturbs the Hamiltonian, and hence, shifts the core-level energy accordingly. ZPS also confirms that oxidation enhances the effect of atomic undercoordination on the positive 4f7/2 energy shift, with the associated valence electron polarization contributing to the catalytic ability of undercoordinated Au atoms.
通过结合键序-键长-键强（BOLS）关联、紧束缚（TB）方法和区域选择性光电子能谱（ZPS），我们能够解析金原子团簇、不同暴露时长于臭氧的Au(100, 110, 111)表面以及金箔中的局部键弛豫和相关的4f7/2芯能级位移。除了诸如局部键长、键能、结合能密度和原子内聚能等定量信息外，结果证实了我们的预测：键序缺陷会缩短并强化低配位原子之间的键，这导致键合电子的局部致密化和量子捕获。这种捕获会扰动哈密顿量，因此相应地使芯能级能量发生位移。ZPS还证实，氧化增强了原子低配位对正4f7/2能量位移的影响，相关的价电子极化有助于低配位金原子的催化能力。
