Coordination-Resolved Spectrometrics of Local Bonding and Electronic Dynamics of Au Atomic Clusters, Solid Skins, and Oxidized Foils.
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.
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).
Wang
W
Yu
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).
Maolin
M
Bo
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). huangyongli@xtu.edu.cn.
Yongli
Y
Huang
School of Information and Electronic Engineering, Hunan University of Science and Technology, Xiangtan 411201 (China).
Yan
Y
Wang
Institute of Coordination Bond metrology and Engineering, College of Materials Science and Engineering, China Jiliang University, Hangzhou 310018 (China).
Can
C
Li
School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore). ecqsun@ntu.edu.sg.
Chang Q
CQ
Sun
atomic clusters; gold; oxidation; photoelectron spectroscopy; thin films