Geometric and electronic structure of methane adsorbed on a Pt surface.
Geometric and electronic structure of methane adsorbed on a Pt surface.
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吸附在 Pt 表面上的甲烷的几何和电子结构。
DOI：
10.1063/1.2781470
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
A. Nilsson
中科院分区：
文献类型：
--
作者：
H. Oström;H. Ogasawara;L. Näslund;K. Andersson;L. Pettersson;A. Nilsson
用角分辨X射线吸收光谱(XAS)结合密度泛函理论光谱计算方法研究了甲烷在铂(977)表面的电子结构。XAS对空态原子的具体探测表明，由于S-p的重新杂化，出现了对称性禁忌的气相最低空态分子轨道。此外，在费米能级上方还出现了新的吸附感应态。系统的研究表明，指向表面的C-H键伸长为1.18+/-0.05A，这是由于成键和反键C-H轨道的混合引起的。计算的电荷密度差图表明，在吸附时，吸附物与底物之间没有形成共价化学键。电子结构的变化是为了使泡利排斥力最小，因为它将电荷从表面极化到甲烷分子的碳原子上。
The electronic structure of methane adsorbed on Pt(977) is investigated using angle-resolved x-ray absorption spectroscopy (XAS) in combination with density functional theory spectrum calculations. XAS, which probes the unoccupied states atom specifically, shows the appearance of the symmetry-forbidden gas-phase lowest unoccupied molecular orbital due to s-p rehybridization. In addition new adsorption-induced states appear just above the Fermi level. A systematic investigation, where computed XA spectra are compared with the experiment, indicates elongation of the C-H bond pointing toward the surface to 1.18+/-0.05 A. The bond elongation arises due to mixing between bonding and antibonding C-H orbitals. Computed charge density difference plots show that no covalent chemical bond is formed between the adsorbate and substrate upon adsorption. The changes in electronic structure arise in order to minimize the Pauli repulsion by polarizing charge away from the surface toward the carbon atom of the methane molecule.