Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA.
J Phys Chem A. 2011 Sep 1;115(34):9479-84. doi: 10.1021/jp111932r. Epub 2011 Apr 20.
We report a systematic investigation of the electronic structure of chemisorbed alkali atoms (Li-Cs) on a Ag(111) surface by two-photon photoemission spectroscopy. Angle-resolved two-photon photoemission spectra are obtained for 0-0.1 monolayer coverage of alkali atoms. The interfacial electronic structure as a function of periodic properties and the coverage of alkali atoms is observed and interpreted assuming ionic adsorbate/substrate interaction. The energy of the alkali atom σ-resonance at the limit of zero coverage is primarily determined by the image charge interaction, whereas at finite alkali atom coverages, it follows the formation of a dipolar surface field. The coverage- and angle-dependent two-photon photoemission spectra provide information on the photoinduced charge-transfer excitation of adsorbates on metal surfaces. This work complements the previous work on alkali/Cu(111) chemisorption [Phys. Rev. B 2008, 78, 085419].
我们通过双光子光电子能谱系统地研究了化学吸附在 Ag(111)表面上的碱金属原子（Li-Cs）的电子结构。我们获得了 0-0.1 单层覆盖度的碱金属原子的角分辨双光子光电子能谱。我们假设离子吸附物/衬底相互作用，观察并解释了界面电子结构作为周期性性质和碱金属原子覆盖度的函数。在零覆盖度极限下，碱原子 σ 共振的能量主要由镜像电荷相互作用决定，而在有限的碱金属原子覆盖度下，它遵循形成偶极表面场的规律。覆盖度和角度相关的双光子光电子能谱提供了关于金属表面吸附物光致电荷转移激发的信息。这项工作补充了之前关于碱/Cu(111)化学吸附的工作[Phys. Rev. B 2008, 78, 085419]。
