Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
Phys Chem Chem Phys. 2012 Jul 21;14(27):9601-5. doi: 10.1039/c2cp40922d. Epub 2012 Jun 8.
Dispersions of image potential states on a graphite surface (denoted IPS1) and on 1 monolayer (ML) film (denoted IPS2) of lead phthalocyanine (PbPc) are investigated by the micro-spot angle-resolved two-photon photoemission (micro-AR-2PPE) spectroscopy. On the graphite surface, whole dispersions of the two members of IPS1 (n = 1 and 2) are observed. The n = 1 IPS1 peak is weakly visible at energy higher than the vacuum level. The effective mass of an electron in the n = 1 IPS1 becomes slightly light at the high momentum region, suggesting the interaction between the IPS1 and the unoccupied σ-band of graphite. On the PbPc film, the IPS2 band forms a band gap and back-folds at the boundary of the Brillouin zone. A 1-dimensional Kronig-Penny model is used to reproduce the effective mass and the shift of binding energy.
利用微区角分辨双光子光发射谱（micro-AR-2PPE）光谱研究了石墨表面（表示为 IPS1）和单层（ML）膜上的铅酞菁（PbPc）的图像势能态分散体（表示为 IPS2）。在石墨表面，观察到 IPS1 的两个成员（n = 1 和 2）的整个分散体。n = 1 IPS1 峰在高于真空能级的能量处微弱可见。在高动量区域，n = 1 IPS1 中电子的有效质量略有减轻，表明 IPS1 与石墨的空 σ 带之间存在相互作用。在 PbPc 薄膜上，IPS2 带形成带隙，并在布里渊区边界处折叠。一维 Kronig-Penny 模型用于再现有效质量和结合能的位移。
