Analysis of Solid Surfaces by Means of Penning Ionization Electron Spectroscopy and High Resolution Electron Energy Loss Spectroscopy

虽然固体表面的研究近年来取得了很大进展，但在表面上发生的反应过程还没有得到很好的理解。这似乎是由于这样的事实，即表面分析方法，有选择地敏感的最外层的表面层没有得到很好的应用。本研究尝试将潘宁电离电子能谱（PIES）和高分辨电子能量损失谱（HREELS）相结合，发展一种新的表面分析方法。PIES能选择性地提供固体最外层的电子态信息，而HREELS能灵敏地探测固体最外层的原子和分子振动（低能电子衍射），AES（俄歇电子能谱）和UPS（紫外光电子能谱）以及PIES和HREELS的那些。使用 ...更多信息 用LEED和AES研究了清洁Ni（100）表面的结构和原子组成，用PIES和UPS研究了表面的电子态，用HREELS研究了表面的振动态。<He^*> PIES的测量给出了以下结果。在清洁的Ni表面上，亚稳态氦原子的2s电子转移到Ni表面，形成<He^+>离子。因此，相应的光谱与INS（离子中和光谱）给出的光谱相似。在吸附表面，另一方面，Penning电离过程发生，因为Ni表面被CO原子屏蔽。在这种情况下，暴露在吸附表面外的各个轨道的电子分布的直接信息，可以通过PIES.In addition上述研究，各种有机薄膜的表面进行表征PIES和UPS。已经证实，PIES使我们能够灵敏地检测分子取向和电子状态的变化在固体的最外表面层。特别是，最近注意到的LB（Langmuir-Blodgett）膜中的分子取向已被发现是直接已知的PIES，即使在由一个到几个单层组成的超薄膜的情况下。少

Although much progress has recently been made in the study of solid surfaces, the process of reactions taking place on the surfaces has not been well understood. This seems to be due to the fact that surface-analysis methods which are selectively sensitive to the outermost surface layer have not been well applied. In this study, we tried to develop a new method of surface analysis with the combination of PIES (Penning ionization electron spectroscopy) and HREELS (high resolution electron energy loss spectroscopy). PIES provides information on the electronic state of the outermost surface layer of solid selectively, whereas HREELS enables us to detect atomic and molecular vibrations at the outermost layer sensitively.To achieve the above purpose, we designed and constructed an instrument including the appratuses for LEED (low energy electron diffraction), AES (Auger electron spectroscopy), and UPS (ultraviolet photoelectron spectroscopy) together with those for PIES and HREELS. Using th … More is instrument, we studied surfaces of clean Ni(100) and CO adsorbed on it. The structure and atomic composition of the surfaces were investigated by LEED and AES, the electronic state by PIES and UPS, and the vibrational state was examined by HREELS. The measurements of <He^*> PIES gave the following results. On the clean Ni surface the 2s electon of a metastable helium atom transfers to the Ni surface to form a <He^+> ion. Therefore, the corresponding spectrum is similar to that given by INS (ion neutralization spectroscopy). On the adsorbed surface, on the other hand, Penning ionization process takes place because the Ni surface is shielded by CO atoms. In this case, direct information on the electron distribution of individual orbitals exposed outside the adsorbed surface can be obtained by PIES.In adition to the above study, the characterization of surfaces of various organic thin films was performed by PIES and UPS. It has been confirmed that PIES enables us to detect sensitively the changes in the molecular orientation and electronic state at the outermost surface layer of solid. In particular, the molecular orientation in LB (Langmuir-Blodgett) films noted recently has been found to be directly known by PIES even in the cases of ultra-thin films composed of one to several monolayers. Less