- 作者: 張哲政 ; 龍健華
- 作者服務機構: 台灣大學化學系
- 中文摘要: The power of the angle-resolved ion desorption technique for straightforward characterization of surfaces is demonstrated. The structural sensitivity of secondary ion desorption has led to a successful application of angle- resolved ion sputtering yield measurements to the determination of the Cl chemical bonding structure on the Ag.lbrace.100.rbrace. surface. Angular distributions of the sputtered Cl/sup -/ ions show that chlorine dissociates at the surface to yield a bonding state of atomic form at the room temperature. Both the polar and the azimuthal angle dependencies of the sputter intensity for Ag/sup +/ and Cl/sup -/ ions reveal that the Cl adatom is chemisorbed high above the topmost substrate layer of Ag atoms. At all Cl exposures, the Ag-Cl bond is oriented along the <100> azimuth with the adsorbate occupying a C/sub 4/ symmetry site, not an a-top, a bridge, or a high symmetry site. Shadow-cone enhanced ion desorption spectra show that the geometrical structure of the Cl chemisorbed surface changes slightly as the exposure is increased.
- 英文摘要: --
- 中文關鍵字: Secondary Ion Mass Spectrometry; Ion Desorption; Catalysis; Ethylene Epoxidation
- 英文關鍵字: 二極離子質譜儀;離子脫附;催化;乙烯環氧化