| Project/Area Number |
02453005
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
物理化学一般
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| Research Institution | University of Tokyo |
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Principal Investigator |
KURODA Haruo University of Tokyo, Faculty of Science, Professor, 理学部, 教授 (00011479)
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| Co-Investigator(Kenkyū-buntansha) |
ASAKURA Kiyotaka University of Tokyo, Faculty of Science, Assistant, 理学部, 助手 (60175164)
NAMBA Hideotshi University of Tokyo, Faculty of Science, Assistant, 理学部, 助手 (40118766)
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| Project Period (FY) |
1990 – 1991
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| Project Status |
Completed (Fiscal Year 1991)
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| Budget Amount *help |
¥8,400,000 (Direct Cost: ¥8,400,000)
Fiscal Year 1991: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1990: ¥7,000,000 (Direct Cost: ¥7,000,000)
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| Keywords | Step / Chemisorption / SEXAFS / ARUPS / Local Structure / Electronic States / Nickel / Sulfur / 単結晶 / 単結晶ステップ面 / 局所構造解析 |
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| Research Abstract |
Atomic views of surface defects which play important roles in surface reactions have not been revealed clearly. Steps arranged periodically on vicinal surfaces of single crystals can be a model of surface defects. We studied atomic arrangement and electronic structure of Ni(7 9 11) surfaces by surface extended x-ray absorption fine structure (SEXAFS) and angle resolved photoelectron spectroscopy (ARUPS) by using synchrotron radiation. We also studied the adsorption of alkali metals as promoter and of sulfur as poison in surface reactions on Ni(7 9 11) surfaces. Two important results are summarized as follows.
(1)At early stages of adsorption at room temperature, sulfur atoms occupy 4-fold sites at step edges on Ni(7 9 11) surfaces. The atomic arrangement at the 4-fold step site was determined by the polarization dependence of SEXAFS spectra. By further adsorption of sulfur, the sulfur layer showing the ROO<3>xROO<3> structure is formed on terrace planes. Sulfur atoms adsorbed at step edges may act as nuclei of the layer formation.
(2)New electronic states localized at step edges were found by the polarization dependence of ARUPS spectra. The dispersion relation of the step electronic states determined in the present experiment suggests one dimensional character in the direction of steps. The step electronic states are more surface sensitive than the surface states on terrace planes.
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