2006 Fiscal Year Final Research Report Summary
Auger-Electron-Probe Time-Resolved Surface XAFS Technique and Its Application to Study of Surface Dynamics
| Project/Area Number |
16072205
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| Research Category |
Grant-in-Aid for Scientific Research on Priority Areas
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| Allocation Type | Single-year Grants |
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| Review Section |
Science and Engineering
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KONDOH Hiroshi The University of Tokyo, Graduate School of Science, Associate Professor (80302800)
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| Co-Investigator(Kenkyū-buntansha) |
AMEMIYA Kenta High-Energy Acceleration Organization, Institute of Materials Structure Science, Associate Professor (80313196)
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| Project Period (FY) |
2004 – 2006
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| Keywords | Time resolved / XAFS / XPS / reaction dynamics / reaction kinetics / reaction mechanism |
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| Research Abstract |
We have developed a fast surface x-ray absorption fine structure(XAFS)technique where solid substrates are irradiated by energy-dispersed synchrotron-radiation x rays and auger electrons emitted from x-ray absorbing surface species are collected at once with a spatially resolved way. In this project we aimed further development of this technique and its application to mechanistic studies on chemical reactions on solid substrates. The present improvement enabled us to trace changes in both surface and gas-phase species simultaneously every approximately 1 s. If this technique is applied to repeatable processes, we can detect submonolayer surface species with a time resolution of 10 ms by using a time gate for the detector. Furthermore we extended this technique to the undulator-based time-resolved x-ray photoelectron spectroscopy, which enabled us to observe dynamic processes of submonolayer surface species with a time resolution of 2 ms.
Real-time monitoring of surface reaction kinetics based on these techniques provided following three major achievements in research that have never been achieved by previous methods.
(1) Finding of a novel reaction pathway involving a NO dimer as a reaction intermediate under the reaction condition of NO reduction on Rh
(2) Elucidation of cirrelation between phase transition of surface oxygen and reactivity under the reaction condition of CO oxidation on Pd
(3) Detection of a transient high-density adsorption state with a life time of less than millisecond order induced by NO pulsed molecular beam
The present development of the fast observation technique for surface species and its application to surface dynamic processes open a way to study novel dynamic processes that have not been detected with previous static surface techniques.
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