1991 Fiscal Year Final Research Report Summary
High Temperature Laser Photolysis in Reflected Shock Waves : Pulse Generation of Radicals and Their Chemical Reactions
| Project/Area Number |
02640332
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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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, Faculty of Engineering |
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Principal Investigator |
KOSHI Mitsuo University of Tokyo, Department of Reaction Chemistry, Associate Professor, 工学部, 助教授 (20133085)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Laser Photolysis / Reflected Shock Waves / Atomic Resonance Absorption / Ethynyl Radical / Transition state Theory / Tunnel Effect / Hydrogen Atom / Nitrogen Atom |
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| Research Abstract |
A new method for the pulse generation of radicals in reflected shock waves has been developed to measure the rates of radical-molecule reactions at high temperatures. An intense pulse of ArF (193 nm) or KrF (248nm) laser was used to photolyze O_2, CO_2, NO, H_2S, and C_2H_2 in reflected shock waves. Concentrations of atomic species such as H, O, and N atoms were measured by atomic resonance absorption spectroscopy. By using this method, following results were obtained.
(1) It has been shown that O_2 and CO_2 could be photodecomposed at 193 nm in the reflected shock waves via the absorption from vibrationally excited states. It was also shown that O_2 could be phtolysed even at 248 nm by the absorption from v"=7. Vibrational relaxation rates of O_2 in v"=2 and 7 were determined.
(2) Rate constants for the reactions of N+H_2 were directly determined at high temperatures for the first time.
(3) Non-Arrhenius temperature dependence of the rate constant was found for the H+H_2S reaction. This temperature dependence was explained by a transition state theory based on the quantum mechanical calculation of the transition state.
(4) The C_2H radical was produced by ArF laser photolysis of C_2H_2 in reflected shock waves. The rate constants of C_2H+C_2H_2 and C_2H+H_2 reactions were directly determined at high temperatures for the first time.
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