1986 Fiscal Year Final Research Report Summary
Elementary Chemical Reaction at Ultralow Temperature
| Project/Area Number |
60470008
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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 | Faculty of Engineering, Nagoya University |
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Principal Investigator |
MIYAZAKI Tetsuo Faculty of Engineering, Nagoya University, 工学部, 助教授 (90023126)
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| Project Period (FY) |
1985 – 1986
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| Keywords | Ultralow temperature / Tunneling effect / Macroscopic quantum effect / Solid hydrogen / Hydrogen atom-molecule reaction / Elementary chemical reaction / 電子スピン共鳴吸収 |
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| Research Abstract |
Basic to any theory of elementary chemical reactions is an understanding of the simplest atom-diatomic molecule exchange reaction of <H_2> (or <D_2> or HD). The role of a quantum-mechanical tunneling effect of the <H_2> + H reaction has been one of the important problems in the theory of chemical kinetics. Since the previous studies have been undertaken above 200 K, it was difficult to discriminate clearly between the reaction caused by the quantum-mechanical tunneling effect and the reaction which proceeds by passing over a potential energy barrier.
In order to clarify the tunneling effect, Miyazaki has studied the <H_2> (or HD or <D_2> ) + D(or H) reaction in the radiolysis of solid hydrogen at 4.2 and 1.9 K by ESR spectroscopy. The following results were obtained. (1) The fast decay of H atoms in solid <H_2> was explained by a model of tunneling migration in which the H atoms repeat tunneling abstraction reactions with <H_2> ( <H_2> + H -> H + <H_2> ) and migrate through solid <H_2> to recombine with other H atoms. (2) A direct evidence for tunneling reaction HD + D -> H + <D_2> was obtained in the radiolysis of a <D_2> -HD mixture. (3) The rate constants for tunneling reactions of HD + D -> H + <D_2> and <D_2> + D -> D + <D_2> were measured.
Recoil tritium reaction in rare gas-ethane solid mixtures has been studied at 11 - 20 K. It was found that tritium atoms react with ethane by quantum tunneling.
Mechanism of paired radical formation in the radiolysis of solid methane has been studied by ESR spectroscopy at 4.2 K. Ionic fragmentation was observed in the radiolysis of rare gas-alkane mixtures at 4.2 K. The initial energy of hot H atoms produced by the radiolysis of alkane was estimated by ESR spectroscopy at 4.2 K.
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