2020 Fiscal Year Final Research Report
Direct observation for steric effect in chemical reaction by controlling molecular orientation of reactants
Project/Area Number |
17KT0008
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Research Category |
Grant-in-Aid for Scientific Research (B)
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Allocation Type | Multi-year Fund |
Section | 特設分野 |
Research Field |
Transition State Control
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Research Institution | Osaka University |
Principal Investigator |
CHE DOCK-CHIL 大阪大学, 理学研究科, 講師 (20273732)
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Project Period (FY) |
2017-07-18 – 2021-03-31
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Keywords | 配向状態選別 / 光解離 / 反応分岐比 / ベクトル相関 / ハロタン / イソハロエタン |
Outline of Final Research Achievements |
Photodissociation dynamics of halothane molecule state-selected using a hexapolar was studied at 235 nm laser light. The scattering distribution of competitively formed Br and Cl atoms was determined by a two-dimensional imaging technique. As a result, it was found that the Br atom is formed by the direct dissociation, and the Cl atom has two formation pathways. It was found that the reaction branching ratio of Cl atom formation is about twice as large as that of Br atom. This is different from the results predicted from the conventional dissociation energy and absorption spectrum correlated atoms, and suggests that a new dissociation mechanism needs to be considered. On the other hand, the direction of the transition dipole moment in the photoexcitation of isohaloethane was experimentally determined by selecting the orientation state and examining the correlation with the polarization vector of the laser.
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Free Research Field |
反応物理化学
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Academic Significance and Societal Importance of the Research Achievements |
ハロタン分子の光解離の研究を実施し、競争的に生成するBr及びCl原子生成の反応機構を解明した。反応分岐比を測定したところ、Cl原子生成はBr原子に比べ反応分岐比が大きいことが明らかとなった。この結果は、結合エネルギーや分子の吸収スペクトルから予測される結果と全く異なり、新しい解離メカニズムの必要性を提案する結果であった。一方で、対象軸を持たない分子の遷移モーメントの方向を調べることは困難とされていた。今回、イソハロタン分子の双極子モーメントとレーザーの偏光ベクトルのベクトル相関を調べることで分子が光を吸収する際の遷移双極子モーメントの方向を実験的に決定することに成功した。
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