Analysis of the dynamic factors promoting the chemical reaction by combining the quantum mechanical and the molecular dynamics methods

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K05766
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Physical chemistry
• Research Institution: Kanagawa University
• Principal Investigator: Matsubara Toshiaki 神奈川大学, 理学部, 教授 (60239069)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 量子力学的手法 / 分子動力学法 / SN2反応 / 動的因子 / 溶媒効果

Outline of Final Research Achievements

We analyzed how the chemical reaction starts and how the substrate goes over the energy barrier from a dynamic point of view by combining the quantum mechanical and the molecular dynamics methods. We selected the SN2 reaction of 2-chlorobutane with OH- as a model reaction and performed the QM- and the ONIOM-MD simulations in the gas phase and the water solvent, respectively. As a result, it was found that the kinetic energy concentrates on the atoms participating in the reaction just before the reaction, and the substrate climbs up and down the energy barrier only when the velocity vector of those atoms satisfies a certain pattern. The pattern of the velocity vector changes in the water solvent due to the dynamic effects of the water solvent molecules on the substrate.

Free Research Field

計算化学

Academic Significance and Societal Importance of the Research Achievements

量子力学的手法は今や分子設計、反応設計の強力な手段となっているが、エネルギープロフィールの平衡構造や遷移状態の停留点、あるいは固有反応座標に関する情報は与えてくれるものの、ダイナミックな情報は与えてくれない。どのようにして化学反応が始まり、どのようにエネルギー障壁を越えていくのか、といった問題は非常に興味深い。化学反応が起こる瞬間に何が起こっているのかは依然未知の課題と言える。量子力学的手法を分子動力学法と組み合わせることで、本研究で得られた化学反応を推進する動的因子の知見は、今後の化学反応理論の発展への貢献が期待される。