Li Shihao, Huang Jiayu, Lu Zhibing, Shu Yiyang, Chen Wentao, Yuan Daofu, Wang Tao, Fu Bina, Zhang Zhaojun, Wang Xingan, Zhang Dong H, Yang Xueming
Department of Chemical Physics, University of Science and Technology of China, Hefei, 230026, China.
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, China.
Nat Commun. 2024 Feb 24;15(1):1698. doi: 10.1038/s41467-024-45843-6.
Quantum interference between reaction pathways around a conical intersection (CI) is an ultrasensitive probe of detailed chemical reaction dynamics. Yet, for the hydrogen exchange reaction, the difference between contributions of the two reaction pathways increases substantially as the energy decreases, making the experimental observation of interference features at low energy exceedingly challenging. We report in this paper a combined experimental and theoretical study on the H + HD → H + D reaction at the collision energy of 1.72 eV. Although the roaming insertion pathway constitutes only a small fraction (0.088%) of the overall contribution, angular oscillatory patterns arising from the interference of reaction pathways were clearly observed in the backward scattering direction, providing direct evidence of the geometric phase effect at an energy of 0.81 eV below the CI. Furthermore, theoretical analysis reveals that the backward interference patterns are mainly contributed by two distinct groups of partial waves (J ~ 10 and J ~ 19). The well-separated partial waves and the geometric phase collectively influence the quantum reaction dynamics.
锥形交叉点（CI）周围反应路径之间的量子干涉是详细化学反应动力学的超灵敏探针。然而，对于氢交换反应，随着能量降低，两条反应路径贡献的差异会大幅增加，使得在低能量下对干涉特征进行实验观测极具挑战性。我们在本文中报告了对碰撞能量为1.72 eV时H + HD → H + D反应的实验与理论相结合的研究。尽管漫游插入路径在总贡献中仅占一小部分（0.088%），但在向后散射方向上清晰地观察到了由反应路径干涉产生的角振荡模式，这为在低于CI能量0.81 eV处的几何相位效应提供了直接证据。此外，理论分析表明，向后干涉模式主要由两组不同的分波（J ~ 10和J ~ 19）贡献。分得很开的分波和几何相位共同影响量子反应动力学。
