Xu Xin, Chen Jun, Lu Xiaoxiao, Fang Wei, Liu Shu, Zhang Dong H
State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences Dalian 116023 Liaoning China
State Key Laboratory of Structure Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences Fuzhou 350002 Fujian China.
Chem Sci. 2022 Jun 13;13(26):7955-7961. doi: 10.1039/d2sc01958b. eCollection 2022 Jul 6.
The OH + HCl → HO + Cl reaction releases Cl atoms, which can catalyze the ozone destruction reaction in the stratosphere. The measured rate coefficients for the reaction deviate substantially from the Arrhenius limit at low temperatures and become essentially independent of temperature when < 250 K, apparently due to quantum tunneling; however, the nature of the quantum tunneling is unknown. Here, we report a time-dependent wave packet study of the reactions on two newly constructed potential energy surfaces. It is found that the OH + HCl reaction possesses many Feshbach resonances trapped in a bending/torsion excited vibrational adiabatic potential well in the entrance channel due to hydrogen bond interaction. These resonance states greatly induce quantum tunneling of a hydrogen atom through the reaction barrier, causing the reaction rates to deviate substantially from Arrhenius behavior at low temperature, as observed experimentally.
OH + HCl → HO + Cl 反应会释放出氯原子，这些氯原子能够催化平流层中的臭氧破坏反应。该反应的实测速率系数在低温下与阿仑尼乌斯极限有很大偏差，当温度低于250 K时，速率系数基本与温度无关，这显然是由于量子隧穿效应；然而，量子隧穿的本质尚不清楚。在此，我们报告了在两个新构建的势能面上对该反应进行的含时波包研究。研究发现，由于氢键相互作用，OH + HCl反应在入射通道的弯曲/扭转激发振动绝热势阱中存在许多费什巴赫共振。这些共振态极大地诱发了氢原子通过反应势垒的量子隧穿，导致反应速率在低温下与阿仑尼乌斯行为有很大偏差，这与实验观测结果一致。
