Jiao Zhirun, Zhang Hongtao, Wang Hao, Li Yu, Wang Heilong, Xiao Chunlei, Yang Xueming
State Key Laboratory of Chemical Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, Liaoning 116023, China.
School of Chemical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
J Phys Chem A. 2025 Sep 25;129(38):8766-8771. doi: 10.1021/acs.jpca.5c04227. Epub 2025 Sep 11.
Reaction resonances have been extensively studied in barrier reactions, whereas the observation of reaction resonances is rarely reported in barrierless reactions. In this work, a high-resolution crossed molecular beam experiment using the D atom Rydberg tagging technique was systematically carried out to investigate the barrierless reaction of O(D) + D → OD + D over a collision energy range of 20-168 cm. Four experimental observations were found, including the dramatic changes of OD product angular distributions, the peak structures of collision energy-dependent differential cross sections (DCSs) in the forward and backward scattering directions, the ridge features in the 3D-DCS plot of σ(θ, ), and the valley structure of the collision energy-dependent integral cross section. These resonance-like features may offer fresh insights into the intricate dynamics of this prototype barrierless reaction at low collision energies.
反应共振在势垒反应中已得到广泛研究，而在无势垒反应中反应共振的观测却鲜有报道。在这项工作中，利用D原子里德堡标记技术系统地开展了一项高分辨率交叉分子束实验，以研究在20 - 168厘米的碰撞能量范围内O(D) + D → OD + D的无势垒反应。发现了四个实验观测结果，包括OD产物角分布的显著变化、前向和后向散射方向上碰撞能量依赖的微分截面（DCS）的峰结构、σ(θ, )的三维DCS图中的脊状特征以及碰撞能量依赖的积分截面的谷结构。这些类似共振的特征可能为低碰撞能量下这种典型无势垒反应的复杂动力学提供新的见解。
