Poline Mathias, Dochain Arnaud, Rosén Stefan, Ji MingChao, Cederquist Henrik, Zettergren Henning, Schmidt Henning T, Larsson Mats, Ard Shaun G, Shuman Nicholas S, Viggiano Albert A, Thomas Richard D
Department of Physics, Stockholm University, Stockholm, SE-10691, Sweden.
Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Louvain-la-Neuve, B-1348, Belgium.
Nat Commun. 2025 Sep 26;16(1):8528. doi: 10.1038/s41467-025-64198-0.
Product distributions and dynamics of low-collision-energy mutual neutralisation reactions involving even simple molecular ions are largely unknown. Reactions which involve oxygen ions, e.g., with O, are expected to be important in atmospheric phenomena such as sprites and in high-pressure air or oxygen discharges. Here we show, by combining cryogenically stored-and-merged ion beams with coincident product-imaging techniques, that the with O mutual neutralisation reaction results predominantly in dissociation of the molecule. Three competing reaction pathways yields both O(P) (84%) and O(D) (16%) products, but no O(S) products. Analysis of the momentum-correlated dynamics of the reaction reveals the dominance of two-step mechanisms involving the 3pλ and 3sσ Rydberg states of O. Furthermore, use of the isotopologue shows that the reaction products strongly depend on the vibrational levels of the ion for the channel leading to two O(D) products.
涉及甚至简单分子离子的低碰撞能相互中和反应的产物分布和动力学在很大程度上是未知的。涉及氧离子的反应，例如与O的反应，预计在诸如精灵等大气现象以及高压空气或氧气放电中很重要。在这里，我们通过将低温储存和合并的离子束与重合产物成像技术相结合，表明与O的相互中和反应主要导致分子解离。三种竞争反应途径产生O(P)（84%）和O(D)（16%）产物，但没有O(S)产物。对反应的动量相关动力学分析揭示了涉及O的3pλ和3sσ里德堡态的两步机制的主导地位。此外，使用同位素显示，对于导致两个O(D)产物的通道，反应产物强烈依赖于离子的振动能级。
