Liu Yang, Ončák Milan, Meyer Jennifer, Ard Shaun G, Shuman Nicholas S, Viggiano Albert A, Guo Hua
Department of Chemistry and Chemical Biology, Center for Computational Chemistry, University of New Mexico, Albuquerque, New Mexico 87131, United States.
Universität Innsbruck, Institut für Ionenenphysik und Angewandte Physik, Technikerstraße 25, Innsbruck 6020, Austria.
J Phys Chem A. 2024 Aug 22;128(33):6943-6953. doi: 10.1021/acs.jpca.4c04067. Epub 2024 Aug 8.
The transfer of an oxygen atom from carbon dioxide (CO) to a transition metal cation in the gas phase offers atomic level insights into single-atom catalysis for CO activation. Given that these reactions often involve open-shell transition metals, they may proceed through intersystem crossing between different spin manifolds. However, a definitive understanding of such spin-forbidden reaction requires dynamical calculations on multiple global potential energy surfaces (PESs) coupled by spin-orbit couplings. In this work, we report global PESs and spin-orbit couplings for three low-lying spin (quintet, triplet, and singlet) states for the reaction between the niobium cation (Nb) and CO, which are used to investigate the nonadiabatic reaction dynamics and kinetics. Comparison with experimental data of kinetics and collision dynamics shows satisfactory agreement. This reaction is found to be very similar to that between Ta + CO. Specifically, our theoretical findings suggest that the rate-limiting step in this reaction is intersystem crossing, rather than potential barriers.
在气相中，将一个氧原子从二氧化碳（CO）转移到过渡金属阳离子上，这为CO活化的单原子催化提供了原子层面的见解。鉴于这些反应通常涉及开壳层过渡金属，它们可能通过不同自旋流形之间的系间窜越进行。然而，要对这种自旋禁阻反应有确切的理解，需要在由自旋轨道耦合耦合的多个全局势能面（PES）上进行动力学计算。在这项工作中，我们报告了铌阳离子（Nb）与CO反应的三个低自旋（五重态、三重态和单重态）态的全局PES和自旋轨道耦合，用于研究非绝热反应动力学和动力学。与动力学和碰撞动力学的实验数据比较显示出令人满意的一致性。发现该反应与Ta + CO之间的反应非常相似。具体而言，我们的理论结果表明，该反应的速率限制步骤是系间窜越，而不是势垒。
