德国马克斯-普朗克化学能源转换研究所Park, G. Barratt团队，报道了石墨中氧原子散射的自旋相关反应性和自旋翻转动力学。相关研究成果于2023年5月22日发表在国际顶尖学术期刊《自然—化学》。

两个电子化学键的形成需要自旋的排列。因此，对于气相反应来说，改变分子的电子自旋状态可以显著改变其反应性是众所周知的。对于发生在表面的反应，在多相催化等过程中引起了人们的极大兴趣，目前还没有能够观察到自旋守恒确定的状态对状态实验，因此电子自旋在表面化学中的作用仍然存在争议。

该文中，研究人员使用入射/出射相关离子成像技术对O（³P）和O（¹D）原子与石墨表面碰撞进行散射实验，其中控制初始自旋态分布并确定最终自旋态。研究发现O（¹D）与石墨的反应性比O（³P）更强。研究人员还确定了电子非绝热途径，通过该途径入射的O（¹D）被猝灭为离开表面的O（³P）。在高维机器学习辅助的第一性原理势能面上进行的分子动力学模拟的帮助下，一看就人员对这个系统获得了一个机制上的理解：自旋禁止跃迁确实会发生，但概率很低。

附：英文原文

Title: Spin-dependent reactivity and spin-flipping dynamics in oxygen atom scattering from graphite

Author: Zhao, Zibo, Wang, Yingqi, Yang, Ximei, Quan, Jiamei, Krger, Bastian C., Stoicescu, Paula, Nieman, Reed, Auerbach, Daniel J., Wodtke, Alec M., Guo, Hua, Park, G. Barratt

Issue&Volume: 2023-05-22

Abstract: The formation of two-electron chemical bonds requires the alignment of spins. Hence, it is well established for gas-phase reactions that changing a molecule’s electronic spin state can dramatically alter its reactivity. For reactions occurring at surfaces, which are of great interest during, among other processes, heterogeneous catalysis, there is an absence of definitive state-to-state experiments capable of observing spin conservation and therefore the role of electronic spin in surface chemistry remains controversial. Here we use an incoming/outgoing correlation ion imaging technique to perform scattering experiments for O(3P) and O(1D) atoms colliding with a graphite surface, in which the initial spin-state distribution is controlled and the final spin states determined. We demonstrate that O(1D) is more reactive with graphite than O(3P). We also identify electronically nonadiabatic pathways whereby incident O(1D) is quenched to O(3P), which departs from the surface. With the help of molecular dynamics simulations carried out on high-dimensional machine-learning-assisted first-principles potential energy surfaces, we obtain a mechanistic understanding for this system: spin-forbidden transitions do occur, but with low probabilities.

DOI: 10.1038/s41557-023-01204-2

Source: https://www.nature.com/articles/s41557-023-01204-2