The Born–Oppenheimer approximation, assuming separable nuclear and electronic motion, is widely adopted for characterizing chemical reactions in a single electronic state. However, the breakdown of the Born–Oppenheimer approximation is omnipresent in chemistry, and a detailed understanding of the non-adiabatic dynamics is still incomplete. Here we investigate the non-adiabatic quenching of electronically excited OH(A²Σ⁺) molecules by H₂ molecules using full-dimensional quantum dynamics calculations for zero total nuclear angular momentum using a high-quality diabatic-potential-energy matrix. Good agreement with experimental observations is found for the OH(X²Π) ro-vibrational distribution, and the non-adiabatic dynamics are shown to be controlled by stereodynamics, namely the relative orientation of the two reactants. The uncovering of a major (in)elastic channel, neglected in a previous analysis but confirmed by a recent experiment, resolves a long-standing experiment–theory disagreement concerning the branching ratio of the two electronic quenching channels.

Born-Oppenheimer 近似假设可分离的核和电子运动，被广泛用于表征单个电子态的化学反应。然而，玻恩-奥本海默近似的分解在化学中无处不在，对非绝热动力学的详细了解仍然不完整。在这里，我们使用高质量绝热势能矩阵对零总核角动量进行全维量子动力学计算，研究电子激发的 OH(A ² Σ ⁺ ) 分子被 H ₂分子的非绝热猝灭。OH(X ²Π) ro-振动分布和非绝热动力学显示受立体动力学控制，即两种反应物的相对取向。一个主要（非）弹性通道的发现，在先前的分析中被忽略但被最近的实验证实，解决了一个长期存在的实验——关于两个电子淬火通道的分支比的理论分歧。