Electron transfer reactions facilitate energy transduction and photoredox processes in biology and chemistry. Recent findings show that molecular vibrations can enable the dramatic acceleration of some electron transfer reactions, and control it by suppressing and enhancing reaction paths. Here, we report ultrafast spectroscopy experiments and quantum dynamics simulations that resolve how quantum vibrations participate in an electron transfer reaction. We observe ballistic electron transfer (~30 fs) along a reaction coordinate comprising high-frequency promoting vibrations. Along another vibrational coordinate, the system becomes impulsively out of equilibrium as a result of the electron transfer reaction. This leads to the generation (by the electron transfer reaction, not the laser pulse) of a new vibrational coherence along this second reaction coordinate in a mode associated with the reaction product. These results resolve a complex reaction trajectory composed of multiple vibrational coordinates that, like a sequence of ratchets, progressively diminish the recurrence of the reactant state.

电子转移反应促进了生物学和化学中的能量转导和光氧化还原过程。最近的研究结果表明，分子振动可以使某些电子转移反应急剧加速，并通过抑制和增强反应路径来控制它。在这里，我们报告了解决量子振动如何参与电子转移反应的超快光谱实验和量子动力学模拟。我们沿包含高频促进振动的反应坐标观察弹道电子转移（~30 fs）。沿着另一个振动坐标，系统由于电子转移反应而冲动地失去平衡。这导致产生（通过电子转移反应，不是激光脉冲）沿该第二反应坐标的新振动相干性以与反应产物相关的模式。这些结果解决了由多个振动坐标组成的复杂反应轨迹，就像一系列棘轮一样，逐渐减少反应物状态的重现。