Department of Chemistry, Princeton University, Princeton, NJ, USA.
Nat Chem. 2021 Jan;13(1):70-77. doi: 10.1038/s41557-020-00607-9. Epub 2020 Dec 7.
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.
电子转移反应在生物学和化学中促进能量转导和光还原过程。最近的发现表明，分子振动可以显著加速一些电子转移反应，并通过抑制和增强反应途径来控制它。在这里，我们报告超快光谱实验和量子动力学模拟，以解决量子振动如何参与电子转移反应。我们观察到沿着由高频促进振动组成的反应坐标的弹道电子转移（~30fs）。在另一个振动坐标上，由于电子转移反应，系统会突然失去平衡。这导致在与反应产物相关的模式下沿着第二个反应坐标产生新的振动相干性（由电子转移反应产生，而不是激光脉冲）。这些结果解析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，逐步减少反应物状态的重现。
