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.
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The experimental and theoretical data associated with the reported findings are available in this manuscript or the Supplementary Information. Data for the Supplementary figures are available from the corresponding author upon reasonable request. Source data are provided with this paper.
The codes for the quantum dynamics simulations are available from the corresponding author upon request.
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Financial support was provided by the Division of Chemical Sciences, Geosciences and Biosciences, Office of Basic Energy Sciences, of the US Department of Energy through grant no. DE-SC0015429. We thank the Imaging and Analysis Center in PRISM at Princeton University for providing access to the Raman facility. B.F. thanks T. Ikeda for helpful discussions. B.K. acknowledges the NSF for a Graduate Research Fellowship (DGE-1656466).
The authors declare no competing interests.
Peer review information Nature Chemistry thanks the anonymous reviewers for their contribution to the peer review of this work.
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Experimental and theoretical methodology, Supplementary Figs. 1–11 and Discussion.
Source Data Fig. 1
Fourier transform maps.
Source Data Fig. 2
Fourier transform data comparison.
Source Data Fig. 3
Quantum dynamics simulations data.
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Rafiq, S., Fu, B., Kudisch, B. et al. Interplay of vibrational wavepackets during an ultrafast electron transfer reaction. Nat. Chem. 13, 70–76 (2021). https://doi.org/10.1038/s41557-020-00607-9