Hidden Vibronic and Excitonic Structure and Vibronic Coherence Transfer in the Bacterial Reaction Center

Veronica R. Policht; Andrew Niedringhaus; Rhiannon Willow; Philip D. Laible; David F. Bocian; Christine Kirmaier; Dewey Holten; Tomáš Mančal; Jennifer P. Ogilvie

doi:10.1126/sciadv.abk0953

arXiv · 2103.02601

Hidden Vibronic and Excitonic Structure and Vibronic Coherence Transfer in the Bacterial Reaction Center

Veronica R. Policht·Andrew Niedringhaus·Rhiannon Willow·Philip D. Laible·David F. Bocian·Christine Kirmaier·Dewey Holten·Tomáš Mančal·Jennifer P. Ogilvie

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Abstract

We report two-dimensional electronic spectroscopy (2DES) experiments on the bacterial reaction center (BRC) from purple bacteria, revealing hidden excitonic and vibronic structure. Through analysis of the coherent dynamics of the BRC we resolve specific coherent signatures that allow us to definitively assign the upper exciton energy of the "special pair." This assignment is supported by simulations of coherent dynamics of a reduced excitonic model of the BRC. The simulations also identify nonsecular vibronic coherence transfer processes neglected in standard models of photosynthetic energy transfer and charge separation. In addition, the coherent dynamics reveal multiple quasi-resonances between key intramolecular pigment vibrations and excited state energy gaps in the BRC. The functional significance of such electronic-vibrational resonances for photosynthetic energy transfer and charge separation remains an open question.

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Veronica R. Policht, Andrew Niedringhaus, Rhiannon Willow, Philip D. Laible, David F. Bocian, Christine Kirmaier, Dewey Holten, Tomáš Mančal, Jennifer P. Ogilvie. 2021-03-03. Hidden Vibronic and Excitonic Structure and Vibronic Coherence Transfer in the Bacterial Reaction Center. https://doi.org/10.1126/sciadv.abk0953

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