@article{380521539c74464fb7260fb22bde9143,
title = "High Magnetic Field Detunes Vibronic Resonances in Photosynthetic Light Harvesting",
abstract = "The origin and role of oscillatory features detected in recent femtosecond spectroscopy experiments of photosynthetic complexes remain elusive. A key hypothesis underneath of these observations relies on electronic-vibrational resonance, where vibrational levels of an acceptor chromophore match the donor-acceptor electronic gap, accelerating the downhill energy transfer. Here we identify and detune such vibronic resonances using a high magnetic field that exclusively shifts molecular exciton states. We implemented ultrafast pump-probe spectroscopy into a specialized 25 T magnetic field facility and studied the light-harvesting complex PC645 from a cryptophyte algae where strongly coupled chromophores form molecular exciton states. We detected a change in high-frequency coherent oscillations when the field was engaged. Quantum chemical calculations coupled with a vibronic model explain the experiment as a magnetic field-induced shift of the exciton states, which in turn affects the electronic-vibrational resonance between pigments within the protein. Our results demonstrate the delicate sensitivity of interpigment coherent oscillations of vibronic origin to electronic-vibrational resonance interactions in light-harvesting complexes.",
author = "Margherita Maiuri and Oviedo, {Maria B.} and Dean, {Jacob C.} and Michael Bishop and Bryan Kudisch and Toa, {Zi S.D.} and Wong, {Bryan M.} and McGill, {Stephen A.} and Scholes, {Gregory D.}",
note = "Funding Information: The authors acknowledge financial support by the National Science Foundation, MRI No. DMR-1229217, and by Princeton University through the Innovation Fund for New Ideas in the Natural Sciences. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by the National Science Foundation Cooperative Agreement No. DMR-1157490 and the State of Florida. M.M. acknowledges financial support by European Community (H2020 Marie Sk{\l}odowska-Curie Actions), Project No. 655059. M.B.O. acknowledges financial support by the National Science Foundation - Institute for Complex Adaptive Matter (NSF-ICAM) and the National Science Foundation for the use of supercomputing resources through the Extreme Science and Engineering Discovery Environment (XSEDE), Project No. TG-CHE140097. B.K. acknowledges support by the National Science Foundation Graduate Research Fellowship under Grant Number DGE-1656466. M.M., J.C.D., M.B., and S.A.G. acknowledge Dmitry Semenov for valuable support during the magnet time. Funding Information: The authors acknowledge financial support by the National Science Foundation, MRI No. DMR-1229217, and by Princeton University through the Innovation Fund for New Ideas in the Natural Sciences. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by the National Science Foundation Cooperative Agreement No. DMR-1157490 and the State of Florida. M.M. acknowledges financial support by European Community (H2020 Marie Sklodowska-Curie Actions), Project No. 655059. M.B.O. acknowledges financial support by the National Science Foundation - Institute for Complex Adaptive Matter (NSF-ICAM) and the National Science Foundation for the use of supercomputing resources through the Extreme Science and Engineering Discovery Environment (XSEDE) Project No. TG-CHE140097. B.K. acknowledges support by the National Science Foundation Graduate Research Fellowship under Grant Number DGE-1656466. M.M., J.C.D., M.B., and S.A.G. acknowledge Dmitry Semenov for valuable support during the magnet time. Publisher Copyright: Copyright {\textcopyright} 2018 American Chemical Society.",
year = "2018",
month = sep,
day = "20",
doi = "10.1021/acs.jpclett.8b02748",
language = "English (US)",
volume = "9",
pages = "5548--5554",
journal = "Journal of Physical Chemistry Letters",
issn = "1948-7185",
publisher = "American Chemical Society",
number = "18",
}