Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems

  title={Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems},
  author={Gregory S. Engel and Tessa R. Calhoun and Elizabeth L. Read and Tae Kyu Ahn and Tom{\'a}{\vs} Man{\vc}al and Yuan-Chung Cheng and Robert Eugene Blankenship and Graham R. Fleming},
Photosynthetic complexes are exquisitely tuned to capture solar light efficiently, and then transmit the excitation energy to reaction centres, where long term energy storage is initiated. The energy transfer mechanism is often described by semiclassical models that invoke ‘hopping’ of excited-state populations along discrete energy levels. Two-dimensional Fourier transform electronic spectroscopy has mapped these energy levels and their coupling in the Fenna–Matthews–Olson (FMO… 
Direct evidence of quantum transport in photosynthetic light-harvesting complexes
Experimental evidence is provided that interaction between the bacteriochlorophyll chromophores and the protein environment surrounding them not only prolongs quantum coherence, but also spawns reversible, oscillatory energy transfer among excited states.
Nature does not rely on long-lived electronic quantum coherence for photosynthetic energy transfer
2D spectroscopy of the excitation energy transfer in the FMO protein is revisited and it is shown that the optical 2D photon echo spectra of this complex at ambient temperature in aqueous solution do not provide evidence of any long-lived electronic quantum coherence, but confirm the orthodox view of rapidly decaying electronic quantumCoherence on a timescale of 60 fs.
Long-lived quantum coherence in photosynthetic complexes at physiological temperature
Evidence that quantum coherence survives in FMO at physiological temperature for at least 300 fs, long enough to impact biological energy transport is presented, proving that the wave-like energy transfer process discovered at 77 K is directly relevant to biological function.
Quantum coherence explored at the level of individual light-harvesting complexes
Quantum mechanical effects in biological processes, such as natural photosynthesis, are intriguing and lively debated issues. The initial steps of photosynthesis comprise the absorption of sunlight
Towards quantification of vibronic coupling in photosynthetic antenna complexes.
A direct experimental observation from a mutant of LH2, which does not have B800 chromophores, is given to distinguish between electronic, vibrational, and vibronic coherence and a minimal theoretical model is presented to characterize the coherences both in the two limiting cases of purely vibrational and purely electronic coherence as well as in the intermediate, vibronic regime.
Quantum coherence spectroscopy reveals complex dynamics in bacterial light-harvesting complex 2 (LH2)
  • E. Harel, G. Engel
  • Physics, Chemistry
    Proceedings of the National Academy of Sciences
  • 2012
This work provides experimental evidence of long-lived quantum coherence between the spectrally separated B800 and B850 rings of the light-harvesting complex 2 (LH2) of purple bacteria and suggests that quantum mechanical interference between different energy transfer pathways may be important even at ambient temperature.
Quantum Coherent Energy Transfer over Varying Pathways in Single Light-Harvesting Complexes
It is found that quantum coherences between electronically coupled energy eigenstates persist at least 400 femtoseconds and that distinct energy-transfer pathways that change with time can be identified in each complex.
Unravelling coherent dynamics and energy dissipation in photosynthetic complexes by 2D spectroscopy.
The complex chirality and fundamental symmetries of multidimensional optical signals are used to design new sequences of ultrashort laser pulses that can distinguish between coherent quantum oscillations and incoherent energy dissipation during the exciton relaxation.
Theoretical examination of quantum coherence in a photosynthetic system at physiological temperature
The numerical results reveal that quantum wave-like motion persists for several hundred femtoseconds even at physiological temperature, and suggest that the FMO complex may work as a rectifier for unidirectional energy flow from the peripheral light-harvesting antenna to the reaction center complex by taking advantage of quantum coherence and the energy landscape of pigments tuned by the protein scaffold.
Quantum Coherent Excitation Energy Transfer by Carotenoids in Photosynthetic Light Harvesting.
It is reported that broad-band two-dimensional electronic spectroscopy indeed reveals the initial presence of exciton relaxation pathways that enable transfer of excitation from peridinin to chlorophyll a in <20 fs, but the quantum coherence that permits this is very short-lived.


Two-dimensional spectroscopy of electronic couplings in photosynthesis
This work directly measures electronic couplings in a molecular complex, the Fenna–Matthews–Olson photosynthetic light-harvesting protein, and finds distinct energy transport pathways that depend sensitively on the detailed spatial properties of the delocalized excited-state wavefunctions of the whole pigment–protein complex.
Coherent Versus Incoherent Energy Transfer and Trapping in Photosynthetic Antenna Complexes
  • J. Leegwater
  • Physics
    EQEC'96. 1996 European Quantum Electronic Conference
  • 1996
In this paper we present a study of a model in which there is energy transfer as well as a special site where an irreversible reaction takes place. This model has an arbitrary ratio of homogeneous
Exciton dynamics in ring-like photosynthetic light-harvesting complexes: a hopping model
Excitation localization and dynamics in circular molecular aggregates is considered. It is shown that the Anderson localization of the excitons is taking place even in the finite size of the
We have simulated the excited state dynamics of the FMO (Fenna−Matthews−Olson) bacteriochlorophyll a-protein complexes of the green sulfur bacteria Chlorobium (C.) tepidum and Prosthecochloris (P.)
Two-dimensional optical three-pulse photon echo spectroscopy. II. Signatures of coherent electronic motion and exciton population transfer in dimer two-dimensional spectra.
It is shown that coherent electronic motion, an electronic analog of a vibrational wave packet, can manifest itself in two-dimensional optical spectra of molecular aggregate systems as a periodic modulation of both the diagonal and off-diagonal peaks.
Intra- and interband transfers in the B800-B850 antenna of Rhodospirillum molischianum Redfield theory modeling of polarized pump-probe kinetics
We use an exciton model for the B800−B850 LH2 light-harvesting antenna of Rhodospirillum molischianum to explain the absorption, excitation-wavelength-dependent pump−probe kinetics, and induced
Exciton analysis in 2D electronic spectroscopy.
An analytic expression for numerical simulations of time- and frequency-resolved 2D photon echo signals is obtained and it is found that there are two noncascading exciton energy relaxation pathways.
Two-dimensional femtosecond spectroscopy.
  • D. Jonas
  • Physics, Chemistry
    Annual review of physical chemistry
  • 2003
This review provides an introduction to two-dimensional Fourier transform experiments exploiting second- and third-order vibrational and electronic nonlinearities.