1
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Wang XP, Yu B, Qi CH, Wang GL, Zou M, Zhang C, Yu LJ, Ma F. Energy Transfer and Exciton Relaxation in B880-B800-RC Complex through Two-Dimensional Electronic Spectroscopy. J Phys Chem Lett 2024; 15:3619-3626. [PMID: 38530255 DOI: 10.1021/acs.jpclett.4c00181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/27/2024]
Abstract
The light-harvesting (LH) and reaction center (RC) core complex of purple bacterium Roseiflexus castenholzii, B880-B800-RC, are different from those of the typical photosynthetic unit, (B850-B800)x-B880-RC. To investigate the excitation flowing dynamics in this unique complex, two-dimensional electronic spectroscopy is employed. The obtained time constants for the exciton relaxation in B880, exciton relaxation in B800, B800 → B880 energy transfer (EET), and B880 → closed RC EET are 43 fs, 177 fs, 1.9 ps, and 205 ps, respectively. These time constants result in an overall EET efficiency similar to that of the typical photosynthetic unit. Analysis of the oscillatory signals reveals that while several vibronic coherences are involved in the exciton relaxation process, only one prominent vibronic coherence, with a frequency of 27 cm-1 and coupled to the B880 electronic transition, may contribute to the B800 → B880 EET process.
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Affiliation(s)
- Xiang-Ping Wang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Buyang Yu
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Chen-Hui Qi
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Guang-Lei Wang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Meijuan Zou
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Chunfeng Zhang
- National Laboratory of Solid State Microstructures, School of Physics, and Collaborative Innovation Center for Advanced Microstructures, Nanjing University, Nanjing 210093, China
| | - Long-Jiang Yu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fei Ma
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
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2
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Zerah Harush E, Dubi Y. Signature of Quantum Coherence in the Exciton Energy Pathways of the LH2 Photosynthetic Complex. ACS OMEGA 2023; 8:38871-38878. [PMID: 37901547 PMCID: PMC10601065 DOI: 10.1021/acsomega.3c02676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 06/15/2023] [Indexed: 10/31/2023]
Abstract
Unraveling the energy transfer pathways in photosynthetic complexes is an important step toward understanding their structure-function interplay. Here, we use an open quantum systems approach to investigate energy transfer within the LH2 photosynthetic apparatus and its dependence on environmental conditions. We find that energy transfer pathways strongly depend on the environment-induced dephasing time. A comparison between the computational results and experiments performed on similar systems demonstrates that quantum coherences are present in these systems under physiological conditions and have an important role in shaping the energy transfer pathways. Moreover, our calculations indicate that relatively simple spectroscopy experiments can be used to detect traces of quantum coherence. Finally, our results suggest that quantum coherence may play a role in photosynthesis, but not in enhancing the efficiency as was previously suggested.
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Affiliation(s)
- Elinor Zerah Harush
- Department of Chemistry and
Ilse Katz Center for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
| | - Yonatan Dubi
- Department of Chemistry and
Ilse Katz Center for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105, Israel
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3
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A polarization scheme that resolves cross-peaks with transient absorption and eliminates diagonal peaks in 2D spectroscopy. Proc Natl Acad Sci U S A 2022; 119:2117398119. [PMID: 35115405 PMCID: PMC8833161 DOI: 10.1073/pnas.2117398119] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/16/2021] [Indexed: 11/18/2022] Open
Abstract
Two-dimensional (2D) optical spectroscopy contains cross-peaks that are helpful features for determining molecular structure and monitoring energy transfer, but they can be difficult to resolve from the much more intense diagonal peaks. Transient absorption (TA) spectra contain transitions similar to cross-peaks in 2D spectroscopy, but in most cases they are obscured by the bleach and stimulated emission peaks. We report a polarization scheme, <0°,0°,+θ2(t2),-θ2(t2)>, that can be easily implemented in the pump-probe beam geometry, used most frequently in 2D and TA spectroscopy. This scheme removes the diagonal peaks in 2D spectroscopies and the intense bleach/stimulated emission peaks in TA spectroscopies, thereby resolving the cross-peak features. At zero pump-probe delay, θ2 = 60° destructively interferes two Feynman paths, eliminating all signals generated by field interactions with four parallel transition dipoles, and the intense diagonal and bleach/stimulated emission peaks. At later delay times, θ2(t2) is adjusted to compensate for anisotropy caused by rotational diffusion. When implemented with TA spectroscopy or microscopy, the pump-probe spectrum is dominated by the cross-peak features. The local oscillator is also attenuated, which enhances the signal two times. This overlooked polarization scheme reduces spectral congestion by eliminating diagonal peaks in 2D spectra and enables TA spectroscopy to measure similar information given by cross-peaks in 2D spectroscopy.
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4
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Bourne Worster S, Stross C, Vaughan FMWC, Linden N, Manby FR. Structure and Efficiency in Bacterial Photosynthetic Light Harvesting. J Phys Chem Lett 2019; 10:7383-7390. [PMID: 31714789 DOI: 10.1021/acs.jpclett.9b02625] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Photosynthetic organisms use networks of chromophores to absorb and deliver solar energy to reaction centers. We present a detailed model of the light-harvesting complexes in purple bacteria, including explicit interaction with sunlight, radiative and nonradiative energy loss, and dephasing and thermalizing effects of coupling to a vibrational bath. We capture the effect of slow vibrations by introducing time-dependent disorder. Our model describes the experimentally observed high efficiency of light harvesting, despite the absence of long-range quantum coherence. The one-exciton part of the quantum state fluctuates continuously but remains highly mixed at all times. These results suggest a relatively minor role for structure in determining efficiency. We build hypothetical models with randomly arranged chromophores but still observe high efficiency when nearest-neighbor distances are comparable to those in nature. This helps explain the high transport efficiency in organisms with widely differing antenna structures and suggests new design criteria for artificial light-harvesting devices.
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Affiliation(s)
- Susannah Bourne Worster
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Bristol BS8 1TS , U.K
| | - Clement Stross
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Bristol BS8 1TS , U.K
- School of Mathematics , University of Bristol , Bristol BS8 1UG , U.K
| | - Felix M W C Vaughan
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Bristol BS8 1TS , U.K
- School of Mathematics , University of Bristol , Bristol BS8 1UG , U.K
- Bristol Centre for Complexity Sciences , University of Bristol , Bristol BS2 8BB , U.K
| | - Noah Linden
- School of Mathematics , University of Bristol , Bristol BS8 1UG , U.K
| | - Frederick R Manby
- Centre for Computational Chemistry, School of Chemistry , University of Bristol , Bristol BS8 1TS , U.K
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5
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Meneghin E, Pedron D, Collini E. Characterization of the coherent dynamics of bacteriochlorophyll a in solution. Chem Phys 2019. [DOI: 10.1016/j.chemphys.2018.12.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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6
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Kunsel T, Tiwari V, Matutes YA, Gardiner AT, Cogdell RJ, Ogilvie JP, Jansen TLC. Simulating Fluorescence-Detected Two-Dimensional Electronic Spectroscopy of Multichromophoric Systems. J Phys Chem B 2019; 123:394-406. [PMID: 30543283 PMCID: PMC6345114 DOI: 10.1021/acs.jpcb.8b10176] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Indexed: 11/28/2022]
Abstract
We present a theory for modeling fluorescence-detected two-dimensional electronic spectroscopy of multichromophoric systems. The theory is tested by comparison of the predicted spectra of the light-harvesting complex LH2 with experimental data. A qualitative explanation of the strong cross-peaks as compared to conventional two-dimensional electronic spectra is given. The strong cross-peaks are attributed to the clean ground-state signal that is revealed when the annihilation of exciton pairs created on the same LH2 complex cancels oppositely signed signals from the doubly excited state. This annihilation process occurs much faster than the nonradiative relaxation. Furthermore, the line shape difference is attributed to slow dynamics, exciton delocalization within the bands, and intraband exciton-exciton annihilation. This is in line with existing theories presented for model systems. We further propose the use of time-resolved fluorescence-detected two-dimensional spectroscopy to study state-resolved exciton-exciton annihilation.
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Affiliation(s)
- Tenzin Kunsel
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Vivek Tiwari
- Department
of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Yassel Acosta Matutes
- Department
of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | | | - Richard J. Cogdell
- Institute
for Molecular Biology, University of Glasgow, Glasgow G12 8TA, U.K.
| | - Jennifer P. Ogilvie
- Department
of Physics, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Thomas L. C. Jansen
- Zernike
Institute for Advanced Materials, University
of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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7
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Rathbone HW, Davis JA, Michie KA, Goodchild SC, Robertson NO, Curmi PMG. Coherent phenomena in photosynthetic light harvesting: part two-observations in biological systems. Biophys Rev 2018; 10:1443-1463. [PMID: 30242555 PMCID: PMC6233342 DOI: 10.1007/s12551-018-0456-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 09/06/2018] [Indexed: 10/28/2022] Open
Abstract
Considerable debate surrounds the question of whether or not quantum mechanics plays a significant, non-trivial role in photosynthetic light harvesting. Many have proposed that quantum superpositions and/or quantum transport phenomena may be responsible for the efficiency and robustness of energy transport present in biological systems. The critical experimental observations comprise the observation of coherent oscillations or "quantum beats" via femtosecond laser spectroscopy, which have been observed in many different light harvesting systems. Part Two of this review aims to provide an overview of experimental observations of energy transfer in the most studied light harvesting systems. Length scales, derived from crystallographic studies, are combined with energy and time scales of the beats observed via spectroscopy. A consensus is emerging that most long-lived (hundreds of femtoseconds) coherent phenomena are of vibrational or vibronic origin, where the latter may result in coherent excitation transport within a protein complex. In contrast, energy transport between proteins is likely to be incoherent in nature. The question of whether evolution has selected for these non-trivial quantum phenomena may be an unanswerable question, as dense packings of chromophores will lead to strong coupling and hence non-trivial quantum phenomena. As such, one cannot discern whether evolution has optimised light harvesting systems for high chromophore density or for the ensuing quantum effects as these are inextricably linked and cannot be switched off.
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Affiliation(s)
- Harry W Rathbone
- School of Physics, The University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Jeffery A Davis
- Centre for Quantum and Optical Science, Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria, 3122, Australia
| | - Katharine A Michie
- School of Physics, The University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Sophia C Goodchild
- Department of Chemistry and Biomolecular Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Neil O Robertson
- School of Physics, The University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Paul M G Curmi
- School of Physics, The University of New South Wales, Sydney, New South Wales, 2052, Australia.
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8
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Jumper CC, van Stokkum IHM, Mirkovic T, Scholes GD. Vibronic Wavepackets and Energy Transfer in Cryptophyte Light-Harvesting Complexes. J Phys Chem B 2018; 122:6328-6340. [PMID: 29847127 DOI: 10.1021/acs.jpcb.8b02629] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Determining the key features of high-efficiency photosynthetic energy transfer remains an ongoing task. Recently, there has been evidence for the role of vibronic coherence in linking donor and acceptor states to redistribute oscillator strength for enhanced energy transfer. To gain further insights into the interplay between vibronic wavepackets and energy-transfer dynamics, we systematically compare four structurally related phycobiliproteins from cryptophyte algae by broad-band pump-probe spectroscopy and extend a parametric model based on global analysis to include vibrational wavepacket characterization. The four phycobiliproteins isolated from cryptophyte algae are two "open" structures and two "closed" structures. The closed structures exhibit strong exciton coupling in the central dimer. The dominant energy-transfer pathway occurs on the subpicosecond timescale across the largest energy gap in each of the proteins, from central to peripheral chromophores. All proteins exhibit a strong 1585 cm-1 coherent oscillation whose relative amplitude, a measure of vibronic intensity borrowing from resonance between donor and acceptor states, scales with both energy-transfer rates and damping rates. Central exciton splitting may aid in bringing the vibronically linked donor and acceptor states into better resonance resulting in the observed doubled rate in the closed structures. Several excited-state vibrational wavepackets persist on timescales relevant to energy transfer, highlighting the importance of further investigation of the interplay between electronic coupling and nuclear degrees of freedom in studies on high-efficiency photosynthesis.
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Affiliation(s)
- Chanelle C Jumper
- Department of Chemistry , University of Toronto , 80 St. George Street , Toronto , Ontario M5S 3H6 , Canada.,Department of Chemistry , Princeton University , Washington Road , Princeton , New Jersey 08544 , United States
| | - Ivo H M van Stokkum
- LaserLaB, Department of Physics and Astronomy , Vrije Universiteit Amsterdam , De Boelelaan 1081 , 1081 HV Amsterdam , The Netherlands
| | - Tihana Mirkovic
- Department of Chemistry , University of Toronto , 80 St. George Street , Toronto , Ontario M5S 3H6 , Canada
| | - Gregory D Scholes
- Department of Chemistry , University of Toronto , 80 St. George Street , Toronto , Ontario M5S 3H6 , Canada.,Department of Chemistry , Princeton University , Washington Road , Princeton , New Jersey 08544 , United States
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9
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Mallus MI, Schallwig M, Kleinekathöfer U. Relation between Vibrational Dephasing Time and Energy Gap Fluctuations. J Phys Chem B 2017. [PMID: 28625060 DOI: 10.1021/acs.jpcb.7b02693] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Dephasing processes are present in basically all applications in which quantum mechanics plays a role. These applications certainly include excitation energy and charge transfer in biological systems. In a previous study, we have analyzed the vibrational dephasing time as a function of energy gap fluctuation for a large set of molecular simulations. In that investigation, individual molecular subunits were the focus of the calculations. The set of studied molecules included bacteriochlorophylls in Fenna-Matthews-Olson and light-harvesting system 2 complexes as well as bilins in PE545 aggregates. The present work extends this study to entire complexes, including the respective intermolecular couplings. Again, it can be concluded that a universal and inverse proportionality exists between dephasing time and variance of the excitonic energy gap fluctuations, whereas the respective proportionality constants can be rationalized using the energy gap autocorrelation functions. Furthermore, these findings can be extended to the gaps between higher-lying neighboring excitonic states.
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Affiliation(s)
- Maria Ilaria Mallus
- Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany
| | - Maximilian Schallwig
- Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany
| | - Ulrich Kleinekathöfer
- Department of Physics and Earth Sciences, Jacobs University Bremen , Campus Ring 1, 28759 Bremen, Germany
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10
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Sisto A, Stross C, van der Kamp MW, O’Connor M, McIntosh-Smith S, Johnson GT, Hohenstein EG, Manby FR, Glowacki DR, Martinez TJ. Atomistic non-adiabatic dynamics of the LH2 complex with a GPU-accelerated ab initio exciton model. Phys Chem Chem Phys 2017; 19:14924-14936. [DOI: 10.1039/c7cp00492c] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We present GPU-accelerated ab initio molecular dynamics simulations of nonadiabatic dynamics in the LH2 complex in full atomistic detail.
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Affiliation(s)
- Aaron Sisto
- PULSE Institute and Department of Chemistry
- Stanford University
- Stanford
- USA
- SLAC National Accelerator Laboratory
| | - Clem Stross
- School of Chemistry
- University of Bristol
- Bristol
- UK
| | | | - Michael O’Connor
- School of Chemistry
- University of Bristol
- Bristol
- UK
- Department of Computer Science
| | | | - Graham T. Johnson
- California Institute for Quantitative Biosciences (QB3)
- University of California
- San Francisco
- USA
- Department of Bioengineering and Therapeutic Sciences
| | | | | | - David R. Glowacki
- School of Chemistry
- University of Bristol
- Bristol
- UK
- Department of Computer Science
| | - Todd J. Martinez
- PULSE Institute and Department of Chemistry
- Stanford University
- Stanford
- USA
- SLAC National Accelerator Laboratory
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11
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Bolzonello L, Fassioli F, Collini E. Correlated Fluctuations and Intraband Dynamics of J-Aggregates Revealed by Combination of 2DES Schemes. J Phys Chem Lett 2016; 7:4996-5001. [PMID: 27973862 PMCID: PMC5165657 DOI: 10.1021/acs.jpclett.6b02433] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Accepted: 11/22/2016] [Indexed: 05/22/2023]
Abstract
The intraband exciton dynamics of molecular aggregates is a crucial initial step to determine the possibly coherent nature of energy transfer and its implications for the ensuing interband relaxation pathways in strongly coupled excitonic systems. In this work, we fully characterize the intraband dynamics in linear J-aggregates of porphyrins, good model systems for multichromophoric assemblies in biological antenna complexes. Using different 2D electronic spectroscopy schemes together with Raman spectroscopy and theoretical modeling, we provide a full characterization of the inner structure of the main one-exciton band of the porphyrin aggregates. We find that the redistribution of population within the band occurs with a characteristic time of 280 fs and dominates the modulation of an electronic coherence. While we do not find that the coupling to vibrations significantly affects the dynamics of excitonic coherence, our results suggest that exciton fluctuations are nevertheless highly correlated.
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Affiliation(s)
- Luca Bolzonello
- Department
of Chemical Sciences, University of Padova, Via Marzolo 1, Padova 35131, Italy
| | - Francesca Fassioli
- Department
of Physics, University of Trieste, Strada Costiera 11, Trieste 34151, Italy
- E-mail:
| | - Elisabetta Collini
- Department
of Chemical Sciences, University of Padova, Via Marzolo 1, Padova 35131, Italy
- E-mail:
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12
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Löhner A, Ashraf K, Cogdell RJ, Köhler J. Fluorescence-excitation and Emission Spectroscopy on Single FMO Complexes. Sci Rep 2016; 6:31875. [PMID: 27545197 PMCID: PMC4992959 DOI: 10.1038/srep31875] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 07/29/2016] [Indexed: 12/26/2022] Open
Abstract
In green-sulfur bacteria sunlight is absorbed by antenna structures termed chlorosomes, and transferred to the RC via the Fenna-Matthews-Olson (FMO) complex. FMO consists of three monomers arranged in C3 symmetry where each monomer accommodates eight Bacteriochlorophyll a (BChl a) molecules. It was the first pigment-protein complex for which the structure has been determined with high resolution and since then this complex has been the subject of numerous studies both experimentally and theoretically. Here we report about fluorescence-excitation spectroscopy as well as emission spectroscopy from individual FMO complexes at low temperatures. The individual FMO complexes are subjected to very fast spectral fluctuations smearing out any possible different information from the ensemble data that were recorded under the same experimental conditions. In other words, on the time scales that are experimentally accessible by single-molecule techniques, the FMO complex exhibits ergodic behaviour.
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Affiliation(s)
- Alexander Löhner
- Experimental Physics IV and Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth, Germany
| | - Khuram Ashraf
- Institute of Molecular, Cell & Systems Biology, College of Medical Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Richard J. Cogdell
- Institute of Molecular, Cell & Systems Biology, College of Medical Veterinary and Life Sciences, University of Glasgow, United Kingdom
| | - Jürgen Köhler
- Experimental Physics IV and Bayreuth Institute for Macromolecular Research (BIMF), University of Bayreuth, Germany
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13
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Dahlberg PD, Norris GJ, Wang C, Viswanathan S, Singh VP, Engel GS. Communication: Coherences observed in vivo in photosynthetic bacteria using two-dimensional electronic spectroscopy. J Chem Phys 2016; 143:101101. [PMID: 26373989 DOI: 10.1063/1.4930539] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Energy transfer through large disordered antenna networks in photosynthetic organisms can occur with a quantum efficiency of nearly 100%. This energy transfer is facilitated by the electronic structure of the photosynthetic antennae as well as interactions between electronic states and the surrounding environment. Coherences in time-domain spectroscopy provide a fine probe of how a system interacts with its surroundings. In two-dimensional electronic spectroscopy, coherences can appear on both the ground and excited state surfaces revealing detailed information regarding electronic structure, system-bath coupling, energy transfer, and energetic coupling in complex chemical systems. Numerous studies have revealed coherences in isolated photosynthetic pigment-protein complexes, but these coherences have not been observed in vivo due to the small amplitude of these signals and the intense scatter from whole cells. Here, we present data acquired using ultrafast video-acquisition gradient-assisted photon echo spectroscopy to observe quantum beating signals from coherences in vivo. Experiments were conducted on isolated light harvesting complex II (LH2) from Rhodobacter sphaeroides, whole cells of R. sphaeroides, and whole cells of R. sphaeroides grown in 30% deuterated media. A vibronic coherence was observed following laser excitation at ambient temperature between the B850 and the B850(∗) states of LH2 in each of the 3 samples with a lifetime of ∼40-60 fs.
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Affiliation(s)
- Peter D Dahlberg
- Graduate Program in the Biophysical Sciences, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Graham J Norris
- Department of Chemistry, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Cheng Wang
- Department of Chemistry, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Subha Viswanathan
- Department of Chemistry, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Ved P Singh
- Department of Chemistry, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Gregory S Engel
- Department of Chemistry, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
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14
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Lee MK, Huo P, Coker DF. Semiclassical Path Integral Dynamics: Photosynthetic Energy Transfer with Realistic Environment Interactions. Annu Rev Phys Chem 2016; 67:639-68. [DOI: 10.1146/annurev-physchem-040215-112252] [Citation(s) in RCA: 96] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Mi Kyung Lee
- Department of Chemistry, Boston University, Boston, Massachusetts 02215;
| | - Pengfei Huo
- Department of Chemistry, University of Rochester, Rochester, New York 14627;
| | - David F. Coker
- Department of Chemistry, Boston University, Boston, Massachusetts 02215;
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15
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Singh VP, Westberg M, Wang C, Dahlberg PD, Gellen T, Gardiner AT, Cogdell RJ, Engel GS. Towards quantification of vibronic coupling in photosynthetic antenna complexes. J Chem Phys 2016; 142:212446. [PMID: 26049466 DOI: 10.1063/1.4921324] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Photosynthetic antenna complexes harvest sunlight and efficiently transport energy to the reaction center where charge separation powers biochemical energy storage. The discovery of existence of long lived quantum coherence during energy transfer has sparked the discussion on the role of quantum coherence on the energy transfer efficiency. Early works assigned observed coherences to electronic states, and theoretical studies showed that electronic coherences could affect energy transfer efficiency--by either enhancing or suppressing transfer. However, the nature of coherences has been fiercely debated as coherences only report the energy gap between the states that generate coherence signals. Recent works have suggested that either the coherences observed in photosynthetic antenna complexes arise from vibrational wave packets on the ground state or, alternatively, coherences arise from mixed electronic and vibrational states. Understanding origin of coherences is important for designing molecules for efficient light harvesting. Here, we give a direct experimental observation from a mutant of LH2, which does not have B800 chromophores, to distinguish between electronic, vibrational, and vibronic coherence. We also present a minimal theoretical model 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.
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Affiliation(s)
- V P Singh
- Department of Chemistry, The James Franck Institute and The Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - M Westberg
- Department of Chemistry, The James Franck Institute and The Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - C Wang
- Department of Chemistry, The James Franck Institute and The Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - P D Dahlberg
- Graduate Program in the Biophysical Sciences, The James Franck Institute and The Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - T Gellen
- Department of Chemistry, The James Franck Institute and The Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
| | - A T Gardiner
- Department of Botany, Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, Scotland
| | - R J Cogdell
- Department of Botany, Institute of Molecular Cell and Systems Biology, University of Glasgow, Glasgow, Scotland
| | - G S Engel
- Department of Chemistry, The James Franck Institute and The Institute for Biophysical Dynamics, The University of Chicago, Chicago, Illinois 60637, USA
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16
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Egorova D. Detection of dark states in two-dimensional electronic photon-echo signals via ground-state coherence. J Chem Phys 2016; 142:212452. [PMID: 26049472 DOI: 10.1063/1.4921636] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Several recent experiments report on possibility of dark-state detection by means of so called beating maps of two-dimensional photon-echo spectroscopy [Ostroumov et al., Science 340, 52 (2013); Bakulin et al., Ultrafast Phenomena XIX (Springer International Publishing, 2015)]. The main idea of this detection scheme is to use coherence induced upon the laser excitation as a very sensitive probe. In this study, we investigate the performance of ground-state coherence in the detection of dark electronic states. For this purpose, we simulate beating maps of several models where the excited-state coherence can be hardly detected and is assumed not to contribute to the beating maps. The models represent strongly coupled electron-nuclear dynamics involving avoided crossings and conical intersections. In all the models, the initially populated optically accessible excited state decays to a lower-lying dark state within few hundreds femtoseconds. We address the role of Raman modes and of interstate-coupling nature. Our findings suggest that the presence of low-frequency Raman active modes significantly increases the chances for detection of dark states populated via avoided crossings, whereas conical intersections represent a more challenging task.
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Affiliation(s)
- Dassia Egorova
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstr. 40, D-24098 Kiel, Germany
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17
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Ferretti M, Hendrikx R, Romero E, Southall J, Cogdell RJ, Novoderezhkin VI, Scholes GD, van Grondelle R. Dark States in the Light-Harvesting complex 2 Revealed by Two-dimensional Electronic Spectroscopy. Sci Rep 2016; 6:20834. [PMID: 26857477 PMCID: PMC4746630 DOI: 10.1038/srep20834] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 01/08/2016] [Indexed: 12/03/2022] Open
Abstract
Energy transfer and trapping in the light harvesting antennae of purple photosynthetic bacteria is an ultrafast process, which occurs with a quantum efficiency close to unity. However the mechanisms behind this process have not yet been fully understood. Recently it was proposed that low-lying energy dark states, such as charge transfer states and polaron pairs, play an important role in the dynamics and directionality of energy transfer. However, it is difficult to directly detect those states because of their small transition dipole moment and overlap with the B850/B870 exciton bands. Here we present a new experimental approach, which combines the selectivity of two-dimensional electronic spectroscopy with the availability of genetically modified light harvesting complexes, to reveal the presence of those dark states in both the genetically modified and the wild-type light harvesting 2 complexes of Rhodopseudomonas palustris. We suggest that Nature has used the unavoidable charge transfer processes that occur when LH pigments are concentrated to enhance and direct the flow of energy.
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Affiliation(s)
- Marco Ferretti
- Department of Physics and Astronomy, VU University, 1081 HV Amsterdam, The Netherlands
| | - Ruud Hendrikx
- Department of Physics and Astronomy, VU University, 1081 HV Amsterdam, The Netherlands
| | - Elisabet Romero
- Department of Physics and Astronomy, VU University, 1081 HV Amsterdam, The Netherlands
| | - June Southall
- Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Richard J Cogdell
- Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Vladimir I Novoderezhkin
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119991 Moscow, Russia
| | - Gregory D Scholes
- Department of Chemistry, Princeton University, Washington Rd, Princeton NJ 08544, USA
| | - Rienk van Grondelle
- Department of Physics and Astronomy, VU University, 1081 HV Amsterdam, The Netherlands
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18
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Anda A, Hansen T, De Vico L. Multireference Excitation Energies for Bacteriochlorophylls A within Light Harvesting System 2. J Chem Theory Comput 2016; 12:1305-13. [DOI: 10.1021/acs.jctc.5b01104] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- André Anda
- Department of Chemistry, Copenhagen University, Universitetsparken 5, DK-2100, Copenhagen Ø, Denmark
| | - Thorsten Hansen
- Department of Chemistry, Copenhagen University, Universitetsparken 5, DK-2100, Copenhagen Ø, Denmark
| | - Luca De Vico
- Department of Chemistry, Copenhagen University, Universitetsparken 5, DK-2100, Copenhagen Ø, Denmark
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19
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Chorošajev V, Rancova O, Abramavicius D. Polaronic effects at finite temperatures in the B850 ring of the LH2 complex. Phys Chem Chem Phys 2016; 18:7966-77. [DOI: 10.1039/c5cp06871a] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Energy transfer and relaxation dynamics in the B850 ring of LH2 molecular aggregates are described, taking into account the polaronic effects, by a stochastic time-dependent variational approach.
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Affiliation(s)
- Vladimir Chorošajev
- Department of Theoretical Physics
- Faculty of Physics
- Vilnius University
- LT-10222 Vilnius
- Lithuania
| | - Olga Rancova
- Department of Theoretical Physics
- Faculty of Physics
- Vilnius University
- LT-10222 Vilnius
- Lithuania
| | - Darius Abramavicius
- Department of Theoretical Physics
- Faculty of Physics
- Vilnius University
- LT-10222 Vilnius
- Lithuania
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20
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Akimov AV, Asahi R, Jinnouchi R, Prezhdo OV. What Makes the Photocatalytic CO2 Reduction on N-Doped Ta2O5 Efficient: Insights from Nonadiabatic Molecular Dynamics. J Am Chem Soc 2015; 137:11517-25. [DOI: 10.1021/jacs.5b07454] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alexey V. Akimov
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089, United States
| | - Ryoji Asahi
- Toyota Central Research and Development Laboratories, Inc., 41-1 Yokomichi, Nagakute-shi, Aichi 480-1192, Japan
| | - Ryosuke Jinnouchi
- Toyota Central Research and Development Laboratories, Inc., 41-1 Yokomichi, Nagakute-shi, Aichi 480-1192, Japan
| | - Oleg V. Prezhdo
- Department
of Chemistry, University of Southern California, Los Angeles, California 90089, United States
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21
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Chorošajev V, Gelzinis A, Valkunas L, Abramavicius D. Dynamics of exciton-polaron transition in molecular assemblies: the variational approach. J Chem Phys 2015; 140:244108. [PMID: 24985619 DOI: 10.1063/1.4884275] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Dynamics of excitonic polaron formation in molecular systems coupled to an overdamped bath are investigated using the Dirac-Frenkel variational principle and Davydov D1 Ansatz. Using a two-site model system we show that a few qualitatively distinct relaxation regimes of an optically created exciton are possible, depending on the timescale of bath fluctuations. A slow bath always leads to adiabatic polaron formation. Non-adiabatic exciton self-trapping occurs when the system is strongly coupled to a fast bath. Weak coupling to such bath does not perturb the excitonic picture. The complex system-bath dynamics can then be mapped to an effective model where the resonant coupling between sites is quenched during relaxation. The timescale of the polaron formation can be defined by the timescale of resonant coupling quenching, and is found to directly correlate with the bath relaxation time.
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Affiliation(s)
- Vladimir Chorošajev
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio 9-III, 10222 Vilnius, Lithuania
| | - Andrius Gelzinis
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio 9-III, 10222 Vilnius, Lithuania
| | - Leonas Valkunas
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio 9-III, 10222 Vilnius, Lithuania
| | - Darius Abramavicius
- Department of Theoretical Physics, Faculty of Physics, Vilnius University, Sauletekio 9-III, 10222 Vilnius, Lithuania
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22
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Abstract
Oxygenic photosynthesis is the principal converter of sunlight into chemical energy on Earth. Cyanobacteria and plants provide the oxygen, food, fuel, fibers, and platform chemicals for life on Earth. The conversion of solar energy into chemical energy is catalyzed by two multisubunit membrane protein complexes, photosystem I (PSI) and photosystem II (PSII). Light is absorbed by the pigment cofactors, and excitation energy is transferred among the antennae pigments and converted into chemical energy at very high efficiency. Oxygenic photosynthesis has existed for more than three billion years, during which its molecular machinery was perfected to minimize wasteful reactions. Light excitation transfer and singlet trapping won over fluorescence, radiation-less decay, and triplet formation. Photosynthetic reaction centers operate in organisms ranging from bacteria to higher plants. They are all evolutionarily linked. The crystal structure determination of photosynthetic protein complexes sheds light on the various partial reactions and explains how they are protected against wasteful pathways and why their function is robust. This review discusses the efficiency of photosynthetic solar energy conversion.
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Affiliation(s)
- Nathan Nelson
- Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel;
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23
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Huo P, Miller III TF. Electronic coherence and the kinetics of inter-complex energy transfer in light-harvesting systems. Phys Chem Chem Phys 2015; 17:30914-24. [DOI: 10.1039/c5cp02517f] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Comparison of inter-complex excitation energy transfer rates obtained in a general system (original, red) and in an alternative parameterization of the system that preserves static coherence while eliminating dynamic coherence (SCP, black) reveals that static coherence largely governs the kinetics of incoherent inter-complex EET in model light-harvesting networks, whereas dynamic coherence plays only a minor role.
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Affiliation(s)
- Pengfei Huo
- Division of Chemistry and Chemical Engineering
- California Institute of Technology
- Pasadena, USA
| | - Thomas F. Miller III
- Division of Chemistry and Chemical Engineering
- California Institute of Technology
- Pasadena, USA
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24
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Egorova D. Self-Analysis of Coherent Oscillations in Time-Resolved Optical Signals. J Phys Chem A 2014; 118:10259-67. [DOI: 10.1021/jp509657u] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dassia Egorova
- Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany
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25
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Rancova O, Abramavicius D. Static and Dynamic Disorder in Bacterial Light-Harvesting Complex LH2: A 2DES Simulation Study. J Phys Chem B 2014; 118:7533-7540. [DOI: 10.1021/jp5043156] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Olga Rancova
- Department of Theoretical
Physics, Faculty of Physics, Vilnius University, Sauletekio av. 9 III bld., LT-10222 Vilnius, Lithuania
| | - Darius Abramavicius
- Department of Theoretical
Physics, Faculty of Physics, Vilnius University, Sauletekio av. 9 III bld., LT-10222 Vilnius, Lithuania
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26
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Abstract
Biological electron-transfer (ET) reactions are typically described in the framework of coherent two-state electron tunneling or multistep hopping. However, these ET reactions may involve multiple redox cofactors in van der Waals contact with each other and with vibronic broadenings on the same scale as the energy gaps among the species. In this regime, fluctuations of the molecular structures and of the medium can produce transient energy level matching among multiple electronic states. This transient degeneracy, or flickering electronic resonance among states, is found to support coherent (ballistic) charge transfer. Importantly, ET rates arising from a flickering resonance (FR) mechanism will decay exponentially with distance because the probability of energy matching multiple states is multiplicative. The distance dependence of FR transport thus mimics the exponential decay that is usually associated with electron tunneling, although FR transport involves real carrier population on the bridge and is not a tunneling phenomenon. Likely candidates for FR transport are macromolecules with ET groups in van der Waals contact: DNA, bacterial nanowires, multiheme proteins, strongly coupled porphyrin arrays, and proteins with closely packed redox-active residues. The theory developed here is used to analyze DNA charge-transfer kinetics, and we find that charge-transfer distances up to three to four bases may be accounted for with this mechanism. Thus, the observed rapid (exponential) distance dependence of DNA ET rates over distances of ≲ 15 Å does not necessarily prove a tunneling mechanism.
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27
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Fidler AF, Singh VP, Long PD, Dahlberg PD, Engel GS. Probing energy transfer events in the light harvesting complex 2 (LH2) of Rhodobacter sphaeroides with two-dimensional spectroscopy. J Chem Phys 2014; 139:155101. [PMID: 24160544 DOI: 10.1063/1.4824637] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Excitation energy transfer events in the photosynthetic light harvesting complex 2 (LH2) of Rhodobacter sphaeroides are investigated with polarization controlled two-dimensional electronic spectroscopy. A spectrally broadened pulse allows simultaneous measurement of the energy transfer within and between the two absorption bands at 800 nm and 850 nm. The phased all-parallel polarization two-dimensional spectra resolve the initial events of energy transfer by separating the intra-band and inter-band relaxation processes across the two-dimensional map. The internal dynamics of the 800 nm region of the spectra are resolved as a cross peak that grows in on an ultrafast time scale, reflecting energy transfer between higher lying excitations of the B850 chromophores into the B800 states. We utilize a polarization sequence designed to highlight the initial excited state dynamics which uncovers an ultrafast transfer component between the two bands that was not observed in the all-parallel polarization data. We attribute the ultrafast transfer component to energy transfer from higher energy exciton states to lower energy states of the strongly coupled B850 chromophores. Connecting the spectroscopic signature to the molecular structure, we reveal multiple relaxation pathways including a cyclic transfer of energy between the two rings of the complex.
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Affiliation(s)
- Andrew F Fidler
- Department of Chemistry, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
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28
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Jumper CC, Anna JM, Stradomska A, Schins J, Myahkostupov M, Prusakova V, Oblinsky DG, Castellano FN, Knoester J, Scholes GD. Intramolecular radiationless transitions dominate exciton relaxation dynamics. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.03.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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29
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Caram JR, Zheng H, Dahlberg PD, Rolczynski BS, Griffin GB, Fidler AF, Dolzhnikov DS, Talapin DV, Engel GS. Persistent Inter-Excitonic Quantum Coherence in CdSe Quantum Dots. J Phys Chem Lett 2014; 5:196-204. [PMID: 24719679 PMCID: PMC3976995 DOI: 10.1021/jz402336t] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The creation and manipulation of quantum superpositions is a fundamental goal for the development of materials with novel optoelectronic properties. In this letter, we report persistent (~80 fs lifetime) quantum coherence between the 1S and 1P excitonic states in zinc-blende colloidal CdSe quantum dots at room temperature, measured using Two-Dimensional Electronic Spectroscopy. We demonstrate that this quantum coherence manifests as an intradot phenomenon, the frequency of which depends on the size of the dot excited within the ensemble of QDs. We model the lifetime of the coherence and demonstrate that correlated interexcitonic fluctuations preserve relative phase between excitonic states. These observations suggest an avenue for engineering long-lived interexcitonic quantum coherence in colloidal quantum dots.
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Affiliation(s)
- Justin R. Caram
- Department of Chemistry, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Haibin Zheng
- Department of Chemistry, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Peter D. Dahlberg
- Graduate Program in the Biophysical Sciences, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, IL 60637
| | - Brian S. Rolczynski
- Department of Chemistry, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Graham B. Griffin
- Department of Chemistry, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Andrew F. Fidler
- Department of Chemistry, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Dmitriy S. Dolzhnikov
- Department of Chemistry, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Dmitri V. Talapin
- Department of Chemistry, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
| | - Gregory S. Engel
- Department of Chemistry, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
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30
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Fidler AF, Singh VP, Long PD, Dahlberg PD, Engel GS. Dynamic localization of electronic excitation in photosynthetic complexes revealed with chiral two-dimensional spectroscopy. Nat Commun 2014; 5:3286. [PMID: 24504144 PMCID: PMC3976994 DOI: 10.1038/ncomms4286] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 01/21/2014] [Indexed: 01/18/2023] Open
Abstract
Time-resolved ultrafast optical probes of chiral dynamics provide a new window allowing us to explore how interactions with such structured environments drive electronic dynamics. Incorporating optical activity into time-resolved spectroscopies has proven challenging because of the small signal and large achiral background. Here we demonstrate that two-dimensional electronic spectroscopy can be adapted to detect chiral signals and that these signals reveal how excitations delocalize and contract following excitation. We dynamically probe the evolution of chiral electronic structure in the light-harvesting complex 2 of purple bacteria following photoexcitation by creating a chiral two-dimensional mapping. The dynamics of the chiral two-dimensional signal directly reports on changes in the degree of delocalization of the excitonic states following photoexcitation. The mechanism of energy transfer in this system may enhance transfer probability because of the coherent coupling among chromophores while suppressing fluorescence that arises from populating delocalized states. This generally applicable spectroscopy will provide an incisive tool to probe ultrafast transient molecular fluctuations that are obscured in non-chiral experiments.
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Affiliation(s)
- Andrew F. Fidler
- Department of Chemistry, Institute for Biophysical Dynamics, and The James Franck Institute, 929 East 57 Street, The University of Chicago, Chicago, Illinois 60637, USA
| | - Ved P. Singh
- Department of Chemistry, Institute for Biophysical Dynamics, and The James Franck Institute, 929 East 57 Street, The University of Chicago, Chicago, Illinois 60637, USA
| | - Phillip D. Long
- Program in the Biophysical Sciences, 929 East 57 Street, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637
| | - Peter D. Dahlberg
- Program in the Biophysical Sciences, 929 East 57 Street, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637
| | - Gregory S. Engel
- Department of Chemistry, Institute for Biophysical Dynamics, and The James Franck Institute, 929 East 57 Street, The University of Chicago, Chicago, Illinois 60637, USA
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31
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Dahlberg PD, Fidler AF, Caram JR, Long PD, Engel GS. Energy Transfer Observed in Live Cells Using Two-Dimensional Electronic Spectroscopy. J Phys Chem Lett 2013; 4:3636-3640. [PMID: 24478821 PMCID: PMC3902138 DOI: 10.1021/jz401944q] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Two-dimensional electronic spectroscopy (2DES) elucidates electronic structure and dynamics on a femtosecond time scale and has proven to be an incisive tool for probing congested linear spectra of biological systems. However, samples that scatter light intensely frustrate 2DES analysis, necessitating the use of isolated protein chromophore complexes when studying photosynthetic energy transfer processes. We present a method for conducting 2DES experiments that takes only seconds to acquire thousands of 2DES spectra and permits analysis of highly scattering samples, specifically whole cells of the purple bacterium Rhodobacter sphaeroides. These in vivo 2DES experiments reveal similar timescales for energy transfer within the antennae complex (light harvesting complex 2, LH2) both in the native photosynthetic membrane environment and in isolated detergent micelles.
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Affiliation(s)
- Peter D. Dahlberg
- Graduate Program in the Biophysical Sciences, Institute for Biophysical Dynamics, and the James Franck Institute, The University of Chicago, Chicago, IL 60637
| | - Andrew F. Fidler
- Department of Chemistry, Institute for Biophysical Dynamics, and the James Franck Institute, The University of Chicago, Chicago, IL, 60637
| | - Justin R. Caram
- Department of Chemistry, Institute for Biophysical Dynamics, and the James Franck Institute, The University of Chicago, Chicago, IL, 60637
| | - Phillip D. Long
- Graduate Program in the Biophysical Sciences, Institute for Biophysical Dynamics, and the James Franck Institute, The University of Chicago, Chicago, IL 60637
| | - Gregory S. Engel
- Department of Chemistry, Institute for Biophysical Dynamics, and the James Franck Institute, The University of Chicago, Chicago, IL, 60637
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