1
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Li Y, Sun B, Liu C, Zhao Z, Ning H, Zhang P, Li F, Sun L, Li F. Promoting Water Oxidation by Proton Acceptable Groups Surrounding Catalyst on Electrode Surface. CHEMSUSCHEM 2024:e202400735. [PMID: 38771427 DOI: 10.1002/cssc.202400735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 05/10/2024] [Accepted: 05/21/2024] [Indexed: 05/22/2024]
Abstract
Large-scale hydrogen production through water splitting represents an optimal approach for storing sustainable but intermittent energy sources. However, water oxidation, a complex and sluggish reaction, poses a significant bottleneck for water splitting efficiency. The impact of outer chemical environments on the reaction kinetics of water oxidation catalytic centers remains unexplored. Herein, chemical environment impacts were integrated by featuring methylpyridinium cation group (Py+) around the classic Ru(bpy)(tpy) (bpy=2,2'-bipyridine, tpy=2,2' : 6',2''-terpyridine) water oxidation catalyst on the electrode surface via electrochemical co-polymerization. The presence of Py+ groups could significantly enhance the turnover frequencies of Ru(bpy)(tpy), surpassing the performance of typical proton acceptors such as pyridine and benzoic acid anchored around the catalyst. Mechanistic investigations reveal that the flexible internal proton acceptor anions induced by Py+ around Ru(bpy)(tpy) are more effective than conventionally anchored proton acceptors, which promoted the rate-determining proton transfer process and enhanced the rate of water nucleophilic attack during O-O bond formation. This study may provide a novel perspective on achieving efficient water oxidation systems by integrating cations into the outer chemical environments of catalytic centers.
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Affiliation(s)
- Yingzheng Li
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, 116024, Dalian, Liaoning, China
| | - Bin Sun
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, 116024, Dalian, Liaoning, China
| | - Chang Liu
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, 116024, Dalian, Liaoning, China
| | - Ziqi Zhao
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, 116024, Dalian, Liaoning, China
| | - Hongxia Ning
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, 116024, Dalian, Liaoning, China
| | - Peili Zhang
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, 116024, Dalian, Liaoning, China
| | - Fei Li
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, 116024, Dalian, Liaoning, China
| | - Licheng Sun
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, 116024, Dalian, Liaoning, China
- Center of Artificial Photosynthesis for Solar Fuels, School of Science, Westlake University, 310024, Hangzhou, Zhejiang, China
| | - Fusheng Li
- State Key Laboratory of Fine Chemicals, Frontier Science Center for Smart Materials, Dalian University of Technology, 116024, Dalian, Liaoning, China
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2
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Riedl M, Renger T, Seibt J. Theory of 2D electronic spectroscopy of water soluble chlorophyll-binding protein (WSCP): Signatures of Chl b derivate. J Chem Phys 2024; 160:184114. [PMID: 38726933 DOI: 10.1063/5.0200876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 04/21/2024] [Indexed: 06/29/2024] Open
Abstract
We investigate how electronic excitations and subsequent dissipative dynamics in the water soluble chlorophyll-binding protein (WSCP) are connected to features in two-dimensional (2D) electronic spectra, thereby comparing results from our theoretical approach with experimental data from the literature. Our calculations rely on third-order response functions, which we derived from a second-order cumulant expansion of the dissipative dynamics involving the partial ordering prescription, assuming a fast vibrational relaxation in the potential energy surfaces of excitons. Depending on whether the WSCP complex containing a tetrameric arrangement of pigments composed of two dimers with weak excitonic coupling between them binds the chlorophyll variant Chl a or Chl b, the resulting linear absorption and circular dichroism spectra and particularly the 2D spectra exhibit substantial differences in line shapes. These differences between Chl a WSCP and Chl b WSCP cannot be explained by the slightly modified excitonic couplings within the two variants. In the case of Chl a WSCP, the assumption of equivalent dimer subunits facilitates a reproduction of substantial features from the experiment by the calculations. In contrast, for Chl b WSCP, we have to assume that the sample, in addition to Chl b dimers, contains a small but distinct fraction of chemically modified Chl b pigments. The existence of such Chl b derivates has been proposed by Pieper et al. [J. Phys. Chem. B 115, 4042 (2011)] based on low-temperature absorption and hole-burning spectroscopy. Here, we provide independent evidence.
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Affiliation(s)
- Michael Riedl
- Institute for Theoretical Physics, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria
| | - Thomas Renger
- Institute for Theoretical Physics, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria
| | - Joachim Seibt
- Institute for Theoretical Physics, Johannes Kepler University Linz, Altenberger Str. 69, 4040 Linz, Austria
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3
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Kizmann M, Yadalam HK, Chernyak VY, Mukamel S. Intraband Exciton Transitions in Photosynthetic Complexes Revealed by Novel Five-Wave-Mixing Spectroscopy. J Chem Theory Comput 2024; 20:280-289. [PMID: 38128473 DOI: 10.1021/acs.jctc.3c00919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
We calculate the χ(4) optical response of an oriented photosystem II reaction center of purple bacteria described by the Frenkel exciton model using nonlinear exciton equations (NEE). This approach treats each chromophore as an anharmonic oscillator and provides an intuitive quasiparticle picture of nonlinear spectroscopic signals of interacting excitons. It provides a computationally powerful description of nonlinear spectroscopic signals that avoids complete diagonalization of the total Hamiltonian. Expressions for the second- and the fourth-order nonlinear signals are derived. The NEE have been successfully employed in the past to describe even-order-wave-mixing. Here, we extend them to aggregates with broken inversion symmetries. Even-order susceptibilities require the introduction of permanent dipoles, which allow to directly probe low-frequency intraband transitions of excitons.
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Affiliation(s)
- Matthias Kizmann
- Department of Chemistry, University of California, Irvine, California 92614, United States
- Department of Physics and Astronomy, University of California, Irvine, California 92614, United States
| | - Hari Kumar Yadalam
- Department of Chemistry, University of California, Irvine, California 92614, United States
- Department of Physics and Astronomy, University of California, Irvine, California 92614, United States
| | - Vladimir Y Chernyak
- Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, Michigan 48202, United States
- Department of Mathematics, Wayne State University, 656 W. Kirby, Detroit, Michigan 48202, United States
| | - Shaul Mukamel
- Department of Chemistry, University of California, Irvine, California 92614, United States
- Department of Physics and Astronomy, University of California, Irvine, California 92614, United States
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4
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Gemeinhardt FG, Lahav Y, Schapiro I, Noy D, Müh F, Lindorfer D, Renger T. Short-Range Effects in the Special Pair of Photosystem II Reaction Centers: The Nonconservative Nature of Circular Dichroism. J Phys Chem Lett 2023; 14:11758-11767. [PMID: 38117270 PMCID: PMC10758115 DOI: 10.1021/acs.jpclett.3c02693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Revised: 11/29/2023] [Accepted: 12/04/2023] [Indexed: 12/21/2023]
Abstract
Photosystem II reaction centers extract electrons from water, providing the basis of oxygenic life on earth. Among the light-sensitive pigments of the reaction center, a central chlorophyll a dimer, known as the special pair, so far has escaped a complete theoretical characterization of its excited state properties. The close proximity of the special pair pigments gives rise to short-range effects that comprise a coupling between local and charge transfer (CT) excited states as well as other intermolecular quantum effects. Using a multiscale simulation and a diabatization technique, we show that the coupling to CT states is responsible for 45% of the excitonic coupling in the special pair. The other short-range effects cause a nonconservative nature of the circular dichroism spectrum of the reaction center by effectively rotating the electric transition dipole moments of the special pair pigments inverting and strongly enhancing their intrinsic rotational strength.
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Affiliation(s)
- Felix G. Gemeinhardt
- Institut
für Theoretische Physik, Johannes
Kepler Universität Linz, Altenberger Strasse 69, 4040 Linz, Austria
| | - Yigal Lahav
- Fritz
Haber Center for Molecular Dynamics Research, Institute of Chemistry, Hebrew University of Jerusalem, 9190401 Jerusalem, Israel
- MIGAL
- Galilee Research Institute, S. Industrial Zone, 1101602 Kiryat Shmona, Israel
| | - Igor Schapiro
- Fritz
Haber Center for Molecular Dynamics Research, Institute of Chemistry, Hebrew University of Jerusalem, 9190401 Jerusalem, Israel
| | - Dror Noy
- MIGAL
- Galilee Research Institute, S. Industrial Zone, 1101602 Kiryat Shmona, Israel
- Faculty
of Sciences and Technology, Tel-Hai Academic
College, 1220800 Upper Galilee, Israel
| | - Frank Müh
- Institut
für Theoretische Physik, Johannes
Kepler Universität Linz, Altenberger Strasse 69, 4040 Linz, Austria
| | - Dominik Lindorfer
- Institut
für Theoretische Physik, Johannes
Kepler Universität Linz, Altenberger Strasse 69, 4040 Linz, Austria
| | - Thomas Renger
- Institut
für Theoretische Physik, Johannes
Kepler Universität Linz, Altenberger Strasse 69, 4040 Linz, Austria
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5
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Sirohiwal A, Pantazis DA. Reaction Center Excitation in Photosystem II: From Multiscale Modeling to Functional Principles. Acc Chem Res 2023; 56:2921-2932. [PMID: 37844298 PMCID: PMC10634305 DOI: 10.1021/acs.accounts.3c00392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Indexed: 10/18/2023]
Abstract
Oxygenic photosynthesis is the fundamental energy-converting process that utilizes sunlight to generate molecular oxygen and the organic compounds that sustain life. Protein-pigment complexes harvest light and transfer excitation energy to specialized pigment assemblies, reaction centers (RC), where electron transfer cascades are initiated. A molecular-level understanding of the primary events is indispensable for elucidating the principles of natural photosynthesis and enabling development of bioinspired technologies. The primary enzyme in oxygenic photosynthesis is Photosystem II (PSII), a membrane-embedded multisubunit complex, that catalyzes the light-driven oxidation of water. The RC of PSII consists of four chlorophyll a and two pheophytin a pigments symmetrically arranged along two core polypeptides; only one branch participates in electron transfer. Despite decades of research, fundamental questions remain, including the origin of this functional asymmetry, the nature of primary charge-transfer states and the identity of the initial electron donor, the origin of the capability of PSII to enact charge separation with far-red photons, i.e., beyond the "red limit" where individual chlorophylls absorb, and the role of protein conformational dynamics in modulating charge-separation pathways.In this Account, we highlight developments in quantum-chemistry based excited-state computations for multipigment assemblies and the refinement of protocols for computing protein-induced electrochromic shifts and charge-transfer excitations calibrated with modern local correlation coupled cluster methods. We emphasize the importance of multiscale atomistic quantum-mechanics/molecular-mechanics and large-scale molecular dynamics simulations, which enabled direct and accurate modeling of primary processes in RC excitation at the quantum mechanical level.Our findings show how differential protein electrostatics enable spectral tuning of RC pigments and generate functional asymmetry in PSII. A chlorophyll pigment on the active branch (ChlD1) has the lowest site energy in PSII and is the primary electron donor. The complete absence of low-lying charge-transfer states within the central pair of chlorophylls excludes a long-held assumption about the initial charge separation. Instead, we identify two primary charge separation pathways, both with the same pheophytin acceptor (PheoD1): a fast pathway with ChlD1 as the primary electron donor (short-range charge-separation) and a slow pathway with PD1PD2 as the initial donor (long-range charge separation). The low-energy spectrum is dominated by two states with significant charge-transfer character, ChlD1δ+PheoD1δ- and PD1δ+PheoD1δ-. The conformational dynamics of PSII allows these charge-transfer states to span wide energy ranges, pushing oxygenic photosynthesis beyond the "red limit". These results provide a quantum mechanical picture of the primary events in the RC of oxygenic photosynthesis, forming a solid basis for interpreting experimental observations and for extending photosynthesis research in new directions.
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Affiliation(s)
- Abhishek Sirohiwal
- Department
of Biochemistry and Biophysics, Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden
| | - Dimitrios A. Pantazis
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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6
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Novoderezhkin VI. Resonant vibrations produce quantum bridge over high-energy states in heterogeneous antenna. PHOTOSYNTHESIS RESEARCH 2023; 158:13-21. [PMID: 37584896 DOI: 10.1007/s11120-023-01042-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 07/29/2023] [Indexed: 08/17/2023]
Abstract
Photosynthetic light-harvesting complexes usually contain several pools of molecules with a big difference in transition energies, for example, chlorophylls a and b in plant antennas. Some pathways of the excitation energy transfer may include pigments from the low-energy pool separated by a site occupied by a high-energy molecule. We demonstrate that such pathways may be functional if high-frequency intramolecular vibrations fall in resonance with the energy gap between the neighboring molecules belonging to different pools. In this case, a vibration-assisted mixing of the excited states can produce delocalized vibronic states playing a role of 'quantum bridge' that facilitates a passage over high-energy barrier. We perform calculations of the excitation dynamics in the model three-state system with the parameters emerging from our previous studies of real antennas. Simulation of the dynamics in an explicit electron-vibrational basis demonstrates that the rate of transfer between the two chlorophylls a through the chlorophyll b intermediate is increased by a factor of 1.7-2 in the presence of resonant vibration. A possible influence of energetic disorder and other (non-resonant) vibrations on this effect is discussed.
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Affiliation(s)
- Vladimir I Novoderezhkin
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, 119992, Moscow, Russia.
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7
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Novoderezhkin VI. Excitonic interactions and Stark fluorescence spectra. J Chem Phys 2023; 159:054114. [PMID: 37548302 DOI: 10.1063/5.0158393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 07/20/2023] [Indexed: 08/08/2023] Open
Abstract
We develop the theory for the Stark fluorescence (SF) of molecular aggregates by taking into account the mixing of the excited states [including the states with charge-transfer (CT) characters]. We use the sum-over-state approach and modified rotating wave approximation to describe interactions of the static and optical fields with the permanent and transition dipoles of the excited states. The SF spectral profiles are calculated using the standard and modified Redfield theories for the emission lineshapes. The resulting expression allows an interpretation of the SF response based on the calculation of only one-exciton states (i.e., the calculation of two-exciton states is not needed). The shape and amplitude of the SF spectrum can exhibit dramatic changes in the presence of the CT states, especially when the CT state is mixed with the red-most emitting exciton levels. In this case, the SF responses are much more sensitive to the exciton-CT mixing as compared with the usual Stark absorption. The limitation of the proposed theory is related to the simplified nature of the Redfield picture, which neglects the dynamic localization within the mixed exciton-CT configuration.
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Affiliation(s)
- Vladimir I Novoderezhkin
- A. N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Leninskie Gory, Moscow 119992, Russia
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8
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Nguyen HH, Song Y, Maret EL, Silori Y, Willow R, Yocum CF, Ogilvie JP. Charge separation in the photosystem II reaction center resolved by multispectral two-dimensional electronic spectroscopy. SCIENCE ADVANCES 2023; 9:eade7190. [PMID: 37134172 PMCID: PMC10156117 DOI: 10.1126/sciadv.ade7190] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The photosystem II reaction center (PSII RC) performs the primary energy conversion steps of oxygenic photosynthesis. While the PSII RC has been studied extensively, the similar time scales of energy transfer and charge separation and the severely overlapping pigment transitions in the Qy region have led to multiple models of its charge separation mechanism and excitonic structure. Here, we combine two-dimensional electronic spectroscopy (2DES) with a continuum probe and two-dimensional electronic vibrational spectroscopy (2DEV) to study the cyt b559-D1D2 PSII RC at 77 K. This multispectral combination correlates the overlapping Qy excitons with distinct anion and pigment-specific Qx and mid-infrared transitions to resolve the charge separation mechanism and excitonic structure. Through extensive simultaneous analysis of the multispectral 2D data, we find that charge separation proceeds on multiple time scales from a delocalized excited state via a single pathway in which PheoD1 is the primary electron acceptor, while ChlD1 and PD1 act in concert as the primary electron donor.
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Affiliation(s)
- Hoang H Nguyen
- Department of Physics and Biophysics, University of Michigan, 450 Church St., Ann Arbor, MI 48109, USA
| | - Yin Song
- Department of Physics and Biophysics, University of Michigan, 450 Church St., Ann Arbor, MI 48109, USA
- School of Optics and Photonics, Beijing Institute of Technology, 5 Zhongguancun South Street, Haidian District, Beijing, 100081, China
| | - Elizabeth L Maret
- Department of Physics and Biophysics, University of Michigan, 450 Church St., Ann Arbor, MI 48109, USA
| | - Yogita Silori
- Department of Physics and Biophysics, University of Michigan, 450 Church St., Ann Arbor, MI 48109, USA
| | - Rhiannon Willow
- Department of Physics and Biophysics, University of Michigan, 450 Church St., Ann Arbor, MI 48109, USA
| | - Charles F Yocum
- Department of Molecular, Cellular and Developmental Biology and Department of Chemistry, University of Michigan, 450 Church St, Ann Arbor, MI 48109, USA
| | - Jennifer P Ogilvie
- Department of Physics and Biophysics, University of Michigan, 450 Church St., Ann Arbor, MI 48109, USA
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9
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Seibt J, Lindorfer D, Renger T. Signatures of intramolecular vibrational and vibronic Q[Formula: see text]-Q[Formula: see text] coupling effects in absorption and CD spectra of chlorophyll dimers. PHOTOSYNTHESIS RESEARCH 2023; 156:19-37. [PMID: 36040654 PMCID: PMC10070234 DOI: 10.1007/s11120-022-00946-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 07/25/2022] [Indexed: 06/15/2023]
Abstract
An electron-vibrational coupling model that includes the vibronic (non-adiabatic) coupling between the Q[Formula: see text] and Q[Formula: see text] transitions of chlorophyll (Chl), created by Reimers and coworkers (Scientific Rep. 3, 2761, 2013) is extended here to chlorophyll dimers with interchlorophyll excitonic coupling. The model is applied to a Chl a dimer of the water-soluble chlorophyll binding protein (WSCP). As for isolated chlorophyll, the vibronic coupling is found to have a strong influence on the high-frequency vibrational sideband in the absorption spectrum, giving rise to a band splitting. In contrast, in the CD spectrum the interplay of vibronic coupling and static disorder leads to a strong suppression of the vibrational sideband in excellent agreement with the experimental data. The conservative nature of the CD spectrum in the low-energy region is found to be caused by a delicate balance of the intermonomer excitonic coupling between the purely electronic Q[Formula: see text] transition and the Q[Formula: see text] transition involving intramolecular vibrational excitations on one hand and the coupling to higher-energy electronic transitions on the other hand.
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Affiliation(s)
- Joachim Seibt
- Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Str. 69, 4040, Linz, Austria.
| | - Dominik Lindorfer
- Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Str. 69, 4040, Linz, Austria
| | - Thomas Renger
- Institut für Theoretische Physik, Johannes Kepler Universität Linz, Altenberger Str. 69, 4040, Linz, Austria
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10
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Zakutauskaitė K, Mačernis M, Nguyen HH, Ogilvie JP, Abramavičius D. Extracting the excitonic Hamiltonian of a chlorophyll dimer from broadband two-dimensional electronic spectroscopy. J Chem Phys 2023; 158:015103. [PMID: 36610982 DOI: 10.1063/5.0108166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We apply Frenkel exciton theory to model the entire Q-band of a tightly bound chlorophyll dimer inspired by the photosynthetic reaction center of photosystem II. The potential of broadband two-dimensional electronic spectroscopy experiment spanning the Qx and Qy regions to extract the parameters of the model dimer Hamiltonian is examined through theoretical simulations of the experiment. We find that the local nature of Qx excitation enables identification of molecular properties of the delocalized Qy excitons. Specifically, we demonstrate that the cross-peak region, where excitation energy is resonant with Qy while detection is at Qx, contains specific spectral signatures that can reveal the full real-space molecular Hamiltonian, a task that is impossible by considering the Qy transitions alone. System-bath coupling and site energy disorder in realistic systems may limit the resolution of these spectral signatures due to spectral congestion.
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Affiliation(s)
- Kristina Zakutauskaitė
- Institute of Chemical Physics, Vilnius University, Sauletekio al. 9-III, Vilnius, Lithuania
| | - Mindaugas Mačernis
- Institute of Chemical Physics, Vilnius University, Sauletekio al. 9-III, Vilnius, Lithuania
| | - Hoang H Nguyen
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Jennifer P Ogilvie
- Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Darius Abramavičius
- Institute of Chemical Physics, Vilnius University, Sauletekio al. 9-III, Vilnius, Lithuania
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11
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Mikalčiūtė A, Gelzinis A, Mačernis M, Büchel C, Robert B, Valkunas L, Chmeliov J. Structure-based model of fucoxanthin-chlorophyll protein complex: Calculations of chlorophyll electronic couplings. J Chem Phys 2022; 156:234101. [PMID: 35732526 DOI: 10.1063/5.0092154] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Diatoms are a group of marine algae that are responsible for a significant part of global oxygen production. Adapted to life in an aqueous environment dominated by the blue-green light, their major light-harvesting antennae-fucoxanthin-chlorophyll protein complexes (FCPs)-exhibit different pigment compositions than of plants. Despite extensive experimental studies, until recently the theoretical description of excitation energy dynamics in these complexes was limited by the lack of high-resolution structural data. In this work, we use the recently resolved crystallographic information of the FCP complex from Phaeodactylum tricornutum diatom [Wang et al., Science 363, 6427 (2019)] and quantum chemistry-based calculations to evaluate the chlorophyll transition dipole moments, atomic transition charges from electrostatic potential, and the inter-chlorophyll couplings in this complex. The obtained structure-based excitonic couplings form the foundation for any modeling of stationary or time-resolved spectroscopic data. We also calculate the inter-pigment Förster energy transfer rates and identify two quickly equilibrating chlorophyll clusters.
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Affiliation(s)
- Austėja Mikalčiūtė
- Institute of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio Avenue 9, LT-10222 Vilnius, Lithuania
| | - Andrius Gelzinis
- Institute of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio Avenue 9, LT-10222 Vilnius, Lithuania
| | - Mindaugas Mačernis
- Institute of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio Avenue 9, LT-10222 Vilnius, Lithuania
| | - Claudia Büchel
- Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue Straße 9, 60438 Frankfurt, Germany
| | - Bruno Robert
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Leonas Valkunas
- Institute of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio Avenue 9, LT-10222 Vilnius, Lithuania
| | - Jevgenij Chmeliov
- Institute of Chemical Physics, Faculty of Physics, Vilnius University, Saulėtekio Avenue 9, LT-10222 Vilnius, Lithuania
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12
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Do TN, Nguyen HL, Akhtar P, Zhong K, Jansen TLC, Knoester J, Caffarri S, Lambrev PH, Tan HS. Ultrafast Excitation Energy Transfer Dynamics in the LHCII-CP29-CP24 Subdomain of Plant Photosystem II. J Phys Chem Lett 2022; 13:4263-4271. [PMID: 35522529 DOI: 10.1021/acs.jpclett.2c00194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
We measure the two-dimensional electronic spectra of the LHCII(M)-CP29-CP24 complex in photosystem II (PSII) and provide the first study of the ultrafast excitation energy transfer (EET) processes of an asymmetric and native light-harvesting assembly of the antenna of PSII. With comparisons to LHCII, we observe faster energy equilibrations in the intermediate levels of the LHCII(M)-CP29-CP24 complex at 662 and 670 nm. Notably, the putative "bottleneck" states in LHCII exhibit faster effective dynamics in the LHCII(M)-CP24-CP29 complex, with the average lifetime shortening from 2.5 ps in LHCII to 1.2 ps in the bigger assembly. The observations are supported by high-level structure-based calculations, and the accelerated dynamics can be attributed to the structural change of LHCII(M) in the bigger complex. This study shows that the biological functioning structures of the complexes are important to understand the overall EET dynamics of the PSII supercomplex.
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Affiliation(s)
- Thanh Nhut Do
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Hoang Long Nguyen
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
| | - Parveen Akhtar
- Biological Research Center, Szeged, Temesvári körút 62, Szeged 6726, Hungary
- ELI-ALPS, ELI-HU Nonprofit Limited, Wolfgang Sandner utca 3, Szeged 6728, Hungary
| | - Kai Zhong
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
| | - Thomas L C Jansen
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
| | - Jasper Knoester
- Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG Groningen, Netherlands
| | - Stefano Caffarri
- Aix Marseille Université, CEA, CNRS, BIAM, LGBP, 13009 Marseille, France
| | - Petar H Lambrev
- Biological Research Center, Szeged, Temesvári körút 62, Szeged 6726, Hungary
| | - Howe-Siang Tan
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
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13
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Searching for a Unique Exciton Model of Photosynthetic Pigment–Protein Complexes: Photosystem II Reaction Center Study by Differential Evolution. MATHEMATICS 2022. [DOI: 10.3390/math10060959] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Studying the optical properties of photosynthetic pigment–protein complexes (PPCs) in the visible light range, both experimentally and theoretically, is one of the ways of gaining knowledge about the function of the photosynthetic machinery of living species. To simulate the PPC optical response, it is necessary to use semiclassical theories describing the effect of external fields–matter interaction, energy migration in molecular crystals, and electron–phonon coupling. In this paper, we report the results of photosystem II reaction center (PSIIRC) linear optical response simulations. Applying the multimode Brownian oscillator model and the theory of molecular excitons, we have demonstrated that the absorption, circular and linear dichroism, and steady-state fluorescence of PSIIRC can be accurately fitted with the help of differential evolution (DE), the multiparametric evolutionary optimization algorithm. To explore the effectiveness of DE, we used the simulated experimental data as the target functions instead of those actually measured. Only 2 of 10 DE strategies have shown the best performance of the optimization algorithm. With the best tuning parameters of DE/rand-to-best/1/exp strategy determined from the strategy tests, we found the exact solution for the PSIIRC exciton model and fitted the spectra with a reasonable convergence rate.
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14
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Braver Y, Valkunas L, Gelzinis A. Stark absorption and Stark fluorescence spectroscopies: Theory and simulations. J Chem Phys 2021; 155:244101. [PMID: 34972359 DOI: 10.1063/5.0073962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Stark spectroscopy experiments are widely used to study the properties of molecular systems, particularly those containing charge-transfer (CT) states. However, due to the small transition dipole moments and large static dipole moments of the CT states, the standard interpretation of the Stark absorption and Stark fluorescence spectra in terms of the Liptay model may be inadequate. In this work, we provide a theoretical framework for calculations of Stark absorption and Stark fluorescence spectra and propose new methods of simulations that are based on the quantum-classical theory. In particular, we use the forward-backward trajectory solution and a variant of the Poisson bracket mapping equation, which have been recently adapted for the calculation of conventional (field-free) absorption and fluorescence spectra. For comparison, we also apply the recently proposed complex time-dependent Redfield theory, while exact results are obtained using the hierarchical equations of motion approach. We show that the quantum-classical methods produce accurate results for a wide range of systems, including those containing CT states. The CT states contribute significantly to the Stark spectra, and the standard Liptay formalism is shown to be inapplicable for the analysis of spectroscopic data in those cases. We demonstrate that states with large static dipole moments may cause a pronounced change in the total fluorescence yield of the system in the presence of an external electric field. This effect is correctly captured by the quantum-classical methods, which should therefore prove useful for further studies of Stark spectra of real molecular systems. As an example, we calculate the Stark spectra for the Fenna-Matthews-Olson complex of green sulfur bacteria.
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Affiliation(s)
- Yakov Braver
- Faculty of Physics, Institute of Chemical Physics, Vilnius University, Saulėtekio Ave. 9-III, LT-10222 Vilnius, Lithuania and Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Saulėtekio Ave. 3, LT-10257 Vilnius, Lithuania
| | - Leonas Valkunas
- Faculty of Physics, Institute of Chemical Physics, Vilnius University, Saulėtekio Ave. 9-III, LT-10222 Vilnius, Lithuania and Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Saulėtekio Ave. 3, LT-10257 Vilnius, Lithuania
| | - Andrius Gelzinis
- Faculty of Physics, Institute of Chemical Physics, Vilnius University, Saulėtekio Ave. 9-III, LT-10222 Vilnius, Lithuania and Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Saulėtekio Ave. 3, LT-10257 Vilnius, Lithuania
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15
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Ueno S, Tanimura Y. Modeling and Simulating the Excited-State Dynamics of a System with Condensed Phases: A Machine Learning Approach. J Chem Theory Comput 2021; 17:3618-3628. [PMID: 33999606 DOI: 10.1021/acs.jctc.1c00104] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Simulating the irreversible quantum dynamics of exciton- and electron-transfer problems poses a nontrivial challenge. Because the irreversibility of the system dynamics is a result of quantum thermal activation and dissipation caused by the surrounding environment, it is necessary to include infinite environmental degrees of freedom in the simulation. Because the capabilities of full quantum dynamics simulations that include the surrounding molecular degrees of freedom are limited, employing a system-bath model is a practical approach. In such a model, the dynamics of excitons or electrons are described by a system Hamiltonian, while the other degrees of freedom that arise from the environmental molecules are described by a harmonic oscillator bath (HOB) and system-bath interaction parameters. By extending on a previous study of molecular liquids [ J. Chem. Theory Comput. 2020, 16, 2099], here, we construct a system-bath model for exciton- and electron-transfer problems by means of a machine learning approach. We determine both the system and system-bath interaction parameters, including the spectral distribution of the bath, using the electronic excitation energies obtained from a quantum mechanics/molecular mechanics (QM/MM) simulation that is conducted as a function of time. Using the analytical expressions of optical response functions, we calculate linear and two-dimensional electronic spectra (2DES) for indocarbocyanine dimers in methanol. From these results, we demonstrate the capability of our approach to elucidate the nonequilibrium exciton dynamics of a quantum system in a nonintuitive manner.
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16
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Non-conservative circular dichroism of photosystem II reaction centers: Is there an enhancement by a coupling with charge transfer states? J Photochem Photobiol A Chem 2021. [DOI: 10.1016/j.jphotochem.2020.112883] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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17
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Sirohiwal A, Neese F, Pantazis DA. Protein Matrix Control of Reaction Center Excitation in Photosystem II. J Am Chem Soc 2020; 142:18174-18190. [PMID: 33034453 PMCID: PMC7582616 DOI: 10.1021/jacs.0c08526] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Indexed: 02/06/2023]
Abstract
Photosystem II (PSII) is a multisubunit pigment-protein complex that uses light-induced charge separation to power oxygenic photosynthesis. Its reaction center chromophores, where the charge transfer cascade is initiated, are arranged symmetrically along the D1 and D2 core polypeptides and comprise four chlorophyll (PD1, PD2, ChlD1, ChlD2) and two pheophytin molecules (PheoD1 and PheoD2). Evolution favored productive electron transfer only via the D1 branch, with the precise nature of primary excitation and the factors that control asymmetric charge transfer remaining under investigation. Here we present a detailed atomistic description for both. We combine large-scale simulations of membrane-embedded PSII with high-level quantum-mechanics/molecular-mechanics (QM/MM) calculations of individual and coupled reaction center chromophores to describe reaction center excited states. We employ both range-separated time-dependent density functional theory and the recently developed domain based local pair natural orbital (DLPNO) implementation of the similarity transformed equation of motion coupled cluster theory with single and double excitations (STEOM-CCSD), the first coupled cluster QM/MM calculations of the reaction center. We find that the protein matrix is exclusively responsible for both transverse (chlorophylls versus pheophytins) and lateral (D1 versus D2 branch) excitation asymmetry, making ChlD1 the chromophore with the lowest site energy. Multipigment calculations show that the protein matrix renders the ChlD1 → PheoD1 charge-transfer the lowest energy excitation globally within the reaction center, lower than any pigment-centered local excitation. Remarkably, no low-energy charge transfer states are located within the "special pair" PD1-PD2, which is therefore excluded as the site of initial charge separation in PSII. Finally, molecular dynamics simulations suggest that modulation of the electrostatic environment due to protein conformational flexibility enables direct excitation of low-lying charge transfer states by far-red light.
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Affiliation(s)
- Abhishek Sirohiwal
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
- Fakultät
für Chemie und Biochemie, Ruhr-Universität
Bochum, 44780 Bochum, Germany
| | - Frank Neese
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Dimitrios A. Pantazis
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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18
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Kavanagh MA, Karlsson JKG, Colburn JD, Barter LMC, Gould IR. A TDDFT investigation of the Photosystem II reaction center: Insights into the precursors to charge separation. Proc Natl Acad Sci U S A 2020; 117:19705-19712. [PMID: 32747579 PMCID: PMC7443915 DOI: 10.1073/pnas.1922158117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Photosystem II (PS II) captures solar energy and directs charge separation (CS) across the thylakoid membrane during photosynthesis. The highly oxidizing, charge-separated state generated within its reaction center (RC) drives water oxidation. Spectroscopic studies on PS II RCs are difficult to interpret due to large spectral congestion, necessitating modeling to elucidate key spectral features. Herein, we present results from time-dependent density functional theory (TDDFT) calculations on the largest PS II RC model reported to date. This model explicitly includes six RC chromophores and both the chlorin phytol chains and the amino acid residues <6 Å from the pigments' porphyrin ring centers. Comparing our wild-type model results with calculations on mutant D1-His-198-Ala and D2-His-197-Ala RCs, our simulated absorption-difference spectra reproduce experimentally observed shifts in known chlorophyll absorption bands, demonstrating the predictive capabilities of this model. We find that inclusion of both nearby residues and phytol chains is necessary to reproduce this behavior. Our calculations provide a unique opportunity to observe the molecular orbitals that contribute to the excited states that are precursors to CS. Strikingly, we observe two high oscillator strength, low-lying states, in which molecular orbitals are delocalized over ChlD1 and PheD1 as well as one weaker oscillator strength state with molecular orbitals delocalized over the P chlorophylls. Both these configurations are a match for previously identified exciton-charge transfer states (ChlD1+PheD1-)* and (PD2+PD1-)*. Our results demonstrate the power of TDDFT as a tool, for studies of natural photosynthesis, or indeed future studies of artificial photosynthetic complexes.
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Affiliation(s)
- Maeve A Kavanagh
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, United Kingdom
- Institute of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, United Kingdom
| | - Joshua K G Karlsson
- Molecular Photonics Laboratory, School of Natural and Environmental Sciences, Newcastle University, Newcastle Upon Tyne NE1 7RU, United Kingdom
| | - Jonathan D Colburn
- School of Chemistry, University of St. Andrews, St. Andrews KY16 9ST, Scotland
| | - Laura M C Barter
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, United Kingdom;
- Institute of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, United Kingdom
| | - Ian R Gould
- Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, United Kingdom;
- Institute of Chemical Biology, Molecular Sciences Research Hub, Imperial College London, W12 0BZ London, United Kingdom
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19
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Asymmetry in Charge Transfer Pathways Caused by Pigment–Protein Interactions in the Photosystem II Reaction Center Complex. Catalysts 2020. [DOI: 10.3390/catal10060718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
This article discusses the photoinduced charge transfer (CT) kinetics within the reaction center complex of photosystem II (PSII RC). The PSII RC exhibits a structural symmetry in its arrangement of pigments forming two prominent branches, D1 and D2. Despite this symmetry, the CT has been observed to occur exclusively in the D1 branch. The mechanism to realize such functional asymmetry is yet to be understood. To approach this matter, we applied the theoretical tight-binding model of pigment excitations and simulated CT dynamics based upon the framework of an open quantum system. This simulation used a recently developed method of computation based on the quasi-adiabatic propagator path integral. A quantum CT state is found to be dynamically active when its site energy is resonant with the exciton energies of the PSII RC, regardless of the excitonic landscape we utilized. Through our investigation, it was found that the relative displacement between the local molecular energy levels of pigments can play a crucial role in realizing this resonance and therefore greatly affects the CT asymmetry in the PSII RC. Using this mechanism phenomenologically, we demonstrate that a near 100-to-1 ratio of reduction between the pheophytins in the D1 and D2 branches can be realized at both 77 K and 300 K. Our results indicate that the chlorophyll Chl D 1 is the most active precursor of the primary charge separation in the D1 branch and that the reduction of the pheophytins can occur within pico-seconds. Additionally, a broad resonance of the active CT state implies that a large static disorder observed in the CT state originates in the fluctuations of the relative displacements between the local molecular energy levels of the pigments in the PSII RC.
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20
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Song Y, Schubert A, Maret E, Burdick RK, Dunietz BD, Geva E, Ogilvie JP. Vibronic structure of photosynthetic pigments probed by polarized two-dimensional electronic spectroscopy and ab initio calculations. Chem Sci 2019; 10:8143-8153. [PMID: 31857881 PMCID: PMC6836992 DOI: 10.1039/c9sc02329a] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/02/2019] [Indexed: 12/29/2022] Open
Abstract
Bacteriochlorophyll a (Bchl a) and chlorophyll a (Chl a) play important roles as light absorbers in photosynthetic antennae and participate in the initial charge-separation steps in photosynthetic reaction centers. Despite decades of study, questions remain about the interplay of electronic and vibrational states within the Q-band and its effect on the photoexcited dynamics. Here we report results of polarized two-dimensional electronic spectroscopic measurements, performed on penta-coordinated Bchl a and Chl a and their interpretation based on state-of-the-art time-dependent density functional theory calculations and vibrational mode analysis for spectral shapes. We find that the Q-band of Bchl a is comprised of two independent bands, that are assigned following the Gouterman model to Q x and Q y states with orthogonal transition dipole moments. However, we measure the angle to be ∼75°, a finding that is confirmed by ab initio calculations. The internal conversion rate constant from Q x to Q y is found to be 11 ps-1. Unlike Bchl a, the Q-band of Chl a contains three distinct peaks with different polarizations. Ab initio calculations trace these features back to a spectral overlap between two electronic transitions and their vibrational replicas. The smaller energy gap and the mixing of vibronic states result in faster internal conversion rate constants of 38-50 ps-1. We analyze the spectra of penta-coordinated Bchl a and Chl a to highlight the interplay between low-lying vibronic states and their relationship to photoinduced relaxation. Our findings shed new light on the photoexcited dynamics in photosynthetic systems where these chromophores are primary pigments.
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Affiliation(s)
- Yin Song
- Department of Physics , University of Michigan , 450 Church St , Ann Arbor , MI 48109 , USA .
| | - Alexander Schubert
- Department of Chemistry , University of Michigan , 930 N University Ave , Ann Arbor , MI 48109 , USA
- Department of Chemistry and Biochemistry , Kent State University , 1175 Risman Drive , Kent , OH 44242 , USA
| | - Elizabeth Maret
- Applied Physics Program , University of Michigan , 450 Church St , Ann Arbor , MI 48109 , USA
| | - Ryan K Burdick
- Department of Chemistry , University of Michigan , 930 N University Ave , Ann Arbor , MI 48109 , USA
| | - Barry D Dunietz
- Department of Chemistry and Biochemistry , Kent State University , 1175 Risman Drive , Kent , OH 44242 , USA
| | - Eitan Geva
- Department of Chemistry , University of Michigan , 930 N University Ave , Ann Arbor , MI 48109 , USA
| | - Jennifer P Ogilvie
- Department of Physics , University of Michigan , 450 Church St , Ann Arbor , MI 48109 , USA .
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21
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Fujihashi Y, Higashi M, Ishizaki A. Intramolecular Vibrations Complement the Robustness of Primary Charge Separation in a Dimer Model of the Photosystem II Reaction Center. J Phys Chem Lett 2018; 9:4921-4929. [PMID: 30095266 DOI: 10.1021/acs.jpclett.8b02119] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The energy conversion of oxygenic photosynthesis is triggered by primary charge separation in proteins at the photosystem II reaction center. Here, we investigate the impacts of the protein environment and intramolecular vibrations on primary charge separation at the photosystem II reaction center. This is accomplished by combining the quantum dynamic theories of condensed phase electron transfer with quantum chemical calculations to evaluate the vibrational Huang-Rhys factors of chlorophyll and pheophytin molecules. We report that individual vibrational modes play a minor role in promoting charge separation, contrary to the discussion in recent publications. Nevertheless, these small contributions accumulate to considerably influence the charge separation rate, resulting in subpicosecond charge separation almost independent of the driving force and temperature. We suggest that the intramolecular vibrations complement the robustness of the charge separation in the photosystem II reaction center against the inherently large static disorder of the involved electronic energies.
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Affiliation(s)
- Yuta Fujihashi
- Institute for Molecular Science , National Institutes of Natural Sciences , Okazaki 444-8585 , Japan
| | - Masahiro Higashi
- Department of Chemistry, Biology, and Marine Science , University of the Ryukyus , 1 Senbaru , Nishihara , Okinawa 903-0213 , Japan
| | - Akihito Ishizaki
- Institute for Molecular Science , National Institutes of Natural Sciences , Okazaki 444-8585 , Japan
- School of Physical Sciences , The Graduate University for Advanced Studies , Okazaki 444-8585 , Japan
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22
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Sakamoto S, Tanimura Y. Exciton-Coupled Electron Transfer Process Controlled by Non-Markovian Environments. J Phys Chem Lett 2017; 8:5390-5394. [PMID: 29039960 DOI: 10.1021/acs.jpclett.7b01535] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We theoretically investigate an exciton-coupled electron transfer (XCET) process that is conversion of an exciton into a charge transfer state. This conversion happens in an exciton transfer (XT) process, and the electron moves away in an electron transfer (ET) process in multiple environments (baths). This XCET process plays an essential role in the harvesting of solar energy in biological and photovoltaic materials. We develop a practical theoretical model to study the efficiency of the XCET process that occurs either in consecutive or concerted processes under the influence of non-Markovian baths. The role of quantum coherence in the XT-ET system and the baths is investigated using reduced hierarchal equations of motion (HEOM). This model includes independent baths for each XT and ET state, in addition to a XCET bath for the conversion process. We found that, while quantum system-bath coherence is important in the XT and ET processes, coherence between the XT and ET processes must be suppressed in order to realize that an efficient irreversible XCET process through the weak off-diagonal interaction between the XT and ET bridge sites arises from an XCET bath.
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Affiliation(s)
- Souichi Sakamoto
- Department of Chemistry, Graduate School of Science, Kyoto University , Sakyoku, Kyoto 606-8502, Japan
| | - Yoshitaka Tanimura
- Department of Chemistry, Graduate School of Science, Kyoto University , Sakyoku, Kyoto 606-8502, Japan
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