Excitation energy transfer in isolated chlorosomes from Chloroflexus aurantiacus

Martiskainen, Jari; Linnanto, Juha; Kananavičius, Robertas; Lehtovuori, Viivi; Korppi-Tommola, Jouko

doi:10.1016/j.cplett.2009.06.080

Cited by 34 publications

(73 citation statements)

References 30 publications

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“…4 The second exception is the energy transfer from the blue part of the Q y absorption band of BChl aggregates to their redshifted states, which was observed in chlorosomes from different species with transfer times between 100 and 1000 fs. [7][8][9][10] This process corresponds to exciton relaxation from higher to lower exciton levels. Particularly for Cba.…”

Section: Introductionmentioning

confidence: 98%

Unraveling the nature of coherent beatings in chlorosomes

Mančal

Vácha

Pšenčı́k

et al. 2014

The Journal of Chemical Physics

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Coherent two-dimensional (2D) spectroscopy at 80 K was used to study chlorosomes isolated from green sulfur bacterium Chlorobaculum tepidum. Two distinct processes in the evolution of the 2D spectrum are observed. The first being exciton diffusion, seen in the change of the spectral shape occurring on a 100-fs timescale, and the second being vibrational coherences, realized through coherent beatings with frequencies of 91 and 145 cm(-1) that are dephased during the first 1.2 ps. The distribution of the oscillation amplitude in the 2D spectra is independent of the evolution of the 2D spectral shape. This implies that the diffusion energy transfer process does not transfer coherences within the chlorosome. Remarkably, the oscillatory pattern observed in the negative regions of the 2D spectrum (dominated by the excited state absorption) is a mirror image of the oscillations found in the positive part (originating from the stimulated emission and ground state bleach). This observation is surprising since it is expected that coherences in the electronic ground and excited states are generated with the same probability and the latter dephase faster in the presence of fast diffusion. Moreover, the relative amplitude of coherent beatings is rather high compared to non-oscillatory signal despite the reported low values of the Huang-Rhys factors. The origin of these effects is discussed in terms of the vibronic and Herzberg-Teller couplings.

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Section: Introductionmentioning

confidence: 98%

Unraveling the nature of coherent beatings in chlorosomes

Mančal

Vácha

Pšenčı́k

et al. 2014

The Journal of Chemical Physics

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“…12,13 It was observed that the energy transfer of the Q absorption band in BChl aggregates was followed by a rapid exciton relaxation with transfer time between 100 and 1000 fs. 14,15 This process followed by long-range energy transfer within the aggregates leading to excitation equilibration over the whole chlorosome. 16 In addition, Sytina et al 17 elucidated the existence of chargetransfer (CT) states in protochlorophyllide aggregates and determined the relaxation from the exciton states to the CT state occurring with a time scale of 500 fs.…”

Section: ■ Introductionmentioning

confidence: 99%

Excitonic Relaxation and Coherent Vibrational Dynamics in Zinc Chlorin Aggregates for Artificial Photosynthetic Systems

Han

Kobayashi

et al. 2015

J. Phys. Chem. B

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The excitonic relaxation and coherent vibrational dynamics in stairlike zinc chlorin aggregates prepared for mimicking chlorosome in nature have been studied simultaneously by 6.8 fs real-time vibrational laser spectroscopy. The relaxation from Q-exciton state to the dark nonfluorescent charge-transfer (CT) state is determined to be 850 ± 70 fs. The spectral distribution of the molecular vibrational amplitude has been discussed in terms of the difference in the equilibrium positions of potential curves between the ground state and the excited state. Since the displacement in the coordinate space from the potential minimum of the ground state to that of the excited states is small, coherent oscillations generated by the impulsive excitation are strongest where the slope of the excitonic resonance is largest. Consequently, the probe wavelength dependence of the amplitude modulation follows the first derivative of the excitonic resonance, and π phase jump has been observed. Excitonic transition energy modulation caused by the coherent molecular vibrations has also been studied, and the vibrational mode with a low frequency of 146 cm(-1) is found to play a dominating role in the transition energy shift effect.

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“…The times increase rapidly with the distance. The experimental times of few ps, [23,25] were achieved at about 2.0 nm, which might be a good guess for the distance between the chlorosome and baseplate complexes.…”

Section: Inter-complex Distances and Orientationsmentioning

confidence: 79%

“…2) that is known to bind physically to the chlorosomes antenna complex, making down-hill energy transfer processes possible between these two antennae, as already suggested. [22,23] Analyses of relative positions of the energy levels in the baseplate, B808-866, and RC complexes shows that the baseplate energy levels appear in same region as the states of the B808 pigments of the B808-866 complex, and that one of the states of the RC complex is isoenergetic with a state of the baseplate, suggesting that resonance energy transfer from the baseplate to both the B808-866 and RC complexes may be possible. It is important to notice that such energy resonance is only fulfilled, if vibrations of BChl molecules are properly taken into account.…”

Section: Energy Levelsmentioning

confidence: 99%

Computation studies into architecture and energy transfer properties of photosynthetic units from filamentous anoxygenic phototrophs

Linnanto¹,

Freiberg²

2014

AIP Conference Proceedings

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We have used different computational methods to study structural architecture, and light-harvesting and energy transfer properties of the photosynthetic unit of filamentous anoxygenic phototrophs. Due to the huge number of atoms in the photosynthetic unit, a combination of atomistic and coarse methods was used for electronic structure calculations. The calculations reveal that the light energy absorbed by the peripheral chlorosome antenna complex transfers efficiently via the baseplate and the core B808-866 antenna complexes to the reaction center complex, in general agreement with the present understanding of this complex system.

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Excitation energy transfer in isolated chlorosomes from Chloroflexus aurantiacus

Cited by 34 publications

References 30 publications

Unraveling the nature of coherent beatings in chlorosomes

Unraveling the nature of coherent beatings in chlorosomes

Excitonic Relaxation and Coherent Vibrational Dynamics in Zinc Chlorin Aggregates for Artificial Photosynthetic Systems

Computation studies into architecture and energy transfer properties of photosynthetic units from filamentous anoxygenic phototrophs

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