scholarly journals How Static Disorder Mimics Decoherence in Anisotropy Pump–Probe Experiments on Purple-Bacteria Light Harvesting Complexes

2016 ◽  
Vol 120 (44) ◽  
pp. 11449-11463 ◽  
Author(s):  
Clement Stross ◽  
Marc W. Van der Kamp ◽  
Thomas A. A. Oliver ◽  
Jeremy N. Harvey ◽  
Noah Linden ◽  
...  
2019 ◽  
Vol 10 (42) ◽  
pp. 9650-9662 ◽  
Author(s):  
Felipe Cardoso Ramos ◽  
Michele Nottoli ◽  
Lorenzo Cupellini ◽  
Benedetta Mennucci

The spectral tuning of LH2 antenna complexes arises from H-bonding, acetyl torsion, and inter-chromophore couplings.


2012 ◽  
Vol 136 (24) ◽  
pp. 245104 ◽  
Author(s):  
Jun Ye ◽  
Kewei Sun ◽  
Yang Zhao ◽  
Yunjin Yu ◽  
Chee Kong Lee ◽  
...  

2021 ◽  
Vol 22 (18) ◽  
pp. 10031
Author(s):  
Roman Y. Pishchalnikov ◽  
Denis D. Chesalin ◽  
Andrei P. Razjivin

Considering bacteriochlorophyll molecules embedded in the protein matrix of the light-harvesting complexes of purple bacteria (known as LH2 and LH1-RC) as examples of systems of interacting pigment molecules, we investigated the relationship between the spatial arrangement of the pigments and their exciton transition moments. Based on the recently reported crystal structures of LH2 and LH1-RC and the outcomes of previous theoretical studies, as well as adopting the Frenkel exciton Hamiltonian for two-level molecules, we performed visualizations of the LH2 and LH1 exciton transition moments. To make the electron transition moments in the exciton representation invariant with respect to the position of the system in space, a system of pigments must be translated to the center of mass before starting the calculations. As a result, the visualization of the transition moments for LH2 provided the following pattern: two strong transitions were outside of LH2 and the other two were perpendicular and at the center of LH2. The antenna of LH1-RC was characterized as having the same location of the strongest moments in the center of the complex, exactly as in the B850 ring, which actually coincides with the RC. Considering LH2 and LH1 as supermolecules, each of which has excitation energies and corresponding transition moments, we propose that the outer transitions of LH2 can be important for inter-complex energy exchange, while the inner transitions keep the energy in the complex; moreover, in the case of LH1, the inner transitions increased the rate of antenna-to-RC energy transfer.


2018 ◽  
Vol 70 (2) ◽  
pp. 225
Author(s):  
Bei-Bei He ◽  
Meng-Meng Ming ◽  
Chang-Yong Liu ◽  
Guo-Dong Wang ◽  
Li Qin ◽  
...  

2016 ◽  
Vol 113 (11) ◽  
pp. 2934-2939 ◽  
Author(s):  
Pavel Malý ◽  
J. Michael Gruber ◽  
Richard J. Cogdell ◽  
Tomáš Mančal ◽  
Rienk van Grondelle

Energy relaxation in light-harvesting complexes has been extensively studied by various ultrafast spectroscopic techniques, the fastest processes being in the sub–100-fs range. At the same time, much slower dynamics have been observed in individual complexes by single-molecule fluorescence spectroscopy (SMS). In this work, we use a pump–probe-type SMS technique to observe the ultrafast energy relaxation in single light-harvesting complexes LH2 of purple bacteria. After excitation at 800 nm, the measured relaxation time distribution of multiple complexes has a peak at 95 fs and is asymmetric, with a tail at slower relaxation times. When tuning the excitation wavelength, the distribution changes in both its shape and position. The observed behavior agrees with what is to be expected from the LH2 excited states structure. As we show by a Redfield theory calculation of the relaxation times, the distribution shape corresponds to the expected effect of Gaussian disorder of the pigment transition energies. By repeatedly measuring few individual complexes for minutes, we find that complexes sample the relaxation time distribution on a timescale of seconds. Furthermore, by comparing the distribution from a single long-lived complex with the whole ensemble, we demonstrate that, regarding the relaxation times, the ensemble can be considered ergodic. Our findings thus agree with the commonly used notion of an ensemble of identical LH2 complexes experiencing slow random fluctuations.


2016 ◽  
Vol 81 (2) ◽  
pp. 176-186 ◽  
Author(s):  
Z. K. Makhneva ◽  
A. A. Ashikhmin ◽  
M. A. Bolshakov ◽  
A. A. Moskalenko

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