Parametric projection operator technique for second order non-linear response

Olšina, Jan; Mančal, Tomáš

doi:10.1016/j.chemphys.2012.02.022

Cited by 15 publications

(10 citation statements)

References 54 publications

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“…(3) and Eq. (4) , as we have shown elsewhere 47 . A rigorous derivation of the equations of the excited state population as a second order equation in the external field is presented in the SI.…”

Section: Resultssupporting

confidence: 77%

Single Molecule Spectroscopy of Monomeric LHCII: Experiment and Theory

Malý

Gruber

Grondelle

et al. 2016

Sci Rep

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We derive approximate equations of motion for excited state dynamics of a multilevel open quantum system weakly interacting with light to describe fluorescence-detected single molecule spectra. Based on the Frenkel exciton theory, we construct a model for the chlorophyll part of the LHCII complex of higher plants and its interaction with previously proposed excitation quencher in the form of the lutein molecule Lut 1. The resulting description is valid over a broad range of timescales relevant for single molecule spectroscopy, i.e. from ps to minutes. Validity of these equations is demonstrated by comparing simulations of ensemble and single-molecule spectra of monomeric LHCII with experiments. Using a conformational change of the LHCII protein as a switching mechanism, the intensity and spectral time traces of individual LHCII complexes are simulated, and the experimental statistical distributions are reproduced. Based on our model, it is shown that with reasonable assumptions about its interaction with chlorophylls, Lut 1 can act as an efficient fluorescence quencher in LHCII.Photosynthesis, arguably the most important photo-induced process on Earth, converts the energy of light into its chemically/biologically useful form. It is often argued that this conversion is remarkably efficient. However, it has to be distinguished between the quantum efficiency, reaching almost unity 1,2 , and light-to-chemical energy efficiency, which is significantly lower, in the order of several percent 3 . This is given by an evolutionary pressure on the development of a robust photosynthetic machinery optimized for survival rather than energy conversion efficiency. Energy relaxation processes are integral part of the photosynthetic function as they enable the energy transfer to proceed unidirectionally 4 , and provide protection of the photosynthetic apparatus against harmful over-excitation. The photosynthetic machinery of plants has developed a complex hierarchy of self-regulatory mechanisms to avoid excess excitation or (when unavoidable) to dissipate it into heat 5 . Starting from processes controlled on the macroscopic level (e.g. orientation of leaves), over spontaneous microscopic (cellular) events such as chloroplast movements, to truly nano-and sub-nanoscopic mechanisms such as reorganization of antenna complexes and direct regulation of energy transfer on the level of small groups of interacting chromophores, plants actively react to changing illumination conditions. The sub-nanoscopic processes, which are the focus of the present study, operate in response to the increase of Δ pH across the thylakoid membrane. Such an increase is an indicator of high illumination. Nowadays it is generally accepted that carotenoids are involved in these energy dissipation processes. The precise molecular mechanism is, however, still subject of discussion 6-13 . It is likely that different mechanisms evolved in different classes of organisms and/or that several mechanisms operate at once.Most of our current knowledge about the early pro...

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Section: Resultssupporting

confidence: 77%

Single Molecule Spectroscopy of Monomeric LHCII: Experiment and Theory

Malý

Gruber

Grondelle

et al. 2016

Sci Rep

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“…Even if electronic coherence and not coupling to vibrations [6][7][8][9][10] is observed in lightharvesting complexes, it is not clear whether coherent transport is important for the efficiency of the harvesting mechanism. If so, what are the parameters to be optimized in artificial systems that improve the role of coherent transport?…”

Section: Introductionmentioning

confidence: 99%

The role of the environment time scale in light-harvesting efficiency and coherent oscillations

Dijkstra

Tanimura

2012

New J. Phys.

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We study the efficiency of exciton transport as a function of the typical reorganization time scale of the environment using the hierarchy of equations of motion. As a model system, we choose the Fenna-Matthews-Olson (FMO) complex. An environment in which the dynamics is not much faster than the system leads to prolonged quantum coherent transport, even at room temperature. We find that this does not make the transport process more efficient for standard FMO parameters, but does increase the efficiency in the case when exciton decay competes with trapping at the reaction center. We furthermore find that initial correlations do not influence population oscillations. Contents

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“…Theoretically, it is a very complicated problem, as it requires to keep track of the correlations between distinct time intervals [44,45]. Approaches that use a reduced description by tracing out the bath degrees of freedom are difficult to apply for this problem.…”

Section: Discussionmentioning

confidence: 99%