Berlin 2001 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 17: Poster: Spectroscopy and Single Particle Spectroscopy of Molecular Systems, Photoprocesses, Biological Systems
CPP 17.19: Poster
Dienstag, 3. April 2001, 12:30–15:00, AT1
Energy transport and optical absorption in photosynthetic antennae systems — •Peter Reineker1, Christoph Warns1, and Ivan Barvik2 — 1Theor. Physik, Univ. Ulm, 89069 Ulm, Germany — 2Inst. of Physics, Charles University, ke Karlovu 5, 12-126 Prague
The light harvesting system LH2 of rhodopseudomonas acidophila is a ring shaped molecular aggregate with C9 symmetry. In the upper aggregate plane there are 9 bacterio chlorophyll pairs B850, in the lower plane 9 molecules B800. We determine the influence of the coupled coherent and incoherent energy transport on the optical line shape of LH2. In the model we consider the molecular excitation energy, and take into account a possible dimerization using two different transfer matrix elements between nearest neighbors. The influence of the slow motion of the protein scaffold and of the inner molecular vibrations is described by dichotomic stochastic processes with long and short time constants, respectively. The optical line shape is investigated in dependence on the parameters of the stochastic processes and on the deformation strength of the ring system. We show that the experimental data can be well described for reasonable values of the quasi-static noise. The consequences of the deformation of the ring are discussed with respect to the experimental data.