Dresden 2009 – scientific programme

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BP: Fachverband Biologische Physik

BP 26: Photobiophysics

BP 26.5: Talk

Friday, March 27, 2009, 12:00–12:15, ZEU 260

Dynamics of light induced charge separation in PS II Core Complexes from thermophilic cyanobacteria (Thermosynechococcus elongatus) and higher plants (spinach) — •Rachel Olliges¹, Franz-Josef Schmitt¹, Athina Zouni², and Gernot Renger² — ¹Institut für Optik und Atomare Physik — ²Max Volmer Laboratorium TU Berlin, Straße des 17.Juni 135, 10623 Berlin

The key steps of solar energy exploitation through photosynthetic water splitting take place in Photosystem II (PS II) of cyanobacteria, alga and higher plants. The light absorbed by antenna systems generates excited singlet-states that are efficiently funnelled to the photoactive pigment P680 of the reaction-center (RC) where the transformation takes place leading to the radical ion pair P680^{+ •} Q_A^{− •}. The rate of these processes can be gathered from measurements of the time resolved fluorescence decay and model based data evaluation. At present two basically different types of models are discussed: a) radicalpair/exciton equilibrium (REE) model and b) transfer to the trap limited (TTL) model (diffusion limited model).

Time resolved fluorescence-spectroscopy was performed on PS II core complexes (PS IICC) from thermophilic cyanobacteria (Thermosynechococcus elongatus) and higher plants (spinach) by using single photon counting techniques providing a time resolution of about 10 ps. The data shows that the widely used REE model is not able to describe the dynamics completely.