Dresden 2003 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 10: Experimente mit Einzelmolekülen
CPP 10.5: Vortrag
Donnerstag, 27. März 2003, 11:00–11:15, ZEU/160
Spectroscopy of Individual Light–Harvesting 1 Complexes of Rhodopseudomonas acidophila — •M. Richter1, M. Ketelaars2, C. Hofmann1, T.D. Howard3, R.J. Cogdell3, J. Schmidt4, T.J. Aartsma2, and J. Köhler1 — 1Experimental Physics IV, University of Bayreuth — 2Department of Biophysics, Leiden University — 3Department of Chemistry, University of Glasgow — 4Centre for the Study of Excited States of Molecules, Leiden University
The inital steps in photosynthesis involve the absorption of light by so called light harvesting complexes (LH1 and LH2) and the subsequent transfer of the excitation energy to the reaction centre (RC) where it is used for charge seperation. The efficiency and the speed of the process are determined by the molecular interactions as reflected in the electronic structure of the excited states of the building blocks of the photosynthetic pigments. With conventional optical spectroscopy only very limited information about these states is accessible due to inhomogeneous broadening effects caused by sample heterogeneity. However, with the use of single molecule spectroscopy a profound investigation of the electronic structure of single photosynthetic antenna complexes is possible. The fluorescence–excitation spectra of individual LH1–RC complexes from Rhodopseudomonas acidophila will be presented and compared with simulations of a closed/open ring structure based on a C16 symmetry. The large spectral variety suggests that besides site heterogeneity also structural heterogeneity determines the optical spectrum of the individual core complexes.