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CPP: Chemische Physik und Polymerphysik
CPP 3: Biomoleküle
CPP 3.10: Talk
Monday, March 24, 2003, 12:30–12:45, ZEU/118
Femtosecond dynamics in the anisotropy of emission in LH2 units — •U. Kleinekathöfer1, P. Heřman2, I. Barvik3, I. Kondov4, and M. Schreiber1,4 — 1International University Bremen, 28725 Bremen, Germany — 2Dept. of Physics, University of Hradec Králové, Czech Republic — 3Institute of Physics of Charles University, Prague, Czech Republic — 4Institut für Physik, Technische Universität, 09107 Chemnitz
Circular aggregates of 18 pigments are studied to model the B850 ring of bacteriochlorophylls within the LH2 complexes of the purple bacterium Rhodopseudomonas acidophila. Previously, the time evolution of the anisotropy of emission after an impulsive excitation has been calculated for varying degrees of static disorder but without dynamic disorder (interaction with a heat bath). In this case, modest degrees of static disorder are sufficient to cause the experimentally found initial drop of the anisotropy on a sub-100 fs time scale. We have taken into account the simultaneous influence of static and dynamic disorders [1] and found that larger static disorder is needed to guarantee the temperature independence of this initial drop. In the present contribution we extend our previous calculations and investigate non-Markovian effects and effects of elliptical deformations of the ring [2].
[1] P. Heřman, U. Kleinekathöfer, I. Barvìk, and M. Schreiber, Chem. Phys. 275, 1(2002).
[2] I. Barvìk, I. Kondov, P. Heřman, M. Schreiber, and U. Kleinekathöfer, Nonlin. Opt. 29, 151 (2002).