Regensburg 2002 – wissenschaftliches Programm

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SYBM: Physik biologischer Materie

SYBM 401: Physics of biological matter: Poster

SYBM 401.27: Poster

Dienstag, 12. März 2002, 18:00–19:30, H37

Exciton Annihilation in Antenna Systems: Single Molecule Dynamics — •Ben Brüggemann and Volkhard May — Institut für Physik, Humboldt-Universität zu Berlin, Hausvogteiplatz 5-7, 10117 Berlin

We simulate transient absorption spectra at higher pump pulse intensities, both for ideal symmetric systems and systems with individual disorder. Dependent on the pump pulse intesity the exciton-exciton annihilation (EEA) process dominates the transient absorption kinetics on a timescale of a few hundreds of femtoseconds [1]. In time and frequency dependent pump-probe simulations, this effect can be depicted very well, and consistent with experimental results. For a global fit of the experimental data we include static disorder [2], and repeat the calculation for every individually disordered chromophore-complex, which gives a rich insight into the interaction of static disorder with the dynamic of the system. The calculations were done with an extended density matrix formalism [3], as experimentral reference we use the B850 ring of the LH2 complex [1].

[1] B. Brüggemann, J. L. Herek, V. Sundström, T. Pullerits, and V. May, J. Phys. Chem. B, 105 (2001), 11391 [2] A. M. van Oijen, M. Ketelaars, J. Köhler, T. J. Aartsma, and J. Schmidt, Science 285 (1999) 400. [3] Th. Renger, V. May, and O. Kühn, Phys. Rep. 343 (2001) 137.