Regensburg 2013 – scientific programme
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DS: Fachverband Dünne Schichten
DS 5: Charge Transfer Effects in Molecular Materials I (jointly with BP, CPP, HL)
DS 5.3: Talk
Monday, March 11, 2013, 12:45–13:00, H1
Screening Effects on Excitation Energy Transfer in Supramolecular Complexes in a Mixed Quantum Classical Description — •Jörg Megow1, Thomas Renger2, and Volkhard May1 — 1Humboldt-Universität zu Berlin, Deutschland — 2Johannes Kepler Universität Linz, Österreich
Excitation energy transfer (EET) within the supramolecular complex P16 (sixteen pheophorbide a molecules covalently linked to a DAB-dendrimer) is studied using a mixed quantum classical methodology [1,2] that takes the screening of excitonic coupling into acount. The excitonic coupling between two chromophores is calculated as Coulomb-coupling between transition partial charges. This treatment neglects the screening effects due to interaction with the solvent molecules. The Poisson-TrEsp (transition charges from electrostatic potentials) method [3], developed in the group of Renger, allows the calculation of screening factors that correct the excitonic coupling between two chromophores dependent on their distance, mutual orientation and conformation. A new method is proposed that allows to obtain the orientation and conformation dependence of the Poisson-TrEsp screening factors in a mixed quantum-classical description by introducing a novel fitting procedure. While all screening ansatzes result in a deceleration of the EET, the new approach results in a considerable acceleration of the EET compared to standard screening approaches.
[1] J. Megow et al., ChemPhysChem 12, 645 (2011) [2] J. Megow et al., Chem. Phys. 377, 10 (2010) [3] J. Adolphs et al., Photosynth. Res. 95 (2008)