Regensburg 2010 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 7: Electronic and Optical Properties of Organic Systems II

CPP 7.5: Vortrag

Montag, 22. März 2010, 15:00–15:15, H39

Excitation Energy Transfer in Pheophorbide-a Complexes: A Mixed Quantum Classical Computation — •Jörg Megow, Zheng-wang Qu, Thomas Ronneberg, Beate Röder, and Volkhard May — Institut für Physik, Humboldt-Universität zu Berlin

The excitation energy transfer in a chromophore complex dissolved in ethanol is computed utilizing a mixed quantum classical methodology. The complex is formed by a butanediamine dendrimer to which four pheophorbide-a molecules are covalently linked. While all nuclear coordinates are described classically by carrying out room-temperature MD-simulations the electronic excitations are treated quantum mechanically utilizing a Frenkel-exciton model. A new approach is introduced to directly include intramolecular vibrations from MD-simulations into the former mixed quantum classical technique. Making a harmonic approximation to the single atom positions in respect of the so called reference structure atom positions a highly fluctuating energy was calculated and added to the chromophore complex Hamiltonian. This approach was used to further improve the existing calculations of excitation energy transfer, linear absorbance and time- and frequency resolved emission spectra, where the intramolecular vibrations were implemented parametrical only.