Regensburg 2010 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 12: Poster: Electronic and Optical Properties of Organic Systems

CPP 12.7: Poster

Monday, March 22, 2010, 16:30–18:00, Poster C

Coupling of Frenkel excitons, charge transfer excitons and vibrations in linear absorption spectra of polyacene crystals — Ivan Lalov^1,2, •Christoph Warns², and Peter Reineker² — ¹Faculty of Physics, Sofia University, Sofia 1164, Bulgaria — ²Institute for Theoretical Physics, Ulm University, 89069 Ulm, Germany

The linear absorption spectra of the crystals of anthracene, tetracene, and pentacene have been calculated in the case of coupling between Frenkel excitons (FEs), charge transfer excitons (CTEs) and intramolecular vibrations. The models and their parametrization for FEs and CTEs in the (a,b) plane of those crystals, first developped by P. Petelenz et al., have been used in the numerical simulations of the linear absorption.

The calculated excitonic and vibronic spectra allow to draw two main conclusions. First, CTEs and their vibronics will manifest themselves in linear absorption of light polarized along the monoclinic axis only (i.e. for tetracene and pentacene along the crystallographic b-axis). Second, the vibronic coupling (FE-phonon and CTEs-phonon) emphasizes and increases the number of the maxima of CTEs manifested in the linear absorption.