Dresden 2006 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 16: Electronic Structure and Spectroscopy II
CPP 16.7: Talk
Wednesday, March 29, 2006, 16:15–16:30, ZEU 160
Torsional Potentials for the Ground and Excited State of Bithiophene Calculated by Time-dependent Density Functional Theory — •Wichard J.D. Beenken1, Sebastian Westenhoff2, and Tõnu Pullerits3 — 1Technische Universität Ilmenau, FG Theoretische Physik I, Postfach 100565, D-98684 Ilmenau — 2University of Cambridge, Optoelectronics Group, Cavendish Laboratory, CB3 0HE, UK — 3Lunds Universitet, Kemisk Fysik, Box 124, SE-22100 Lund
We have studied bithiophene by time-dependent density functional theory. In particular we have analyzed the dependence of singlet excitation energies and transition dipoles on the torsional angle between the two thiophenyl groups. The torsional spectrum has been computed quantum-mechanically as well as semi-classically in order to understand, how this influences the broadening of absorption and luminescence spectra. We discuss the general consequences for the spectral broadening, Stokes shift and energy relaxation in poly-thiophenes, in particular, how torsional disorder effects the absorption and photoluminescence spectra. Furthermore, such results are necessary input parameters for molecular dynamics. In particular for simulation of polythiophenes in the excited state reliable data are rare. We will show some exemplary simulations.