Bulg. J. Phys. vol.43 no.4 (2016), pp. 279-295



Excitonic and Vibronic Spectra in the Model of a 3D Hexagonal Donor--Acceptor Crystal

I.J. Lalov, I. Zhelyazkov
Faculty of Physics, St. Kliment Ohridski University of Sofia, 5 James Bourchier Blvd., 1164 Sofia, Bulgaria
Abstract. This paper explores the excitonic spectra and their manifestation in the linear absorption in the 3D model of a hexagonal donor–acceptor crystal of the crystallographic point group 6̅. A similar two-component crystal of alternative parallel layers with hexagonal order in each layer has been synthesized. Two types of excitons, Frenkel excitons (FEs) and charge-transfer excitons (CTEs) have been considered along with their coupling and the exciton--phonon coupling with one mode of intramolecular vibrations. We find also the symmetry allowed combinations of FEs and CTEs. The excitonic and vibronic spectra have been calculated and numerically simulated.

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