Anomalous strong exchange narrowing in excitonic systems
Abstract
We investigate theoretically the phenomenon of exchange narrowing in the absorption spectrum of a chain of monomers, which are coupled via resonant dipole-dipole interaction. The individual (uncoupled) monomers exhibit a broad absorption line shape due to the coupling to an environment consisting of a continuum of vibrational modes. Upon increasing the interaction between the monomers, the absorption spectrum of the chain narrows. For a non-Markovian environment with a Lorentzian spectral density, we find a narrowing of the peak width (full width at half maximum (FWHM)) by a factor 1/N, where N is the number of monomers. This is much stronger than the usual 1/sqrt{N} narrowing. Furthermore it turns out that for a Markovian environment no exchange narrowing at all occurs. The relation of different measures of the width (FWHM, standard deviation) is discussed.
Cite
@article{arxiv.1101.3558,
title = {Anomalous strong exchange narrowing in excitonic systems},
author = {J. Roden and A. Eisfeld},
journal= {arXiv preprint arXiv:1101.3558},
year = {2011}
}