Effects of correlated disorder on optical properties of molecular aggregates |
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| Sebastian Möbius | |
| mpipks Dresden | |
| Static disorder, due to the presence of environment,t is an approach often used to model optical dynamics of molecular aggregates. Fluctuations of site energies, which mimic the effect, play a crucial role when calculating aggregate absorption spectra and/or exciton localization length. In the most studies, an uncorrelated Gaussian static disorder of the aggregate molecular energies has been used. Recent results obtained by Eisfeld et. al.[1] have shown that for certain types of non-Gaussian (Levy-stable) distributions the other effects can be observed, in particular, no exchange narrowing of the aggregateabsorption spectra but rather a broadening can occur. For these type of distributions,only uncorrelated disorder has been studied so far. Using an atomistic model, we show how different types of system-environment interaction leads to various Levy-stable distributions. Within the model, correlations between molecular transition energies can be naturally taking into account. They crucially depend on the distance between aggregate molecules and on the density of environmental units. Furthermore, we propose a method to numerically generate correlated Levy-stable distributions. This allow us to study the influence of molecular transition energy correlations on aggregate absorption spectra and exciton localization length. [1] A.Eisfeld, S.M.Vlaming, V.A.Malyshev and J.Knoester, PRL 105, 137402 (2010) |