Vibronic effects and destruction of exciton coherence in optical spectra of J-aggregates: a variational polaron transformation approach

Bloemsma, E.A., Silvis, M.H., Stradomska, A. and Knoester, J. (2016) Vibronic effects and destruction of exciton coherence in optical spectra of J-aggregates: a variational polaron transformation approach. Chemical Physics, 481, pp. 250-261. (doi:10.1016/j.chemphys.2016.06.018)

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Abstract

Using a symmetry adapted polaron transformation of the Holstein Hamiltonian, we study the interplay of electronic excitation-vibration couplings, resonance excitation transfer interactions, and temperature in the linear absorption spectra of molecular J-aggregates. Semi-analytical expressions for the spectra are derived and compared with results obtained from direct numerical diagonalization of the Hamiltonian in the two-particle basis set representation. At zero temperature, we show that our polaron transformation reproduces both the collective (exciton) and single-molecule (vibrational) optical response associated with the appropriate standard perturbation limits. Specifically, for the molecular dimer excellent agreement with the spectra from the two-particle approach for the entire range of model parameters is obtained. This is in marked contrast to commonly used polaron transformations. Upon increasing the temperature, the spectra show a transition from the collective to the individual molecular features, which results from the thermal destruction of the exciton coherence.

Item Type:Articles
Additional Information:A.S. acknowledges the Netherlands Organization for Scientific Research for support through a VENI grant.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Stradomska-Szymczak, Dr Anna
Authors: Bloemsma, E.A., Silvis, M.H., Stradomska, A., and Knoester, J.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Chemical Physics
Publisher:Elsevier
ISSN:0301-0104
ISSN (Online):1873-4421
Published Online:02 July 2016
Copyright Holders:Copyright © 2016 Elsevier B.V.
First Published:First published in Chemical Physics 481: 250-261
Publisher Policy:Reproduced in accordance with the publisher copyright policy

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