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.

References in corpus (4)

• Non-Markovian quantum state diffusion: Perturbation approach
• Influence of Complex Exciton-Phonon Coupling on Optical Absorption and Energy Transfer of Quantum Aggregates
• Excitons in Molecular Aggregates with Lévy Disorder: Anomalous Localization and Exchange Broadening of Optical Spectra
• Localization properties of one-dimensional Frenkel excitons: Gaussian versus Lorentzian diagonal disorder

Cited by in corpus (2)

• Non-Markovian quantum state diffusion for absorption spectra of molecular aggregates
• Spectral signatures of the Markovian to Non-Markovian transition in open quantum systems