Spectrum, lifetime distributions and relaxation in a dimer with strong excitonic-vibronic coupling

The fine structure of the complex quantum spectrum of a dimer constituted by monomers with a finite lifetime in the excited states and a strong excitonic-vibronic coupling has been investigated in detail. Lifetime distributions of the spectrum are analysed for different system parameter sets. It is shown that in case of an asymmetric configuration the spectrum may be characterised by a broad distribution of the lifetimes of the eigenstates. This can give rise to a strongly varying relaxation behaviour, which is due to the mixing of the monomer spectra with two different excitonic lifetimes in the dimer spectrum. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)