Comparison of emission spectra of single LH2 complex for different types of disorder

Abstract

We have studied the emission spectra for a single LH2 complex. The observed spectral fluctuations reflect degree of exciton delocalization and different strength of exciton-phonon coupling. We compare the measured spectra with calculated ones obtained using the model of the B850 ring with two types of uncorrelated static disorder. The positions and spectral shapes of the main exciton components are given by the shift of exciton eigenvalues (associated with static disorder) and the effects of phonon bath. These effects are dependent on the realization of the disorder and produce different forms of emission profile. Different degree of delocalization and coupling to the phonon bath manifests itself in different type of excitation dynamics.