Non-Markovian effects in the anisotropy of fluorescence in LH2 units

Using the reduced density matrix formalism the time dependence of the anisotropy of fluorescence in the B850 ring of the purple bacterium Rhodopseudomonas acidophila is calculated. Fast fluctuations of the environment are simulated by dynamic disorder and slow fluctuations by static disorder. Both type of disorders are taken into account simultaneously. Earlier calculations within the Markovian–Redfield theory are extended by including memory effects within the exciton dynamics.