Memory effects in single-molecule spectroscopy

From the time series of LH2 optical single-molecule fluorescence excitation spectra of Rhodospirillum molischianum the memory function of the Mori–Zwanzig equation for the optical intensity is derived numerically. We show that the time dependence of the excited states is determined by at least three different non-Markovian stochastic processes with decay constants for the Mori–Zwanzig kernel on the order of image. We suggest that this decay stems from the conformational motion of the protein scaffold of LH2.