  A master equation, derived from the non-Markovian quantum state diffusion
(NMQSD), is used to calculate excitation energy transfer in the photosynthetic
Fenna-Matthews-Olson (FMO) pigment-protein complex at various temperatures.
This approach allows us to treat spectral densities that contain explicitly the
coupling to internal vibrational modes of the chromophores. Moreover, the
method is very efficient, with the result that the transfer dynamics can be
calculated within about one minute on a standard PC, making systematic
investigations w.r.t. parameter variations tractable. After demonstrating that
our approach is able to reproduce the results of the numerically exact
hierarchical equations of motion (HEOM) approach, we show how the inclusion of
vibrational modes influences the transfer.
