Comparison of methods to study excitation energy transfer in molecular multichromophoric systems

We compare theoretical methods for calculating excitation energy transfer rates in multichromophoric systems. The employed methods are the multichromophoric Förster resonance energy transfer (MC-FRET), the numerical integration of the Schrödinger equation (NISE), and the Haken-Strobl-Reineker (HSR) model. As a reference, we use the numerically exact Hierarchy of Equations of Motion (HEOM). We examine these methods in various system and bath parameter regimes including the regime relevant to biological light-harvesting systems. We apply them to a model system of a monomeric donor coupled to a multichromophoric acceptor ring of varying size in two limiting configurations, namely symmetric and asymmetric. We find that the symmetric case is more sensitive to the approximations of the methods studied. The NISE method gives the most reasonable results throughout the parameter regimes tested, while still being computationally tractable.