Coulombic couplings between pigments in the major light-harvesting complex LHC II calculated by the transition density cube method

An ab initio transition density cube calculation of the inter-pigment couplings in the major light-harvesting pigment-protein complex of photosystem II provides important details about excitonic interactions and energy path ways in LHC II and the break down of the ideal dipole approximation for inter-pigment distances smaller than ∼25 Å.