For the discussion of charge separation in light harvesting and energy conversion devices, it is of central importance to understand at which energies the charge separation takes place and which electronically excited states are responsible for this process. To facilitate this analysis, we chose a set of well-defined reference states and use these as a basis for the analysis of spectral properties. An intuitive and meaningful choice of reference states are the electronic states at the optimized geometry, i.e. the FC geometry. We analyse their characters via charge transfer numbers 42 (see Figure ) and natural transition orbitals (see SI). The reference states are characterized in Figure via the charge transfer numbers. For the Chl D1 Pheo D1 pair (Figure ), we find three charge transfer states at 1.64, 2.15 and 2.80 eV. They correspond to the first, third and seventh state, and have pure Chl D1 →Pheo D1 CT character. For the P D1 P D2 pair (Figure ), we also find three CT states, here at 2.90, 3.19 and 3.35 eV, which correspond to the fifth, sixth and seventh states at the FC point. These states have either P D1 →P D2 or P D2 →P D1 character mixed with local excitation character.