Charge transfer numbers were computed using the TheoDORE package. The molecule was divided into two fragments corresponding to the two monomers, i.e. Chl D1 and Pheo D1 , or P D1 and P D2 . Since the TD-DFT calculations were performed without the Tamm-Dancoff approximation which employs different normalization of the excitation vector (X), the charge transfer numbers for each state needed to be renormalized to sum up to one.