where µ F a F ,a F is the dipole moment of the APCembedded site state F a F , while µ F a F ,b F is the transition dipole moment between F a F and F b F . Therefore, to obtain the electronic spectrum of the full system, one has to provide the APCembedded site energies, the site state/transition density matrices (which are in practice given by site-specific geometry, atomic basis set, and density-matrix coefficients, see Appendix B), and all (transition) dipole moments of the site states, for each chromophore.