After the self-consistent ESP charges are obtained, they can be used in the generation of all (ground and excited) APC-embedded site states for the ECI calculation, and hence all site states will be affected by the same embedding. This approach (of using self-consistent ESP charges in embedding) is expected to be similar to the one used in the exciton model of Morrison et al. The APC-embedded site states calculated with the self-consistent ESP charges are the excitonic analogues of the canonical HF orbitals, given that these site states are obtained by considering the mean-field interaction between fragments in their aufbau configurations in a self-consistent manner. For this reason, we call the presented procedure excitonic Hartree-Fock (EHF) and the self-consistent ESP charges EHF charges. Within the EHF procedure, we expect that a reasonable initial guess for the APCs is to set them all to zero, which implies that the initial APC-embedded ground states will be equal to the ground states of the isolated fragments (as discussed for the FDA above). Then, at the end of the first EHF cycle, one obtains the ESP charges of the isolated fragments. After convergence of EHF, the APC-embedded ground state of one fragment is then self-consistent with the ground states of all other fragments.