6. Using the final Q F f s, evaluate the groundstate energy by equation ( ) with modifications (18). This procedure is equivalent to McWeeny's selfconsistent procedure, with the simplification that the ground state of one fragment is not directly affected by the exact ground-state mean field of the other fragments, but rather by the field of the ESP atomic charges of the other fragments' ground states. It is also analogous to so-called "freeze-and-thaw" procedures in frozendensity embedding, but again in our approach the electrostatic interaction is described via the ESP charges.