Following the logic of the GFT, McWeeny furthermore developed (Chapter 14.2 of Ref. 15) an approach for the variational calculation of the full system using a single antisymmetrized product given in equation 3 as the test function, and varying each site state in order to minimize the expected value of energy, given by equation 8. This simplifies to the iterative minimization of each summand in equation 8 (one for each chromophore F ) separately, until the self-consistency is reached, i.e., until all site states stop changing. If one starts from the antisymmetrized product of the site ground states, the obtained state will presumably be an estimation of the full-system ground state, and this procedure can be viewed as the GFT analogue of the Hartree-Fock (HF) method.