In addition to the calculation of the total properties, such as the energy, energy gradient, dipole moment etc., the pair interaction is obtained for each pair of fragments.
In FMO, various wave functions can be used for ab initio calculations of fragments and their dimers, such as Hartree-Fock, Density functional theory (DFT), Multi-configurational self-consistent field (MCSCF), time-dependent DFT (TDDFT), configuration interaction (CI), second order Møller-Plesset perturbation theory (MP2), and coupled cluster (CC).