where the first term is the sum of monomer energies, the second the sum of dimer energies, and so on. Such fragment-based methods are now a common method to approximating more expensive periodic levels of theory . Of particular relevance is the Hybrid-Many Body Interaction (HMBI) scheme, which employs polarizable force fields for many-body and long-range pairwise interactions, combined with quantum mechanical (QM) methods such as Møller-Plesset perturbation theory or Coupled Cluster theory for short-range pairwise interactions.