To identify two-body interactions that contribute significantly to the lattice energy, the variance of the sum of the force field dimer energies with R c is used as a guide. For each crystal structure, a rolling average of the sum of dimer energies is retained with the addition of each shell of interacting molecules. When the addition of a new shell (taken as an increase in R c of 0.5Å) results in a variance of less than 0.1 kJ/mol, the energy is assumed to be sufficiently converged, with interactions beyond this distance left at the force field level of theory. To reduce the chance of identifying convergence erroneously, a minimum R c of 8 Å was used, calculated as the nearest intermolecular atom-atom distance from the reference molecule.