where the indices i and j run over the molecules of the unit cell denoted in brackets, n is the unit cell vector, E M describes the long range coulomb interactions, P the pressure, V the unit cell volume and the apostrophe denotes the exclusion of the cases i = j and n = 0 from the summation. The monomer energies E i(0) and E j(n) and dimer energies E i(0)j(n) can in principle be obtained at every level of theory, where the crystal field is accounted for by an embedding scheme in dipoles or point charges, obtained by ab initio calculations. The pressure is simulated by optimizing the box lattice parameters for a specific pressure. It should be highlighted that BIM does not strictly rely on periodic boundary conditions and therefore is applicable to non-periodic systems. It has been used to extensively study phase diagrams, e.g., of carbon dioxide and ice. A more detailed discussion of simulated phase diagrams can be found in Section 3.2.2.