The lattice energy has additional implicit fixed dependencies not shown in Equation ( ). This includes the space group symmetry of the unit cell which relates the positions of symmetry related molecules in the unit cell to the asymmetric unit cell. The lattice energy is also dependent on other physics-based parameters in the model. These include electrostatic parameters, Q(θ) (i.e., atom-centred multipoles or point-charges), which are dependent on the molecular conformation. Both the intramolecular and electrostatic parameters are supplied to the model in advance and are derived from isolated-molecule QM calculations.