From the MC simulations, we can extract expectation values of relevant structural parameters as a function of temperature. Of main interest for probing the ferroelectric-to-paraelectric phase transition in TMCMCdCl 3 is the total polarisation of the simulation cell. In Fig. , the polarisation as a function of temperature is shown for model Hamiltonians based on DFT internal energies and free energies including vibrational contributions. The polarisation is calculated from the molecular orientations using the (normalised) 1 13 and 113 family of directions as stated above for the orientation of the dipole of two different sites, and averaged over the number of molecules.