: Comparison of the ACN structures calculated using the point chargeand SCME potential to the QM structures. All QM energies were computed using PBE0+MBD@rsSCS. The COM RMSD is the center-of-mass root mean square deviation from QM geometries. Since both MM models have rigid geometries, we reset the internal geometry of each of the QM monomers to the MM monomer geometry, to exclude di↵erences from QM monomer distortion, before calculating their COMs. Simulations were carried out using 216 molecules in various fixed volumes. The systems were coupled to a Langevin thermostat at 300 K. After equilibration had been reached, as judged from the potential energies as a function of time, the sampling was carried out for 100 ps for each point, to evaluate the average potential energy for each density. The minimum of the average potential energy can be seen in figure at the 0.85 g/cm 3 point.