As a final assessment of nonbonded interactions of our PET model, we calculated the BHET dimer interaction based on PET crystal packing geometry. As shown in Figure , our parameters yielded an interaction energy of -10.54 kcal/mol while the QM target value was -11.54 kcal/mol. For comparison, the same interaction using the additive CGenFF coun-terpart of the BHET model yielded an energy of -9.64 kcal/mol, suggesting that electronic polarization might play a role in PET crystal packing energies.