The overestimation of dispersion coefficients in these force fields may be the result of the neglect of some components of the intermolecular interactions. Because the C 6 coefficients are parameterized to empirical liquid properties, the C 6 coefficients will be assigned spuriously large values to compensate for these neglected intermolecular interactions. For instance, the generalized force-field models use fixed atomic charges to represent electrostatic interactions.