To test if XDM-derived C 6 coefficients can be used to parameterize a molecular-mechanical force field, we developed new Lennard-Jones parameters for benzene, toluene, cyclohexane, n-pentane, and n-hexane using XDM data. The internal energy terms and atomic charges of the CGenFF force field models of these molecules were used without modification, but the atomic Lennard-Jones parameters were selected such that the molecular C 6 dispersion coefficient is near the XDM value.