A comparison of sublimation enthalpies with lattice energies calculated using force fields

Experimental sublimation enthalpies in a range of molecular crystals were c ompared with their lattice energies as calculated by molecular mechanics, u sing several force fields. This enables an evaluation of the capability of these force fields to determine intermolecular interaction energies. The be st agreement between calculated energies and sublimation enthalpies is foun d in the case of Gavezzotti's force field, while significant discrepancies are found with the DREIDING force field and CVFF. With all force fields, th e level of accuracy obtained in energy calculation is insufficient for conf ident use in determining the enthalpy difference between two polymorphs of a given compound. (C) 1998 Elsevier Science B.V. All rights reserved.