Intermolecular interactions in crystals of carboxylic acids. IV. Empirical interatomic potential functions

Abstract

An intermolecular force field for carboxylic acids has been derived by a least-squares fit of the parameters of non-bonded atom-atom potentials and a hydrogen-bond potential to experimental data. The latter include heats of dimerization and dimer structures of formic, acetic and propionic acid, and heats of sublimation and crystal structures of acetic, α and β-oxalic, α and β-fumaric and isophthalic acid. It was found that (exp - 6 - 1) atom-atom potentials and the Lippincott-Schroeder potential for the hydrogen bonds reproduce fairly well the experimental energies as well as the structures. The transferability of the potentials was studied with respect to the crystal structure of allene dicarboxylic acid and to the crystal structure and the lattice energy of formic acid, and was found to be good. A comparison is made with the results of other authors.