Towards an effective potential for the monomer, dimer, hexamer, solid, and liquid forms of hydrogen fluoride

We present an attempt to build up a two-body effective potential for hydrogen fluoride, fitted to theoretical and experimental data relevant not only to the gas and liquid phases, but also to the crystal. The model is simple enough to be used in molecular-dynamics and Monte Carlo simulations. The potential consists of (a) an intramolecular contribution, allowing for variations of the molecular length, plus (b) an intermolecular part, with three charged sites on each monomer and a Buckingham “exp-6” interaction between fluorines. The model is able to reproduce a significant number of observables on the monomer, dimer, hexamer, solid, and liquid forms of HF. The shortcomings of the model are pointed out and possible improvements are finally discussed.