Liquid dibromomethane under pressure: a computational study.

Molecular dynamics simulations have been performed on liquid dibromomethane at thermodynamic states corresponding to temperature in the range 268-328 K and pressure varying from 1 bar to 3000 bar. The interaction model is a simple effective two-body pair potential with atom-atom Coulomb and Lennard-Jones interactions and molecules are rigid. Thermodynamic properties have been studied, including the isobaric thermal expansion coefficient, the isothermal compressibility, the heat capacities and the speed of sound. The simulation results exhibit a crossing of the isotherms of the isobaric thermal expansion coefficient at about 800 bar in very good agreement with the prediction of an isothermal fluctuation equation of state predicting such a crossing in the pressure range 650-900 bar, though experimental results up to 1000 bar do not find any crossing.