The liquid-state structure of difluoromethane

Neutron scattering experiments have been performed on liquid difluoromethane (CH₂F₂, R32) resulting in the first experimental determination of the total structure factor and total pair distribution function of difluoromethane. Analysis of the measurements has led to the liquidstate intramolecular structure of this fluid. The structure has been compared with that obtained for some other halogenated methanes. A comparison with results obtained for trifluoromethane (CHF₃, R23) suggests that there is less long-range order in liquid-state difluoromethane than trifluoromethane. Subtraction of the intramolecular structure leads to an intermolecular structure factor and an intermolecular pair distribution function, both of which are crucially important for assessing the reliability of models of the pair potentials used in computer simulations.