The liquid-state structure of difluoromethane

Neutron scattering experiments have been performed on liquid difluoromethan e (CH2F2, R32) resulting in the first experimental determination of the tot al structure factor and total pair distribution function of difluoromethane . Analysis of the measurements has led to the liquid-state intramolecular s tructure 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 i ntramolecular structure leads to an intermolecular structure factor and an intermolecular pair distribution function, both of which are crucially impo rtant for assessing the reliability of models of the pair potentials used i n computer simulations.