High-pressure neutron diffraction on liquid sulphur hexafluoride and interpretation by statistical-mechanical theories and computer simulations

Abstract

High pressure neutron diffraction measurements of the static structure factor of fluid SF6 are presented. The density of the liquid was varied in a range of ρ=0.85 g cm−3 up to ρ=1.85g cm−3 at the supercritical temperature 398 K. Aspects of the measurements and data evaluation, as far as they are specific for high pressure studies, are discussed. The intramolecular structure parameters are determined. The measurements were interpreted with statistical mechanical calculations (XRISM) as well as reverse Monte Carlo (RMC) calculations. The individual atom pair correlation functions are given and their dependence on density is discussed. An intermolecular potential of (12–6) LJ-type with added point charges is deduced. The density dependent measurements proved to be useful for appraising the intermolecular potential.