The temperature and density dependence of fluid xenon self-diffusion coefficients: a comparison between experimental, theoretical and molecular dynamics results

The molecular dynamics (MD) simulation technique has been employed to investigate the self-diffusion coefficients of neat liquid and supercritical (SC) Xenon over a wide range of thermodynamic conditions. The fluid has been studied at densities in the range 0.0700-3.2141 g/cm3 and temperatures from 203 to 343 K. The simulations were based on a pair-wise additive potential model with ɛ/kB = 212 K and σ = 0.3905 nm, which is presented for the first time here. The self-diffusion coefficients obtained are shown to be in good agreement with experimental values reported by Prins and coworkers [P.W.E. Peereboom, H. Luigjes, K.O. Prins, An NMR Spin-echo study of self-diffusion in Xenon, Physica A 156 (1989) 260], covering PVT data up to 1500 bar. Theoretical results for self-diffusion coefficients from various theoretical and empirical models are tested against experimental and MD results. In addition, the structure of the fluid is presented in terms of the pair distribution functions and possible correlation of its local behaviour with diffusivity is briefly discussed.