Prediction of liquid-liquid phase equilibria of He+H₂ mixtures by NpT molecular dynamics simulations

Thermodynamic quantities of the classical He+H₂ mixtures were simulated in the isothermalisobaric ensemble at T=300 K, P =54 kbar, and several concentrations. The chemical potentials were extrapolated in three directions (T,P,x) with their derivatives calculated by the energy difference method in combination with a modified Kirkwood-Buff fluctuation theory. The phase equilibria at different pressures and temperatures were successfully determined.