Molecular simulation of the thermodynamics, structural and transport properties of the liquid binary mixture methane + nitrogen

Equilibrium molecular dynamics (MD) simulations have been carried out to determine the thermodynamics, structural and transport properties of the binary mixture CH4-N2 in the dense liquid state as a function of composition at three temperatures 110 K, 130 K and 155 K. The methane molecule is represented by a single site, while the nitrogen molecule is represented by a two site plus a point quadrupole. All sites interact via Lennard-Jones pair potential with Lorentz Berthelot mixing rules for the unlike interactions. A quadrupolar interaction is added for the nitrogen-nitrogen interaction. The shear viscosity and self-diffusion coefficients at various compositions are determined in the NVT ensemble at a density obtained in the NPT ensemble when fixing the pressure value. The results obtained for the viscosity coefficient as a function of composition are found to be in good agreement with the available experimental data.