The self-diffusion coefficient in stable and metastable states of the Lennard–Jones fluid

Molecular-dynamics simulations have been employed to calculate the self-diffusion coefficient of a Lennard–Jones fluid for 198 sets of state parameters in the range of temperatures 0.35 ≤ kBT/ɛ ≤ 2.0 and densities 0.005 ≤ ρσ3 ≤ 1.2. Calculations have been made in stable and metastable states to the boundary of spontaneous nucleation in a model containing 2048 interacting particles. Results of computations, performed in the parameter range of stable states, are compared with the results of previous papers. Equations have been formulated, which describe the dependences of the self-diffusion coefficient on temperature and density and on temperature and pressure in the whole range of parameters including both the stable and metastable (supersaturated vapor, superheated and supercooled liquid) states of fluid.

► The self-diffusion coefficient D* of LJ fluid is calculated for 198 state points.
► Calculations have been made both in stable and metastable states of a fluid.
► The range of reduced temperatures is 0.35 ≤ T* ≤ 2.0 and of densities 0.005 ≤ ρ* ≤ 1.2.
► The dependence D*ρ*(T*,ρ*) in a gas and liquid has been approximated.
► The behavior of D* in supercooled liquids is described by dependence ln D*(T*,p*).