Calculations of the diffusion coefficients in gases and liquids by the molecular dynamics method

Abstract In this paper the calculation results of the diffusion coefficients in gases and liquids by the method of molecular dynamics are presented. The modified intermolecular Lennard-Jones potential has been used. The diffusion coefficients dependences on temperature and density have been calculated. Using the diffusion coefficients dependence on temperature it has been found, that the collisional mechanism in rarefied and dense gases changed for the collective one in liquids. In the field of the thermodynamics parameters of two phase coexistence, drops of liquid occur in the vapour or bubbles occur in the liquid. The comparison of the experimental data with our calculations results in a satisfactory agreement.