Role of attractive forces in self-diffusion in dense Lennard-Jones fluids

Abstract

The Lennard‐Jones potential is separated into a purely repulsive and a purely attractive part, V_R and V_A, respectively. The velocity correlation function (vcf) is computed by molecular dynamics separately for (V_R + V_A) and for V_R in both isotropic and nematic liquids for several thermodynamic states. It is found that in dense fluids, the results for these two different potentials are in qualitative agreement. The role of the attractive force is discussed. This work is motivated by the recent success of perturbation theories in connection with the equilibrium properties of fluids.