Molecular dynamics evaluation of self-diffusion in Yukawa systems

Self-diffusion coefficients of Yukawa systems in the fluid phase are obtain ed from molecular dynamics simulations in a wide range of the thermodynamic al parameters. The Yukawa system is a collection of particles interacting t hrough Yukawa (i.e., screened Coulomb) potentials, which may serve as a mod el for charged dust particles in a plasma or colloidal particles in electro lytes. The self-diffusion coefficients are found to follow a simple scaling law with respect to the system temperature, which is consistent with the u niversal scaling (i.e., temperature scaling independent of the ratio of int erparticle distance to screening length) observed by Robbins [J. Chem. Phys . 88, 3286 (1988)] if the fluid system is near solidification. Also discuss ed is the velocity autocorrelation function, which is in part used to deter mine the self-diffusion coefficients through the Green-Kubo formula.(C) 200 0 American Institute of Physics. [S1070-664X(00)04811-4].