Time correlation functions in isotopic liquid mixtures

Molecular dynamics simulations of isothermal dense liquid mixtures of isotopes of Ar have been carried out. Systems with different isotopes and isotopic concentrations but identical interaction potentials and structures have been considered. The velocity autocorrelation functions, memory functions, mean-square displacements and self-diffusion coefficients have been evaluated and they have been used for the analysis of the dynamical behavior of single particles in terms of both their mass and the mean mass of the complete system. (orig.)