Evidence of a nondiffusive transport in a monodisperse screened Coulomb system by a molecular-dynamics simulation

Abstract

A molecular-dynamics simulation is carried out for particles (tracers) interacting with a screened Coulomb potential in three dimensions. A phase transition is observed from a liquid to an fcc solid on reducing the temperature at a fixed density, consistent with previous studies. In the liquid phase, the variation of the rms displacement R "ofthe charged particles with time seems to depend on the density and the temperature. In the short-time regime, the e6'ective exponent k for the subdiffusive power-law behavior, i.e. , R"-t, decreases on increasing the density and lowering the temperature. A crossover from subdiffusive to a diC'usive behavior is observed for a wide density regime in the liquid phase. At high temperatures and large densities, a single power law does not seem to describe the variation of R" with t.