Structure and dynamic behavior in LJ and soft-sphere fluids: A molecular dynamics simulation study

A deep knowledge of the role of different interaction potentials is of great interest for understanding the microscopic mechanisms of the transport properties in liquids. In order to characterize the influence of different parts of the interaction potentials on the structure and dynamic behavior of simple liquids, we have determined the radial distribution function, velocity autocorrelation function, transverse current and intermediate scattering function from molecular dynamics simulations of LJ and soft-sphere fluids. In particular, the influence of both the attractive forces in LJ liquids and the softness of the cores of the interaction potentials are discussed by comparing the results from simulations of different systems. The results of this work suggest that, the influence of the short-range attractive forces is considerably less significant than the softness of the cores, and the oscillatory phenomena of dynamic behavior are associated with the soft cores of liquids.