Structural and dynamical anomalies of soft particles interacting through harmonic repulsions
Abstract
Molecular dynamics (MD) simulations are carried out to investigate the structural and dynamical anomalies in the core-softened fluid with harmonic repulsions. At sufficiently low temperature and densities, a general scaling relation between the Rosenfeld diffusivity DR and excess entropy Sex holds true because the ultrasoft particles tend to avoid overlapping and behave like effective hard spheres. When the temperature is increased high enough, the system acts as a weakly correlated mean-field fluid so that an alternative scaling relation between temperature scaled diffusion DT and Sex does work. Interestingly, the plots of DRversus two-body excess entropy S2 approximately collapse onto a single master curve despite the structural and dynamical anomalies, which has also been observed in other core-softened fluids with bounded potential.