Scaling of local density correlations in a fluid close to freezing

We simulated the equilibrium properties of some reference model fluids, with hard-core, Yukawa and Lennard-Jones interactions, and compared their local density profiles in thermodynamic states where the residual multiparticle entropy (RMPE), an established and rather sensitive indicator of the incipient ordering of the fluid into a more structured phase, happens to vanish. We found that, once interparticle distances have been referred to the average separation between nearest-neighbor particles, the radial distribution functions (RDF) coalesce—from the second coordination shell onwards—onto nearly the same spatial profile. This property was ascertained for different model systems in different thermodynamic conditions but for the shared zero-RMPE constraint. The emergence of a scaling relation for the RDF’s in the fluid phase further enlightens the nature of the structural condition that is singled out by the vanishing of the RMPE.