Water-like Anomalies of Core-Softened Fluids: Dependence on the Trajectories in ($P\rho T$) Space

TL;DR

This study uses molecular dynamics to explore how water-like anomalies in core-softened fluids depend on the thermodynamic path taken in pressure-density-temperature space, revealing that anomalies are trajectory-dependent.

Contribution

It demonstrates that water-like anomalies and the applicability of Rosenfeld entropy scaling relations vary with the chosen thermodynamic trajectory in $P- ho-T$ space.

Findings

Anomalies appear along isotherms but not along isochores and isobars.

Density anomaly is observed along isochors.

Rosenfeld scaling validity depends on the trajectory in $P- ho-T$ space.

Abstract

In the present article we carry out a molecular dynamics study of the core-softened system and show that the existence of the water-like anomalies in this system depends on the trajectory in $P-\rho-T$ space along which the behavior of the system is studied. For example, diffusion and structural anomalies are visible along isotherms, but disappears along the isochores and isobars, while density anomaly exists along isochors. We analyze the applicability of the Rosenfeld entropy scaling relations to this system in the regions with the water-like anomalies. It is shown that the validity of the of Rosenfeld scaling relation for the diffusion coefficient also depends on the trajectory in the $P-\rho-T$ space along which the kinetic coefficients and the excess entropy are calculated.