Waterlike thermodynamic anomalies in a repulsive-step potential system

TL;DR

This study uses computer simulations to explore how particles with a repulsive step potential exhibit water-like anomalies, revealing how these anomalies depend on potential parameters and disappear as the repulsive step widens.

Contribution

It provides the first detailed phase diagram of a repulsive step potential system, showing water-like anomalies and their dependence on potential parameters.

Findings

Water-like density and diffusion anomalies observed

Anomalies disappear with increasing repulsive step width

Anomalies shift inside the crystalline phase region

Abstract

We report a computer-simulation study of the equilibrium phase diagram of a three-dimensional system of particles with a repulsive step potential. The phase diagram is obtained using free-energy calculations. At low temperatures, we observe a number of distinct crystal phases. We show that at certain values of the potential parameters the system exhibits the water-like thermodynamic anomalies: density anomaly and diffusion anomaly. The anomalies disappear with increasing the repulsive step width: their locations move to the region inside the crystalline phase.