An ubiquitous mechanism for waterlike anomalies

TL;DR

This study demonstrates that a family of two-length-scale potentials can universally produce water-like anomalies, with specific behaviors depending on the potential's parameters, highlighting the fundamental role of such potentials in anomalous fluid behavior.

Contribution

It introduces a tunable two-length-scale potential that universally exhibits water-like anomalies, including density and structural anomalies, across a range of parameters.

Findings

Density and structural anomalies observed in all potentials tested.

Diffusion anomaly present except in the square-shoulder potential.

Square-shoulder potential confirms the ubiquity of two-length-scale interactions for anomalies.

Abstract

Using collision driven molecular dynamics a system of spherical particles interacting through an effective two length scales potential is studied. The potential can be tuned by means of a single parameter, $\lambda$, from a ramp $(\lambda=0.5)$ to a square-shoulder potential $(\lambda=1.0)$ representing a family of two length scales potential in which the shortest interaction distance has higher potential energy than the largest interaction distance. For all the potentials, ranging between the ramp and the square-shoulder, density and structural anomalies were found, while the diffusion anomaly is found in all but in the square-shoulder potential. The presence anomalies in square-shoulder potential, not observed in previous simulations, confirm the assumption that the two length scales potential is an ubiquitous ingredient for a system to exhibit water-like anomalies