Effects of attractive interactions in the thermodynamic, dynamic and structural anomalies of a two length scale potential

TL;DR

This study uses molecular dynamics simulations to explore how attractive interactions influence the thermodynamic, dynamic, and structural anomalies in a two-length-scale potential system, revealing that stronger attractions diminish certain anomalies.

Contribution

It demonstrates how increasing attractive interactions in a two-length-scale potential system affects the presence and extent of density and diffusion anomalies.

Findings

Stronger attractions shrink the anomalous regions in pressure.

Excessive attraction leads particles to favor one length scale, eliminating anomalies.

Structural anomalies persist regardless of attraction strength.

Abstract

Using molecular dynamic simulations we study a system of particles interacting through a continuous core-softened potentials consisting of a hard core, a shoulder at closest distances and an attractive well at further distance. We obtain the pressure-temperature phase diagram of of this system for various depths of the tunable attractive well. Since this is a two length scales potential, density, diffusion and structural anomalies are expected. We show that the effect of increasing the attractive interaction between the molecules is to shrink the region in pressure in which the density and the diffusion anomalies are present. If the attractive forces are too strong, particle will be predominantly in one of the two length scales and no density of diffusion anomaly is observed. The structural anomalous region is present for all the cases.