The FCC-BCC-Fluid triple point for model pair interactions with variable softness

TL;DR

This paper investigates the triple point where fcc, bcc, and fluid phases coexist in systems with variable interaction softness, demonstrating a narrow region in parameter space and proposing a predictive framework based on a corresponding states principle.

Contribution

It introduces a unified approach to predict the fcc-bcc-fluid triple point across different pair interactions using a softness and strength parameterization.

Findings

Triple point coordinates are confined to a narrow region in softness-strength space.

The proposed method can predict the triple point for various interaction models.

Relation to experimental dusty plasma studies is discussed.

Abstract

It is demonstrated that the coordinates of the fcc-bcc-fluid triple point of various model systems are located in a relatively narrow region, when expressed in terms of the two proper variables, characterizing the softness and strength of the interaction force at the mean interparticle separation. This can be regarded as a consequence of the "corresponding states principle" for strongly interacting particle systems we have put forward recently [S. A. Khrapak, M. Chaudhuri, and G. E. Morfill, J. Chem. Phys. {\bf 134}, 241101 (2011)]. The related possibilities to predict the existence and approximate location of the fcc-bcc-fluid triple point for a wide range of pair interactions with variable softness are illustrated. Relation of the obtained results to experimental studies of complex (dusty) plasmas are briefly discussed.