The free energy of a liquid when viewed as a population of overlapping clusters

Abstract

The expression of the free energy of a liquid in terms of an explicit decomposition of the particle configurations into local coordination clusters is examined. We argue that the major contribution to the entropy associated with structural fluctuations arises from the local athermal constraints imposed by the overlap of adjacent coordination shells. In the context of the recently developed Favoured Local Structure model [Soft Matt. 11, 3322 (2015)], we derive explicit expressions for the structural energy and entropy in the high-temperature limit, compare this approximation with simulation data and consider the extension of this free energy to the case of spatial inhomogeneity in the distribution of local structures.

Keywords:

• Liquid structure
• freezing transition
• glass transition

Acknowledgements

PH acknowledges the financial support of the Australian Research Council. PR is supported by ‘Initiative Doctorale Interdisciplinaire 2013’ from IDEX Paris-Saclay. Figures realised with Matplotlib [23] and Mayavi2 [24].

Notes

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Australian Research Council [grant number Discovery Grant].