Critical cavity in the stretched fluid studied using square-gradient density-functional model with triple-parabolic free energy

TL;DR

This study uses a square-gradient density-functional model with triple-parabolic free energy to analyze the stability and properties of critical cavities in stretched liquids, comparing them with critical bubbles and confirming some conjectures.

Contribution

It provides a theoretical analysis of critical cavities in stretched liquids using a specific density-functional model, extending previous conjectures to broader liquid types.

Findings

Critical cavity size is smaller than critical bubble size.

Work of formation for critical cavities is higher than for critical bubbles.

Scaling relations for critical cavities are only marginally valid near the spinodal.

Abstract

The generic square-gradient density-functional model with triple-parabolic free energy is used to study the stability of a cavity introduced into the stretched liquid. The various properties of the critical cavity, which is the largest stable cavity within the liquid, are compared with those of the critical bubble of the homogeneous bubble nucleation. It is found that the size of the critical cavity is always smaller than that of the critical bubble, while the work of formation of the former is always higher than the latter in accordance with the conjectures made by Punnathanam and Corti [J. Chem. Phys. {\bf 119}, 10224 (2003)] deduced from the Lennard-Jones fluids. Therefore their conjectures about the critical cavity size and the work of formation would be more general and valid even for other types of liquid such as metallic liquid or amorphous. However, the scaling relations they found for the critical cavity in the Lennard-Jones fluid are marginally satisfied only near the spinodal.