Limits of structure stability of simple liquids revealed by study of relative fluctuations

TL;DR

This study investigates the universal exponential behavior of inverse reduced fluctuations in simple liquids near melting, linking experimental data with theoretical models to explore structural stability and diffusion properties.

Contribution

It reveals the exponential nature of inverse reduced fluctuations in simple liquids near melting and connects experimental data with mean-field theoretical predictions.

Findings

Inverse reduced fluctuations exhibit universal exponential behavior near melting.

The behavior aligns with mean-field lattice fluid model predictions.

Potential methods for determining self-diffusion and structural properties are proposed.

Abstract

We analyse the inverse reduced fluctuations (inverse ratio of relative volume fluctuation to its value in the hypothetical case where the substance acts an ideal gas for the same temperature-volume parameters) for simple liquids from experimental acoustic and thermophysical data along a coexistence line for both liquid and vapour phases. It has been determined that this quantity has a universal exponential character within the region close to the melting point. This behaviour satisfies the predictions of the mean-field (grand canonical ensemble) lattice fluid model and relates to the constant average structure of a fluid, i.e. redistribution of the free volume complementary to a number of vapour particles. The interconnection between experiment-based fluctuational parameters and self-diffusion characteristics is discussed. These results may suggest experimental methods for determination of self-diffusion and structural properties of real substances.