Anomalous temperature dependence of surface tension and capillary waves at liquid gallium

TL;DR

This study investigates the unusual temperature dependence of surface tension in liquid gallium, combining theoretical models and experimental light scattering data, revealing a sign change in the temperature derivative near 100°C.

Contribution

It provides a combined theoretical and experimental analysis of surface tension and capillary waves in liquid gallium, highlighting the anomalous temperature behavior.

Findings

The temperature derivative of surface tension changes sign near 100°C.

Capillary waves positively contribute to surface entropy.

Dipole layer effects negatively influence surface entropy.

Abstract

The temperature dependence of surface tension \gamma(T) at liquid gallium is studied theoretically and experimentally using light scattering from capillary waves. The theoretical model based on the Gibbs thermodynamics relates the temperature derivative of \gamma to the surface excess entropy -\Delta S. Although capillary waves contribute to the surface entropy with a positive sign the effect of dipole layer on \Delta S is negative. Experimental data collected at a free Ga surface in the temperature range from 30 to 160 C show that the temperature derivative of the tension changes sign near 100 C.