A rare gas mixture: From rigid to gas-like fluid by a mutual concentration change

TL;DR

This paper investigates how the sound speed in argon-helium mixtures varies with concentration, revealing minima linked to the transition between rigid and gas-like states near the Frenkel line, supported by computer simulations.

Contribution

It provides the first simulation-based explanation for sound speed minima in high-pressure gas mixtures related to state transitions near the Frenkel line.

Findings

Sound speed minima occur at specific concentrations.

The behavior aligns with the Frenkel line theory.

Simulations match experimental observations.

Abstract

For a number of mixtures of rate gases at high pressures, sound speed minima are experimentally observed depending on the concentration. This behavior has not yet been explained. We have studied the behavior of a mixture of argon and helium using computer simulation. Sound speed minima have been discovered at a certain concentration, which is in good agreement with experimental data. It is shown that this behavior is due to the fact that the P and T parameters for gas mixtures are near the Frenkel line, separating the states of "rigid" and quasi-gas fluid.