On the existence of the Brillouin peaks in a simple dilute dissipative gas

TL;DR

This paper analyzes light scattering in a dilute inert gas using irreversible thermodynamics, establishing a criterion for observing Rayleigh-Brillouin spectra and providing a physical interpretation and potential generalizations.

Contribution

It introduces a simple criterion for the existence of Brillouin peaks in dilute gases based on dispersion relations derived from thermodynamics.

Findings

Criterion for Brillouin peak observation established

Physical interpretation of scattering spectrum provided

Generalizations suggested for other physical scenarios

Abstract

Light scattering due to the interaction of photons and acoustic waves present in a dilute inert gas is analyzed through the use of irreversible thermodynamics. The dispersion relation, which governs the dynamics of the density fluctuation of the gas allows the establishment of a simple criterion for the corresponding Rayleigh-Brillouin spectrum to be observed. The criterion here proposed allows a clear physical interpretation and suggests generalizations for other interesting physical scenarios.