Comment on "Collective dynamics in liquid lithium, sodium, and aluminum"

TL;DR

This paper critiques a recent interpretation of collective dynamics in liquid metals, arguing that associating the quasielastic component with thermal relaxation results in non-physical thermodynamic and transport behaviors.

Contribution

It provides a critical analysis of a new theoretical interpretation, demonstrating its inconsistencies with established experimental data and thermodynamic principles.

Findings

The interpretation contradicts Inelastic X-ray Scattering results.

It predicts non-physical behavior of thermodynamic parameters.

The critique emphasizes the need for alternative models.

Abstract

In a recent paper, S. Singh and K. Tankeshwar (ST), [Phys. Rev. E \textbf{67}, 012201 (2003)], proposed a new interpretation of the collective dynamics in liquid metals, and, in particular, of the relaxation mechanisms ruling the density fluctuations propagation. At variance with both the predictions of the current literature and the results of recent Inelastic X-ray Scattering (IXS) experiments, ST associate the quasielastic component of the $S(Q,\omega)$ to the thermal relaxation, as it holds in an ordinary adiabatic hydrodynamics valid for non-conductive liquids and in the $Q \to 0$ limit. We show here that this interpretation leads to a non-physical behaviour of different thermodynamic and transport parameters.