Viscoelastic model for the dynamic structure of binary systems

TL;DR

This paper introduces a viscoelastic model for the dynamic structure factors of liquid binary mixtures, successfully reproducing key features and aligning well with simulation data, including the fast sound phenomenon.

Contribution

The paper develops a viscoelastic model that accurately describes the dynamic structure factors of binary liquid mixtures and their limits, extending previous models.

Findings

Good qualitative agreement with simulation data.

Reproduces the fast sound phenomenon.

Models behavior of both binary and one-component systems.

Abstract

This paper presents the viscoelastic model for the Ashcroft-Langreth dynamic structure factors of liquid binary mixtures. We also provide expressions for the Bhatia-Thornton dynamic structure factors and, within these expressions, show how the model reproduces both the dynamic and the self-dynamic structure factors corresponding to a one-component system in the appropriate limits (pseudobinary system or zero concentration of one component). In particular we analyze the behavior of the concentration-concentration dynamic structure factor and longitudinal current, and their corresponding counterparts in the one-component limit, namely, the self dynamic structure factor and self longitudinal current. The results for several lithium alloys with different ordering tendencies are compared with computer simulations data, leading to a good qualitative agreement, and showing the natural appearance in the model of the fast sound phenomenon.