Dynamic structure factors of a dense mixture

TL;DR

This paper calculates the dynamic structure factors of dense binary mixtures, revealing how particle size disparity influences the slowing down or speeding up of dynamics, with implications for neutron scattering experiments.

Contribution

It provides new computational insights into how particle size and composition affect the dynamic structure factors in dense mixtures.

Findings

Large particles slow down dynamics significantly.

Spectrum narrows in nearly equal mixture compositions.

Small particles diffuse easily in dense large-particle backgrounds.

Abstract

We compute the dynamic structure factors of a dense binary liquid mixture. These describe dynamics on molecular length scales, where structural relaxation is important. We find that the presence of a few large particles in a dense fluid of small particles slows down the dynamics considerably. We also observe a deep narrowing of the spectrum for a disordered mixture composed of a nearly equal packing of the two species. In contrast, a few small particles diffuse easily in the background of a dense fluid of large particles. We expect our results to describe neutron scattering from a dense mixture.