Structural properties of additive binary hard-sphere mixtures. II. Asymptotic behavior and structural crossovers

TL;DR

This paper investigates the asymptotic decay and structural crossovers in additive binary hard-sphere mixtures, analyzing how density, composition, and size ratio influence the long-range behavior of correlation functions.

Contribution

It introduces a combined approach using rational-function approximation, molecular dynamics data, and pole analysis to study structural crossovers and asymptotic behavior in such mixtures.

Findings

Identification of how poles determine asymptotic decay of correlations.

Analysis of structural crossover lines with varying size ratios and densities.

Insights into discontinuous changes in oscillation wavelengths of correlation functions.

Abstract

The structural properties of additive binary hard-sphere mixtures are addressed as a follow-up of a previous paper [S. Pieprzyk et al., Phys. Rev. E 101, 012117 (2020)]. The so-called rational-function approximation method and an approach combining accurate molecular dynamics simulation data, the pole structure representation of the total correlation functions, and the Ornstein-Zernike equation are considered. The density, composition, and size-ratio dependencies of the leading poles of the Fourier transforms of the total correlation functions $h_{ij} (r)$ of such mixtures are presented, those poles accounting for the asymptotic decay of $h_{ij} (r)$ for large $r$. Structural crossovers, in which the asymptotic wavelength of the oscillations of the total correlation functions changes discontinuously, are investigated. The behavior of the structural crossover lines as the size ratio and densities of the two species are changed is also discussed.