Asymptotic decay of pair correlations in a Yukawa fluid

TL;DR

This paper investigates the long-range behavior of pair correlations in a Yukawa fluid, revealing the transition from monotonic to oscillatory decay and demonstrating the effectiveness of pole analysis in describing these correlations.

Contribution

It introduces a detailed analysis of the asymptotic decay of correlations in Yukawa fluids using pole analysis and the hypernetted-chain closure, extending understanding of crossover phenomena in Coulomb-like systems.

Findings

Crossover occurs via coalescence of imaginary poles.

Pole contributions accurately describe correlations at various distances.

The mechanism is similar to that in classical Coulomb fluids.

Abstract

We analyse the $r \to \infty$ asymptotic decay of the total correlation function, $h(r)$, for a fluid composed of particles interacting via a (point) Yukawa pair potential. Such a potential provides a simple model for dusty plasmas. The asymptotic decay is determined by the poles of the liquid structure factor in the complex plane. We use the hypernetted-chain closure to the Ornstein-Zernike equation to determine the line in the phase diagram, well-removed from the freezing transition line, where crossover occurs in the ultimate decay of $h(r)$, from monotonic to damped oscillatory. We show: i) crossover takes place via the same mechanism (coalescence of imaginary poles) as in the classical one-component plasma and in other models of Coulomb fluids and ii) leading-order pole contributions provide an accurate description of $h(r)$ at intermediate distances $r$ as well as at long range.