Description of longitudinal modes in moderately coupled Yukawa systems with the static local field correction

TL;DR

This paper derives a more accurate theoretical dispersion relation for longitudinal modes in moderately coupled Yukawa fluids using a dielectric formulation with static local field corrections, improving upon previous semi-phenomenological models.

Contribution

It provides a rigorous derivation of the dispersion relation based on dielectric theory, enhancing accuracy over prior semi-phenomenological approaches.

Findings

The derived relation aligns well with simulations.

It outperforms other theoretical models at moderate coupling.

The approach offers a more precise understanding of longitudinal modes.

Abstract

In moderately coupled Yukawa fluids, longitudinal mode dispersion is determined by the competition between kinetic and potential effects. In a recent paper [Khrapak and Cou\"edel, Phys. Rev. E 102, 033207 (2020)], a semi-phenomenological dispersion relation was constructed by the ad-hoc addition of the Bohm-Gross kinetic term to the generalized instantaneous excess bulk modulus, which showed very good agreement with simulations. In this paper, a nearly identical dispersion relation is derived in a rigorous manner based on a dielectric formulation with static local field corrections. At moderate coupling, this formalism is revealed to be more accurate than other successful theoretical approaches.