Fickian yet non-Gaussian diffusion in two-dimensional Yukawa liquids

Zahra Ghannad
Phys. Rev. E 100, 033211 – Published 25 September 2019

Abstract

We investigate Fickian diffusion in two-dimensional (2D) Yukawa liquids using molecular dynamics simulations. We compute the self–van Hove correlation function Gs(r,t) and the self-intermediate scattering function Fs(k,t), and we compare these functions with those obtained from mean-squared displacement (MSD) using the Gaussian approximation. According to this approximation, a linear MSD with time implies a Gaussian behavior for Gs(r,t) and Fs(k,t) at all times. Surprisingly, we find that these functions deviate from Gaussian at intermediate timescales, indicating the failure of the Gaussian approximation. Furthermore, we quantify these deviations by the non-Gaussian parameter, and we find that the deviations increase when the temperature of the liquid decreases. The origin of the non-Gaussian behavior may be the heterogeneous dynamics of dust particles observed in 2D Yukawa liquids.

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  • Received 5 August 2019

DOI:https://doi.org/10.1103/PhysRevE.100.033211

©2019 American Physical Society

Physics Subject Headings (PhySH)

Plasma Physics

Authors & Affiliations

Zahra Ghannad*

  • Department of Physics, Alzahra University, P.O. Box 19938-93973, Tehran, Iran

  • *z.ghannad@alzahra.ac.ir

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Vol. 100, Iss. 3 — September 2019

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