Creating conditions of anomalous self-diffusion in a liquid with molecular dynamics

TL;DR

This paper introduces a computational molecular dynamics method to induce and study anomalous self-diffusion in a simple liquid by applying soft-core interactions and out-of-equilibrium conditions, revealing non-Gaussian displacement distributions.

Contribution

It presents a novel simulation approach combining soft-core potentials and intermittent system forcing to explore anomalous diffusion phenomena.

Findings

Non-Gaussian displacement distributions observed during out-of-equilibrium periods

Method links soft-core interactions with anomalous diffusion behavior

Simulation resembles driven sandpile models with self-organised criticality

Abstract

We propose a computational method to simulate anomalous self-diffusion in a simple liquid. The method is based on a molecular dynamics simulation on which we impose the following two conditions: firstly, the inter-particle interaction is described by a soft-core potential and secondly, the system is forced out of equilibrium. The latter can be achieved by subjecting the system to changes in the length scale at intermittent times. In many respects, our simulation system bears resemblance to slowly driven sandpile models displaying self-organised criticality. We find non-Gaussian single time step displacement distributions during the out-of-equilibrium time periods of the simulation.