Diffusive and Superdiffusive Motion of sorbates in Carbon nanotubes

TL;DR

This study uses molecular dynamics simulations to explore how sorbate size influences their motion inside carbon nanotubes, revealing a transition from diffusive to superdiffusive to ballistic behavior based on size.

Contribution

It demonstrates how the crossover from diffusive to ballistic motion depends on sorbate size and the levitation parameter, providing a new understanding of confined molecular dynamics.

Findings

Small sorbates exhibit diffusive motion.

Intermediate sorbates show superdiffusive behavior.

Large sorbates move ballistically.

Abstract

Molecular dynamics simulations of sorbates of different sizes confined to the interior of carbon nanotubes are reported. The mean squared displacement shows gradual change from diffusive for small sorbates to superdiffusive for intermediate sized-sorbates to ballistic for sizes comparable to the channel diameter. We show that this crossover behaviour can be understood on the basis of a gradual decrease of the x-y component of the force with the levitation parameter. The analysis can also help to rationalize some recently published results.