Nanotube field of C60 molecules in carbon nanotubes: atomistic versus continuous tube approach

TL;DR

This study compares atomistic and continuous models for calculating van der Waals energy of C60 molecules inside carbon nanotubes, revealing the approximation's validity depends on tube radius and chirality effects.

Contribution

It introduces a detailed atomistic calculation of C60 in nanotubes and compares it with continuous models, highlighting the conditions for approximation accuracy.

Findings

Continuous approximation valid for large and medium radii

Minor chirality effects at small radii

Three orientational regimes identified

Abstract

We calculate the van der Waals energy of a C60 molecule when it is encapsulated in a single-walled carbon nanotube with discrete atomistic structure. orientational degrees of freedom and longitudinal displacements of the molecule are taken into account, and several achiral and chiral carbon nanotubes are considered. A comparison with earlier work where the tube was approximated by a continuous cylindrical distribution of carbon atoms is made. We find that such an approximation is valid for high and intermediate tube radii; for low tube radii, minor chirality effects come into play. Three molecular orientational regimes are found when varying the nanotube radius.