The Shape of Bucky Onions

TL;DR

This paper uses ab initio calculations to show that large Bucky onions favor spherical shapes over polyhedral forms, with stability influenced by inter-shell interactions, aligning well with recent experimental observations.

Contribution

It introduces a new computational approach to analyze Bucky onion morphology and demonstrates the stability of spherical multi-shell structures for large carbon clusters.

Findings

Spherical morphology has lower energy than polyhedral for large fullerenes.

Formation energy per atom follows a simple scaling law.

Spherical multi-shell Bucky onions are likely the most stable large carbon structures.

Abstract

The morphology of Bucky onions is investigated by {\it ab initio} calculations using Yang's new $O(N)$ method. It is found that for large single shell fullerenes with $I_h$ symmetry, the spherical morphology has the lower energy than that of polyhedrons. The formation energy per atom follows a simple scaling law. Including an estimate of inter-shell van de Waals interactions leads to the conclusion that spherical multiple shell Bucky onions are likely the most stable structure of large carbon clusters. These results are in good agreement with recent observation.