AUTHOR=Hernández-Rojas Javier , Calvo Florent 

TITLE=The Structure of Adamantane Clusters: Atomistic vs. Coarse-Grained Predictions From Global Optimization

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 7 - 2019

YEAR=2019

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2019.00573

DOI=10.3389/fchem.2019.00573

ISSN=2296-2646

ABSTRACT=Candidate structures for the global minima of adamantane clusters,
(C$_{10}$H$_{16}$)$_N$, are presented. Based on a rigid model
for individual molecules with atom-atom pairwise interactions that
include Lennard-Jones and Coulomb contributions, low-energy structures
were obtained up to $N=42$ using the basin-hopping method. The results
indicate that adamantane clusters initially grow accordingly with an
icosahedral packing scheme, followed above $N=13$ by a structural
transition toward face-centered cubic structures.  The special
stabilities obtained at $N=13$, $19$, and $38$ are consistent with these
two structural families, and agree with recent mass spectrometry
measurements on cationic adamantane clusters. Coarse-graining the
intermolecular potential by averaging over all posible orientations
only partially confirm the all-atom results, the magic numbers at $13$
and $38$ being preserved. However, the details near the structural
transition are not captured well, because despite their high
symmetry the adamantane molecules are still rather
anisotropic.