Structural trends in clusters of quadrupolar spheres

TL;DR

This study explores how quadrupolar interactions influence the structure of small clusters of particles, revealing various motifs and growth patterns that are relevant for colloidal self-assembly.

Contribution

It introduces a systematic analysis of quadrupolar effects on cluster structures, combining potential energy calculations with basin-hopping algorithms.

Findings

Identification of structural motifs like stars, tubes, shells, and sheets.

Competition between sheet-like and compact structures depending on quadrupole strength.

Global minima for clusters up to 25 particles obtained and characterized.

Abstract

The influence of quadrupolar interactions on the structure of small clusters is investigated by adding a point quadrupole of variable strength to the Lennard-Jones potential. Competition arises between sheet-like arrangements of the particles, favoured by the quadrupoles, and compact structures, favoured by the isotropic Lennard-Jones attraction. Putative global potential energy minima are obtained for clusters of up to 25 particles using the basin-hopping algorithm. A number of structural motifs and growth sequences emerge, including star-like structures, tubes, shells and sheets. The results are discussed in the context of colloidal self-assembly.