Identification and classification of clusters of dipolar colloids in an external field

Fuente: arXiv
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Main Authors: Skipper, Katherine, Moore, Fergus J., Royall, C. Patrick
Format: Preprint
Published: 2024
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author Skipper, Katherine
Moore, Fergus J.
Royall, C. Patrick
author_facet Skipper, Katherine
Moore, Fergus J.
Royall, C. Patrick
contents Colloids can acquire a dipolar interaction in the presence of an external electric field. At high field strength, the particles form strings in the field direction. However at weaker field strength, competition with isotropic interactions is expected. One means to investigate this interplay between dipolar and isotropic interactions is to consider clusters of such particles. We have therefore identified, using the GMIN basinhopping tool, a rich library of lowest energy clusters of a dipolar colloidal system where the dipole orientation is fixed with respect to the z-axis, and the dipole strength is varied for m--membered clusters of 7 <= m <=13. In the regime where the isotropic and dipolar interactions are comparable, we find elongated polytetrahedral, octahedral and spiral clusters as well as a set of non--rigid clusters which emerge close to the transition to strings. We further implement a search algorithm which identifies these minimum energy clusters in bulk systems using the topological cluster classification [J. Chem. Phys. 139 234506 (2013)]. We demonstrate this methodology with computer simulations which shows instances of these clusters as a function of dipole strength.
format Preprint
id arxiv_https___arxiv_org_abs_2406_16076
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Identification and classification of clusters of dipolar colloids in an external field
Skipper, Katherine
Moore, Fergus J.
Royall, C. Patrick
Soft Condensed Matter
Materials Science
Statistical Mechanics
Colloids can acquire a dipolar interaction in the presence of an external electric field. At high field strength, the particles form strings in the field direction. However at weaker field strength, competition with isotropic interactions is expected. One means to investigate this interplay between dipolar and isotropic interactions is to consider clusters of such particles. We have therefore identified, using the GMIN basinhopping tool, a rich library of lowest energy clusters of a dipolar colloidal system where the dipole orientation is fixed with respect to the z-axis, and the dipole strength is varied for m--membered clusters of 7 <= m <=13. In the regime where the isotropic and dipolar interactions are comparable, we find elongated polytetrahedral, octahedral and spiral clusters as well as a set of non--rigid clusters which emerge close to the transition to strings. We further implement a search algorithm which identifies these minimum energy clusters in bulk systems using the topological cluster classification [J. Chem. Phys. 139 234506 (2013)]. We demonstrate this methodology with computer simulations which shows instances of these clusters as a function of dipole strength.
title Identification and classification of clusters of dipolar colloids in an external field
topic Soft Condensed Matter
Materials Science
Statistical Mechanics
url https://arxiv.org/abs/2406.16076