Structural search for dense packing of concave and convex shapes in two dimensions

Elias, Nabiha; Hudson, Toby

doi:10.1088/1742-6596/402/1/012005

Cited by 2 publications

(1 citation statement)

References 17 publications

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“…The structural searches for the maximum density crystals, reported in this Section, have been carried out using the Isopointal Search Algorithm introduced by Hudson and Harrowell [26] and implemented for anisotropic particles by Elias and Hudson [27]. This search involves a systematic calculation of the maximum density packings of all possible 2D crystals that satisfy a given restriction on the particles in the unit cell.…”

Section: Densest Crystal Packingmentioning

confidence: 99%

Packing concave molecules in crystals and amorphous solids: on the connection between shape and local structure

et al. 2015

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The structure of the densest crystal packings is determined for a variety of concave shapes in 2D constructed by the overlap of two or three discs. The maximum contact number per particle pair is defined and proposed as a useful means of categorizing particle shape. We demonstrate that the densest packed crystal exhibits a maximum in the number of contacts per particle but does not necessarily include particle pairs with the maximum contact number. In contrast, amorphous structures, generated by energy minimisation of high temperature liquids, typically do include maximum contact pairs. The amorphous structures exhibit a large number of contacts per particle corresponding to over-constrained structures. Possible consequences of this over-constraint are discussed.

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Section: Densest Crystal Packingmentioning

confidence: 99%

Packing concave molecules in crystals and amorphous solids: on the connection between shape and local structure

et al. 2015

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Communication: From rods to helices: Evidence of a screw-like nematic phase

Kolli

Frezza

Cinacchi

et al. 2014

The Journal of Chemical Physics

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Evidence of a special chiral nematic phase is provided using numerical simulation and Onsager theory for systems of hard helical particles. This phase appears at the high density end of the nematic phase, when helices are well aligned, and is characterized by the C2 symmetry axes of the helices spiraling around the nematic director with periodicity equal to the particle pitch. This coupling between translational and rotational degrees of freedom allows a more efficient packing and hence an increase of translational entropy. Suitable order parameters and correlation functions are introduced to identify this screw-like phase, whose main features are then studied as a function of radius and pitch of the helical particles. Our study highlights the physical mechanism underlying a similar ordering observed in colloidal helical flagella [E. Barry, Z. Hensel, Z. Dogic, M. Shribak, and R. Oldenbourg, Phys. Rev. Lett. 96, 018305 (2006)] and raises the question of whether it could be observed in other helical particle systems, such as DNA, at sufficiently high densities.

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Structural search for dense packing of concave and convex shapes in two dimensions

Cited by 2 publications

References 17 publications

Packing concave molecules in crystals and amorphous solids: on the connection between shape and local structure

Packing concave molecules in crystals and amorphous solids: on the connection between shape and local structure

Communication: From rods to helices: Evidence of a screw-like nematic phase

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