Solid-solid phase transition in hard ellipsoids

We present a computer simulation study of the crystalline phases of hard ellipsoids of revolution. A previous study [ P. Pfleiderer and T. Schilling , Phys. Rev. E 75 , 020402 ( 2007 ) ]. showed that for aspect ratios a / b ≥ 3 the previously suggested stretched-fcc phase [ D. Frenkel and B. Mulder...

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Veröffentlicht in:The Journal of chemical physics 2009-10, Vol.131 (16), p.164513-164513-6
Hauptverfasser: Radu, M., Pfleiderer, P., Schilling, T.
Format: Artikel
Sprache:eng
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Zusammenfassung:We present a computer simulation study of the crystalline phases of hard ellipsoids of revolution. A previous study [ P. Pfleiderer and T. Schilling , Phys. Rev. E 75 , 020402 ( 2007 ) ]. showed that for aspect ratios a / b ≥ 3 the previously suggested stretched-fcc phase [ D. Frenkel and B. Mulder , Mol. Phys. 55 , 1171 ( 1985 ) ] is unstable with respect to a simple monoclinic phase with two ellipsoids of different orientations per unit cell (SM2). In order to study the stability of these crystalline phases at different aspect ratios and as a function of density we have calculated their free energies by thermodynamic integration. The integration path was sampled by an expanded ensemble method in which the weights were adjusted by the Wang-Landau algorithm. We show that for aspect ratios a / b ≥ 2.0 the SM2 structure is more stable than the stretched-fcc structure for all densities above solid-nematic coexistence. Between a / b = 1.55 and a / b = 2.0 our calculations reveal a solid-solid phase transition.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.3251054