Phase behavior of parallel hard cylinders

Abstract

We test the performance of a recently proposed fundamental measure density functional of aligned hard cylinders by calculating the phase diagram of a monodisperse fluid of these particles. We consider all possible liquid crystalline symmetries, namely nematic, smectic and columnar, as well as the crystalline phase. For this purpose we introduce a Gaussian parameterization of the density profile and use it to minimize numerically the functional. We also determine, from the analytic expression for the structure factor of the uniform fluid, the bifurcation points from the nematic to the smectic and columnar phases. The equation of state, as obtained from functional minimization, is compared to the available Monte Carlo simulation. The agreement is is very good, nearly perfect in the description of the inhomogeneous phases. The columnar phase is found to be metastable with respect to the smectic or crystal phases, its free energy though being very close to that of the stable phases. This result justifies the observation of a window of stability of the columnar phase in some simulations, which disappears as the size of the system increases. The only important deviation between theory and simulations shows up in the location of the nematic-smectic transition. This is the common drawback of any fundamental measure functional of describing the uniform phase just with the accuracy of scaled particle theory.

17 pages, 5 figures

References in corpus (8)

• Dimensional crossover of the fundamental-measure functional for parallel hard cubes
• Fluid mixtures of parallel hard cubes
• Density functional theory for colloidal mixtures of hard platelets, rods, and spheres
• Density Functional for Anisotropic Fluids
• Bulk inhomogeneous phases of anisotropic particles: A fundamental measure functional study of the restricted orientations model
• Fundamental measure theory for mixtures of parallel hard cubes. II. Phase behavior of the one-component fluid and of the binary mixture
• A fundamental-measure density functional for mixtures of parallel hard cylinders
• Melting of Hard Cubes

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• Smectic and columnar ordering in length-polydisperse fluids of parallel hard cylinders
• Effect of polydispersity and soft interactions on the nematic vs. smectic phase stability in platelet suspensions
• Phase behaviour and correlations of parallel hard squares: From highly confined to bulk systems
• Mesophase formation in a system of top-shaped hard molecules: Density functional theory and Monte Carlo simulation
• Dimensional cross-over of hard parallel cylinders confined on cylindrical surfaces