- 9:33 AM

Does Confining the Equilibrium Hard-Sphere Fluid between Hard Walls Change Its Average Properties?

Jeetain Mittal, Department of Chemical Engineering, The University of Texas at Austin, Austin, TX 78712, Jeffrey R. Errington, University at Buffalo, Dept. of Chemical and Biological Engineering, 509 Furnas Hall, Buffalo, NY 14260, and Thomas M. Truskett, Chemical Engineering and Institute for Theoretical Chemistry, The University of Texas at Austin, 1 University Station, C0400, Austin, TX 78712.

The equilibrium hard-sphere fluid confined between smooth, parallel hard walls represents arguably the most basic model for inhomogeneous fluids [1]. If the walls are separated by only a few sphere diameters, the structural constraints of confinement introduce pronounced layering in the normal direction. The resulting inhomogeneous density profiles have long been a central focus of classical density functional theory studies. In this talk, we present a comprehensive investigation of the thermodynamics, structure, and dynamics of this system using event-driven molecular dynamics [2] and transition-matrix Monte Carlo [3] simulations. Our main finding is that, despite the strong structural ordering of the fluid normal to the walls, many of the average properties are virtually indistinguishable from the bulk hard-sphere fluid if compared at equal values of an appropriately defined density [4].

[1] H. T. Davis, Statistical Mechanics of Phases, Interfaces and Thin Films (Wiley-VCH, New York, 1995).

[2] D. C. Rapaport, The Art of Molecular Dynamics Simulation (Cambridge University Press, Cambridge, England 2004), 2nd ed.

[3] J. R. Errington, J. Chem. Phys. 118, 9915 (2003).

[4] J. Mittal, J. R. Errington, and T. M. Truskett, Phys. Rev. Lett. (in press).