(352d) Does Confining the Equilibrium Hard-Sphere Fluid between Hard Walls Change Its Average Properties?

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).