8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P7.100Thu 811:10-14:00Equation of state for confined hard-sphere fluidsMiguel Robles, 1 Mariano López de Haro, 1 and Andres Santos 21 Centro de Investigación en Energía, Universidad Nacional Autónoma de Mexico,Priv. Xochicalco SN Col. Centro, 62250, Temixco, Mexico2 Depto. de Física, Universidad de Extremadura, Badajoz, SpainIn this work we present a numerical study of hard-sphere fluids confined between parallel planesbased on molecular dynamics simulations. The virial pressure has been obtained for low andmoderate densities at different distances between the planes. The main aim of the study is toexplore the question of whether confined systems can be regarded as systems with a effectivenon-integer dimension. From the available known virial coefficiens for hard-disk, hard-sphere,and hard-hypersphere fluids [1] we have obtained some approximate equations of state that couldrepresent the equation of state of hard-core fluids for non-integer dimensions at low and moderatedensities. Comparing the analytical and simulation results for systems where the confinement isbetween two and three dimensions, it appears that the introduction of a confinement parameterh ∗ = h/σ with h the plane separation and σ the diameter of the (three-dimensional) sphere foreach effective dimension d may make both results compatible if the reduced density ρ ∗ d = ρ d σ dscales as ρ d = γ(h ∗ )ρ ∗ where ρ ∗ = ρσ 3 . The form of the function γ(h ∗ ) will be numericallydetermined.[1] N. Clisby and B. McCoy in J. Stat. Phys. 122, 15 (2006) and M. Bishop, N. Clisby and P.Whitlock in J. Chem. Phys. 128, 034506 (2008)100