EFFECT OF PORE GEOMETRY ON A CONFINED HARD-SPHERE FLUID

The structure of a hard sphere fluid confined by model slit and cylind rical pores is investigated. Results from grand canonical Monte Carlo (GCMC) simulations and from the hypernetted chain/mean spherical appro ximation (HNC/MSA) equation are reported. GCMC results are compared wi th those from the HNC/MSA equation, and agreement is good. The effect of confinement on liquids at the same chemical potentials is that the absorption of the hard sphere fluid into the pores decreases with incr easing confinement, i.e., when going from planar to cylindrical geomet ry or by narrowing the pores. The adsorption on the pore walls has, in general, the opposite behaviour. For high bulk concentrations and cer tain values of cylindrical pore diameter the concentration profile is higher at the centre of the pore than next to the pore wall. A very st rong, but continuous, transition occurs in the concentration profile, as a function of the cylinder's diameter. These results could be of so me interest in catalysis studies.