Critical properties of Lennard-Jones fluids in narrow slit-shaped pores

The critical properties of the Lennard-Jones fluid in slitlike pores of dif ferent widths have been studied by the Gibbs ensemble Monte Carlo method an d the lattice gas model. Graphite pores up to 10 molecular diameters in wid th and similar pores with weaker solid-fluid interactions have been conside red. Strong layering of the adsorbate in the graphite pores confirmed the a pplicability of the lattice gas model to such systems. The vapor-liquid pha se diagrams for the confined fluids obtained with the two methods are in re asonable agreement with each other. Linear dependence of the critical tempe rature on the inverse pore width was found. It is demonstrated that the cri tical temperature may depend strongly on the strength of the sold-fluid int eractions. The lattice gas model showed nonmonotonic dependence of the crit ical density on the pore width.