  We explore the thermodynamic behavior of gases adsorbed within a nanopore.
The theoretical description employs a simple lattice gas model, with two
species of site, expected to describe various regimes of adsorption and
condensation behavior. The model includes four hypothetical phases: a
cylindrical shell phase (S), in which the sites close to the cylindrical wall
are occupied, an axial phase (A), in which sites along the cylinder's axis are
occupied, a full phase (F), in which all sites are occupied, and an empty phase
(E). We obtain exact results at T=0 for the phase behavior, which is a function
of the interactions present in any specific problem. We obtain the
corresponding results at finite T from mean field theory. Finally, we examine
the model's predicted phase behavior of some real gases adsorbed in nanopores.
