  Several model fluids in contact with planar, spherical, and cylindrical walls
are investigated for small number densities within density functional theory.
The dependence of the solid-fluid interfacial tension on the curvature of
spherical and cylindrical walls is examined and compared with the corresponding
expression derived within the framework of morphometric thermodynamics.
Particular attention is paid to the implications of the choice of the interface
location, which underlies the definition of the interfacial tension. We find
that morphometric thermodynamics is never exact for the considered systems and
that its quality as an approximation depends sensitively on the choice of the
interface location.
