We present measurements of equilibrium multilayer physical adsorption on porous, heterogeneous ice films using nonlinear light scattering. The dependence of scattering intensity on surface coverage is modeled using the adsorption theory of Brunauer, Emmett, and Teller, and an extension based on the Bragg-Williams formalism. We show that a complete equation of state for an adsorbed species can be experimentally determined within this simple framework.

• Received 17 December 1996

DOI:https://doi.org/10.1103/PhysRevLett.79.1531