ABSTRACT
The study of the adsorption of rare gases on solid surfaces has led to a great advance in the
theoretical development needed to understand physical adsorption (or physisorption) phenomena
(for general definitions, terminology, and symbols used in physisorption or other surface
processes, see Refs. 1-3). The lack of chemical reactions and the simplicity of the molecular
properties of the rare gases permits one to consider simple models in order to reproduce their
behavior in adsorption phenomena. Also, the experimental results obtained for the adsorption of
rare gases on simple solid surfaces, such as graphite, have been used as a reference in the
development of very precise temperature control systems, as well as in the study of the most
important characteristics of the adsorption of fluids onto solids. Moreover, the discovery of
nonsimple phase diagrams for rare gases adsorbed on a homogeneous graphite surface has
generated a large number of new experimental trends and theoretical models.
