The concept of dispersion selfenergy of a molecule of finite size is used to study the role of dispersion forces in physical adsorption on dielectric surfaces. The adsorption energy, given in terms of readily accessible macroscopic data, remains dways finite, enabling the removal of a phenomenological parameter which occurs in previous theories. Using a statistical theory similar to that of Brunauer, Emmett and Teller, the Lifshitz theory of thick films is shown to emerge as a special case, and its region of validity studied. Restricted adsorption and the H i l l equation arise as special cases of the theory. The influence of molecule size on adsorption processes is built in automatically.Corresponding to eqn (B2) and (B8) we require also expressions for DISPERSION FORCES I N PHYSICAL ADSORPTION 00 s2 = C j e --4 -c / j 2 .
j = 1We find in the same way that s z x (C/A)+Ol ( A < 1, c 9 1, (A2C) 9 1) 1 S , w -{l +&(A2c) In (A2c)+ . .
A2for A 4 1, c 9 1, A2c < 1.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.