A UNIFIED INTERPRETATION OF PHYSICAL ADSORPTION .1. PHYSICAL AND MATHEMATICAL BASES

The physical basis of the intention indicated in the title of this paper is that a physical meaning can be attributed to the variable psi(THETA/p(r))(dp(r)/d-THETA), introduced in the Gibbs equation. The mathematical basis of the interpretation lies in the fact that the differential relation psi may be written in forms of two differential equations and the solutions of those lead to all isotherm equations which are already known or can be derived in the future. This interpretation has further advantages as follows: (i) Based on the function psi(p(r)) belonging to a measured isotherm the physically and mathematically appropriate isotherm equation can be selected. (ii) A new parameter appears in the isotherm equations which essentially influences the values of specific surfaces calculated from isotherms Type I. (iii) The mono- and multilayer parts of a measured isotherm can be distinguished.