Quantum Treatment of the Physical Adsorption of Isotopic Species

Abstract

The results of isotopic substitution in the adsorption of H2, D2, CH4, and CD4 on a graphitized carbon black observed by Constabaris, Sams, and Halsey are explained in terms of two competing effects: the quantum statistical mass effect on the vibrational energy levels normal to the surface and the quantum mechanical effect of isotopic substitution on the dispersion energy.