Adsorption of xenon on films of gold, aluminium and silver

Abstract

A comparative study of the adsorption of xenon on films of gold, aluminium and silver prepared in an ultra-high vacuum system is reported. Sets of isotherms in the temperature range 77–90 K have been measured for two different surface preparations of each metal. The Dubinin-Radush-kevich equation is inappropriate except at very low coverage. Isosteric heats and differential entropies of adsorption are plotted as a function of coverage for each film. Equilibrium heats, molar entropies and energies of adsorption are evaluated. Calculation of the heat of adsorption from the theoretical expression of Mavroyannis yields values considerably lower than those obtained by experiment.