Adsorption of Inert Gases on Tungsten: Measurements on Single Crystal Planes

Abstract

The adsorption of Ar, Kr, and Xe on the (110), (120), (100), (211), and (111) planes of a tungsten field emitter was studied under conditions of immobile adsorption and also under conditions of surface equilibrium. The relative dipole moments and heats of binding could be determined, and it was found that both these quantities were largest on the (110) plane. A discussion in terms of charge transfer bonding is presented to rationalize these results. It was found that chemisorption of oxygen prevented the relatively strong first layer adsorption observed on the clean surface, and also the dipole moment associated with it.