GAS ADSORPTION BY REFRACTORY-METAL SINGLE-CRYSTALS

Mass spectrometric data are given for low-pressure oxygen interaction with various crystallographic surfaces of tungsten and molybdenum. Oxygen thermodesorption occurs only as unbound oxygen atoms and as a set of metal oxides. A correlation is discussed between quantitative data on surface concentration, sticking probability and adsorption heat of oxygen on tungsten, and the atomic structure of the various crystallographic faces. Data are also given on inhibition of oxygen adsorption when part of the surface is covered with carbon monoxide or nitrogen. The electron processes of coadsorption are discussed.