Interaction of H-2, CO and O-2 with a vanadium (111) surface

Adsorption of hydrogen and deuterium on V(111) is governed by dynamical ste ering at low molecular energies whereas at high beam energies direct adsorp tion is observed. Strong rotational effects and clear isotope effects in th e adsorption dynamics of H-2 and D-2 can be seen. At elevated surface tempe ratures hydrogen dissolves in the bulk; the absorption coefficient is stron gly dependent on surface temperature. For CO a large fraction dissociates u pon adsorption. At the clean surface an intrinsic precursor facilitates ads orption and at finite coverages an extrinsic precursor leads to a sticking coefficient independent of coverage. Oxygen can adsorb up to a saturation c overage of 3.8 monolayers followed by surface oxidation. For all three gase s calibration procedures for surface coverages are presented as well as qua ntitative values for the sticking coefficients. (C) 2000 Elsevier Science B .V. All rights reserved.