The adsorption of oxygen on Cu(210)

The system Cu(210)-O₂ has been examined using LEED and AES, combined with optical simulation of diffraction patterns to investigate the detailed structure of the adsorbed layer. Exposure at 300 K and 5 × 10^?9 Torr resulted in LEED patterns showing pronounced streaks. The corresponding structures are believed to require an adsorption mechanism in which O₂ dissociation can occur only at a limited number of surface sites and in which O atoms after dissociation diffuse over quite large distances (?10 nm) before becoming chemisorbed. Heating these structures to 500–600 K produced a sharp (2 × 1) pattern; this step is thought to involve equilibration of the adsorbed layer. Further combinations of exposure (?1 × 10^?6Torr) and heating (up to 500 K) resulted in a series of (2 × 1) and (3 × 1) patterns, while heating to 800 K at any stage of the oxygen interaction regenerated the clean surface.