Molecular oxygen adsorption on partially hydrogenated diamond(100) surfaces

Molecular oxygen has been found to be easily adsorbed on the partially hydrogenated; diamond C(100)-(2x1): H surfaces, whereas the clean and fully hydrogenated C(100) surfaces are completely inert to molecular oxygen. The partially hydrogenated, diamond C (100) - (2 X 1) surfaces have been prepared by (i) in situ hydrogen photodesorption from the fully hydrogenated, surface and (ii) in situ hydrogen adsorption on the clean surface. The. surface reactivity has been monitored through the changes of the valence band photoemission spectra upon molecular oxygen exposure. These results suggest that oxygen adsorption occurs on the isolated carbon dangling bonds produced, on partially - hydrogenated surfaces, from the breaking of the pi-bonding of paired dangling bonds. (C) 2004 American Institute of Physics.