INFLUENCE OF ARGON BOMBARDMENT ON THE REACTIVITY OF (110) PLATINUM WITH OXYGEN

The influence of 500 eV Ar+ bombardments on the oxygen adsorption by an initially well annealed (1 × 2) reconstructed Pt (110) surface has been studied. It is found that the bombarded surface is more reactive (vs oxygen) than the initial one. The effects of bombardment are extremely rapid. Ion doses as small as 0.05 Ar+/ surface atom reduce the superlattice spot intensity by 50%. The oxygen surface concentration increases by 100% after an ion dose of only 0.01 Ar+/surface atom. Oxygen adsorption on a heavily bombarded surface, showing a (1 × 1) LEED pattern, gives rise to a structure with a (1 × 2) symmetry. Subsequent removal of the oxygen by interaction with the residual gas restores the (1 × 1) pattern. Although the influence of the surface defects cannot be dismissed, local rearrangement of the surface after ion bombardment seems a more likely explanation of these effects. © 1980 American Institute of Physics.