Dynamics and kinetics of oxygen dissociative adsorption on Pt{110}(1x2)

The interaction of oxygen with Pt{110}(1X2) has been investigated using supersonic molecular beams and low-energy electron, diffraction (LEED) at incident kinetic energies of 60-900 meV and surface temperatures from 170 to 1100 K. LEED studies indicate that at low exposures and low beam energies (<190 meV) oxygen does not induce a reconstruction to (1X1). However at high exposures and low beam energies, a variable unit mesh dimension Frenkel-Kontorova domain structure is observed. Sticking probability measurements on the clean surface indicate that oxygen dissociative adsorption on Pt{110}(1X2) is a predominantly precursor mediated process. At low surface temperatures (<200 K) and low beam energies, the precursor has a strong influence on the adsorption kinetics, and mixed. islands of dioxygen and adatoms are formed. Adsorption at beam temperatures below 880 K produces two states in the the thermal desorption spectroscopy spectra, but at higher incident gas temperatures a new high temperature desorption state (T-p=1020 K) can be populated, which inhibits the formation of the usual dissociatively chemisorbed states at T-p=720 and 820 K. (C) 1998 American Institute of Physics. [S0021-9606(98)70740-8].