Kd. Gibson et al., High density adsorbed oxygen on Rh(111) and enhanced routes to metallic oxidation using atomic oxygen, J CHEM PHYS, 110(6), 1999, pp. 2757-2760
Exposure of Rh(111) to atomic oxygen leads to the facile formation of a ful
l-coverage and ordered (1X1)-O monolayer which is stable at room temperatur
e. This result differs markedly from the half-coverage (2X1)-O overlayer wh
ich forms at saturation when using molecular oxygen. This demonstrates that
kinetic rather than thermodynamic constraints inhibit the formation of den
se oxygen overlayers when O-2 is the oxidant. We also report that O absorpt
ion into the bulk proceeds much more readily when using O rather than O-2,
a finding with direct implications for enhanced methods of low-temperature
metallic oxidation. These results demonstrate that there are important fund
amental differences in the way in which low-energy beams of atomic and mole
cular oxygen interact with metals. (C) 1999 American Institute of Physics.
[S0021-9606(99)71406-6].