Structure and dynamics of oxygen adsorbed on Ag(100) vicinal surfaces (original) (raw)
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Surface Science, 1995
We have investigated the interaction of oxygen with Ag(lll) by using a supersonic molecular beam in the impact energy range 93-800 meV. At 105 K, contrary to the results of Carley et al. [Surf. Sci. 238 (1990) L467], we find no evidence for O 2 adsorption even after very high O 2 exposures (~ 25000 L) indicating that for a clean surface the sticking probability S is lower than 6 X 10 -7 for the whole impact energy range. At room temperature dissociative oxygen adsorption occurs at E i = 0.80 eV, with S = 9 x 10 -7. The data show however evidence that the adsorption process is mediated also in this case by adsorbed OH so that S is even smaller for the clean surface.
The growth of oxygen adlayers on Ag(110)
Surface Science, 1996
Molecular beam techniques have been used to measure the dissociative sticking probability of oxygen on Ag(110) as a function of the surface oxygen coverage. An initial rapid uptake is found to be followed by a region of much slower adsorption. The transition between these two regimes occurs upon formation of the first extended AgO added row structures and an explanation is given in agreement with models arising from STM studies. The reflectivity of the surface to helium decreases smoothly with oxygen coverage to a value characteristic of the oxygen adlayer.