An XPS study of oxygen adsorption on Cu(110)
1985; Elsevier BV; Volume: 159; Issue: 2-3 Linguagem: Inglês
10.1016/0039-6028(85)90433-9
ISSN1879-2758
AutoresG. R. Gruzalski, D. M. Zehner, J. F. Wendelken,
Tópico(s)Ion-surface interactions and analysis
ResumoXPS was used to study oxygen adsorption on Cu(110) and to follow changes in oxygen coverage θ resulting from isochronal anneals at up to 880 K. Clean surfaces or surfaces preexposed to oxygen and then annealed to effect adsorbate ordering were exposed at a surface temperature of 83 ± 1 K (denoted as Tℓ or between 300 and 320 K (denoted as Th) to up to 105 L of room-temperature molecular oxygen. Spectra for clean surfaces exposed at Tℓ or Th exhibited peaks near 530.15 ± 0.2 eV BE having FWHM's of about 1.9 or 1.6 eV, respectively. These peaks are attributed to photoemission from 1s levels of chemisorbed oxygen. Normalized areas under these peaks were used to obtain curves of θ versus exposure and sticking probability versus θ. Adsorption at both Tℓ and Th is describable in terms of a mobile-precursor kinetics, with initial sticking probabilities of about 0.77 and 0.23, respectively. Chemisorption at Tℓ was greatly inhibited by the presence of a preadsorbed layer of ordered atomic oxygen. The broadest O 1s XPS spectra remained broad even after anneals to 180 K but began to sharpen during anneals at 230 K. Anneals at up to 480 K produced no measurable change in θ. Higher-temperature anneals reduced θ to about 0.50 if θ ≳ 0.50 initially; no change in θ was observed if θ ≲ 0.50 initially.
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