Digitale Medien
College Park, Md.
:
American Institute of Physics (AIP)
The Journal of Chemical Physics
97 (1992), S. 8789-8797
ISSN:
1089-7690
Quelle:
AIP Digital Archive
Thema:
Physik
,
Chemie und Pharmazie
Notizen:
CO adsorption on Ni{110} and on hydrogen precovered Ni{110} surfaces at 180 K has been studied by FT-RAIRS. On a clean Ni{110} surface CO adsorbs at on-top sites upto a coverage of 0.7 ML. At higher coverages the on-top CO band at 2060 cm−1 decreases in intensity with a concomitant increase in a band at 1960 cm−1 which shifts up in frequency. The (2×1)p2mg structure at 1.0 ML CO coverage shows a single band at 1998 cm−1 attributed to CO tilted at bridged sites. FT-RAIRS of CO adsorption on H precovered Ni{110} surfaces shows complex CO site switching within different CO and H coverage regimes. A model is presented involving compression of H into islands of high coverage and both mixed H and CO and unmixed CO islands are formed. CO adsorbs in the unmixed CO islands the same as that on clean Ni{110}. Within the mixed H/CO islands the first layer nickel atoms reconstruct and a new hydrogen desorption state is observed. The CO site switching observed by FT-RAIRS within the various H and CO coverage regimes is discussed in terms of a dominant indirect interaction.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.463348
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