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Infrared Absorption Spectra of CO Adsorbed on Cu-Ru(001)

Published online by Cambridge University Press:  25 February 2011

F. M. Hoffmann  and
J. Paul
F. M. Hoffmann
Affiliation:
Exxon Research and Engineering Company, Corporate Research Science Laboratories, Annandale, NJ 08801, U.S.A.
J. Paul
Affiliation:
Exxon Research and Engineering Company, Corporate Research Science Laboratories, Annandale, NJ 08801, U.S.A.
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Abstract

The electronic properties and dispersion of copper layers on Ru(001) are investigated utilizing high resolution vibrational spectroscopy (FTIR) and carbon monoxide as a molecular probe. Adsorption of CO on an annealed, epitaxial copper monolayer reveals that copper is modified by the underlying substrate. Both the C-O stretching frequency at low CO coverage and its shift upon increase in coverage indicate stronger backdonation than for thick copper films which exhibit Cu(lll) behavior. At submonolayer coverages (0.25 < θCu < 1.0), copper forms islands on Ru(001) which behave similar to the copper monolayer. Rough copper films evaporated at 85K exhibit a drastically different behavior upon CO adsorption. Vibrational spectra allow us to distinguish 2-dimensional and 3-dimensional copper aggregates of random orientation as well as clusters of small size (1–3 atoms). Annealing of a θCu = 1.0 layer leads to 2- and 3-dimensional ordering at 250K and to complete surface wetting of the copper monolayer at 350K to 540K.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 83: Symposium J – Physical and Chemical Properties of Thin Metal Overlayers and Alloy Surfaces , 1986 , 113
Copyright
Copyright © Materials Research Society 1987

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References

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