Electronic structure and chemical activity of modified metal surfaces

Thesis/Dissertation · Thu Jan 01 04:00:00 EST 1987

OSTI ID:5257777

Pan, X

Angle-resolved synchrotron radiation photoemission was used, together with k-resolved inverse photoemission, low-energy electron diffraction, and Auger electron spectroscopy to study the occupied and unoccupied electronic states, the morphology, and the chemical activity of Ni, Pd, and Pt overlayers of Nb(110) and Ta(110) substrates. The strong adlayer-substrate bonding leads to formation of highly strained commensurate Pd and Pt layers in the early growth stage. However, Ni agglomerates and forms incommensurate structures because the additional lattice mismatch cannot be overcome by the adsorbate-substrate bonding. In the photoemission studies of these metal-metal systems, the adlayer derived bonding interface resonance is observed at a higher binding energy part of the d-band below the Fermi level (E/sub F/). The dominance of this bonding interface resonance and the absence of d-states near E/sub F/ makes the valence-band electronic structure of Pt and Pd monolayer noble-metal-like. Chemisorption studies at 300 K show that CO does not chemisorb on the surface of a monolayer of Pt or Pd on Nb(110). However, both dissociative and molecular CO adsorption occurs on Nb(110) covered by a equivalent monolayer of Ni. K-resolved inverse photoemission identifies an antibonding interface resonance at 1.6 eV above E/sub F/ for a monolayer of Pd on Nb(110)

• Research Organization: City Univ. of New York, NY (USA)
• OSTI ID: 5257777
• Country of Publication: United States
• Language: English

Related Subjects

656003* -- Condensed Matter Physics-- Interactions between Beams & Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BONDING
BREMSSTRAHLUNG
DEPOSITION
ELECTROMAGNETIC RADIATION
ELEMENTS
EMISSION
FABRICATION
FILMS
JOINING
METALS
NICKEL
NIOBIUM
PALLADIUM
PHOTOEMISSION
PLATINUM
PLATINUM METALS
RADIATIONS
SECONDARY EMISSION
SUBSTRATES
SURFACE COATING
SYNCHROTRON RADIATION
TANTALUM
THIN FILMS
TRANSITION ELEMENTS