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Time-resolved VLEED from the O-Cu(001): atomic processes of oxidation

Sun, C.Q. (1997) Time-resolved VLEED from the O-Cu(001): atomic processes of oxidation. Vacuum, 48 (6). pp. 525-530.

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Decoding of time-resolved VLEED data for oxidation processes for Cu reveals that, apart from long-term ageing, the reaction upon ageing and annealing differs slightly from that upon increasing exposure of the O-Cu(001) surface. It is realised that the annealing supplies disturbance other than a driving force for the processes of oxidation. Besides the tetrahedral Cu2O bond geometry, pyramid c(2 × 2)-O structures were examined in detail for the initial stage of the reaction. The off-centred pyramid with oxygen higher than 0.4 Å above the top layer or the centred pyramid with four identical O-Cu bonds were excluded. It is suggested that oxygen reacts with the Cu(001) surface by evolving a CuO2 (Cu+2+2O-1) pairing pyramid with a single contracting ionic bond into a Cu3O2 (Cu+2+2Cu+1+2O-2) pairing tetrahedra with sp3-hybridisation of oxygen. This process transfers the nanometer-scale c(2 × 2)-O domains into the ordered missing-row type (√2×2√2)R45°-O reconstruction. Calculations also reveal that the O-chemisorption affects the energy states dominantly in the upper of valence bands. As a result of the O-Cu bonding, the O-2-hybrid with nonbonding states and the Cu-dipole induced by either the O-1 or the O-2 as well as the vacating atoms play key roles in the atomic processes of oxidation and corrosion.

Item Type: Journal Article
Murdoch Affiliation(s): School of Mathematical and Physical Sciences
Publisher: Elsevier
Copyright: © 1997 Elsevier Science Ltd.
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