AVS 47th International Symposium
    Surface Science Thursday Sessions
       Session SS1+MC-ThA

Paper SS1+MC-ThA7
The Nature of Oxygen at Rocksalt and Spinel Oxide Surfaces

Thursday, October 5, 2000, 4:00 pm, Room 208

Session: Oxidation and Molecule-Oxide Interactions
Presenter: M.A. Langell, University of Nebraska
Authors: M.A. Langell, University of Nebraska
J.G Kim, University of Nebraska
S. Chapman, University of Nebraska
H.Y. Xu, University of Nebraska
Correspondent: Click to Email
The chemical environment of oxygen in mixed metal oxides with compositions M@subx@M'@sub(x-1)@O and M@subx@M'@sub(3x-1)@O@sub4@, (M, M' = Li, Mn, Fe, Ni, Co) has been studied by Auger electron spectroscopy, x-ray photoelectron spectroscopy and high resolution electron energy loss spectroscopy. While there is a single type of lattice oxygen in the bulk structure of simple rocksalt and spinel oxides, the nature of oxygen at the surface of the mixed-metal oxide materials is considerably more complex. Photoemission from core oxygen states in these materials often shows multiple peaks and satellite structure which have been attributed to a range of intrinsic and extrinsic oxygen states. Mixed-metal oxides form an ideal set of systems to investigate the nature of the lattice oxygen through their ability to tailor cation oxidation state and site occupancy within the crystal structure and thus affect the chemical environment of the lattice oxygen. All of these 3d transition metal oxides show a single, intense O1s core photoemission peak at approximately 529.6 eV. However, a second peak is often observed at about 1-1.5 eV higher binding energy, depending upon the types and distribution of the cations, and the history of the substrate surfaces. Surface hydroxylation, cation clustering and final state effects in the photoemission mechanism can all contribute to the O1s photoemission process and will be discussed in view of the data obtained for the mixed-metal oxides.