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Nanoscale superlattices of samarium-doped ceria layers with varying doping levels have been recently proposed as a novel fuel cell electrolyte. We calculate the equilibrium composition profile across the coherent {100} interfaces present in this system using lattice-gas Monte Carlo simulations with long-range interactions determined from electrostatics and(More)
Oxide surfaces are important for applications in catalysis and thin film growth. An important frontier in solid-state inorganic chemistry is the prediction of the surface structure of an oxide. Comparatively little is known about atomic arrangements at oxide surfaces at present, and there has been considerable discussion concerning the forces that control(More)
We report the solution of the c(4 x 2) reconstruction of SrTiO(3) (001), obtained through a combination of high-resolution transmission electron microscopy, direct methods analysis, and density functional theory. The structure is characterized by a single overlayer of TiO(2) stoichiometry in which TiO(5) polyhedra are arranged into edge-shared structures,(More)
We have recently reported structure solutions for the (2 · 1) and c(4 · 2) reconstructions of SrTiO 3 (0 0 1) based on high-resolution electron microscopy, direct methods analysis of diffraction data and density functional theory. Both reconstructions were found to be TiO 2-rich and feature a single overlayer of TiO 2 stoichiometry on top of a bulk-like TiO(More)
Characterization of lead substitution for calcium in hydroxyapatite (CaHA) is carried out, using experimental techniques and Density Functional theoretical (DFT) analyses. Theoretical modeling is used to obtain information of the Pb chemical environment for occupancy at either Ca(I) or Ca(II) sites of CaHA. Effects of the larger ionic radius of Pb(+2)(More)
a r t i c l e i n f o Keywords: Oxide surface Metal adsorption Density functional X-ray standing wave XAFS Relaxed structures and the related electronic environments of atomic monolayers and half-monolayers of tungsten with varying degrees of oxidation on the (0001) surface of hematite (α-Fe 2 O 3) are modeled using first-principles density functional(More)
The catalytic activity of oxide-supported vanadium oxide is improved by the presence of tungsten oxide for the selective catalytic reduction of nitric oxides. We propose a mechanism for V−W synergy through studies of the reduction−oxidation behavior of near-monolayer VO X and WO X species grown by atomic layer deposition on the α-Al 2 O 3 (0001) single(More)
A method for improved representation of electronic charge and spin densities for molecular and solid state systems is presented, based upon extensions of least squares fits to quantum mechanical "true" densities using basis functions of limited support. Attention is given to optimization of radial degrees of fit freedom, and the design of fit functions(More)
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