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Book ChapterDOI

7 – Defects, Surfaces and Interfaces

01 Jan 1997-pp 185-199
About: The article was published on 1997-01-01. It has received 2 citations till now.
Citations
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Journal ArticleDOI
TL;DR: In this article, a review of catalytic oxidation reactions, which are greatly influenced by solid state effects in the catalyst material, is presented, focusing on the correlation between the presence of mobile ionic defects, together with the associated ionic conductivity, and the catalytic performance.

218 citations

Journal ArticleDOI
TL;DR: In spite of numerous severe difficulties specific to metal-oxygen systems, computer simulation of oxides has developed rapidly in recent years and as mentioned in this paper discusses its successes and some of its limitations with a particular emphasis on silica and on non stoichiometric oxides.
Abstract: In spite of numerous severe difficulties specific to metal-oxygen systems, computer simulation of oxides has developed rapidly in recent years. In this paper, we discuss its successes and some of its limitations with a particular emphasis on silica and on non stoichiometric oxides.

4 citations

References
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Journal ArticleDOI
TL;DR: Etude theorique de la conductivite des solides (NaCl, KCl, RbCl, LiF, NaF, NN, NaBr, NaI, KI, I, KB, KK, KBr, RBCl, NBr, NB, NCl, NaB, NaC, NC, NaD, NaE, NE, NaG, NG, NaX, NX, NaV, NaZ, NaY, NaO, NaW, NaN, N
Abstract: Etude theorique de la conductivite des solides (NaCl, KCl, KBr, RbCl, LiF, NaF, NaBr, NaI, KI, RbBr, RbI). Donnees numeriques

1,214 citations

01 Jan 1989
TL;DR: Etude theorique de la conductivite des solides (NaCl, KCl, RbCl, LiF, NaF, NN, NaBr, NaI, KI, I, KB, KK, KBr, RBCl, NBr, NB, NCl, NaB, NaC, NC, NaD, NaE, NE, NaG, NG, NaX, NX, NaV, NaZ, NaY, NaO, NaW, NaN, N
Abstract: Etude theorique de la conductivite des solides (NaCl, KCl, KBr, RbCl, LiF, NaF, NaBr, NaI, KI, RbBr, RbI). Donnees numeriques

1,166 citations

Journal ArticleDOI
01 May 1950
TL;DR: In this paper, a distinction is made between the surface Helmholtz free energy F, and the surface tension γ, which is the tangential stress (force per unit length) in the surface layer; this stress must be balanced either by external forces or by volume stresses in the body.
Abstract: A distinction is made between the surface Helmholtz free energy F, and the surface tension γ. The surface energy is the work necessary to form unit area of surface by a process of division: the surface tension is the tangential stress (force per unit length) in the surface layer; this stress must be balanced either by external forces or by volume stresses in the body. The surface tension of a crystal face is related to the surface free energy by the relation γ=F+A(dF/dA), where A is the area of the surface. For a one-component liquid, surface free energy and tension are equal. For crystals the surface tension is not equal to the surface energy. The standard thermodynamic formulae of surface physics are reviewed, and it is found that the surface free energy appears in the expression for the equilibrium contact angle, and in the Kelvin expression for the excess vapour pressure of small drops, but that the surface tension appears in the expression for the difference in pressure between the two sides of a curved surface. The surface tensions of inert-gas and alkali-halide crystals are calculated from expressions for their surface energies and are found to be negative. The surface tensions of homopolar crystals are zero if it is possible to neglect the interaction between atoms that are not nearest neighbours.

882 citations

Journal ArticleDOI
TL;DR: In this article, the attachment energy Eatt, defined as the energy per molecule released when one slice of thickness dckl crystallizes onto a crystal face (hkl), was investigated and it was shown that the relative growth rate R of a face always increases with increasing Eatt.

630 citations

Journal ArticleDOI
TL;DR: In this article, the supercell method was used for the energy and the dipole tensor of ionic point defects in periodically repeating geometry, where the point defects carry a net charge, so that the Coulomb energy is divergent.
Abstract: The energy, the elastic dipole tensor and the entropy of point defects in ionic crystals are usually calculated by the Mott-Littleton approach, which treats a single defect in an infinite crystal. The authors suggest that there may be advantages, particularly for the dipole tensor and the entropy, in performing the calculations in periodically repeating geometry. They examine how this 'supercell' method can be used for the energy and the dipole tensor, paying attention to the problem that for charged defects the repeating unit carries a net charge, so that the Coulomb energy is divergent. They test the supercell method on a number of both charged and uncharged defects, and show that the results for the energy and dipole tensor are in close agreement with those obtained by the conventional approach.

433 citations