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John R. Hardy Papers

1972

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Frenkel Defects In Alkali Halides, Paul Schulze, John Hardy Aug 1972

Frenkel Defects In Alkali Halides, Paul Schulze, John Hardy

John R. Hardy Papers

The method of lattice statics and the deformation dipole model have been applied to Frenkel defects in ionic crystals. For isolated interstitials, all short-ranged repulsive and Coulomb-defect host-lattice ion forces were evaluated at the relaxed configuration. The zero-order Coulomb force was allowed to act on the remainder of the host-lattice ions past first neighbors. We have calculated Frenkel-pair formation energies, ionic displacements, and ionic polarizations in the twelve Na, K, Rb halides. Our results show over all that, in ionic crystals of the rocksalt structure, Schottky defect pairs are more likely to be present than Frenkel defect pairs.


Schottky Defects In Alkali Halides, Paul D. Schulze, John R. Hardy Apr 1972

Schottky Defects In Alkali Halides, Paul D. Schulze, John R. Hardy

John R. Hardy Papers

The method of lattice statics and the deformation-dipole model have been applied to Schottky defects in ionic crystals in approximations higher than zero order. For an isolated vacancy, all host-lattice-ion potential energy functions for short-ranged repulsive and Coulomb-defect forces were expanded to terms quadratic in the displacements and dipole moments, and the resulting forces were allowed to act on the first and/or second neighbors to the vacancy. The zero-order Coulomb force was allowed to act on the remainder of the host-lattice ions past first and/or second neighbors. The vacancy and Schottky-pair-formation energies in the 12 Na, K, Rb halides have …