Calculation of Point-Defect Energies and Displacements in Alkali Halides Using the Lattice-Statics Method

Publisher Website
Google Scholar
Abstract
The method of lattice statics, in the zero-order approximation, is used to evaluate the Schottky-pair formation energies and the displacement fields about positive- and negative-ion vacancies for all alkali halide crystals with rock-salt structures. The deformation-dipole model, used extensively in earlier work on the lattice dynamics of these crystals, is employed to describe the host lattice. Long-range Coulomb interactions are included explicitly, and short-range repulsive interactions are described by a simple Born-Mayer potential. Comparison is made with earlier Mott-Littleton—type calculations and very satisfactory agreement is found. Comparison with available experimental values is somewhat less satisfactory, particularly regarding the lithium salts; but for "typical" alkali halides, e.g., Nacl and KCl, the calculated values are within 10% of the experimental values.