A Born Model Calculation of the Energies of Schottky Pair Formation and Cation Migration in Potassium Azide

✍ Scribed by Å. Danemar; D. O. Welch; B. S. H. Royce

• Publisher: John Wiley and Sons
• Year: 1973
• Tongue: English
• Weight: 787 KB
• Volume: 55
• Category: Article
• ISSN: 0370-1972
• DOI: 10.1002/pssb.2220550120

✦ Synopsis

Abstract

Calculations are presented for the energy of Schottky pair formation and for the activation energy of cation vacancy migration in potassium azide (KN~3~). Parameters for the repulsive overlap energy of the azide molecule ion have been derived from a Born model treatment of the lattice interactions with the cohesive energy and its first and second derivatives used in the fitting procedure. Three different representations of the repulsive potential are considered. Point defect calculations are performed first in a rigid lattice approximation and then with the effects of polarization and relaxation included. The polarization energy is calculated by a generalized Mott and Littleton method, which accounts for the anisotropy of the lattice, in both zeroth and first order approximations. Relaxations include displacements and rotations of nearest neighbors of the defect configurations. The sensitivity of the results t o the choice of a repulsive potential are discussed.