Association energies of intrinsic and extrinsic defect pairs in KCl

A generalized formulation is described of the evaluation of configurational energies of isolated defects and defect pairs which includes an improved treatment of the relaxation of ions nearest to the defects. The energies of association between vacancy pairs and divalent cation impurity-vacancy pairs in the first three associated states of KCl are calculated employing this method and these values are compared with earlier theoretical estimates.