Calculation of relaxation volumes, dipole tensors and Kanzaki forces for point defects

The relaxation volumes and dipole tensors associated with point defects in metals are commonly deduced from the results of lattice statistics and computer simulation calculations. Often an approximation introduced by Hardy for weakly disturbing defects is applied in such deductions. However, for strongly disturbing defects such as interstitials, and even in some models vacancies, this approximation breaks down. A more rigorous treatment of the problem which avoids these difficulties is presented.