Computer simulations were made of the kinetics of the correlated annealing of pairs of close -I and F-I centers, as enhanced by I-center diffusion and Coulomb or elastic attractions, respectively. Particular attention was paid to the conditions under which multiple annealing stages arose, as observed experimentally. It was concluded that a weakly elastic interaction affected the recombination kinetics and the survival probability, even of relatively well-separated F-I pairs. This was especially true in the case of Coulomb attraction between charged -I pairs. A multi-step (kink) structure arose only in the case of close (usually up to fourth-nearest neighbor) defects. In order to explain the strongly separated stages (17 to 21K, 30 to 39K in KCl; 18 to 22K, 27 to 30K in KBr) which were observed experimentally in the case of -I, a very special initial defect distribution was required. This consisted of 2 groups of close, and well-separated, defects. This strongly supported the results of other simulations, to the effect that an interstitial ion which was created due to electron-trapping by an H center could be transformed into a crowdion which could then be displaced athermally to large distances (5 to 7 inter-ionic spacings) from a vacancy.

R.I.Eglitis, A.I.Popov, E.A.Kotomin: Physica Status Solidi B, 1995, 190[2], 353-62