A unified model was developed for the loss of interstitial O from solution, and for thermal donor formation. The second-order process at temperatures below 400C was described in terms of the clustering of O dimers which diffused much more rapidly than isolated atoms. This model permitted measured changes in the higher-order kinetics at higher temperatures to be explained by the increasing role that was played by dimer dissociation. The magnitude of this change implied that clusters of less than about 9 atoms were unstable. The attribution of thermal donors to O2N+5 was shown to be consistent with a wide range of experimental observations.

S.A.McQuaid, R.C.Newman, E.Muñoz: Materials Science Forum, 1995, 196-201, 1309-14