Kinetics of isothermal annealing of radiation damage in szilard-chalmers reaction with cobalt complexes

Summary

Isothermal annealing has been found to follow first-order kinetics for the range of temperature studied. It has been found that the previous thermal history is reflected in the rate-constant (k) and the plot of logk versus 1/T exhibits a marked curvature. This has been explained as due to the fact that the annealing reaction leading to the parent specie is not a simple unimolecular one but is complex, involving several stages which in turn exercise mutual influence on other competing reactions preventing annealing.

During an isothermal anneal, the fate of the metastable specie is decided by three competitive reactions—one for annealing to the parent specie and the other two working in the reverse direction—the existence of which have been shown by graphical analysis of experimental data. One of the latter processes seem to be amenable to reversal in the sense that more metastable specie becomes available for anneal at a higher temperature after a run to infinity at a lower one. It seems that this process consists of ‘setting’ or ‘trapping’ of the metastable specie with variable depths—a physical process which inhibits at the particular temperature, the annealing of the metastable specie.

Considerable experimental work would be required to elucidate unambiguously the nature of the damage centre but the indications are that it is of a ‘configurational’ or ‘electronic’ nature, as it is amenable to both ‘thermal’ as well as ‘radiation’ annealing.