Study of tunnel chemical relaxation by the method of emission Moessbauer spectroscopy

Possibilities of a new radiochemical method of investigation - the emission moessbauer spectroscopy (EMS), are studied. The EMS method is especially effective to study the chemical post-effects of nuclear transformations and chemical relaxation of daughter atoms, formed in gamma-resonance sources (57Fe atoms in the sources, containing 57Co, for instance), when these processes take place with the rates close to the rate of the de-excitation of the resonance moessbauer level (lambda approximately 107 s-1 for 57Fe). The investigations in a wide temperature range (from 400 to 4.2 K) of the charge relaxation of iron ions - using as an example the transformation of Turnbull's blue into Berlin blue and their spin relaxation transition from high spin into low spin state using as an example a number of dipyridyl and phenanthroline complexes - resulted in the detection of low temperature plato of the transformation rate, characteristic for the processes of tunnel chemical relaxation and their description on the basis of the theory of nonradiative electron transitions. Thus, the EMS method opened up new possibilities of the study of kinetics and mechanism of rapid chemical reactions in a solid phase, in the region of low temperatures, in particular, characterized by the prevalence of tunnel transitions over the activation (Arrhenius) ones