EMISSION MOSSBAUER SPECTROSCOPIC STUDIES OF FE-57 ATOMS PRODUCED IN CO-57 LABELED TRINUCLEAR COBALT-IRON HALOGENOACETATE COMPLEXES

Mixed-valence states of Fe-57 atoms produced after EC-decay of Co-57 in a series of trinuclear cobalt-iron halogenoacetate complexes, [CoIIFe2IIIO(CH3-nXnCO2)6(H2O)3] (O less-than-or-equal-to n less-than-or-equal-to 3, X=Cl, Br, and I). were studied by comparing the results obtained by emission Mossbauer spectroscopy with those observed in absorption Mossbauer spectra of analogous trinuclear iron complexes. [FeIIFe2IIIO(CH3-nXnCO2)6(H2O)3]. Some of the emission Mossbauer spectra show a temperature-dependent mixed-valence state as found in the absorption Mossbauer spectra Others show a somewhat different temperature dependence compared with the absorption Mossbauer spectra. The results were interpreted in terms of after-effects of the EC-decay.