PHOTOLYSIS AND PYROLYSIS OF EUROPIUM COMPOUNDS IN SOLID AND FROZEN SOLUTION SYSTEMS - MOSSBAUER AND ESR STUDY

Mechanisms of photo-induced reactions and pyrolysis of some europium c ompounds in solid and frozen solution systems were studied by means of Eu-151 Mossbauer and ESR spectroscopy. The Mossbauer spectra indicate the formation of europium(III) ion by photooxidation of europium(II) ion in frozen solution. The yield of oxidation depends on the waveleng th of the light and the solution composition. The initial products of photolysis of europium(III) oxalate at the surface were characterized by Mossbauer spectroscopy. The Mossbauer parameters were compared to t hose of the pyrolysis products. The pyrolysis mechanism of europium(II I) oxalate and other lanthanide oxalates containing minor amounts of e uropium was proposed based on the Mossbauer spectral data.