INVESTIGATIONS OF CHARGE STATES IN CO57-DOPED OXIDES USING MOSSBAUER-EFFECT AND DELAYED-COINCIDENCE TECHNIQUES

The time dependence of Fe57 chemical charge states in sources of Cu2O, MgO, and Al2O3 doped with Co57 has been studied by means of the Mössbauer effect. Charge states of Fe1+, Fe2+, Fe3+, and Fe4+ resulting from the K-capture decay of the Co57 have been detected. Delayed-coincidence measurements showed no time dependence of the relative peak intensities of these charge states. A time-dependent narrowing of the resonance lines is observed which is not ascribable to time filtering" alone. The isomer shifts of the different valence states are discussed in terms of 3d-electron shielding. © 1969 The American Physical Society."