Electron paramagnetic resonance of 239Pu3+ and 243Am4+ in CeO2 and of 241Pu3+ in ThO2

Abstract
The g values of the 5f5 ions Pu3+ and Am4+ in CeO2 cubic symmetry sites have been measured by EPR techniques and found to be 1.333 ± 0.001 and 1.3120 ± 0.0005, respectively. For the case of Pu3+, the cubic crystal field parameters were calculated and compared with those previously obtained for other fluorite‐structure lattices. The EPR spectrum was also observed for 241Pu in ThO2 and the ratio of the magnetic moments 241μI/239μI determined to be 3.52 ± 0.06.