SPECTROSCOPIC STUDY AND CRYSTAL-FIELD ANALYSIS OF CM3-SYMMETRY SITE OF THO2( IN THE CUBIC)

Fluorescence and excitation spectra of Cm3+ diluted in ThO2 powder are reported at room and low temperatures. The observed Cm3+ spectra are from the cubic symmetry lattice site and are assigned to phonon-assist ed electric dipole transitions and to magnetic dipole transitions. Fro m these assignments, the crystal-field parameters B-0(4) = -6436 cm-1 and B-0(6) = 1195 cm-1 have been determined. The experimental energy l evels for the ground term (approximately 80% S-8(7/2)) determined from the optical data and earlier electron paramagnetic resonance spectra are in good agreement with the calculated values.