RAMAN MICROPROBE SPECTROSCOPY OF URANIUM-DIOXIDE SINGLE-CRYSTALS AND ION-IMPLANTED POLYCRYSTALS

Polarized Raman spectra of uranium dioxide single crystals were recorded with the use of a Raman microprobe. Results showed a peak at 448 cm-1, having only off-diagonal tensor elements, which was assigned to the T2g zone center phonon. There was also a broad peak at 1156 cm-1, which was ascribed to electronic Raman scattering. Kr ion implantation of urania polycrystalline pellets produced changes in the Raman spectrum of the implanted specimens. In addition to the two bands observed for the single-crystal material, there was a peak at 576 cm-1. This frequency corresponds to a peak in the calculated phonon density of states and indicates that the scattering is due to a breakdown in the selection rules caused by lattice resulting from implantation.