Raman scattering investigations of nanocrystalline thorium oxide.

Raman scattering investigations are carried out on nanocrystalline thorium oxide powders. Shift and broadening of the Raman peak associated with F2g phonons are observed for the nanocrystalline samples as compared with those of the bulk. The peak shift and broadening are found to increase further as the particle size decreases. A quantitative analysis of the Raman line shape is carried out with a Gaussian confinement model, and the estimated size is found to be consistent with that obtained from X-ray diffraction and transmission electron microscopy.