Raman and Fluorescence Spectroscopy of CeO₂, Er₂O₃, Nd₂O₃, Tm₂O₃, Yb₂O₃, La₂O₃, and Tb₄O₇

Abstract

To better understand and ascertain the mechanisms of flotation reagent interaction with rare earth (RE) minerals, it is necessary to determine the physical and chemical properties of the constituent components. Seven rare earth oxides (CeO 2 , Er 2 O 3 , Nd 2 O 3 , Tm 2 O 3 , Yb 2 O 3 , La 2 O 3 , and Tb 4 O 7 ) that cover the rare earth elements (REEs) from light to heavy REEs have been investigated using Raman spectroscopy. Multiple laser sources (wavelengths of 325 nm, 442 nm, 514 nm, and 632.8 nm) for the Raman shift ranges from 100 cm −1 to 5000 cm −1 of these excitations were used for each individual rare earth oxide. Raman shifts and fluorescence emission have been identified. Theoretical energy levels for Er, Nd, and Yb were used for the interpretation of fluorescence emission. The experimental results showed good agreement with the theoretical calculation for Er 2 O 3 and Nd 2 O 3 . Additional fluorescence emission was observed with Yb 2 O 3 that did not fit the reported energy level diagram. Tb 4 O 7 was observed undergoing laser induced changes during examination.