Discriminating Chemical States of Rare Earth/heavy Elements by EDIXS spectroscopy through L-lines inspection

Abstract

Energy-Dispersive Inelastic X-Ray Scattering (EDIXS) spectroscopy allows for the speciation of various samples under diverse experimental conditions such as total reflection, grazing incidence, and even confocal setups. Until now, this discrimination methodology had been limited only to K lines, which correspond to transitions from L to K inner shells. Because of this, there was a lack of knowledge about the applicability of this method for the discrimination of compounds by the analysis of L lines (transitions from the M to the L atomic shells). This limitation is especially relevant when studying rare earth and heavier elements.In this work, the first results of speciation of erbium and praseodymium compounds using the EDIXS methodology are presented. The measurements were performed at the Brazilian Synchrotron Light Source (LNLS, Campinas) using the typical 45°–45° geometry and an energy dispersive system (EDS). Spectra were analyzed by Principal Component Analysis (PCA). After the data processing using multivariate methods, the results show a clear discrimination of the different element compounds, being even possible an oxidation-state quantification procedure. The outcome is significant since this novel EDIXS tool allowed, for the first time, observing different species of rare earth elements by means of the inspection of a particular emitted L line.