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 thespeciation of various samples under diverse experimental conditions such as totalreflection, grazing incidence, and even confocal setups. Until now, this discriminationmethodology had been limited only to K lines, which correspond to transitions from L toK inner shells. Because of this, there was a lack of knowledge about the applicability ofthis method for the discrimination of compounds by the analysis of L lines (transitionsfrom the M to the L atomic shells). This limitation is especially relevant when studyingrare earth and heavier elements.In this work, the first results of speciation of erbium and praseodymium compoundsusing the EDIXS methodology are presented. The measurements were performed atthe Brazilian Synchrotron Light Source (LNLS, Campinas) using the typical 45°-45°geometry and an energy dispersive system (EDS). Spectra were analyzed by PrincipalComponent Analysis (PCA). After the data processing using multivariate methods, theresults show a clear discrimination of the different element compounds, being evenpossible an oxidation-state quantification procedure. The outcome is significant sincethis novel EDIXS tool allowed, for the first time, observing different species of rareearth elements by means of the inspection of a particular emitted L line.