First Results of Quantitative Speciation of Oxide Mixtures by using Resonant Inelastic X-Ray Scattering

D. PEREZ; JOSE ROBLEDO; H.J. SÁNCHEZ; JUAN JOSÉ LEANI; C. PEREZ

Gotemburgo

Congreso; European Conference on X-Ray Spectrometry (EXRS); 2016

University of Gothenburg

Resonant Inelastic X-Ray Scattering (RIXS), also named X-ray Resonant Raman Scattering (RRS), can be used to discriminate local chemical environments [1-5]. By means of this novel technique, the speciation of samples can be attained in a variety of experimental conditions. Until now, this discrimination methodology had been applied only to pure oxides, achieving the speciation by two different mathematical treatments. Nevertheless, the effectiveness of this technique was not tested in samples containing mixtures of oxides of the same element. Because of this, there exists a lack in knowledge about the sensitivity of the method in discriminating the oxides in mixture compounds.In this work, the first results of quantitative speciation of mixtures of manganese compounds, using Resonant Raman Scattering Spectroscopy are presented.The measurements were carried out at the Brazilian Synchrotron Light Source (LNLS, Campinas) in the D09B beamline in a reflection geometry and using monochromatic photons of 6450 eV, just beneath the K absorption edge of manganese. The samples under analysis were divided into two groups. The first group consisted of pellets with Mn2O3 and MnO2 mixed in different proportions. The second group consisted of mixtures of Mn2O3 and MnO also with different amounts of each oxide. Spectra were analyzed by two independent mathematical methods: fine structure deconvolution and Principal Component Analysis.The results show that it is possible to discriminate oxide mixtures of the same element in slightly different proportions, allowing on this way quantitative speciation of compound mixtures in a variety of experimental conditions; some of them impossible to achieve by conventional spectroscopic techniques.