Determination of the Oxidation State by Resonant-Raman Scattering Spectroscopy

HECTOR JORGE SANCHEZ; J. J. LEANI; M.C. VALENTINUZZI; C. A. PÉREZ

Journal of Analytical Atomic Spectrometry

RSC Publishing

Año: 2011 vol. 26 p. 378 - 382

1364-5544

X-Ray fluorescence spectra present singular characteristics produced by the different scatteringprocesses. When atoms are irradiated with incident energy lower and close to an absorption edge,scattering peaks appear due to an inelastic process known as resonant Raman scattering (RRS). In thisprocess, the emitted photons have a continuous energy distribution with a high energy cut-off limit.This work presents results regarding the possibility of determining the oxidation state by resonantRaman scattering using an energy dispersive system. Pure samples of transition metals (Cu, Fe, Mn)and different oxides of them (CuO, Cu2O, Fe2O3, Mn2O3, MnO2) were irradiated with monochromaticsynchrotron radiation below their absorption edges to inspect the RRS emissions. The spectra wereanalyzed with specific programs using non-conventional functions for data fitting and a FFTsmoothing procedure was applied. After smoothing, the RRS residuals are studied in order to detectvariation with respect to the theoretical curve. These variations are closely related with the chemicalenvironments of the absorbing element and can provide relevant structural information of the sample.The changes existing in the RRS structure between pure elements and their oxides are clearlydiscriminated and suggest the possibility of structural characterization by means of resonant Ramanscattering using an energy-dispersive system combined with synchrotron radiation.