Determination of the Oxidation State by Resonant-Raman Scattering Spectroscopy

H. J. SÁNCHEZ; J. J. LEANI; C. A. PÉREZ; M.C. VALENTINUZZI

Campinas

Congreso; RAU XXI; 2011

X ray fluorescence spectra present singular characteristics produced by the differentscattering processes. When atoms are irradiated with incident energy lower andclose to an absorption edge, scattering peaks appear due to an inelastic processknown as resonant Raman scattering (RRS). In this process, the emitted photonshave a continuous energy distribution with a high energy cut-off limit.This work present results regarding the possibility of determining the oxidationstate by resonant Raman scattering using an energy dispersive system. Pure samplesof transition metals (Cu, Fe, Mn) and different oxides of them (CuO, Cu2O, Fe2O3,Mn2O3, MnO2) were irradiated with monochromatic synchrotron radiation belowtheir absorption edges to inspect the RRS emissions.The spectra were analyzed with specific programs using non-conventional func-tions for data fitting and a FFT smoothing procedure was applied. After smoothing,the RRS residuals are studied in order to detect variation with respect to the theo-retical curve. These variations are closely related with the chemical environmentsof the absorbing element and can provide relevant structural information of thesample.The changes existing in the RRS structure between pure elements and theiroxides are clearly discriminated and suggest the possibility of structural character-ization by means of resonant Raman scattering using an energy-dispersive systemcombined with synchrotron radiation.Acknowledgements: This work was partially supported by the LNLS (Campinas. Brazil).