Determination of the Oxidation State by Resonant-Raman Scattering Spectroscopy

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

Campinas

Congreso; Annual User?s Reunion (RAU) of the Luz Synchrotron National Laboratory (LNLS) 2011; 2011

Laboratorio Nacional de Luz Sincrotron

X ray °uorescence spectra present singular characteristics produced by the di®erent scattering processes. 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 this process, the emitted photons have a continuous energy distribution with a high energy cut-o® limit. This work present results regarding the possibility of determining the oxidation state by resonant Raman scattering using an energy dispersive system. Pure sam- ples of transition metals (Cu, Fe, Mn) and di®erent oxides of them (CuO, Cu2O, Fe2O3, Mn2O3, MnO2) were irradiated with monochromatic synchrotron radiation below their absorption edges to inspect the RRS emissions. The spectra were analyzed with speci¯c programs using non-conventional func- tions for data ¯tting and a FFT smoothing procedure was applied. After smoothing, the RRS residuals are studied in order to detect variation with respect to the the- oretical curve. These variations are closely related with the chemical environments 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 clearly discriminated and suggest the possibility of structural character- ization by means of resonant Raman scattering using an energy-dispersive system combined with synchrotron radiation.