Oxidation state determination by RRS analysis with an energy dispersive system

HÉCTOR JORGE SÁNCHEZ; MARÍA CECILIA VALENTINUZZI; JUAN JOSÉ LEANI

Cabo Frío

Congreso; Seminario Latinoamericano de Análisis por Técnicas de Rayos X, SARX2008; 2008

In this work we present preliminary results regarding the possibility of determining the oxidation state by resonant Raman scattering using an energy dispersive system. Several measurements of samples of Cu, CuO and Cu3O were carried out using synchrotron radiation at the XRF beamline of the LNLS (Campinas, Brazil). The samples were irradiated with monochromatic photons having energy close but lower than the absorption edge of cooper.  In addition, fluorescence-EXAFS spectra were taken by high-resolution energy scannings around the absorption edge of cooper. The RRS peaks were analyzed with specific programs for fitting the experimental data to theoretical expressions. After that, residuals were determined in the low energy side of the RRS peaks. These residuals were treated with FFT smoothing methods taking into account the instrument functions of the detecting system. The results show an oscillation pattern that depends on the sample, i.e. on the oxidation state of cooper. The EXAFS spectra were treated with normal procedures and oscillations were isolated. The results show that the oxidation state can be clearly discriminated by the RRS analysis. Moreover, a significant (and, somehow, surprising) similarity can be appreciated with the EXAFS patterns of the corresponding samples. More measurements in different samples will be carried out in order to verify the present results and, hopefully, to establish a repetitive and reliable method of structural determination.