Chemical environment determination of iron oxides using RRS spectroscopy

This article presents first results of determination of the oxidation state of several Fe samples by means of resonant Raman scattering spectroscopy (RRS) using monochromatic synchrotron radiation with an energy-dispersive system. Measurements of samples of Fe, FeO, Fe(2)O(3) and Fe(3)O(4) were carried out at the XRF station of the D09B-XRF beamline at Brazilian synchrotron facility (LNLS, Campinas, Brazil). The samples were irradiated with monochromatic photons having energy close and lower than the K absorption edge of iron in order to inspect the RRS emissions. The RRS spectra were analyzed with specific programs for fitting the experimental data to theoretical expressions. Then, residuals were determined in the low-energy side of the RRS peaks. These residuals were treated with Fast Fourier Transform (FFT) smoothing methods taking into account the instrument functions of the detecting system. The residuals show an oscillation pattern that depends on the studied sample, i.e. on the oxidation state of Fe. The changes existing in the RRS structure between Fe and its oxides are clearly discriminated, suggesting chemical environment characterization by RRS spectroscopy using an energy-dispersive system combined with synchrotron radiation. Copyright (C) 2011 John Wiley & Sons, Ltd.