IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Oxidation state quantification for Mn oxide mix samples by high resolution Kb spectra
Autor/es:
C. QUINTANA; S. CEPPI; G. STUTZ; G. TIRAO
Lugar:
Campinas, Brasil
Reunión:
Congreso; Actrivity Report LNLS 2008; 2009
Institución organizadora:
LNLS
Resumen:
In transition metals, X-ray Kb spectra consist of main lines (Kb1,3, Kb5) and satellite lines whose origin are related to spin coupling of 3p and 3d electrons or to ligand type. Mn-Kb spectra and their relation with the chemical environment has been quite studied. Synchrotron and high resolution spectrometer facilities allow to improve the information quality obtained about absorption and emission process. In Mn-compounds, with unpaired 3d electrons, the Kb emission is split into the main Kb1,3 line and a less intense, low energy Kb´ satellite, the most intense lines. At the high energy side of the main line, the satellite line Kb" (usually called cross-over transitions) and the Kb5 band can also be observed. Relative variations of spectral parameters in different manganese compounds are useful to characterize the Mn chemical environment, i.e., the oxidation states, the net spin in the valence band, the ligand type and the bonding length.In this work, Kb emission spectra of manganese oxides (MnO and MnO_2) and mixed samples with different oxides concentration were analyzed in order to find a simple method to characterize the sample composition. This method is based on the study of correlation between the spectrum variations and oxidation state, for the purpose to obtain a sensitive parameter convenient tocalculate the oxides concentration.