Determination of Resonant Raman Scattering Cross-Sections on Pure Samples of Mn, Fe, Cu and Zn

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

Campinas, Brasil

Congreso; RAU 17; 2007

Laboratorio Nacional de Luz Sincrotron

X ray °uorescence spectra present singular characteristics produced by the dif-ferent scattering processes. When atoms are irradiated with incident energy lowerand close to an absorption edge, scattering peaks appear due to an inelastic processknown as resonant Raman scattering. It constitutes an important contribution tothe background of the °uorescent line. The Resonant Raman Scattering must betaken into account in the determination of low concentration contaminants, espe-cially when the elements have proximate atomic numbers. The values of the massattenuation coe±cients experimentally obtained when materials are analyzed withmonochromatic x ray beams under resonant conditions di®er from the theoreticalvalues (between 5% and 10%). This di®erence is due, in part, to the resonant Ramanscattering. Monochromatic synchrotron radiation was used to study the Raman ef-fect on pure samples of Mn, Fe, Cu and Zn. Energy scannings were carried outin di®erent ranges of energies near the absorption edge of the target element. Asthe Raman peak has a non-symmetric shape, theoretical models for the di®erentialcross section, convoluted with the instrument function, were used to determine theRRS cross section as a function of the incident energy.