Experimental determination of resonant Raman scattering cross sections for several elements and compounds

HÉCTOR JORGE SÁNCHEZ; MARÍA CECILIA VALENTINUZZI; CARLOS PÉREZ; JOSÉ ABRAHAM

Arica, Chile

Congreso; Seminario Latinoamericano de Análisis por Técnicas de Rayos X SAXR 2006; 2006

The X ray resonant Raman effect takes place when atoms are irradiated with an incident energy lower and close to an absorption edge. This inelastic process can produce an important contribution to the background of the fluorescent line. The resonant Raman effect must be taken into account when samples of pure elements or constituted by elements with proximate atomic numberare analyzed because this effect affects the determination of low concentration contaminants.The values of mass attenuation coefficients experimentally obtained when materials are analyzed with monochromatic x ray beams under resonant conditions differ from the theoretical values, being the resonant Raman scattering in part responsible for this difference. Monochromatic synchrotron radiation was used to study the Raman effect on pure samples and compounds. Energy scannings were carried out in different ranges of energies near the absorption edge of the target element. Theoretical models for the energy distribution of the Raman scattered photons, convoluted with the instrument function, were used to determine the resonant Raman scattering cross sections as a function of the incident energy. It is observed that the RRS cross sections for pure samples are quite similar than those for compounds, indicating that the Raman scattering takes place in the same way in both kinds of samples.