X-ray resonant Raman scattering (RRS) spectra of Al, ${\mathrm{Al}}_2{\mathrm{O}}_3$, Si, and $\mathrm{Si}{\mathrm{O}}_2$ were measured at the European Synchrotron Radiation Facility, using a high-resolution Bragg-type curved crystal spectrometer. The x-ray RRS spectra were collected at several beam energies tuned below the $1s$ absorption thresholds of Al and Si. Differences in the spectral features between the elemental samples and the oxide ones were clearly observed. The data were interpreted using the second-order perturbation theory within the Kramers-Heisenberg (KH) approach. It is shown that, using the KH formalism, oscillator strengths that are similar to the ones deduced from x-ray absorption measurements can be extracted from emission x-ray RRS spectra. The total cross sections for the x-ray RRS process were derived for the different photon beam energies and compared with theoretical predictions. For elemental silicon, the weak $1s\text{−}3p$ excitation was observed and found to be consistent with results of density of states calculations.

• Received 13 November 2006

DOI:https://doi.org/10.1103/PhysRevA.75.022512