Investigation of the pre-edge inelastic X-ray scattering by several 3d transition-metal compounds

Spectra of X-rays scattered by compounds of 3d transition elements exhibit structure when the energies of the incident X-rays are a few electronvolts below the elements' K-absorption edge energies. This structure is the result of an inelastic scattering process and has been studied in compounds of chromium, iron and copper with a high-energy resolution wavelength-dispersive spectrometer. When the energies of the incident X-rays were tuned between the pre edge peak and the absorption edge, the energy of the resonantly scattered Xrays were always measured to be equal to the energy of the characteristic K alpha X-rays. This observation is in disagreement with the prediction of the present theoretical models for resonant scattering which were derived assuming the interactions to be fast collisions.