Exafs like oscillations in X-ray excited autoionization spectra assisted by compton process

Abstract

Oscillating features have been observed in the background of the inelastic electrons excited by high energy monochromatic X-ray photons at kinetic energy above the Cr M 2,3 VV Auger transition. These structures are absent when X-ray photons of h ̵ ω ⩽ 1.5 keV are used. We suggest that these extended features are due to an autoionization process experienced by the 3 p core electron assisted by a Compton scattering with the X-ray photons. Through the inelastic Compton process the incoming photons excite the core electrons towards empty states above the Fermi level in a continuous manner up to a maximum energy, which strongly depends on the incident photon energy. These excited states are modulated in energy by the crystalline structure as it has been shown by means of the EXAFS (Extended X-ray Absorption Fine Structure) spectroscopy. These oscillating structures are compared with those obtained through electron excitation for the same Auger transition in the Extended Fine Auger Structure (EXFAS) spectroscopy.