Three-body signature of the bcc structure in extended energy-loss spectra of Cr metal

The local structure of chromium was studied by extended energy-loss fine-structure (EXELFS) measurements in the transmission mode beyond the L2,3 edges of Cr using a transmission-electron microscope. The data analysis was performed by a comparison with theoretical calculations including several two-body and three-body contributions obtained by means of a continued-fraction expansion. Striking evidence for the presence of a three-body signal associated with the 70.529^∘{} angle in the bcc structure was found. The intensity of this signal is about 30% of that of the first neighbor shell at k=5 A^-1 and can be easily seen in typical EXELFS spectra. This research opens the way to a refined structural analysis of the L edges of transition metals obtained by means of electron spectroscopies that can have useful applications.