Site-Specific Valence Determination by Electron Energy-Loss Spectroscopy

Abstract

The valence of an atom occupying a particular crystal lattice site can be determined from the chemical shift in a transmission electron energy-loss spectrum obtained with the intensity of the incident electron wave maximized at that site by dynamical electron diffraction. The new technique is demonstrated by determining the location of ${\mathrm{Fe}}^{2+}$ and ${\mathrm{Fe}}^{3+}$ ions in a mixed-valence spinel.