ELNES investigations of the oxygen K-edge in spinels

The results of a systematic study of the oxygen K-edge electron energy-loss spectroscopy (ELNES) from a series of aluminium- and chromium-containing s pinels are presented. Extra fine structure in the region up to 10eV above t he edge onset is observed for the chromium-containing compounds and is assi gned to transitions to states created by mixing of oxygen 2p and metal 3d o rbitals. The experimental data has been simulated using the multiple scatte ring code, FEFF8. Good agreement was obtained in the case of magnesium alum inate, but relatively poor agreement was obtained in the case of the chromi tes. The possible fingerprints in the oxygen K-edge ELNES corresponding to a high degree of inversion in the spinel structure and to a tetragonal dist ortion of the cubic structure are discussed. (C) 2001 Elsevier Science B.V. All rights reserved.