3D TRANSITION-METAL L-EDGE X-RAY-ABSORPTION STUDIES OF THE DICHALCOGENIDES OF FE, CO AND NI

The X-ray absorption spectra of the transition metal L(3,2)-edges of t he dichalcogenides FeS2 (pyrite), FeSe2, FeTe2, CoS2, CoSe2, CoTe2, Ni S2, NiSe2 and NiTe2 have been studied. These spectra are compared with theoretical simulations make using the atomic multiplet approach assu ming on octahedral site for the metal atoms. The Ni spectra can be clo sely simulated using this approach but the Fe and Co spectra show less good fits to the experimental data. The reasons for this and its impl ications for the use of L-edge spectra in the study of such minerals a re discussed in terms of the covalency and the ground states of the co mpounds; these results indicate the mixing of the ground states increa ses in the order Ni<Co<Fe.