X-RAY-ABSORPTION NEAR-EDGE SPECTRA OF TRANSITION-METAL DISULFIDES FES2 (PYRITE AND MARCASITE), COS2, NIS(2) AND CUS2, AND THEIR ISOMORPHS FEASS AND COASS

Metal K- and L(3)-, sulfur K- and arsenic K- and L(3)-edge X-ray absor ption near-edge spectra of a series of metal disulfides, FeS2 (both py rite and marcasite), CoS2, NiS2, and CuS2 and their isomorphs, FeAsS a nd CoAsS, are presented. The features in this region of these spectra are interpreted using band structure and molecular orbital calculation s in terms of the transitions from the Is or 2p(3/2) state to unoccupi ed states. The 3d transition metal L(3)-edge spectra of these material s show dependence on the degree of multiplet splitting in the final st ate, and thus offer less information on the electronic ground state. T here are substantial differences in the spectra of the isostructural m aterials, whereas the spectra of the isotopes pyrite and marcasite sho w several similarities, illustrating the dependence of near-edge regio n on electronic structure.