S K- and L-edge XANES and electronic structure of some copper sulfide minerals

Abstract

The S K and L-edge x-ray absorption near-edge structures (XANES) of low bornite, cubanite, chalcocite, covellite, enargite and tetrahedrite have been measured with synchrotron radiation. The near-edge features are interpreted based on comparison with the S K- and L-edge spectra of chalcopyrite and a MO/energy band structure model. The XANES spectra of these sulfides reflect the DOS of unoccupied S s-, p- and d-like states near and above the Fermi level. In tetrahedral Cu-Fe sulfides, the Fe3+ 3d crystal field band has much more significant DOS of unoccupied S 3p-and 3s-like states than the Cu+ 3d crystal field band. For Cu sulfides, the Cu+ 3d crystal field band has the higher DOS of S 3p- and 3 s-like states in tetrahedral structure than in structures with the triangular CuS3 cluster. The shifts in both S K- and L-edges correlate approximately linearly with the energy gap. © 1994, Springer-Verlag. All rights reserved.