EXTENDED FINE-STRUCTURES IN DIAMOND AND RELATED MATERIALS

Many work deal with diamond and related materials (c-BN and the hypoth etical C3N4 compound) thin films synthesis. It is necessary to charact erize the structure of such films at the atomic scale. The X ray absor ption (XAS) and electron energy loss (EELS) spectroscopies are well ad apted for such purposes, but they raise a difficult problem for theore tical codes due to large chemical bonding effects at low energies. Tak ing diamond as an example, we will show that FEFF6 is adequate for EXA FS calculations. Furthermore, FEFF6 can be used as a starting point of a new XANES code that includes an exact full multiple scattering calc ulation. The usefulness of this new code will be illustrated by compar ing theoretical XANES (diamond) and ELNES (c-BN) spectra. Results rela ted to the theoretically predicted C3N4 compound will be also briefly discussed.