CALCULATIONS OF THE X-RAY-ABSORPTION EDGE FORM OF DISORDERED CARBON-CONTAINED COMPOUNDS

The theoretical forms of XANES of the carbon K-edge in transition meta l carbides and nitrocarbides as well as in some alkali-metal-doped int ercalated graphites have been investigated. The calculations have been carried out in terms of the multiple-scattering theory. The distincti ve feature of the local coherent potential method applied is the possi bility of accounting for the disordering of crystalline lattice proper ly. The systems investigated are nonstoichiometric, with substitution and displacement of atoms. To find the form of X-ray absorption spectr a the DOS of empty electron states and transition probabilities were c alculated. The comparison of the calculated XANES with experimental on es made it possible to explain the origin of the fine structure partic ularities.