THE EFFECT OF 3D-ELECTRON EXCITATION ON EELFS AND EXAFS ABOVE M2,3 EDGE OF 3D-TRANSITION METALS

A new mechanism of the EELFS and EXAFS formation above M2,3 edges of 3d-transition metals is proposed. The adequacy of the calculational method developed is confirmed by the good agreement of the theoretical fine structure of the Ni M2,3 spectrum with the experimental one. It is shown that to achieve this agreement one should include the effect of the M4,5-shell ionization on the fine structure above the M2,3 edge. This method eliminates the high error 0.2-0.3 angstrom in the first shell distance determination obtained within traditional EXAFS analysis, resulting in the accuracy of about 0.02-0.03 angstrom.