J. Phys. IV France 7 (1997) C2-131-C2-135
MXD - Model Calculations and a Fully Relativistic Theory for Magnetic EXAFSH. Ebert1, V. Popescu1 and D. Ahlers2
1 Institute for Physical Chemistry, University of Munich, Theresienstr. 37, D-80333 Munchen, Germany
2 Universität Augsburg, Lehrstuhl für Experimentalphysik II, Memmingerstr. 6, 86135 Augsburg, German
New theoretical developments based on a fully relativistic description of magnetic dichroism (MXD) in X-ray absorption spectroscopy are presented. It is demonstrated that it is possible to achieve within this sophisticated framework an unambiguous identification of the role of exchange splitting and spin-orbit coupling for the MXD by means of model calculations. A description of this approach that consists in the separate manipulation of both sources of the MXD is presented together with several applications to K-and L2,3-edge-spectra of transition metals. All fully relativistic calculations on the MXD have been done so far in the XANES region using the standard relativistic (κ, µ)-representation. In dealing with magnetic EXAFS (MEXAFS) it seems to be more advantageous to treat the multiple scattering for the final states in real-space adopting the (l, ml, ms)-representation. A corresponding generalization for the matrix inversion as well as the expansion techniques will be presented.
© EDP Sciences 1997