DIFFERENCES BETWEEN L(3) AND L(2) X-RAY-ABSORPTION SPECTRA

The L(3) and L(2) edges of transition metals show differences in their spectral shape. Also the ratio between the L(3) and L(2) edges is found to deviate from 2:1. The interactions responsible for these effects are: the multiplet effects and the 3d (4d) spin-orbit coupling. The electronic interactions and spin- and orbital polarizations of the valence electrons determine the ground state (symmetry) and determine the shape itself. For 4d systems the L(3) and L(2) are separated by a large core spin-orbit splitting of about 100 eV. Differences between their L(3) and L(2) edge originate from the weight transfer between the t(2g) and e(g) peaks due to the multiplet effects. Because this weight transfer is larger for L(3) edge, it is better to use the t(2g) edge for a comparison to single particle calculations. The only interaction which can affect their branching ratio is the 4d spin-orbit coupling. For 3d systems the multiplet effects dominate all other interactions and the L(3) and L(2) are completely different and show their characteristic multiplet structure. The multiplet effects are large enough to affect also the branching ratio.