Differences between L3 and L2 x-ray absorption spectra

Abstract

The L3 and L2 edges of transition metals show differences in their spectral shape. Also the ratio between the L3 and L2 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 L3 and L2 are seperated by a large core spin-orbit splitting of about 100 eV. Diferences between their L3 and L2 edge originate from the weight transfer between the t2g end e2g peaks due to the multipet effects. Because this weight transfer is larger for L3 edge, it is better to use the L2 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 L3 and L2 are completely different and show their characteristic multiplet structure. The multiplet efects are large enough to affect also the branching ratio.