Differences betweenL3andL2xhyphen;ray absorption spectra of transition metal compounds

摘要

The differences betweenL3andL2edges of 3dand 4dtransition metal complexes and compounds in octahedral symmetry are discussed. The main origin of these differences are the multiplet effects due to the coupling of the 2pcore wave function and the 3dand 4dvalence wave functions. The 3dand 4dspinndash;orbit coupling is a second origin of difference. For 3dsystems the multiplet effects dominate all other interactions and theL3andL2edge are completely mixed and reordered. For 4dsystems the core hole spinndash;orbit coupling is large and theL3andL2are separated by about 100 eV with a ratio close to 2:1. The differences between theL3andL2edge originate from the weight transfer between thet2gandegpeaks due to the multiplet effect. This weight transfer is about 25percnt; for theL3edge and about 5percnt; for theL2edge, which implies that for a comparison to singlehyphen;particle calculations theL2edge is preferable to use. Partly filled 4dsystems are lowhyphen;spin and the occupation of thet2gstates implies a decrease of the first peak. This decrease is stronger for theL2edge, implying an increase in theL3:L2ratio. For 4d5systems transitions to thet2ghole are only possible at theL3edge due to the combined effects of 4dspinndash;orbit coupling and theddmultiplet effects.