X-ray absorption and resonant inelastic x-ray scattering in the rare earths

This paper makes a comparison between x-ray absorption (XAS) and resonant inelastic x-ray scattering (RIXS) in the rare earths. Atomic calculations are given for 2p→4f. The radiative decay of the XAS final states is described for the situations where the core hole created in the absorption process is filled by a valence electron or by an electron from a shallower core level. RIXS spectra 4fⁿ→3d¯4fⁿ⁺¹→4fⁿ integrated over the outgoing photon energy (fluorescence yield) are compared with 3d→4f XAS. Sum rules related to XAS and RIXS and their applicability are discussed.