Evidence of configuration interaction in resonant X-ray scattering from rare earths at the M-4,M-5-thresholds with final 4p excitation

We present the first data on the systematics of the resonant M-4,M-5-scattering (3d(9)4f(n+1) excitation; n ground state occupation) from rare earths with a final state 4p hole. We give evidence for the final state interaction of the 4f(n+1)4p(5) configuration with the configurations (4d(8)4f(n+2)) and (4d(8)4f(n+1)epsilon; epsilon means continuum). The interaction is stronger at the MS threshold. Data on La, Ce7Rh3, CeRh2 and Gd are given.