Soft X-ray scattering dominates emission near the giant resonance of the rare earth compounds

Inelastic scattering of 4d electrons near the 4d-4f thresholds of Gd2O2S and Tm2O3 is studied with monochromatic synchrotron radiation excitation. The emission is dominated by inelastic scattering. We observe two energy loss mechanisms, which are 4f inner-shell excitations (4d104fn→4d94fn+1→4d104fn) and 5p-4f excitations (4d105p64fn→4d95p64fn+1 →4d105p54fn+1). Our atomic calculations are in excellent agreement with the experimental emission spectra indicating strong localization and a low degree of correlation of the 4f electrons. Inelastic scattering can be used to elucidate the relative partial cross sections for the contributing transitions