Direct study of the f-electron configuration in lanthanide systems.

The valence shell electron configurations within a few electron volts above the Fermi level in cerium, ytterbium, europium and samarium compounds were probed by resonant X-ray emission spectroscopy (RXES) at the L3absorption pre-edge. The rare earth systems show distinct spectral signatures depending on the f-electron configuration. The high energy resolution experimental results reported here are well reproduced by atomic multiplet calculations confirming the localized character of the 4f electrons. The magnitude of the electron–electron interactions within the 4f shell and between 3d and 4f electrons is analyzed. The present technique is a powerful tool for the study of the 4f valence electron configuration that, unlike L3absorption spectroscopy at the main edge, is little influenced by valence electron relaxation following core hole creation. [ABSTRACT FROM AUTHOR]