Direct observation of intra-ionic and interconfigurational excitations in an intermediate valence compound by Raman Spectroscopy.

Intra-ionic spin-orbit split multiplet levels have been observed by electronic Raman scattering in the intermediate valence compound EuPd2Si2. From the temperature dependence of the Raman peak positions and widths the interconfigurational excitation energy E(x) and the interconfigurational mixing width T(f) of the multiplet levels have been obtained, respectively. This is the first spectroscopic support for the underlying assumptions of the ionic interconfigurational fluctuation model that has been proposed to describe intermediate valence.