Direct observation of intraionic and interconfigurational excitations in an intermediate-valence compound by Raman spectroscopy

Abstract

Intraionic 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 an upper limit of the interconfigurational mixing width T_f, respectively, have been obtained. This is the first spectroscopic support for the underlying assumptions of the ionic interconfigurational fluctuation model that has been proposed to describe intermediate valence.