Inelastic light scattering and photoluminescence in the mixed valence compoundEu3S4

Abstract

In ${\mathrm{Eu}}_3$ ${\mathrm{S}}_4$, the inelastic light scattering exhibits an anomalous vibrational mode which can be associated to the dynamical frequency factor of hopping, ${\nu }_2=1.3\mathrm{}\times {10}^{13}$ ${\sec }^{-1\mathrm{}}$. With photoluminescence measurements, which have a relatively long time scale (lifetime) of about ${10}^{-6\mathrm{}}$ sec, it was possible to drive the temperature-dependent fluctuation rate through the reference time scale.