Polarized light scattering investigation ofUBe13

The results of a Raman scattering study of single-crystal ${\mathrm{UBe}}_{13}$ are presented and discussed. These results are compared with spectra from the isostructural compounds M${\mathrm{Be}}_{13}$ (M=La, Ce, Th), within the temperature range 3≤T≤350 K. Ten phonons are observed in ${\mathrm{UBe}}_{13}$, displaying symmetries 2$A_{1g}$+4$E_g$+4$T_{2g}$, consistent with predictions using the space- and site-group symmetries previously determined for this compound [space group $O_h^6$ (Fm3c)]. In addition, electronic scattering is evident in our spectra, exhibiting the symmetry of the purely antisymmetric representation, $T_{1g}$. Evidence suggests that this scattering results from localized excitations of the 5f electrons. Various interpretations of this scattering are discussed.