Raman spectra of single-crystal CoSb3 and RhSb3 and of polycrystalline
IrSb3 have been studied. We have also studied four different polycrys
talline-filled skutterudite samples, Ir4LaGe3Sb9, Ir4NdGe3Sb9, Ir4SmGe
3Sb9, and Fe4CeSb12, where rare-earth ions occupy the voids in the sku
tterudite structure. These void-filling ions interact with some of the
lattice vibrations in this structure and produce a shift and broadeni
ng of the observed lines. The most prominent lines in all of the sampl
es are the Sb-4 ring-breathing modes. (C) 1996 American Institute of P
hysics.