59 巻 (2017) 5 号 p. 238-245
We have applied inelastic X-ray scattering （IXS） technique to observing phonon spectra in rare-earth compounds. IXS technique has an advantage to inelastic neutron scattering to avoid seeing magnetic excitations, which are often observed in the low energy spectra of rare-earth compounds. In this review, we mentioned IXS results of filled skutterudite compounds. In a series of ROs4Sb12, we have discussed electron phonon coupling in low-lying optical modes, which is connected with heavy fermion behavior in these compounds. In an alloy system of Pr（Os1－xRux）4Sb12, we have discussed anharmonic potential at the rare-earth site which may be affect by nature of superconductivity and/or heavy fermion behavior.