We present Raman spectroscopic studies of the isostructural and isoelectronic Eu6 xSrxC60 (x = 0, 3, 5, 6) and Ba6C60 compounds. The Raman spectra of the Eu-based fullerides show dramatic changes compared to the pure alkaline-earth systems, including significant broadening, splitting and frequency shifts of the fivefold degenerate Hg intramolecular modes of C60 Moreover, the Ag (2) mode exhibits an even larger downshift and a remarkable broadening. These findings are consistent with distortions of the C60 molecular cages and a considerable electron-phonon coupling strength-strongly enhanced in the Eu containing systems-originating from the strong orbital hybridization between the metal atom and the C60 molecule.
ASJC Scopus subject areas
- Materials Science(all)