Raman spectra are reported for Ba-doped fullerides Ba x C 60 (xϭ3, 4, and 6͒. The lowest-frequency H g modes split into five components for Ba 4 C 60 and Ba 6 C 60 even at room temperature, allowing us a quantitative analysis based on the electron-phonon coupling theory. For the superconducting Ba 4 C 60 , the density of states at the Fermi energy was derived as 7 eV Ϫ1 , while the total value of electron-phonon coupling was found to be 1.0, which is comparable to that of K 3 C 60 . The tangential A g (2) mode, which is known as a sensitive probe for the degree of charge transfer on C 60 molecules, shows a remarkable shift depending on the Ba concentration, being roughly consistent with the full charge transfer from Ba to C 60 . An effect of hybridization between Ba and C 60 orbitals is also discussed.

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