IMPORTANT ROLE OF INTERMOLECULAR VIBRATIONAL-MODES IN THE SUPERCONDUCTIVITY IN ALKALI-METAL-DOPED FULLERENES

Various experiments support a view that the superconductivity in alkal i-metal-doped fullerenes is a conventional one in the strong-coupling regime. From the simple Eliashberg analysis, we indicate that the stro ng-coupling of electrons with ''intermolecular'' modes is indispensabl e to explain both of their superconducting transition temperature and gap measured in tunneling experiments simultaneously. It is also specu lated that the relatively week coupling of electrons with low-lying '' intramolecular'' radial modes is possible to play an additional role t o this main coupling with ''intermolecular'' modes. The calculated NMR ratio (1/T1)s/(1/T1)n from our gap functions DELTA(omega, T) solved w ith these models, explains well the NMR result that no coherence peak has been observed in these materials.