INELASTIC NEUTRON-SCATTERING RESULTS ON PURE AND DOPED FULLERENES

Via inelastic neutron scattering (INS) generalized phonon densities of states are obtained for C60 and superconducting A3C60 (A = K, Rb). Ch anges in the intramolecular modes agree with and augment recent Raman (RA), infrared (IR), and INS measurements, i.e., in the vicinity of th e high-frequency modes of C60 [H(g)(8), A(g)(2), H(g)(7)] we find a pr onounced shift of about 10 meV toward smaller energy transfers upon in tercalating with potassium. Separated from these vibrations by a gap a re the intermolecular spectra which for the doped samples display well -defined optic modes at 11 and 14 meV due to the vibrations of Rb and K ions. Indications of a weak anomalous temperature dependence of low- energy phonons (homegaBAR < 3 meV) near T(c) are observed for K3C60.