INELASTIC NEUTRON-SCATTERING INVESTIGATION OF CSC60 IN ITS POLYMER AND DIMER PHASES

We present an inelastic neutron scattering study of the low frequency vibrational dynamics of CsC60. In its polymeric phase, two main excita tions are observed at 0.65 and 1.15 THz. The Q-dependence of their str ucture factor allows to confirm their assignment to twisting modes. Fo r quenching-prepared samples, the modes shift at lower frequencies in agreement with the formation of dimers. We compare our results to prev ious Raman data and time of flight measurements of Renker et al. on Rb C60 and derive a general description of the vibrational dynamics of al kali-doped C-60 phases. (C) 1997 Elsevier Science Ltd.