LATTICE-DYNAMICS OF RBC60, RBC70 AND PHASE-TRANSITIONS IN A(1)C(60) -A NEUTRON-SCATTERING STUDY

Compounds of A(1)C(60) (A = Rb, Cs, K) and RbC70 have been investigate d by neutron scattering. The studies include measurements in the high temperature rotator-, the polymer-, the dimer- and the low temperature isolator-phase and include investigations of the particular phase tra nsitions. It is found that each of the phases can be characterized by specific features of its lattice dynamics which can be used for detail ed studies of the dynamics of the rotator-polymer and the dimer-polyme r transitions. Particular insight in the lattice dynamics is obtained from model calculations for the RbC60 polymer and dimer phase.