ANOMALOUS DYNAMICAL EFFECTS IN CALCITE CACO3

We present the results of an inelastic neutron scattering study of cal cite. A continuum of excitations is observed, coupled with a soft phon on mode. Similar excitation spectra have been found in a number of oth er materials, due to electronic effects. However, calcite is an insula tor, and we suggest that our results can instead be explained by a rat her unexpected solution of the conventional picture that arises from c oupling between phonon and relaxation modes.