QUASI-ELASTIC LIGHT AND NEUTRON-SCATTERING SPECTRA IN POLYBUTADIENE -RELATION TO THE BOSON PEAK VIBRATIONS

The existence of some intrinsic relation between the broad quasielasti c-scattering spectra and the boson peak is shown by an analysis of the recent neutron-and Raman-scattering data. This relation is explained in the framework of a model which ascribes the quasielastic contributi on to the scattering of light or neutrons by the vibrations around the boson peak, The latter are damped by some relaxation channel and have a quasielastic part in their response function (similar to the Mounta in mode in Brillouin scattering), It is shown that the model describes consistently neutron-, Raman-, and Brillouin-scattering data for poly butadiene.