Collective nature of the boson peak and universal transboson dynamics of glasses

The model-independent measurements of the density of states (DOS) for collective motions were described. The glass dynamics of was studied using probe molecules to distinguish the collective motions from the local ones. The isotope-selective technique of nuclear inelastic scattering and probe molecules with a resonant nucleus in the center of mass were used to monitor the motions of the probes. The results evidence the predominantly collective character of the modes composing the boson peak.