INTERSTITIAL RESONANCE MODES AS A SOURCE OF THE BOSON PEAK IN GLASSESAND LIQUIDS

Although it is recognized that the boson peak is a universal and funda mental feature of glass and liquid dynamics arising from low-frequency vibrational modes which are absent in crystals, the source of these m odes is still under investigation. The effects are detected as a ''bum p'' in low temperature specific heat measurements, an excess vibration al density of states in inelastic neutron scattering and the ''boson'' peak in Raman scattering. It is shown that the magnitude, location, a nd softening of the Boson peak as it persists into the supercooled liq uid state are well accounted for by the interstitialcy model of conden sed matter states as the resonance modes of self-interstitials.