LOW-FREQUENCY VIBRATIONS IN A MODEL GLASS

Previous simulation studies of localized low-frequency vibrational mod es in a soft sphere glass are extended to larger samples. We find a bo son peak in the spectral density and a maximum in the specific heat di vided by T-3 Similar to experiment. These maxima are caused by (quasi) localized vibrations. For finite frequencies these interact strongly w ith each other and with the extended phonons. This leads to an overdam ping of the phonons around the boson peak and to a delocalization of t he localized modes. A procedure to split the resulting modes into thei r bare constituents is presented. The bare localized modes are found t o have a low-dimensional structure. The description in terms of the so ft potential model is essentially verified.