Asymptotic universality in the vibrational spectra of amorphous single-component systems

Abstract

We have numerically investigated the vibrational spectra of bulk single-component systems for which the potential energy depends only on the positions of the constituent units and is of the form of a sum over pairs. When the width of the potential well describing the two-body interaction is reduced progressively, our results suggest that the shape of the entire spectrum in the amorphous state approaches a limit that is independent of the explicit functional form of the potential. We use this observation of asymptotic universality to explain the quasiuniversal nature of vibrational spectra that has been observed in recent experimental studies of bulk molecular glasses [Chumakov et al., Phys. Rev. Lett. 92, 245508 (2004)].