Simulations on 500-particle model glasses suggest a crossover frequency above which, in addition to terms associated with sound propagation, there may be an added contribution to the vibrational density of states D(ω) due to a broad background in the transverse spectral density. Calculations on a 32 678-particle glass show that the value of the crossover frequency depends on the degree of disorder and that, if the disorder is strong enough, the magnitude of the enhancement in D(ω) is of the order required to explain the ‘‘excess $T^3$ term’’ in the low-temperature specific heat.

• Received 25 July 1986

DOI:https://doi.org/10.1103/PhysRevB.34.8667