Résumé
The phonon spectrum of a model glass is investigated by classical microcanonical molecular dynamics. The evolution of the shape of the longitudinal and transverse branches is determined as a function of the quenching rate and the aging time. Immediately after the quench, the minimum frequency for both branches, which is located at the pseudo-Bragg peak wave vector, is the lowest for the ideal quenching rate at which the glass is the most stable. When the glass evolves towards a crystalline phase, this minimum frequency increases and then saturates at higher values, as a result of anisotropy.