Molecular dynamics on a realistic model for a strong glass

Thermal motions in a microscopic model for a strong glass (B₂{O}₃$) are studied by means of computer molecular dynamics simulations. A decomposition of the atomic dynamics in terms of normal modes allows the separation of the truly harmonic components of the generalized frequency distributions. This enables us to discuss a number of magnitudes relevant to current issues on glassy dynamics on quantitative grounds. In particular, the microscopic origin of quantities such as the atomic mean-square displacements, the characterization of mode eigenvectors associated with well-defined spectral features, or the origin of the low-frequency peak appearing in the S(Q,{ω}) dynamic structure factor, are analyzed in some detail. {} 1996 The American Physical Society.