Dynamics in the supercooled liquid : A schematic mode coupling model analysis

Groupe Matière Condensée et Matériaux, UMR CNRS 6626, Université Rennes I Campus de Beaulieu, 35042 Rennes cedex, France

Received: 24 March 1998
Accepted: 15 December 1998

Abstract

The temperature and wave number dependences of the dynamical structure factor obtained in a nonfragile glass-forming liquid by Brillouin scattering and coherent neutron scattering experiments are for the first time described by the solutions of a schematic mode coupling theory model over a wide frequency range. In intermediate regime, the crossover between vibrational excitations and fast relaxational processes observed above the susceptibility minimum in neutron spectra is well reproduced by the theoretical model. At lower Q-values, the temperature dependence of the Brillouin lineshape is also accurately described. Besides, the dynamical transition is shown to occur between 601 K and 637 K (, ) in this supercooled liquid.