Studying the long-wavelength dynamics in glass-forming liquids

We propose to study the long-wavelength dynamics in glass-forming liquids using small-angle XPCS at ID10. The dynamics in glass-forming liquids shows a rich behavior depending on the length scale being considered. In particular, the intermediate Q-range between the hydrodynamic limit (Q → 0) and the structure factor maximum (corresponding to interatomic distances) is largely unexplored and in need of experimental data for a better understanding. The successful operation of EBS should greatly facilitate XPCS measurements in this Q-range where scattering is weak. We propose to measure and compare several different metallic glass formers with various compositions, in order to disentangle the effects of concentration and density fluctuations on the dynamics of glass-forming liquids.