8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Wed 711:10-14:00P5.169Dynamical signature at the freezing transitionWilliam van Megen, 1 Vincent Martinez, 2 Emanuela Zaccarelli, 3 Chantal Valeriani, 4Eduardo Sanz, 2 and Gary Bryant 11 Royal Melbourne Institute of Technology, Swanston street, 3000, Melbourne, VIC,Australia2 University of Edinburgh, Edinburgh, United Kingdom3 Universita La Sapienza, Rome, Italy4 University of Edinburgh, edinburgh, United KingdomThe current-current correlation function (CCCF), obtained by dynamic light scattering for asuspension of colloidal hard spheres and molecular dynamics for a fluid of ballistic hard spheres,is examined for wavectors spanning the main peak of the static structure factor and volumefractions around the freezing value. A certain scaling of the final decay of the CCCF [1], foundin both cases, points to the adequacy of the approximation that allows the slowest numberdensity fluctuations to be considered from a configuration space perspective only. This appliesonly for the respective fluids in thermodynamic equilibrium. In the metastable cases a peak inthe time derivative of the CCCF suggests the emergence of a structural memory not present inthermodynamically stable fluids. These studies provide the spatial resolution of the dynamicalsignatures of freezing inferred previously from the velocity autocorrelation function for bothsystems of hard spheres [2].[1] W. van Megen, V. A. Martinez and G. Bryant, ”Scaling of the current time correlationfunction of a suspension of hard sphere-like particles: exposing when the motion of particles isBrownian. ” Phys. Rev. Lett. 103, 258302 (2009).[2] W. van Megen, ”A dynamical perspective of the freezing transition of a suspension of hardspheres from the velocity auto-correlation function. ”, Phys. Rev. E 73, 020503(R), (2006). S.R. Williams et al. , ”Velocity Autocorrelation Function of Hard-Sphere Fluids: Long-Time Tailsupon Undercooling. ” Phys. Rev. Lett. 96, 087801 (2006).169