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Back to Colloquia
Physics Colloquium Friday, April 28st, 2006,
4:00 P.M.
E300 Math/Science
Center; Refreshments at 3:30 P.M. in
Room E200
University of Massachusetts, Amherst
Squeezing some new facts out of glasses
Molecules in a glass are relatively immobile even though they are arranged in much
the same way as in a freely-flowing liquid. There are two broad classes of
explanations for this state of dynamical arrest: one set of ideas explains it in
terms of the density of these systems. When a liquid contracts on cooling,
molecules that were already hindered in their motion by the dense packing in a
liquid now find no room at all to rearrange themselves. Another explanation is that
lowered temperature renders molecules too inactive to explore an increasingly
mountainous free energy landscape. I will discuss experiments in which we separate
unambiguously the effects of volume restrictions and lowered temperature in a
common glass-forming system.
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