We have examined the correlation between local hexagonal order and relaxation times and found little in the way of significant correlation. While these are just preliminary applications of this strategy, it is quite possible that dynamics reflects a complicated nonlocal dependence on structure. Given the extended chains of particle movements depicted in Figure1, it is quite likely that whether or not a particle undergoes a large displacement may be determined by the environment of a distant particle in the chain. This claim is based on the fact that, down to this temperature, our averaging involves times considerably longer than the structural relaxation time. The enthalpy fluctuations on which our calculation of C P is based can be resolved into fluctuations in potential energy, volume and the cross-correlation.
C P is dominated by volume fluctuations.
We find a similar step-like increase in the thermal expansion coefficient on heating. This raises the interesting possibility that the peak we observe is largely a feature of C P alone. Calculations of C V are currently in progress to resolve this point. The traditional landscape picture associates the increase in the heat capacity on heating to the appearance of fluctuations between different amorphous groundstates. We find that the correlation time for volume fluctuations is very short, roughly that of a single collision time.