The scaling of slow structural relaxation with fast caged dynamics is seen in the molten salt Ca(0.4)K(0.6)(NO(3))(1.4) (CKN) over about 13 decades of the structural relaxation time. Glycerol scaling has been analysed in detail. In glycerol, the short-time mean-square displacement < u(2)>, a measure of the caged dynamics, is contributed by the free volume. It is seen that, in order to see the scaling, the observation time of the fast dynamics must be shorter than the time-scales of the relaxation processes. Systems with both negligible (like CKN, glycerol and network glassformers) and high (like van der Waals liquids and polymers) pressure-energy correlations exhibit scaling between the slow relaxation and the fast caged dynamics. According to the available experiments, an isomorph-invariant expression of the master curve of the scaled data is indistinguishable from a simpler non-invariant expression. Instead, the latter agrees better with the simulations on a wide class of model polymers.
|Autori:||Ottochian A; Leporini D|
|Titolo:||Scaling between structural relaxation and caged dynamics in Ca(0.4)K(0.6)(NO(3))(1.4) and glycerol: free volume, time-scales and implications for pressure-energy correlations|
|Anno del prodotto:||2011|
|Digital Object Identifier (DOI):||10.1080/14786435.2010.521530|
|Appare nelle tipologie:||1.1 Articolo in rivista|