Heterogeneous thermal excitation and relaxation in supercooled liquids

Susan Weinstein, Ranko Richert

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

We investigate a phenomenological model which rationalizes the effects of dielectric hole burning on the basis of heterogeneous dielectric and specific heat relaxation in supercooled liquids. The quantitative agreement between model predictions and dielectric hole-burning observations is lost if the assumption of correlated dielectric and thermal relaxation times is removed from the model. This suggests that dynamically distinct domains in real liquids are associated with a time constant which characterizes both the structural and thermal relaxation behaviors. The calculations demonstrate that the observed burn-induced modifications reflect the spectral selectivity and persistence time of the fictive temperatures within these domains, and that 100 or more cycles of the sinusoidal burn field can be required to saturate the heat accumulated in the slow degrees of freedom. It is also shown that the recovery of dielectric holes is entirely accounted for by the model, and that the persistence times do not provide direct insight into rate exchange processes. Additionally, the model predicts that the heating effects considered here are a significant source of nonlinear dielectric behavior, even in the absence of deliberate frequency selective hole burning.

Original languageEnglish (US)
Article number224506
JournalJournal of Chemical Physics
Volume123
Issue number22
DOIs
StatePublished - 2005

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hole burning
Liquids
liquids
excitation
heat
Relaxation time
time constant
Specific heat
Hot Temperature
degrees of freedom
selectivity
relaxation time
recovery
specific heat
Heating
Recovery
cycles
heating
predictions
Temperature

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Heterogeneous thermal excitation and relaxation in supercooled liquids. / Weinstein, Susan; Richert, Ranko.

In: Journal of Chemical Physics, Vol. 123, No. 22, 224506, 2005.

Research output: Contribution to journalArticle

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