Dipole-dipole correlations and the Debye process in the dielectric response of non-associating glass forming liquids

Abstract

The non-exponential shape of the $\alpha$-process observed in supercooled liquids is considered as one of the hallmarks of glassy dynamics and has thus been under study for decades, but is still poorly understood. For a polar van der Waals liquid, we show here - in line with a recent theory - that dipole-dipole correlations give rise to an additional process in the dielectric spectrum slightly slower than the $\alpha$-relaxation, which renders the resulting combined peak narrower than observed by other experimental techniques. This is reminiscent of the Debye process found in monohydroxy alcohols. The additional peak can be suppressed by weakening the dipole-dipole interaction via dilution with a nonpolar solvent.

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Cited by in corpus (9)

• Universal Structural Relaxation in Supercooled Liquids
• Molecular mechanism of the Debye relaxation in monohydroxy alcohols revealed from rheo-dielectric spectroscopy
• The computational evidence for the crucial role of the dipole cross-correlations in the polar glass-forming liquids
• On the Spectral Shape of the Structural Relaxation in Deeply Supercooled Liquids
• Non-simple flow behavior in a polar van der Waals liquid: structural relaxation under scope
• Observing the Glass and Jamming Transitions of Dense Granular Material in Microgravity
• Non-exponential relaxation without dynamic heterogeneity in van der Waals liquids above the melting point
• A Fresh Perspective on Water Dynamics in Aqueous Salt Solutions
• Competing Supramolecular Structures: Dielectric and Rheological Spectroscopy on Glycerol/Propanol Mixtures