On the Spectral Shape of the Structural Relaxation in Deeply Supercooled Liquids

Abstract

Structural relaxation in deeply supercooled liquids is non-exponential. In susceptibility representation, ${\chi }^{\prime \prime }(\nu )$, the spectral shape of the structural relaxation is observed as an asymmetrically broadened peak with a ${\nu }^1$ low- and ${\nu }^{-\beta }$ high-frequency behavior. In this perspective article we discuss common notions, recent results and open questions regarding the spectral shape of the structural relaxation. In particular, we focus on the observation that a high-frequency behavior of ${\nu }^{-1/2}$ appears to be a generic feature in a broad range of different deeply supercooled liquids. Moreover, we review extensive evidence that contributions from orientational cross-correlations can lead to deviations from the generic spectral shape in certain substances, in particular in dielectric loss spectra. Additionally, intramolecular dynamics can contribute significantly to the spectral shape in substances containing more complex and flexible molecules. Finally, we discuss the open questions regarding potential physical origins of the generic ${\nu }^{-1/2}$ behavior and the evolution of the spectral shape towards higher temperatures.

References in corpus (38)

• Supercooled Liquids for Pedestrians
• Direct observation of molecular cooperativity near the glass transition
• The Excess Wing in the Dielectric Loss of Glass-Formers: A Johari-Goldstein beta-Relaxation?
• Models and algorithms for the next generation of glass transition studies
• Nuclear magnetic resonance measurements reveal the origin of the Debye process in monohydroxy alcohols
• Time-temperature superposition in viscous liquids
• Susceptibility functions for slow relaxation processes in supercooled liquids and the search for universal relaxation patterns
• Short-chain polymer rigidity due to the Debye process of monohydroxy alcohols
• Prevalence of approximate square root t relaxation for the dielectric alpha process in viscous organic liquids
• Approximate square-root-time relaxation in glass-forming liquids
• Thirty milliseconds in the life of a supercooled liquid
• Microscopic origin of excess wings in relaxation spectra of supercooled liquids
• Universal Structural Relaxation in Supercooled Liquids
• On the Nature of the Debye-Process in Monohydroxy Alcohols: 5-Methyl-2-Hexanol Investigated by Depolarized Light Scattering and Dielectric Spectroscopy
• Dipole-dipole correlations and the Debye process in the dielectric response of non-associating glass forming liquids
• Exploring the Absorption Spectrum of Simulated Water from MHz to the Infrared
• Intermolecular Cross-Correlations in the Dielectric Response of Glycerol
• Solid-like mean-square displacement in glass-forming liquids
• Solid-that-flows picture of glass-forming liquids
• Self-induced heterogeneity in deeply supercooled liquids
• The Influence of Molecular Architecture on the Dynamics of H-Bonded Supramolecular Structures in Phenyl-Propanols
• Linear complex susceptibility of long range interacting dipoles acted on by thermal agitation and weak external ac fields
• Relaxation and vibrational properties in metal alloys and other disordered systems
• Solidity of viscous liquids. IV. Density fluctuations
• Time reversibility during the ageing of materials
• Cooperative intramolecular dynamics control the chain-length-dependent glass transition in polymers
• Ten themes of viscous liquid dynamics
• Molecular mechanism of the Debye relaxation in monohydroxy alcohols revealed from rheo-dielectric spectroscopy
• Creating bulk ultrastable glasses by random particle bonding
• Spectral shape simplicity of viscous materials
• Direct link between boson-peak modes and dielectric $\alpha$-relaxation in glasses
• Solidity of viscous liquids. III. Alpha relaxation
• The microscopic origins of stretched exponential relaxation in two model glass-forming liquids as probed by simulations in the isoconfigurational ensemble
• Insights into the Non-exponential Behaviour of the Dielectric Debye-like Relaxation in Monoalcohols
• The relation between stretched-exponential relaxation and the vibrational density of states in glassy disordered systems
• Glassy Dynamics from First-Principles Simulations
• Creating equilibrium glassy states via random particle bonding
• Non-simple flow behavior in a polar van der Waals liquid: structural relaxation under scope

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• Observing the Glass and Jamming Transitions of Dense Granular Material in Microgravity
• Chain-length-dependent correlated molecular motion in polymers
• Competing Supramolecular Structures: Dielectric and Rheological Spectroscopy on Glycerol/Propanol Mixtures
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