Work

On the spectral shape of the structural relaxation in supercooled liquids

Year: 2025

Type: article

Abstract: Structural relaxation in supercooled liquids is non-exponential. In susceptibility representation, χ″(ν), the spectral shape of the structural relaxation is observed as an asymmetrically broadened peak with a ν1 low- and ν-β 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 ν-1/2 appears to be a generic feature in a broad range of 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. In addition, 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 ν-1/2 behavior and the evolution of the spectral shape toward higher temperatures.

Source: The Journal of Chemical Physics

DOI: 10.1063/5.0254534

Authors: Till Böhmer, Florian Pabst, Jan Philipp Gabriel, Rolf Zeißler, Thomas Blochowicz

Institutions: Roskilde University, Scuola Internazionale Superiore di Studi Avanzati, Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR), Technische Universität Darmstadt

Language: English

Topic: Material Dynamics and Properties

Subfield: Materials Chemistry

Field: Materials Science

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,500

Funders: Villum Fonden, Deutsche Forschungsgemeinschaft