A theory for the beta-relaxation process near the liquid-to-glass crossover

Fuchs, Matthias; Götze, Wolfgang; Hildebrand, S.; Latz, Arnulf

A theory for the beta-relaxation process near the liquid-to-glass crossover

Dateien

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Datum

1992

Autor:innen

Fuchs, Matthias

Götze, Wolfgang

Hildebrand, S.

Latz, Arnulf

Publikationstyp

Zeitschriftenartikel

unikn.publication.listelement.citation.prefix.version.undefined

Journal of Physics: Condensed Matter. 1992, 4, pp. 7709-7744. Available under: doi: 10.1088/0953-8984/4/38/007

Zusammenfassung

The mode coupling theory for supercooled liquid dynamics finds a beta-relaxation regime on mesoscopic timeseales. It is caused by the interplay between nonlinear interadions of density fluctuations and phonon-assisted hopping transport. In this regime all correlation functions and spectra can be expressed in terms of a single ß-correlator G, which is a homogeneous function of lime and two relevant control parameters. It is specified by a single number, namely the exponent parameter. Eight regions can be identified, where the equation for G can be solved by series expansions. The various possibilities are discussed in comparison with representative numerical solutions. For temperatures T sufficiently above the critical value Tc hopping effects can be neglected and a stretched susceptibility minimum is found as a crossover from von Sehweidler decay to critical decay. For T near Tc hopping effects balance the cage effect and this results on logarithmic scales in a rather abrupt crossover from the high-frequency delta-peak tail to the critical spectrum. For T telow Tc there appears a frequency window between two knees in the susceptibility spectrum, where hopping effects suppress the enhanced fractal spectra. There occurs a crossover from Debye relaxation to white noise. The resulting susceptibility minimum in the strongly supercooled state exhibits a subtle power law dependence on the separation parameter T - Tc. The measurable features in the susceptibilily, such as position and strength of the minimum, are evaluated and shown to characterize transparently the liquid-to-glass crossover as caused by the underlying glass transition singularity.

Fachgebiet (DDC)

530 Physik

Zitieren

ISO 690

FUCHS, Matthias, Wolfgang GÖTZE, S. HILDEBRAND, Arnulf LATZ, 1992. A theory for the beta-relaxation process near the liquid-to-glass crossover. In: Journal of Physics: Condensed Matter. 1992, 4, pp. 7709-7744. Available under: doi: 10.1088/0953-8984/4/38/007

BibTex

@article{Fuchs1992theor-5178,
  year={1992},
  doi={10.1088/0953-8984/4/38/007},
  title={A theory for the beta-relaxation process near the liquid-to-glass crossover},
  volume={4},
  journal={Journal of Physics: Condensed Matter},
  pages={7709--7744},
  author={Fuchs, Matthias and Götze, Wolfgang and Hildebrand, S. and Latz, Arnulf}
}

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