Regensburg 2013 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: Glasses II (joint session DY/DF/CPP)

CPP 17.4: Talk

Tuesday, March 12, 2013, 10:15–10:30, H46

Modelling the relaxation of glass-forming systems at low temperatures: a potential energy approach — •Andreas Heuer and Christian Rehwald — Institute for Physical Chemistry, Corrensstr. 28/30, D-48149 Münster

Based on finite-size effects of a model glass-forming system we have introduced a model which allows one to express the dynamics of a macroscopic glass-former in terms of coupled subunits of temperature-independent size and temperature-dependent coupling constant [1]. The results are obtained from computer simulations on a binary mixture Lennard-Jones model, interpreted in terms of the underlying potential energy landscape. The model is denoted coupled landscape model (CLM).

After a short review of the CLM we present key predictions of this approach for temperatures far below the range accessible by computer simulations. In particular we present results for the violation of the Stokes-Einstein relation (connecting diffusivity and structural relaxation) and the validity of the time-temperature superposition. Finally, the CLM is compared with other models presently discussed for the explanation of the glass-transition phenomena.

[1] C. Rehwald, O. Rubner, A. Heuer, Phys. Rev. Lett. 105, 117801 (2010)

[2] C. Rehwald, A. Heuer, Phys. Rev. E 86, 051504 (2012)