28 August 2022 to 2 September 2022
Science and Technology Campus, University of Parma
Europe/Rome timezone
Submission deadline for Conference Proceedings extended until 3 October

Microscopic Dynamics of Structural Glasses Investigated by Quasielastic Neutron Scattering

2 Sep 2022, 09:00
40m
Science and Technology Campus, University of Parma

Science and Technology Campus, University of Parma

University of Parma, Italy
Oral Molecular chemistry and chemical physics Invited Talks

Speaker

Dr Reiner Zorn (Forschungszentrum Juelich)

Description

In this presentation I will give a short introduction into quasielastic neutron scattering (QENS) and its application to glass-forming systems. QENS operates on time scales from picoseconds to a microsecond and at the same time has a spatial resolution in the Ångström range. Therefore, it is well suited for the study of molecular and polymeric glass-formers.

The dynamics of glass-formers is still poorly understood, but certain universal features can be found which a theory has to explain. Foremost, there is the α relaxation, which governs what is usually called ‘glass transition’. Its temperature-dependence is highly non-Arrhenius and the shape of correlation functions non-exponential. In addition, faster relaxations may be present, among which the universal ‘fast β relaxation’ in the picosecond range is strongly related to the α relaxation in mode-coupling theory. As the fastest universal process, glasses show an excess of the vibrational density of states above the Debye model in the low frequency range, the so-called ‘boson peak’.

All these phenomena can be observed by QENS with the additional information of a length scale. In addition, it is possible to study them in confined glass-formers in order to access their system-size-dependence. Selected QENS experiments will be presented and discussed.

Primary author

Dr Reiner Zorn (Forschungszentrum Juelich)

Presentation Materials

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