Regensburg 2016 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 27: Poster: Soft Matter Dynamics / Glasses

CPP 27.1: Poster

Dienstag, 8. März 2016, 18:15–21:00, Poster B2

Fragile-to-strong transition in liquid silica — •Julian Geske, Barbara Drossel, and Michael Vogel — Institut für Festkörperphysik, Technische Universität Darmstadt

We investigate anomalies in liquid silica with molecular dynamics simulations and present evidence for a fragile-to-strong transition at around 3000K. To this purpose, we studied the structure and dynamical properties of silica over a wide temperature range, finding three indicators of the fragile-to-strong transition. First, there is a density minimum at around 3000K and a density maximum at 3400K. Second, the local structure characterized by the tetrahedral order parameter changes dramatically around 3000K and changes from a higher-ordered, lower-density phase to a less ordered, higher-density phase. Third, the correlation time τ changes from an Arrhenius behaviour below 3000K to a Vogel-Fulcher behaviour at higher temperatures.