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M: Metallphysik

M 19: Symposium Unterkühlte Metallschmelzen V : Hauptvortrag

M 19.1: Vortrag

Dienstag, 27. März 2001, 09:30–10:00, S8

Towards a Structural Paradigm for Liquids — •Frans Spaepen — Division of Engineering and Applied Sciences, Harvard University, Cambridge MA 02138 USA

Our thinking about the structure of liquids has been strongly influenced by our much better understanding of the simpler structures of crystals and gases. Nevertheless, liquids are phases in their own right: they are not disordered crystals, nor just very dense gases. The closest we have come to a unifying principle for the structure of liquids is the concept of polytetrahedrality. The history of this idea and the evidence for it will be reviewed. Insights obtained from diffraction experiments on undercooled liquids and glasses have played an important role in this development. The fundamental difference between the polytetrahedral structures and most crystalline structures gives rise to a distinct crystal-melt interface with a substantial interfacial tension. Examples of such interfaces will be discussed.