Dresden 2006 – wissenschaftliches Programm

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O: Oberflächenphysik

O 29: Poster session II (Nanostructures, Magnetism, Particles and clusters, Scanning probe techniques, Time-resolved spectroscopy, Structure and dynamics, Semiconductor surfaces and interfaces, Oxides and insulators, Solid-liquid interfaces)

O 29.5: Poster

Mittwoch, 29. März 2006, 14:30–17:30, P2

Preparation of metal nanodroplets and solidification under zero-g conditions — •Anja Habenicht, Paul Leiderer, and Johannes Boneberg — Universität Konstanz, Fachbereich Physik, LS Leiderer, 78457 Konstanz

Flat metal nanostructures on inert substrates (e.g. glass) are illuminated by single intensive laser pulses with fluences above the melting threshold. The liquid structures produced in this way are far from their equilibrium shape and a dewetting process sets in. On a timescale of a few nanesconds the liquid contracts toward a sphere. During this contraction the center of mass moves upward, which can lead to detachment of droplets from the surface due to inertia. The velocity of the detaching nanodroplets is measured with a light barrier technique and compared with the velocity deduced from simple estimations for the dewetting process [1].

Further we show impact experiments where the droplets are landed on another substrate. The particles cool down during the flight due to thermal radiation. They solidify either during flight or when impacting on the substrate. By catching at different distances, the landing temperature and thus, if still liquid, the time on the substrate while liquid can be varied. Snapshots of different stages of droplet impact are shown.

[1] A. Habenicht, M. Olapinski, F. Burmeister, P. Leiderer, J. Boneberg. Science 309 (2005) 2043