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O: Oberflächenphysik

O 19: Nanostrukturen II

O 19.1: Vortrag

Samstag, 5. März 2005, 10:45–11:00, TU EB420

First Principles Simulations of Ice Nucleation at Metal Surfaces — •Angelos Michaelides and Matthias Scheffler — Fritz-Haber-Institut, Faradayweg 4-6, D-14195, Berlin

Ice nucleation at solid surfaces is of relevance to countless scientific and technological processes. In particular the nucleation of ice nano-crystals on metal surfaces is often a key first step in cloud formation and corrosion [1]. Yet unfortunately this remains one of the most poorly understood natural phenomena; severely lacking in atomic level understanding. Here, we discuss detailed density functional theory studies aimed at putting our understanding of ice nucleation at metals on a much firmer footing. Specifically the properties of H₂O hexamers - the smallest ’building blocks’ of ice - adsorbed on a number of close-packed transition metal surfaces have been examined. We find that the competing influences of substrate reactivity and hexamer-substrate epitaxial mismatch conspire to yield a rich variety of (novel) hexameric ice structures, some of which have been observed by recent scanning tunnelling microscopy experiments [2].

[1] H.R. Pruppacher and J.D. Klett, Microphysics of Clouds and Precipitation, (Kluwer, Dordrecht, 2003)

[2] K. Morgenstern, et al., (To be published).