Regensburg 2016 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 63: Interfaces and Thin Films II (joint session CPP/DY, organized by CPP)

CPP 63.8: Vortrag

Freitag, 11. März 2016, 11:30–11:45, H51

A spectroscopic investigation of surface melting of ice — •M.Alejandra Sanchez, Mischa Bonn, and Ellen H.G Backus — Max Planck Polymer Research Institute,Mainz,Germany

In nature, ice is, amongst others, responsible for rock weathering, soil metamorphosis, thunderstorms and the ozone chemistry on stratospheric clouds. It has been generally accepted that from the bulk freezing point down to roughly 240 K, a quasi-liquid-layer is present on ice. However, the nature of this layer has been intensely debated. We study the nature of the interfacial water on well-defined single crystal ice surfaces. The surface sensitive technique sum frequency generation spectroscopy provides the vibrational spectrum of specifically the interfacial molecules. We find a sudden change in the spectrum around 255 K which is assigned to the phase transition from ice/air to ice/quasi-liquid/air. The experimental results are well reproduced by simulations that allow to relate the observed spectral changes to information on the molecular scale.