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O: Fachverband Oberflächenphysik
O 100: Nanostructures at surfaces: Dots, particles, clusters II
O 100.4: Talk
Thursday, March 15, 2018, 16:00–16:15, MA 141
Probing water in confinement: a FT-RAIRS study of D2O nano clusters on a graphene-iridium moiré superstructure — •Robert Taube1, 2, Heshmat Noei1, Marcus Creutzburg1, 2, and Andreas Stierle1, 2 — 1DESY NanoLab, Deutsches Elektronensynchrotron (DESY), Hamburg, Germany — 2Institute of Nanostructure- and Solid State Physics, University of Hamburg, Germany
Confined water is highly interesting due to its unique properties regarding the molecular arrangement, electronic structure and the interaction with its neighboring environment. In this work, periodically arranged D2O nano droplets of about 1 nm size were generated on top of a graphene-iridium moiré superstructure and probed by a state-of-the-art Fourier transformation reflection absorption infrared spectrometer under UHV at 117 K. The infrared bands of the heavy water clusters differ significantly from those observed for amorphous solid or crystalline phases, showing a characteristic gap at 2500 cm-1 between two stretching bands. Furthermore, two features of dangling deuterium atoms originating from undercoordinated water molecules are present in the infrared spectrum. One of these features is located at noticeable lower wavenumbers than reported thus far, which is presumably the result of a rearrangement effect triggered by the coalescence of the droplets. The other feature originates from threefold coordinated water molecules at the surface of the water clusters and the film.