Berlin 2015 – scientific programme

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O: Fachverband Oberflächenphysik

O 10: Metal/Water Interfaces: Structure and Reactivity

O 10.4: Talk

Monday, March 16, 2015, 15:45–16:00, HE 101

Free energy assessment of water structures and their dissociation on Ru(0001) — •Guillem Revilla-López, Piotr Bloński, and Núria López — Institute of Chemical Research of Catalonia, ICIQ, Av. Països Catalans 16, 43007 Tarragona, Spain

The structure and dissociation degree of the first water and heavy water adlayers on hexagonal close-packed metals is a keystone in disciplines such as catalysis, and surface science. Ru(0001) is considered as a model for such interactions since hexagonal Ice patterning and variable water dissociation are present on it. We have assessed the free energy landscape of the adsorption of different water motifs experimentally reported on Ru(0001). Our work provides computational results rationalizing the driving forces of Ice-like bilayer formation on Ru(0001) by describing thermodynamically feasible pathways. The key role of both electrostatics as a driving force and the recently discovered Chains-4a motif as a key intermediate structure have been revealed in the formation of molecular and dissociative Ice-like bilayers and other complex patterns. Thus, new routes for bilayer formation are proposed based on non-cluster structures like Rosette and Island. Further on, the isotopic and temperature dependent balance of dissociation degrees for the Ice-like bilayer and their troubled experimental determination are rationalized by configurational entropy contributions.