title: Experimental and theoretical evidence for bilayer-by-bilayer surface melting of crystalline ice.
abstract: On the surface of water ice, a quasi-liquid layer (QLL) has been extensively reported at temperatures below its bulk melting point at 273 K. Approaching the bulk melting temperature from below, the thickness of the QLL is known to increase. To elucidate the precise temperature variation of the QLL, and its nature, we investigate the surface melting of hexagonal ice by combining noncontact, surface-specific vibrational sum frequency generation (SFG) spectroscopy and spectra calculated from molecular dynamics simulations. Using SFG, we probe the outermost water layers of distinct single crystalline ice faces at different temperatures. For the basal face, a stepwise, sudden weakening of the hydrogen-bonded structure of the outermost water layers occurs at 257 K. The spectral calculations from the molecular dynamics simulations reproduce the experimental findings; this allows us to interpret our experimental findings in terms of a stepwise change from one to two molten bilayers at the transition temperature.
authors.affiliation: Max Planck Institute for Polymer Research, 55128 Mainz, Germany.
authors.forename: M Alejandra
authors.initials: MA
authors.lastname: Sánchez
authors.affiliation: Max Planck Institute for Polymer Research, 55128 Mainz, Germany.
authors.forename: Tanja
authors.initials: T
authors.lastname: Kling
authors.affiliation: Graduate School of Science and Engineering, University of Toyama, Toyama 930-8555, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Ishiyama
authors.affiliation: Max Planck Institute for Polymer Research, 55128 Mainz, Germany.
authors.forename: Marc-Jan
authors.initials: MJ
authors.lastname: van Zadel
authors.affiliation: Laboratory for Water and Surface Studies, Department of Chemistry, Pearson Laboratory, Tufts University, Medford, MA 02155.
authors.forename: Patrick J
authors.identifier: 0000-0002-4985-3077
authors.initials: PJ
authors.lastname: Bisson
authors.affiliation: Max Planck Institute for Polymer Research, 55128 Mainz, Germany.|Institute of Physics, Johannes Gutenberg University Mainz, 55128 Mainz, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Mezger
authors.affiliation: Max Planck Institute for Polymer Research, 55128 Mainz, Germany.|BASF SE, 67117 Limburgerhof, Germany.
authors.forename: Mara N
authors.initials: MN
authors.lastname: Jochum
authors.affiliation: Max Planck Institute for Polymer Research, 55128 Mainz, Germany.
authors.forename: Jenée D
authors.initials: JD
authors.lastname: Cyran
authors.affiliation: FOM Institute AMOLF, 1098 XG Amsterdam, The Netherlands.
authors.forename: Wilbert J
authors.initials: WJ
authors.lastname: Smit
authors.affiliation: FOM Institute AMOLF, 1098 XG Amsterdam, The Netherlands.
authors.forename: Huib J
authors.initials: HJ
authors.lastname: Bakker
authors.affiliation: Laboratory for Water and Surface Studies, Department of Chemistry, Pearson Laboratory, Tufts University, Medford, MA 02155.
authors.forename: Mary Jane
authors.initials: MJ
authors.lastname: Shultz
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan.|Elements Strategy Initiative for Catalysts and Batteries, Kyoto University, Kyoto 615-8520, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Morita
authors.affiliation: Max Planck Institute for Polymer Research, 55128 Mainz, Germany.|Department of Chemistry, University of California, Davis, CA 95616.
authors.forename: Davide
authors.initials: D
authors.lastname: Donadio
authors.affiliation: Max Planck Institute for Polymer Research, 55128 Mainz, Germany.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Nagata
authors.affiliation: Max Planck Institute for Polymer Research, 55128 Mainz, Germany; backus@mpip-mainz.mpg.de bonn@mpip-mainz.mpg.de.
authors.forename: Mischa
authors.initials: M
authors.lastname: Bonn
authors.affiliation: Max Planck Institute for Polymer Research, 55128 Mainz, Germany; backus@mpip-mainz.mpg.de bonn@mpip-mainz.mpg.de.
authors.forename: Ellen H G
authors.initials: EH
authors.lastname: Backus
keywords: crystalline ice; stepwise; sum frequency generation; surface melting; water