Structure of ice multilayers on metals

Witek, Henryk A.; Buch, V.

doi:10.1063/1.477912

Cited by 45 publications

(36 citation statements)

References 31 publications

(29 reference statements)

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“…MD simulations of two, three, and four layer films grown on either a flattened or a puckered first layer also predict that the structures minimize the number of dangling OH bonds protruding into the vacuum. 66 Therefore, we might expect that water monomers in layer n + 1 on top of a water island ͑layer n͒ should be relatively weakly bound compared to molecules in the islands, and should preferentially diffuse off, and incorporate into, islands in layer n, at least for n =1-3. The results for ASW films grown above ϳ100 K and below ϳ130 K, where the islands are expected to be larger than those formed by at lower growth temperatures, are at least consistent with this picture.…”

Section: Discussionmentioning

confidence: 99%

Layer-by-layer growth of thin amorphous solid water films on Pt(111) and Pd(111)

Kimmel

Petrik

Dohnálek

et al. 2006

The Journal of Chemical Physics

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The growth of amorphous solid water (ASW) films on Pt(111) is investigated using rare gas (e.g., Kr) physisorption. Temperature programmed desorption of Kr is sensitive to the structure of thin water films and can be used to assess the growth modes of these films. At all temperatures that are experimentally accessible (20-155 K), the first layer of water wets Pt(111). Over a wide temperature range (20-120 K), ASW films wet the substrate and grow approximately layer by layer for at least the first three layers. In contrast to the ASW films, crystalline ice films do not wet the water monolayer on Pt(111). Virtually identical results were obtained for ASW films on epitaxial Pd(111) films grown on Pt(111). The desorption rates of thin ASW and crystalline ice films suggest that the relative free energies of the films are responsible for the different growth modes. However, at low temperatures, surface relaxation or "transient mobility" is primarily responsible for the relative smoothness of the films. A simple model of the surface relaxation semiquantitatively accounts for the observations.

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Section: Discussionmentioning

confidence: 99%

Layer-by-layer growth of thin amorphous solid water films on Pt(111) and Pd(111)

Kimmel

Petrik

Dohnálek

et al. 2006

The Journal of Chemical Physics

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“…Finally, TPD spectra were simulated and compared with standard experimental TPD line-shape analysis, as a way to verify the validity of our MD procedure. MD simulations were recently employed 24 to study the growth of ice multilayers on a Ru͑001͒-like surface, suggesting a unique packing geometry of the first four bilayers. 24…”

Section: A Molecular Dynamics Simulationsmentioning

confidence: 99%

Formation and dynamics of water clusters on Ru(001)

Lilach¹,

Buch²,

Asscher³

2003

The Journal of Chemical Physics

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The adsorption kinetics of water on Ru͑001͒ was simulated using molecular dynamics ͑MD͒ and equilibrium-model approach. The results nicely reproduce observations from STM imaging, work function change, and IR measurements. The agreement with experimental results is based on the formation of stable clusters already at very low surface coverage and temperature. Tetramers are predicted to be relatively stable compared to smaller and larger clusters. The dipole moment per water molecule continuously decreases from 2.2D for the monomer down to 1.1D for pentamer and larger clusters. Dimers are found to diffuse faster than monomers or larger clusters, with activation energy for diffusion of 2.9 kcal/mol, in agreement with recent STM measurements. A unique mechanism for dimers diffusion is proposed. Temperature programmed desorption ͑TPD͒ spectra from a metal surface were calculated by employing the MD scheme. These spectra were found identical to the standard Redhead line-shape analysis of the experimental TPD spectra of water from Pt͑111͒ and Ru͑001͒, an observation that was used to verify the consistency of the MD procedure. Finally, a kinetic model, fed by the MD calculated decreasing dipole moments per water molecule at larger clusters, explains well the highly nonlinear initial stages ͑up to 0.35BL͒ of the work function change data determined experimentally.

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“…Recently, a polarizable potential was developed with the specific property that it reflects the lower energy of ordered ice XI [Buch et al, 1998]; a property not found with the earlier analytical potentials. The analytical potentials permit detailed studies of large numbers of water molecules in protondisordered ice configurations and have been applied to questions such as the existence of the liquid-like layer at the ice surface near the melting point, the structure of ultrathin films on metal surfaces [Witek and Buch, 1999] and large clusters at much lower temperatures, and the nature of the orientational defects in ice [Podeszwa and Buch, 1999].…”

Section: Bend Mode Frequency Of H20 In Ice Imentioning

confidence: 99%

Structure, spectra, and mobility of low‐pressure ices: Ice I, amorphous solid water, and clathrate hydrates at T < 150 K

Devlin¹

2001

J. Geophys. Res.

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Abstract. Recent advances in the study of low-pressure water ices, including clathrate hydrates, are examined, highlighting aspects of modern science possibly related to the behavior of water ices in extraterrestrial environments. An effort has been made to identify properties of ice that are likely to be important in the conditions that exist in such environments and to review advances in understanding these properties. The basic science of crystalline ice I is relatively mature, but attention is given to concepts, such as point defects, which continue to evolve and which relate in an important manner to the low-temperature behavior of ice ! as well as of amorphous ice and the clathrate hydrates. A concept of amorphous and microporous amorphous ice, developed in the early 1980s, is presented, but more recent characterizations are emphasized. Similarly, fundamental properties of clathrate hydrates are summarized and used in discussions of more recently appreciated characteristics that may be important in space science. Particular emphasis is placed on the formation, infrared spectroscopy, and behavior of clathrate hydrates in vacuo at temperatures below 150 K. The review closes with a section on the properties of ice nanoparticles, which have only recently emerged as a subject of molecular science. Modern experimental and theoretical studies of ice particles have focused on the infrared spectra and structure of the ice surface, and the interaction of the surface with molecular adsorbates. Since, with the exception of highenergy radiation, ice normally interacts with its environment through surface processes, such research may enlighten future studies.

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Structure of ice multilayers on metals

Cited by 45 publications

References 31 publications

Layer-by-layer growth of thin amorphous solid water films on Pt(111) and Pd(111)

Layer-by-layer growth of thin amorphous solid water films on Pt(111) and Pd(111)

Formation and dynamics of water clusters on Ru(001)

Structure, spectra, and mobility of low‐pressure ices: Ice I, amorphous solid water, and clathrate hydrates at T < 150 K

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