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Turning things downside up: Adsorbate induced water flipping on Pt(111).
- Source :
-
Journal of Chemical Physics . 11/14/2014, Vol. 141 Issue 18, p1-8. 8p. 1 Diagram, 5 Graphs. - Publication Year :
- 2014
-
Abstract
- We have examined the adsorption of the weakly bound species N2, O2, CO, and Kr on the (√37 × √37)R25.3° water monolayer on Pt(111) using a combination of molecular beam dosing, infrared reflection absorption spectroscopy, and temperature programmed desorption. In contrast to multilayer crystalline ice, the adsorbate-free water monolayer is characterized by a lack of dangling OH bonds protruding into the vacuum (H-up). Instead, the non-hydrogen-bonded OH groups are oriented downward (H-down) to maximize their interaction with the underlying Pt(111) substrate. Adsorption of Kr and O2 have little effect on the structure and vibrational spectrum of the "√37" water monolayer while adsorption of both N2, and CO are effective in "flipping" H-down water molecules into an H-up configuration. This "flipping" occurs readily upon adsorption at temperatures as low as 20 K and the water monolayer transforms back to the H-down, √37 structure upon adsorbate desorption above 35 K, indicating small energy differences and barriers between the H-down and H-up configurations. The results suggest that converting water in the first layer from H-down to Hup is mediated by the electrostatic interactions between the water and the adsorbates. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00219606
- Volume :
- 141
- Issue :
- 18
- Database :
- Academic Search Index
- Journal :
- Journal of Chemical Physics
- Publication Type :
- Academic Journal
- Accession number :
- 99538416
- Full Text :
- https://doi.org/10.1063/1.4896226