Water Adsorption and Diffusion on NaCl(100)

详细信息    查看全文

• 作者：Pepa Cabrera-Sanfelix ; Andres Arnau ; George R. Darling ; Daniel Sanchez-Portal
• 刊名：Journal of Physical Chemistry B
• 出版年：2006
• 出版时间：December 7, 2006
• 年：2006
• 卷：110
• 期：48
• 页码：24559 - 24564
• 全文大小：189K
• 年卷期：v.110,no.48(December 7, 2006)
• ISSN：1520-5207

文摘

At low coverage and temperature the water-surface interaction determines the adsorption geometry of thewater molecule on the NaCl(100) surface. However, at room temperature the molecules are also able tomove on the surface and form islands where the water molecules are held together by hydrogen bonds. Asa step toward the description of such complex phenomenology, in this work we have used density functionaltheory calculations to study the most favorable adsorption geometry of an isolated water molecule and theenergy barriers associated with different hopping mechanisms between equivalent adsorption configurationson this surface. We propose different hopping processes that can be classified as translations, if the moleculemoves from one adsorption site to the adjacent one, or reorientations, if the molecule only changes its orientationon the surface and remains in the same adsorption site. The straightforward parallel translation of the watermolecule along the surface exhibits the highest barrier. All other processes, either translations or reorientations,involve the rotation of the water molecule around certain axes and present much smaller barriers (at least50% smaller). To obtain a net movement of the molecule along the surface it is always necessary to combineone of these translational and reorientational processes. Such combinations provide favorable and plausiblepathways for the diffusion of the water molecule on the NaCl(100) substrate.