Hydrogen-Bonded Cyclic Water Clusters Nucleated on an Oxide Surface

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• 作者：Coleman X. Kronawitter ; Christoph Riplinger ; Xiaobo He ; Percy Zahl ; Emily A. Carter ; Peter Sutter ; Bruce E. Koel
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：September 24, 2014
• 年：2014
• 卷：136
• 期：38
• 页码：13283-13288
• 全文大小：412K
• ISSN：1520-5126

文摘

We report the observation and molecular-scale scanning probe electronic structure (dI/dV) mapping of hydrogen-bonded cyclic water clusters nucleated on an oxide surface. The measurements are made on a new type of cyclic water cluster that is characterized by simultaneous and cooperative bonding interactions among molecules as well as with both metal and oxygen sites of an oxide surface. Density functional theory + U + D calculations confirm the stability of these clusters and are used to discuss other potential water-oxide bonding scenarios. The calculations show that the spatial distributions of electronic states in the system are similar in character to those of the lowest unoccupied molecular orbitals of hydrogen-bonded water molecules. On the partially oxidized Cu(111) investigated here, experiment and theory together suggest that Cu vacancies in the growing islands of cuprous oxide inhibit water adsorption in the centers of the islands (which have reached thermodynamic equilibrium). A stoichiometric, less stable cuprous oxide likely exists at island edges (the growth front) and selectively binds these water clusters.