An unconventional bilayer ice structure on a NaCl(001) film
An unconventional bilayer ice structure on a NaCl(001) film
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NaCl(001)薄膜上的非常规双层冰结构
DOI：
10.1038/ncomms5056
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发表时间：
2014-05-01
影响因子：
16.6
通讯作者：
Wang, En-Ge
中科院分区：
文献类型：
--
作者：
Chen, Ji;Guo, Jing;Wang, En-Ge
水固相互作用在自然和技术中都具有广泛的重要性。基于 Bernal-Fowler-Pauling 冰规则的六边形双层模型已被广泛采用来描述界面处的水结构。使用低温扫描隧道显微镜，我们在这里报道了一种新型的二维冰状双层结构，该结构由循环水四聚体在绝缘的 NaCl(001) 薄膜上构建，这完全超出了传统的双层结构。一种新颖的桥接机制允许水四聚体互连形成链、薄片，并最终形成包含规则阵列的 Bjerrum D 型缺陷的二维扩展冰双层。从头算密度泛函理论计算证实了这种桥接生长模式，并揭示了惊人的质子无序冰结构。具有异常高密度的周期性 Bjerrum 缺陷的形成可能作为 H 供体位点在引导多层冰生长和催化水涂层盐表面上的异质化学反应中发挥至关重要的作用。
Water-solid interactions are of broad importance both in nature and technology. The hexagonal bilayer model based on the Bernal-Fowler-Pauling ice rules has been widely adopted to describe water structuring at interfaces. Using a cryogenic scanning tunnelling microscope, here we report a new type of two-dimensional ice-like bilayer structure built from cyclic water tetramers on an insulating NaCl(001) film, which is completely beyond this conventional bilayer picture. A novel bridging mechanism allows the interconnection of water tetramers to form chains, flakes and eventually a two-dimensional extended ice bilayer containing a regular array of Bjerrum D-type defects. Ab initio density functional theory calculations substantiate this bridging growth mode and reveal a striking proton-disordered ice structure. The formation of the periodic Bjerrum defects with unusually high density may have a crucial role as H donor sites in directing multilayer ice growth and in catalysing heterogeneous chemical reactions on water-coated salt surfaces.