Templating one-dimensional water chains on the alkali halide surface

Understanding the adsorption structure of water is regarded as a first step in exploring its reaction with specific surfaces. The surface geometry and its components considerably influence both the adsorption energy and the structure of water adsorption. In this study, we report the unusual adsorption structure of water molecules on a KCl(100) film by means of low-temperature scanning tunneling microscopy (LT-STM). Rather than forming a closed-loop hydrogen bond network, water molecules align into a one-dimensional chain on the film. The lateral positioning of individual water molecules, manipulated in a row, successfully recreated the single-molecule-thick chain. Introducing an additional water molecule extended the chain by the K-Cl distance. The creation of the one-dimensional water chain is influenced not only by the large lattice parameter of KCl but also by the weak interactions between the surface and the water molecules.