Scanning tunnelling microscopy investigation of water in submonolayer coverage on Ag(1 1 1)

Water adsorbed at 70 K on Ag(1 1 1) is investigated by low-temperature scanning tunnelling microscopy. At half a bilayer, the H2O molecules form simultaneously hydrogen-bonded networks of different dimensionalities. An apparently zero-dimensional structure is a cyclic hexamer with molecules adsorbed in on-top positions. A one-dimensional amorphous structure forms at the upper step edge. At the lower step edge a two-dimensional bilayer grows on which a second layer nucleates heterogeneously.