Preparation-Dependent Orientation of Crystalline Ice Islands on Ag(111).

We observe the transformation of fractal ice islands grown at 96 K to compact ones annealed at 118 K and compare those to compact islands grown directly at 118 K. The low-temperature grown islands form a four bilayer high wetting layer. The annealing causes a crystallization and reshaping of the islands and a substantial increase in height and roughness in particular at higher coverage. Moreover, it leads to a dewetting of the ice film. The islands grown at the higher temperature show qualitative similarities to the annealed ones at smaller nucleation density. However, their orientation with respect to the surface differs by 30° as compared to the annealed islands.