Intrinsic reconstruction of ice-I surfaces.

Understanding the precise atomic structure of ice surfaces is critical for revealing the mechanisms of physical and chemical phenomena at the surfaces, such as ice growth, melting, and chemical reactions. Nevertheless, no conclusive structure has been established. In this study, noncontact atomic force microscopy was used to address the characterization of the atomic structures of ice Ih(0001) and Ic(111) surfaces. The topmost hydrogen atoms are arranged with a short-range (2 × 2) order, independent of the ice thickness and growth substrates used. The electrostatic repulsion between non-hydrogen-bonded water molecules at the surface causes a reduction in the number of the topmost hydrogen atoms together with a distortion of the ideal honeycomb arrangement of water molecules, leading to a short-range-ordered surface reconstruction.