From water multilayers to ice on calcite (10.4)

Calcite, the most abundant carbonate mineral in Earth’s crust, plays an important role in processes such as the global carbon cycle and biomineralization. To get a deeper understanding of these processes the interaction between water and the most stable calcite (10.4) surface on the nanometer scale is of central importance.

Previously, water coverages ranging from single molecules up to one monolayer were imaged with atomic force microscopy in an ultra-high-vacuum environment. [1] [2] These studies are expanded by several studies of bulk water at ambient conditions. [3] However, the intermediate coverages region of a few multilayers was poorly studied.

We employ atomic force microscopy to follow the growth of water layers at low temperatures. High-resolution imaging reveals, that the first few layers have different superstructures. Depending on temperature and pressure, we observe the formation of amorphous or crystalline ice clusters on top of these layers.

[1] J. Heggemann, Y.S. Ranawat, O. Krejčí, A.S. Foster, P. Rahe, Differences in Molecular Adsorption Emanating from the (2 × 1) Reconstruction of Calcite(104), Journal of Physical Chemistry Letters, 14 (2023) 1983–1989.

[2] L. Klausfering, F. Schneider, R. Bechstein, A. Kühnle, Reconstruction of calcite (10.4) manifests itself in the tip-assisted diffusion of water, Surface Science, 751 (2025) 122598.

[3] H. Söngen, S.J. Schlegel, Y. Morais Jaques, J. Tracey, S. Hosseinpour, D. Hwang, R. Bechstein, M. Bonn, A.S. Foster, A. Kühnle, E.H.G. Backus, Water Orientation at the Calcite-Water Interface, Journal of Physical Chemistry Letters, 12 (2021) 7605–7611.