1,2,1,3,4- 1Institute for Atmospheric and Earth System Research / Physics, University of Helsinki, P.O. Box 64, 00014, Finland (bernhard.reischl@helsinki.fi)
- 2Physical Chemistry I, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany
- 3Physical Chemistry II, Bielefeld University, Universitätsstr. 25, 33615 Bielefeld, Germany
- 4Institute of Physical Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 42, 1090 Vienna, Austria
Ice and mixed-phase clouds can form at moderate supercooling on seed particles through heterogeneous ice nucleation. Feldspar particles constitute a significant fraction of mineral dust in the atmopshere and have been identified as good ice nucleating particles. However, they can exhibit different chemical composition and crystal structure, which affects their ice nucleation activity [1], and the details of the ice nucleation mechanism(s) remain unknown.
Here, we present atomic force microscopy images of ice crystals growing from the vapor phase at low temperature on the (001) surfaces of two types of feldspar crystals: the highly ordered microcline, and the disordered sanidine. In contrast to the prevailing view of active sites such as step edges or cracks being responsible for ice nucleation on feldspar [2], we observe ice growth at random positions on the bare terrace of feldspar microcline (001). For the closely related feldspar sanidine, ice nucleation is only observed at step edges, as previously reported.
Our observations underscore the exceptional ice nucleating ability of microcline as it demonstrates ice nucleation even in the absence of surface defects and raise important questions regarding the different ice nucleation mechanisms on these two feldspar mineral surfaces, which are investigated using atomistic simulations.
[1] Harrison, A. D., et al., Atmos. Chem. Phys., 16, 10927-10940, 2016.
[2] Kiselev, A., et al., Science, 355, 367-371, 2017.
How to cite: Reischl, B., Schneider, F., Nilsson, R., Bechstein, R., Koop, T., Kühnle, A., and Dickbreder, T.: Nanoscopic insights on ice nucleation on feldspar microcline and sanidine , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-18933, https://doi.org/10.5194/egusphere-egu26-18933, 2026.
