Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 49: Oxide and Insulator Interfaces I
O 49.7: Vortrag
Mittwoch, 20. März 2024, 12:00–12:15, MA 144
Atomic-scale imaging of K-feldspar surfaces and their interaction with water — •Luca Lezuo1, Andrea Conti1, Rainer Abart2, Florian Mittendorfer1, Michael Schmid1, Ulrike Diebold1, and Giada Franceschi1 — 1Institute of Applied Physics, TU Wien, Wiedner Hauptstrasse 8-10/E134, 1040 Wien, Austria — 2Department of Lithospheric Research, Universität Wien, 1090 Wien, Austria
K-Feldspars (KAlSi3O8) are common minerals in the Earth’s crust and play a crucial role as ice nucleators in atmospheric processes. In particular, the well-ordered low-temperature polymorph microcline is a very effective ice nucleator.[1] Understanding their interaction with water is essential for various scientific fields, including atmospheric chemistry and climate science.
This study presents experimental atomic-scale imaging of the interaction between K-feldspar and water.[2] We cleaved the mineral in ultra-high vacuum and analyzed the surface using non-contact atomic force microscopy (AFM) and X-ray photoelectron spectroscopy. The surfaces are prone to hydroxylation, exposing arrays of silanol (Si-OH) and aluminol (Al-OH) groups. We studied the onset of ice nucleation by introducing H2O vapor at low temperatures on such hydroxylated surfaces. Ab-initio calculations in tandem with AFM simulations employing the Probe Particle Model [3] helped us interpret our results.
[1] A. Kumar, et al., Atmos. Chem. Phys. 18, 7057 (2018)
[2] G. Franceschi, et al., submitted (2023)
[3] P. Hapala, et al., Phys. Rev. B 90, 085421 (2014)
Keywords: mineral surface chemistry; feldspars; NC-AFM; atomic structures; Probe Particle Model