Berlin 2024 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 49: Oxide and Insulator Interfaces I

O 49.6: Vortrag

Mittwoch, 20. März 2024, 11:45–12:00, MA 144

Atomic-scale Structure of K-Feldspar Microcline (001) — •Tobias Dickbreder¹, Franziska Sabath¹, Bernhard Reischl², Rasmus V. E. Nilsson², Adam S. Foster^3,4, Ralf Bechstein¹, and Angelika Kühnle¹ — ¹Physical Chemistry I, Bielefeld University, Germany — ²Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Finland — ³Department of Applied Physics, Aalto University, Finland — ⁴Nano Life Science Institute (WPI-NanoLSI), Kanazawa University, Japan

Ice nucleation governs the aggregate state of water in clouds and, thus, understanding ice nucleation is essential for improving climate models. Most atmospheric ice nucleation is heterogeneous caused by ice nucleating particles (INP). Among the most important INP under mixed-phase cloud conditions are feldspar minerals. The mechanism by which feldspar minerals facilitate ice nucleation, however, remains elusive. A prerequisite for unravelling this mechanism is a solid understanding of the surface structure of feldspar minerals. In this regard, it is especially crucial that experimental studies on the atomic-scale structure of feldspar minerals are sparse. Here, we present atomic force microscopy images of K-feldspar microcline (001) taken in ultrahigh vacuum. Our high-resolution AFM data reveal features consistent with a hydroxyl-terminated surface as predicted by density functional theory. This finding suggests that water in the residual gas readily reacts with the surface. These insights into the surface structure will contribute to understanding the excellent ice nucleating ability of feldspar minerals.

Keywords: Atomic Force Microscopy; Microcline; Ice Nucleation; Ultrahigh Vacuum; Water