SMuK 2021 – scientific programme
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UP: Fachverband Umweltphysik
UP 6: Poster Session
UP 6.1: Poster
Friday, September 3, 2021, 16:30–18:30, P
Charge induced enhancement of water adsorption on nanoparticle ions — Mario Nachbar3, •Thomas Dresch1, Denis Duft1, and Thomas Leisner1,2 — 1Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, 76344 Eggenstein-Leopoldshafen, Germany — 2Institute of Environmental Physics, University of Heidelberg, 69120 Heidelberg, Germany — 3current address: Bruker AXS GmbH, 76187 Karlsruhe, Germany
Water and other polar molecules experience an attractive force in the inhomogeneous electric field of small molecular ions or charged nanoparticles. This charge induced attractive force increases the collision cross section, and, hence, impacts the adsorption rates compared to neutral particle interactions. While ion-molecule interactions have been studied extensively, experimental data are still lacking regarding the interaction of polar molecules with nanoparticles whose radii exceed the Langevin capture radius. Precise knowledge of this effect is crucial, e.g. for describing the formation and growth of atmospheric nanoparticles and for understanding the role of charged particles in cloud formation. We present experimental results for the charge induced enhancement of the collision cross section between H2O molecules and singly charged nanoparticles with radii between 1.4 nm and 3 nm. The enhancement factor Γ with respect to the geometrical cross section increases with decreasing particle size. We also present a new model for Γ based on Stark effect adiabatic dipole orientations, which is in excellent agreement with the experimental findings.