SAMOP 2023 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 25: Cluster and Experimental Techniques (joint session MO/A)
A 25.4: Vortrag
Donnerstag, 9. März 2023, 15:15–15:30, F142
Experimental cross sections for the uptake of alkyl alcohols by binary HNO3/H2O clusters — Yihui Yan1, Andriy Pysanenko2, Karolina Farnikova2, Eva Pluharova2, Michal Farnik2, and •Jozef Lengyel1 — 1TUM School of Natural Sciences, Technical University of Munich, Garching, Germany — 2Heyrovsky Institute, Czech Academy of Sciences, Prague, Czech Republic
The uptake of oxidized organic compounds by hydrated acid clusters accounts for a substantial portion of atmospheric aerosol particles. Through joint experimental and computational studies, we investigate the uptake of alkyl alcohols on pre-existing hydrated HNO3 clusters. In our experiments, the HNO3/H2O clusters pass through a chamber filled with a particular gas, the molecules collide with the clusters and can stick to the surface. The efficiency of this process is given by the uptake cross section, which is determined experimentally by a combination of mass spectrometry and velocity measurements in a molecular beam. Our previous experiments have shown that the uptake probabilities for the oxidized molecules are significantly larger than for the corresponding volatile organic compounds (VOCs). This increase is attributed to hydrogen bonds between the molecules and clusters, whereas the interactions of the parent VOCs are weaker and nonspecific. In this study, we examine the effect of different O-H bond positions in the oxidized molecule and different carbon chain length on the pickup probability. To learn the details of the pickup process, all experimental measurements are supplemented by MD simulations.