Heidelberg 2015 – wissenschaftliches Programm

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UP: Fachverband Umweltphysik

UP 2: Atmosphäre

UP 2.20: Vortrag

Mittwoch, 25. März 2015, 16:00–16:15, G/gHS

Deposition nucleation and growth of polar and non-polar gases on small nanoparticles in a linear ion trap — •Denis Duft¹, Mario Nachbar^1,2, and Thomas Leisner^1,2 — ¹Karlsruhe Institute of Technology, Institute for Meteorology and Climate Research, Germany — ²University of Heidelberg, Institute of Environmental Physics, Germany

In the higher atmospheres of planets re-condensed particles formed from evaporated meteoric material can act as heterogeneous nuclei for the condensation of gaseous species. These sub-2nm meteoric smoke particles (MSP) are believed to be the precursors for polar mesospheric water ice clouds on Earth as well as for mesospheric carbon dioxide clouds on Mars. However, microphysical understanding of nucleation and growth processes on such nanoscale systems is scarce. To improve our understanding we devised an experiment where meteor smoke analogue particles are stored in a linear ion trap under well-defined supersaturated mesospheric conditions. Nucleation and growth on the nanoparticles are measured as a change in mass with a time-of-flight mass spectrometer. In this contribution we present results of deposition nucleation and growth of polar water vapor on nanoparticles in comparison to measurements of nonpolar carbon dioxide. We show how molecular dipole-moment and different thermal conditions for both gases influence the nucleation and growth behavior. Furthermore the versatility of the experiment allows us to derive sticking coefficients, desorption energies, contact parameters as well as critical supersaturations for nucleation.