Heidelberg 2015 – scientific programme
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UP: Fachverband Umweltphysik
UP 2: Atmosphäre
UP 2.20: Talk
Wednesday, March 25, 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 Nachbar1,2, and Thomas Leisner1,2 — 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.