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A3: Excitation transfer between molecules in transient atmospheric pressure plasmas and its impact on plasma chemistry

Principal Investigators: A. von Keudell

Team


von Keudell, Achim
(Principal Investigator)

Chauvet, Laura
(PostDoc)

Stewig, Christoph
(PhD)

Description

ImageThe internal excitation of molecules and the non-equilibrium population of the degrees of freedom of molecules in a plasma is at the core of plasma chemistry. For example, vibrational excitation lowers activation barriers for electron induced dissociation reactions and determines thereby the energy and conversion efficiency of a plasma chemical process. Metastable states store electronic excitation, which can be transferred to molecules to trigger dissociation. This project aims at a fundamental understanding of the transfer of this excitation depending on the plasma (leading to a specific electron energy distribution function) and the plasma mixture defining the collision partners and thereby the various quenching routes and on the different reactive surfaces. This is evaluated by using Fourier transform infrared absorption (FTIR) spectroscopy for molecules with strong dipole moments such as CO2, CH4, CO, and H2O for lower lying excitation states and threshold ionisation (TI) molecular beam mass spectrometry (MBMS) for higher metastable excitation states. This is combined with an in-situ analysis of the catalytic surfaces using infrared reflection absorption techniques (IRRAS) and spectroscopic ellipsometry (SE). A multi diagnostics set-up will be developed to integrate the various plasma excitation schemes of the CRC 1316 and the different catalytic active surfaces.

Publications

Thesis

  • Christoph Stewig
    Excitation Transfer in AP Plasmas (PhD thesis) - 04/2021
  • Steffen Schüttler
    Plasma Catalysis of CO2 Reduction (BA) - 09/2018
  • Thilo Romba
    Plasma Conversion of CH4 O2 Mixtures (BA) - 09/2018
  • Theresa Urbanietz
    Plasma Catalysis during Conversion of Methane/Oxygen/Hydrogen Gas Mixtures (PhD thesis) - ongoing
  • Marina Falke
    Ns plasmas in liquid for positive and negative polarity (BA) - 05/2021
  • Boris Daniil
    Simulation der Nachweisempfindlichkeit eines Atmosphärendruck-Massenspektrometers (BA) - 11/-0001

Further reading

  • Unexpected O and O3 production in the effluent of He/O2 microplasma jets emanating into ambient air,
    D. Ellerweg, A. von Keudell, and J. Benedikt,
    Plasma Sources Sci. Technol. 21, 034019 (2012)

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