Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 59: Poster Session II (Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: arrays; Nanostructures at surfaces: Wires, tubes; Nanostructures at surfaces: Other; Plasmonics and nanooptics; Metal substrates: Epitaxy and growth; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsoprtion of organic / bio molecules; Metal substrates: Adsoprtion of inorganic molecules; Metal substrates: Adsoprtion of O and/or H; Metal substrates: Clean surfaces; Density functional theory and beyond for real materials)

O 59.108: Poster

Mittwoch, 24. März 2010, 17:45–20:30, Poster B1

Quantum kinetics of electrons at plasma boundaries — •Franz Xaver Bronold, Holger Fehske, Rafael Leslie Heinisch, and Johannes Marbach — Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald, Germany

Macroscopic objects in contact with an ionized gas are usually negatively charged. They accumulate electrons more efficiently than ions leading to the build-up of a quasi-stationary electron film at the plasma boundary. The plasma is strongly affected by surface charges, via sheath formation, electron-ion recombination, and secondary electron emission. A kinetic description of surface charges on par with the kinetic modeling of the bulk plasma is however still missing. As a first step in this direction, we propose a physisorption-inspired model for the formation of surface charges at plasma boundaries and their interaction with the bulk plasma [1]. Besides identifying key issues of the electronic microphysics at plasma boundaries we also discuss results of exploratory calculations for clean metallic boundaries focusing in particular on the electron sticking coefficient s_e, the thermal electron desorption rate 1/τ_e, and the secondary electron emission coefficient due to de-excitation of metastable molecules in front of the boundary γ_e^m.

[1] F. X. Bronold et al., Eur. Phys. J. D 54, 519-544 (2009).