Bochum 2015 – scientific programme

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P: Fachverband Plasmaphysik

P 18: Low Temperature Plasmas II

P 18.3: Talk

Wednesday, March 4, 2015, 11:15–11:30, HZO 30

Investigation of resonant energy transfers in an argon/hdrogen plasma by laser collisional induced fluorescence — •Emile Carbone^{1, 2}, Jan van Dijk¹, and Gerrit Kroesen¹ — ¹Elementary Processes in Gas Discharges group, Technical University of Eindhoven, The Netherlands — ²Institute for Plasma and Atomic Physics, Ruhr-University Bochum, 44780 Germany

Laser collisional induced fluorescence (LCIF) is used to probe resonant excitation transfers by heavy particle collisions in an argon/hydrogen plasma. Different radiative transitions between the 1s and 2p states (in Paschen’s notation) of argon are optically pumped by a nanosecond laser pulse. The spontaneous fluorescence and collisional responses of the argon and hydrogen systems are monitored by optical emission spectroscopy. For the first time, we give a direct experimental evidence of the existence of an efficient excitation transfer

Additionally, measurements are performed to estimate the resonant energy transfer between the resonant argon 1s₂ and 1s₄ states and hydrogen atoms H  (n=1) for which no cross sections could be previously measured in the literature. These are extra quenching channels of argon 1s and 2p states that should be included in collisional radiative modeling of argon-hydrogen discharges. LCIF was previously developed to measure electron or species densities locally in the plasma. We demonstrate that it can be advantageously used to probe collisional transfers between very short-lived species as well which exist only in the plasma phase.