Freiburg 2019 – wissenschaftliches Programm

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FM: Fall Meeting

FM 22: Quantum Control

FM 22.5: Talk

Montag, 23. September 2019, 17:45–18:00, 3042

Quantum-state-controlled reactive atom-atom collisions — Tobias Sixt, Jiwen Guan, Markus Debatin, Frank Stienkemeier, and •Katrin Dulitz — Institute of Physics, University of Freiburg, 79104 Freiburg i. Br., Germany

In our experiments, we study quantum-state-controlled reactive collisions between lithium atoms and metastable helium atoms to explore the influence of electron-spin polarization on the reaction rate and to observe quantum resonance effects at low collision energies. Eventually, these experiments are aimed at controlling the outcome of chemical reaction rates, e.g., using coherent control techniques. In our approach, we use an experimental apparatus which consists of a discharge source for the production of metastable helium atomic beams and a magneto-optical trap (MOT) for ultracold lithium atoms [1]. In this contribution, I will show results illustrating that the reaction rate dramatically depends on the initial electronic state of both metastable helium and lithium, respectively. To distinguish between the relative contribution of the He(2¹S₀) and He(2³S₁) states to the reaction rate, we make use of an original optical quenching scheme [2] which makes it possible to fully deplete the population of He(2¹S₀) in the supersonic beam via optical excitation to the 4¹P₁ state.

[1] Jonas Grzesiak, Takamasa Momose, Frank Stienkemeier, Marcel Mudrich and Katrin Dulitz, J. Chem. Phys. 150(3), 034201, 2019. [2] Jiwen Guan, Vivien Behrendt, Pinrui Shen, Simon Hofsäss, Thilina Muthu-Arachchige, Jonas Grzesiak, Frank Stienkemeier, and Katrin Dulitz, Phys. Rev. Appl., 11(5), 054073, 2019.