SAMOP 2023 – scientific programme
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MO: Fachverband Molekülphysik
MO 10: Collisions (joint session MO/Q)
MO 10.3: Talk
Wednesday, March 8, 2023, 15:00–15:15, F142
Laser induced forced evaporative cooling of molecular anions — •Eric Endres1, Jonas Tauch2, Saba Hassan2, Markus Nötzold1, Roland Wester1, and Matthias Weidemüller2 — 1Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Austria — 2Physikalisches Institut, Universität Heidelberg, Germany
Cooling molecular anions is key for the production of cold antihydrogen and the creation of anionic coulomb crystals and would open up new fundamental research areas in modern physics and chemistry. An established technique to store and cool anions are collisions with buffer gas in multipole radio frequency ion traps. However, the temperature is limited by the temperature of the used cryogenic cooling medium.
In this contribution we present forced evaporative cooling down to 2.2(8) K by means of photodetachment of an anionic OH− ensemble, confined in a multipole wire trap. [1] This enables a phase space density approaching the near-strong Coulomb coupling regime. The anion cooling dynamics are described by a quantitative analysis of the experimental results with a full thermodynamic model [2] without any fitting parameters. In principle, this technique can be used for cooling basically any anionic species below the temperature of liquid helium.
[1] J. Tauch, et al. arXiv preprint arXiv:2211.11264 (2022).
[2] A. Crubellier. J. Phys. B, 23(20), 3585 (1990).