Rostock 2019 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 2: Ultra-cold atoms and molecules I (joint session A/MO/Q)
MO 2.4: Vortrag
Montag, 11. März 2019, 11:15–11:30, S HS 1 Physik
Sympathetic cooling of molecular anions by a localized laser-cooled buffer gas — •Jonas Tauch1, Saba Zia Hassan1, Eric Endres1, Markus Nötzold3, Henry López1, Bastian Höltkemeier1, Roland Wester3, and Matthias Weidemüller1,2 — 1Physikalisches Institut Heidelberg, INF 226, 69120 Heidelberg — 2University of Science and Technology of China, Shanghai Branch, Shanghai, China — 3Institut für Ionenphysik und Angewandte Physik, Technikerstrasse 25/3, 6020 Innsbruck
Sympathetic cooling has become a powerful and universal method for preparing ultracold ions confined in radio frequency traps. This technique enables the study of cold molecular ions, as precision spectroscopy and chemistry at temperatures near to the absolute zero. In the past few years there has been a large debate about the limitations of this method, due to the mass ratio between the ions and the coolant. We developed a theoretical description which predicts that this limitations can be overcome by a localized buffer gas cloud and/or a higher order radio frequency trap. In this contribution I will present recent results of our hybrid atom-ion trap system, consisting of an 8-pole radio frequency wire trap and a dark spontaneous-force optical Rubidium trap. First signs of translational and rotational cooling of the trapped hydroxyl anions are observed. To probe the translational energy distributions of the anions, their time-of-flight is measured after extraction from the trap. The internal degrees of freedom are probed via near threshold photodetachment, revealing an increase of the population in lower rotational states. Thus cooling of the internal degrees of freedom.