SAMOP 2023 – scientific programme
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MO: Fachverband Molekülphysik
MO 13: Poster II
MO 13.5: Poster
Wednesday, March 8, 2023, 16:30–19:00, Empore Lichthof
Spectroscopic and collision studies of the laser-cooling candidate C2− — •Christine Maria Lochmann, Markus Nötzold, Sruthi Purushu Melath, Robert Wild, and Roland Wester — Institut für Ionenphysik und Angewandte Physik, Universität Innsbruck, Austria
The precise control of the external and internal motion of negative ions has been of increasing interest in the past decades. One possible method to reach this control is through laser cooling, which has never been achieved for a negatively charged particle, as only a few anions provide the strongly bound electronic excited and adequate internal energy states suitable for laser cooling schemes. One such candidate is the molecular carbon anion C2−. Here, we present our studies on the spectroscopy of C2− carried out in a cryogenic 16-pole RF wire trap at 6 K to determine precise laser cooling transition frequencies. We are able to resolve the spin-rotation splitting in C2− with an accuracy of 20 MHz and determine the rotational and translational temperature of the ions [1]. A useful method to repopulate the ground state of the molecule could be through vibrational quenching. We studied the quenching rate into the vibrational ground state of C2− in cold collisions with H2. At high H2 densities the collision also leads to a three-body reaction which forms C2H−. We measured the temperature dependent three-body rate between 10 K and 28 K to benchmark quantum calculations.
[1] M. Nötzold et al., Phys. Rev. A 106, 023111 (2022)