SAMOP 2021 – scientific programme
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MO: Fachverband Molekülphysik
MO 8: Cold Molecules
MO 8.1: Talk
Friday, September 24, 2021, 10:45–11:00, H1
Quantum-state-controlled Penning collisions of ultracold lithium atoms with metastable atoms and molecules — •Tobias Sixt, Jiwen Guan, Jonas Grzesiak, Markus Debatin, Frank Stienkemeier, and Katrin Dulitz — Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg im Breisgau, Germany
In our experiment, we study quantum-state-controlled Penning collisions between laser-cooled lithium atoms (Li) and metastable helium atoms (He*) to investigate new ways of controlling the outcome of Penning-ionizing collisions. In this contribution, we report on the efficient suppression of He*-Li Penning ionization by laser excitation of the Li atoms. The results illustrate that not only the electron spin, but also Λ - the projection of the total molecular orbital angular momentum along the internuclear axis - is conserved during the ionization process. Our findings suggest that Λ conservation can be used as a more general means of reaction control, for example, to improve schemes for the simultaneous laser cooling and trapping of ultracold He* and alkali atoms.
Furthermore, we report on the sensitive detection of metastable nitric oxide molecules, produced in a supersonic beam source, by reactive collisions with electronically excited Li atoms in the 22P3/2 state. We infer densities of ≈ 600 NO(a4Πi) molecules/cm3 in the interaction region. Our results also allow for an estimate of the fractional population of NO(a4 Πi, v ≥ 5) prior to the collision process.