Mainz 2026 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 8: Cold Molecules (joint session MO/Q)
MO 8.2: Vortrag
Dienstag, 3. März 2026, 11:30–11:45, P 105
Surface collision and thermalisation of a laser-coolable molecule aluminium monofluoride — •Pulkit Kukreja, Lasse Rautenberg, Sebastian Kray, Gerard Meijer, and Sid Wright — Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin
Until very recently, direct laser cooling of molecules has been restricted to reactive species with 2 Σ electronic ground states. These molecules are challenging to produce and have only been captured into a magneto-optical trap (MOT) from pulsed, cryogenically cooled molecular beam sources. These are rather complex, expensive, and difficult to operate reliably for long periods.
At the Fritz Haber Institute, we have now realised the first MOT of a spin-singlet molecule: aluminum monofluoride (AlF). AlF has high chemical stability compared to 2Σ molecules, and can also be made efficiently at moderate temperatures (∼ 900 K) in an oven. Remarkably, we observe that AlF can survive collisions with, and therefore thermalise to, room temperature vacuum walls of our experiments.
Here, we present the outcomes of single AlF-surface collisions on a camera via Doppler-sensitive laser-induced fluorescence. We observe that AlF undergoes trapping-desorption at surfaces, with complete rovibrational and translational thermalisation to the surface. The collision outcomes are highly surface-dependent, with polydimethylsiloxane (PDMS) coatings having a low sticking coefficient. Our results open a pathway to molecular MOTs loaded from compact and inexpensive beam sources and suggest that the technology employed in atomic vapour cells can be applied to a laser-coolable molecule.
Keywords: Molecule-surface scattering; Laser spectroscopy; Molecular Physics