Erlangen 2022 – scientific programme

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MO: Fachverband Molekülphysik

MO 7: Cold Molecules

MO 7.6: Talk

Tuesday, March 15, 2022, 11:45–12:00, MO-H8

A new perspective on cryogenic buffer gas beams: comparing AlF, CaF, MgF and YbF — •Sidney C. Wright, Maximilian Doppelbauer, Xiangyue Liu, H. Christian Schewe, Simon Hofsäss, Sebastian Kray, Jesús Pérez-Ríos, Gerard Meijer, and Stefan Truppe — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin

Cryogenic buffer gas beams of atoms and molecules are an essential precursor for many experiments with ultracold matter. Whilst the production efficiency and phase-space distribution of the target species determine the scientific applications of a buffer gas source, these properties are not well understood and difficult to compare between experiments.
In the same setup, we produce and compare buffer gas beams of Al, Ca and Yb, with the laser coolable molecules AlF, CaF, MgF and YbF. We deduce that production of AlF from Al is nearly 100% efficient in our source, whereas for the other monofluorides it is about 10%. This is supported by calculations using a combination of molecular dynamics and density functional theory, suggesting it may be possible to predict the production efficiency for other molecular species.
We use a Stark Decelerator to accurately map the longitudinal phase-space distribution of the AlF beam, and measure its rotational state distribution using the convenient optical transitions. Together, this provides new insight into the thermalisation dynamics in the buffer gas cell. Our findings have important implications for the design of future cold molecule sources.