Stuttgart 2012 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 13: Poster 1: Cold Molecules, Femtosecond Spectroscopy, Molecular Dynamics
MO 13.9: Poster
Dienstag, 13. März 2012, 16:30–19:00, Poster.IV
Low energy scattering of Stark-decelerated OH radicals with He atoms with high energy resolution — •H. Christian Schewe1, Moritz Kirste1, Xingan Wang1, Ludwig Scharfenberg1, Nicolas Vanhaecke1, Sebastiaan Y.T. van de Meerakker2, and Gerard Meijer1 — 1Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6,14195 Berlin, Germany — 2Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
For collision studies of molecules, a Stark decelerator offers the advantage that it produces beams of cold neutral polar molecules with a tunable velocity. A second beam of atoms or molecules will be crossed to study scattering down to collision energies of a few wavenumbers.
We present future experiments where in particular the inelastic scattering of Stark-decelerated and state-selected OH(X 2Π3/2, J = 3/2,f) with helium atoms will be carried out [1]. To reach low collision energies down to 10 cm−1 a pulsed valve of the Even-Lavie type is mounted on a helium cryostat. The translational velocity and the speed ratio of Helium beams are characterized and their dependence on the temperature, the stagnation pressure and the opening time of the valve are determined. Simulations are presented to show how the resolution of the collision energy can be optimized by bunching of the molecular packet inside the decelerator. We give a perspective on how theoretically predicted scattering resonances of the inelastic cross section might be resolved.
[1] Kirste et al. Phys. Rev. A 82, 4 (2010).