Bonn 2025 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 65: Poster – Cold Molecules (joint session MO/Q)
Q 65.9: Poster
Donnerstag, 13. März 2025, 17:00–19:00, Tent
Merged-beams study of HD+ with ground-term C Atoms reveals intramolecular kinetic isotope effect. — •L. Berger1, F. Grussie1, M. Grieser1, Á Kálosi2,1, D. Müll1, O. Novotný1, A. Znotins1, F. Dayou3, X. Urbain4, and H. Kreckel1 — 1Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany — 2Columbia Astrophysics Laboratory, Columbia University, New York 10027, USA — 3Sorbonne Université, Observatoire de Paris, PSL University, CNRS, LERMA, F-92195 Meudon, France — 4Institute of Condensed Matter and Nanosciences, Université Catholique de Louvain, Louvain-la-Neuve, B-1248 Belgium
The reaction of HD+ and ground-state C atoms has been studied in a merged-beams experiment at the Cryogenic Storage Ring (CSR) of the Max Planck Institute for Nuclear Physics in Heidelberg. The CSR is cooled by a closed-cycle liquid helium unit, thus reducing the blackbody radiation field strongly compared to room-temperature experiments. HD+ is stored for up to 20 s in the CSR and cools radiatively to the vibrational ground state (within 0.5 s) and rotational states with J≤3 (after 5 s). In contrast to previous studies with internally excited H2+ and D2+ reacting with C, a significant increase in the absolute rate coefficient of the reaction is observed and the production of CH+ is favored over CD+ across all collision energies. Our experimental results agree well with our quasiclassical trajectory calculations based on two reactive potential energy surfaces for vibrationally relaxed HD+ in its lowest rotational states. [1] F. Grussie, et al. Phys. Rev. Lett. 2024, 132.243001 [2] F. Grussie, et al. Phys. Rev. A 2024, 109.062804
Keywords: storage ring; ion-neutral reactions; cold molecules