Hannover 2020 – wissenschaftliches Programm
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MS 2.2: Vortrag
Montag, 9. März 2020, 14:30–14:45, f128
Electron-impact rotational de-excitation of CH+ molecules — •Á Kálosi1, K. Blaum1, S. George1,2, J. Göck1, M. Grieser1, F. Grussie1, R. von Hahn1, N. Jain1, C. Krantz1, H. Kreckel1, C. Meyer1, D. Müll1, O. Novotný1, F. Nuesslein1, D. Paul1, S. Saurabh1, D. W. Savin3, V. C. Schmidt1, P. Wilhelm1, and A. Wolf1 — 1Max Planck Institute for Nuclear Physics, Heidelberg, Germany — 2University of Greifswald, Germany — 3Columbia University, New York, NY, USA
Hydrides are the first molecules to form in the interstellar medium due to the abundance of hydrogen. The CH+ ion was the first molecular cation identified in the interstellar medium. Interpretation of the observed spectrum relies, in part on radiative transfer models built on a knowledge of all the relevant excitation and de-excitation processes, such as inelastic collisions with electrons. Here we present merged beams experiments of CH+ ions with the recently implemented electron cooler at the Cryogenic Storage Ring (CSR) in Heidelberg. This experimental setup facilitates low (meV) collision energy measurements to study inelastic electron-ion collisions. We combined the collision measurements with near-threshold photodissociation to directly probe the populations of the lowest rotational states of the stored CH+ beam. Using a velocity-matched or slightly detuned electron beam, we can for the first time experimentally determine electron-impact rotational excitation and de-excitation rates for CH+ . Here we will present preliminary results.