SAMOP 2023 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 37: Collisions (with Q) (joint session MO/Q)
Q 37.2: Talk
Wednesday, March 8, 2023, 14:45–15:00, F142
Dissociative recombination of ArH+ at the Cryogenic Storage Ring — •Ábel Kálosi1,2, Manfred Grieser2, Leonard W. Isberner3,2, Daniel Paul1,2, Daniel W. Savin1, Stefan Schippers3, Viviane C. Schmidt2, Andreas Wolf2, and Oldřich Novotný2 — 1Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA — 2Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany — 3I. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen, Germany
ArH+ is an important probe of the cosmic ray flux in interstellar space. Cosmic rays are the dominant ionization source for H and H2 in the cold interstellar medium (ISM). This ionization initiates astrochemistry in the cold phases of the ISM. The cosmic ray ionization rate (CRIR) is thus an important parameter for both chemical and dynamical models of the ISM. ArH+ forms via cosmic ray ionization of Ar, but can be destroyed via dissociative recombination (DR) with free electrons. Astronomical observations of ArH+, combined with chemical models, enable one to quantitatively estimate the CRIR. Such models require reliable rate coefficients that take into account the low internal excitation of the ArH+, as occurs in the cold ISM. To this end, we have performed merged-beams DR experiments with ArH+ in the Cryogenic Storage Ring where, at an ambient temperature of ∼ 10 K, the ions relaxed to their lowest rotational states.