Double resonance rotational spectroscopy of CH2D+
I. Physikalisches Institut, Universität zu Köln, Zülpicher Str. 77, 50937 Köln, Germany
Received: 1 June 2016
Accepted: 16 August 2016
Context. Deuterated forms of CH3+ are thought to be responsible for deuterium enrichment in lukewarm astronomical environments. There is no unambiguous detection of CH2D+ in space to date.
Aims. Four submillimetre rotational lines of CH2D+ are documented in the literature. Our aim is to present a complete dataset of highly resolved rotational lines, including millimetre (mm) lines needed for a potential detection.
Methods. We used a low-temperature ion trap and applied a novel IR–mm-wave double resonance method to measure the rotational lines of CH2D+.
Results. We measured 21 low-lying (J ≤ 4) rotational transitions of CH2D+ between 23 GHz and 1.1 THz with accuracies close to 2 ppb.
Key words: astrochemistry / line: identification / molecular data / ISM: molecules / radio lines: ISM
© ESO, 2016