A Search for the COH_2 Dimer in the Galaxy

摘要

We have used the 30 m IRAM millimeter radio telescope to search for two low-lying rotational tran- sitions of the COH_2 dimer in the emission spectra of three Galactic sources and in the absorption spectrum of a low-latitude extragalactic continuum source. We first summarize the structure of this dimer as it can be inferred currently from laboratory infrared spectroscopy. The transitions we have observed and their initial estimated frequencies are the 111-000+ line at 109 GHz and the 110+101- line at 91 GHz.