===== On the Detection of Amidogen, NH2, in the Interstellar Medium ===== The //NKaKc// = 110 – 101 //para// rotational transition of amidogen, NH2, was observed in absorption toward Sgr B2 (N) and (M):\\ E. F. van Dishoek, D. J. Jansen, P. Schilke, and T. G. Philips,\\ **[[https://doi.org/10.1086/187076|Discovery of the Interstellar NH2 Radical]]**\\ //Astrophys. J.// **416**, L83–L86 (1993).\\ Three fine structure components were observed with partially resolved 14N hyperfine structure which obviously secures the identification.\\ \\ Further transitions were reported in\\ J. R. Goicoechea, N. J. Rodríguez-Fernández and J. Cernicharo,\\ **[[https://doi.org/10.1086/379704|The Far-Infrared Spectrum of the Sagittarius B2 Region: Extended Molecular Absorption, Photodissociation, and Photoionization]]**\\ //Astrophys. J.// **600**, 214–233 (2004).\\ \\ M. Melosso, L. Bizzocchi, O. Sipilä, B. M. Giuliano, L. Dore, F. Tamassia, M.-A. Martin-Drumel, O. Pirali, E. Redaelli, and P. Caselli\\ reported on the\\ **[[https://doi.org/10.1051/0004-6361/202038490|First detection of NHD and ND2 in the interstellar medium — Amidogen deuteration in IRAS 16293–2422]]**\\ //Astron. Astrophys.// **641**, Art. No. A153 (2020).\\ Both isotopologs were detected in archival HIFI///Herschel// data taken toward the Class 0 protostar IRAS 16293−2422. Very high degrees of deuteration were inferred.\\ \\ A similar account was given shortly thereafter by\\ A. Bacmann, A. Faure, P. Hily-Blant, K. Kobayashi, H. Ozeki, S. Yamamoto, L. Pagani, and F. Lique,\\ **[[https://doi.org/10.1093/mnras/staa2903|Deuterium fractionation of nitrogen hydrides: detections of NHD and ND2]]**\\ //Mon. Not. R. Astron. Soc.// **499**, 1795 (2020).\\ NHD observations are based on archival APEX data, ND2 observations on archival HIFI///Herschel// data as above. The numbers are very similar to the ones above. One can deduce deuteration degrees per A atom of ~0.25 and ~0.35 for NHD and ND2, respectively, from their total column densities.\\ \\ ---- Contributor(s): H. S. P. Müller; 03, 2007; 02, 2023 ----