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,
Discovery of the Interstellar NH2 Radical
Astrophys. J. 416, L83L86 (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,
The Far-Infrared Spectrum of the Sagittarius B2 Region:
Extended Molecular Absorption, Photodissociation, and Photoionization
Astrophys. J. 600, 214233 (2004).