Knowledge Bank

First identified toward Sgr B2}, the NH$2$ radical has recently been detected in the interstellar medium by the HIFI instrument on board of Herschel}. Despite the fact that this radical has not been detected in brown dwarfs and exoplanets yet, it is already included in physical and chemical models of those environments} (temperature higher than 2000 K expected in several objects). Its detection in those objects will depend on the existence of a reliable high temperature and high resolution spectroscopic database on the NH$2$ radical.The absorption spectrum of NH$2$ has been recorded between 15 and 700 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ at the highest resolution available using the Bruker IFS125HR Fourier transform interferometer connected to the far infrared AILES beamline at SOLEIL (R=0.001~cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$). The radical was produced by an electrical discharge (DC) through a continuous flow of NH$3$ and He using the White-type discharge cell developped on the beamline (optical path: 24m). Thanks to the brilliance of the synchrotron radiation, more than 700 pure rotational transitions of NH$2$ have been identified with high N values (N=25) in its fundamental and first excited vibrational modes. By comparison to the previous FT spectroscopic study on that radical in the FIR spectral range}, asymmetric splitting as well as fine and hyperfine structure have been resolved for several transitions.