Laboratory spectroscopy of MgNC - The first radioastronomical identification of Mg-bearing molecule

Abstract

The linear MgNC radical was detected, for the first time, by laboratory microwave spectroscopy, and six unidentified lines in IRC + 10216 reported by Guélin et al. (1986) were assigned to the transitions of this radical. The radical was produced in a free space absorption cell by a DC discharge in a mixture of magnesium vapor, argon, and cyanogen. Observed spectral lines in the 250-370 GHz region were analyzed by using the 2 Σ energy level expression, to give the rotational, centrifugal distortion and spin-rotation constants: B 0 = 5966.8969(24) MHz, D 0 = 0.004 2338(35) MHz, H 0 = 0.308(16) × 10 -7 MHz, and γ 0 = 15.219(13) MHz, with one standard deviation in parentheses.