0_{0,0},\tfrac{1}{2}$ & 527.1808 & 40.2 & 0.20 & 4.5 & 3.98(7) & 0.83 & 0.66(8) & 2.0(3)\
\

Since the $J = \tfrac{3}{2}-\tfrac{1}{2}$ fine-structure line is detected at ca. 10$\sigma$ level, we could adjust all the four parameters in the model. The $J = \tfrac{1}{2}-\tfrac{1}{2}$ component is about twice weaker and its detection is only at ca. 5$\sigma$ level. In this case, the noise prevented to adjust $T_{\ensuremath{\mathrm{ex}}}$ and $\Delta\varv$, which were then fixed at the values obtained for the strongest component of the fine-structure doublet. For , we found an excitation temperature of $7.4 \pm 0.1$K, slightly lower than that of . This small difference is likely to be produced by the bigger *Herschel* beam size in the 2b band ($\sim 27$[$^{\prime\!\prime}$]{}) compared to that in the 4a band ($\sim 22$[$^{\prime\!\prime}$]{}). Indeed, a larger region is sampled for the lines, and the contribution of the inner warmer gas is expected to be slightly smaller. The average value of the column density is $N = (4.7\pm 0.7)\times 10^{13}$cm$^{-2}$.

Compared to the parent isotopologue, the doubly deuterated form of amidogen has a denser spectrum in the sub-millimeter region, thus both the $N_{Ka,\,Kc} = 1_{1,1} \leftarrow 0_{0,0}$ and $N_{Ka,\,Kc} = 2_{1,2} \leftarrow 