Knowledge Bank

The pure rotational spectrum of FeN in its $X2\Delta i$ electronic ground state has been observed in the region of 190 - 530 GHz using direct absorption techniques. The spectrum of CrN has been recorded in its $X4\Sigma -$ state as well. These nitrides were formed by reacting metal vapor, produced by a Broida-type oven, with either $N2$ or $NH3$ under d.c. discharge conditions. For FeN, eight rotational transitions were measured in the $\Omega =5/2$ spin orbit component, where no evidence of A-type doubling was observed. For CrN, five rotational transitions were recorded in which all fine structure components were resolved. These data have been analyzed and rotational and certain fine-structure parameters have been determined. Bonding in metal nitride species is also discussed.