Fourier Transform Far-Infrared Spectroscopy of the NH2, NHD, and ND2Radicals☆

Abstract The gas-phase far-infrared absorption spectra of the NH 2 , NHD, and ND 2 radicals have been observed in the 51–366 cm −1 region with a high-resolution Fourier transform spectrometer. The NH 2 radical was generated in a multiple-traversal absorption cell by a dc discharge in an NH 3 and Ar mixture. A discharge in an NH 3 , D 2 , and Ar mixture was used for production of NHD and ND 2 . The observed spectra with a resolved fine structure were analyzed by Watson's A-reduced Hamiltonian including a spin–rotation interaction term. The rotational and spin–rotation constants were determined to higher order. In the same experiment of NH 2 , the rotational spectrum of the NH radical was also observed. From the rotational constants, inertia defect Δ and r 0 structure were determined, as follows, with one standard deviation in parentheses:[table]