ABSTRACT: Irradiation of ammonia dispersed in solid neon near 4 K with tunable far-ultraviolet light from a synchrotron yielded amidogen, NH2, and imidogen, NH, radicals as products. The electronic absorption spectra of amidogen radicals in isotopic variants NH2, NHD, and ND2 were recorded in the visible and near-ultraviolet regions after photolysis of NH3 and ND3. The infrared absorption lines of NH2 associated with vibration-rotational levels of vibrational modes ν1 at 3234.3 (00,0-10,1), 3244.9 (00,0-11,1), and 3249.3 cm-1 (00,0-11,0), and ν2 at 1498.7 (10,1-11,1), 1509.5 (11,0-10,1), 1516.5