The electronic emission spectrum of methylnitrene

The à 3E–X̃ 3A2ultraviolet emission spectrum of methylnitrene (CH3N) was obtained in two ways: (1) by reacting methylazide (CH3N3) with metastable N2 in a flowing afterglow; and (2) by discharging a mixture of methylazide (CH3N3) and helium in a corona excited supersonic expansion (CESE). The origin appears at T0=31 811 cm−1. Several vibrational progressions were observed leading to the determination of a number of vibrational frequencies: v″1=2938 , v■2=1350, v″3=1039, v■4=3065, and v″6=902 cm−1. Deuterium substitution confirmed the assignments of the vibrational frequencies. The X̃ 3A2 state is a normal, bound local minimum on the triplet electronic potential surface, and the upper à 3E state is able to support at least one quantum of vibration, assigned to v3, predominantly a C–N stretch. A comparison of flowing afterglow hollow cathode discharge sources and corona excited supersonic expansion sources shows the advantage of the CESE method of radical production for spectroscopy.