Direct observation of the ν1 and ν3 fundamental bands of NH 2 by difference frequency laser spectroscopy
The ν1 and ν3 bands of the NH 2 radical were detected in absorption in the 2.9- to 3.2-μm region using a tunable difference frequency laser and a long-path Zeeman-modulated discharge cell. About 100 rotation-vibration transitions were measured and a simultaneous analysis of the Coriolis-coupled ν1 and ν3 states was made. It was found that the ν1 band is considerably stronger than ν3, in contrast to the similar molecule H 2O. These results may prove useful in a search for interstellar NH 2 by means of its rotation-vibration spectrum.