The Fourier transform infrared spectrum of methyleneimine in the 10 μm region

The infrared spectrum of methyleneimine, CH2NH, has been observed in the gas phase with a resolution of 0.0048 cm−1 using the National Optical Observatory solar Fourier transform spectrometer. The CH2NH was produced by the pyrolysis of CH3NH2 at ∼1000 °C. Vibrational band origins and rotational constants have been determined for the ν7, ν8, and ν9 bands. These were analyzed as a set of three states strongly coupled by Coriolis interaction. More than 2500 transitions were assigned, of which many are ‘‘forbidden’’ transitions, such as qQ branches, induced in the ν9 band by the strong Coriolis interaction between ν7 and ν9. Owing to the high precision of the data, and the high J values of many of the observed transitions, it was necessary to include many of the high order interaction constants in order to achieve a quantitative fit.