HIGH RESOLUTION INFRARED SPECTRUM OF $CH_{2}NH$

Author Institution: Department of Physical Chemistry, University of Helsinki; Department of Physics, University of StratholydeThe infrared spectrum of methyleneimine, $CH_{2}$NH, has been observed in the gas phase with a resolution of $0.0048 cm^{-1}$ ($700 - 1400 cm^{-1}$) and of $0.01 cm^{-1}$ ($2800 - 3400 cm^{-1}$). $CH_{2}$NH was produced by the pyrolysis of $CH_{3}$NH$_{2}$ at ca. $1000^{\circ}$C. Altogether seven bands, $\nu_{1}, \nu_{2}, \nu_{3}, 2\nu_{5}, \nu_{7}, \nu_{8}$ and $\nu_{9}$, have been observed and analyzed to yield accurate spectroscopic parameters. The $\nu_{3}$ and $2\nu_{5}$ bands were coupled by a high order Coriolis type of resonance and the $\nu_{7}$, $\nu_{8}$ and $\nu_{9}$ fundamentals were strongly coupled by Coriolis interaction. For the latter system more than 2500 transitions were assigned, of which many are ``forbidden” transitions, such as $^{q} Q$ branches, induced in the $\nu_{9}$ band by the strong Coriolis interaction between $\nu_{7}$ and $\nu_{9}$. The standard deviation of the fit, $0.00075 cm^{-1}$, shows clearly the excellent quality of the results. The $\nu_{1}, \nu_{2}, \nu_{3}$ and 2$\nu_{5}$ bands showed signs of perturbations at high J and $K_{a}$ quantum numbers and only part of the assigned transitions could be included in the final fits