FOURIER TRANSFORM INFRARED SPECTRA OF FORMALDOXIME: THE $\nu_{7}$, $\nu_{9}$, $\nu_{11}$, $\nu_{12}$, and $2\nu_{12}$, BANDS

Abstract

A first full rotational analysis of high resolution gas phase spectra of the lowest frequency fundamental bands, $\nu_{9}$ and $\nu_{12}$ of formaldoxime, $CH_{2}NOH$, has been completed. In addition the weak $\nu_{7}$ fundamental has been analysed at medium resolution, and the complex structure of the bands in the $\nu_{11}$ and $2\nu_{12}$ region has been revealed. It is shown that the complexity of the spectrum of the latter region is due to Coriolis interaction between the overtone $2\nu_{12}$ and the fundamental band $\nu_{11}$. The region covered in this analysis is from 8-30 pm. Since the molecule has Cs symmetry, in principle all the bands of $A^{\prime}$ symmetry are AB hybrids. Although the $\nu_{4}$, $\nu_{5}$, $\nu_{6}$, and $\nu_{8}$ fundamental bands described previously are predominantly A type, the $\nu_{7}$ band is found to be almost a pure B-type band. The $\nu_{11}$ and $\nu_{12}$ bands are C-type bands. The band origins ($cm^{-1}$) are $\nu_{7}$ 1157.282 $\nu_{9}$ 530.01785 $\nu_{11}$ 772.78, $\nu_{12}$ 397.68499 and 2$\nu_{12}$ 778.517