HIGH RESOLUTION FTIR SPECTRA OF METHYL NITRITE AND ASSIGNMENT OF THE $\nu_{8}$ FUNDAMENTAL OF THE CIS CONFORMER

Abstract

$^{a}$ Turner, P. H., et al., J. Phys. Chem. 83 (11), 1473 1979. $^{b}$ Ghosh, P. N., et al., Chem. Phys. 53 (1-2), 39 1980. $^{c}$ Stidham, H. D., et al. J. Raman Spec. 21 (1-2), 615 1990; da Silva, J. B. P., et al. J. Molec. Struct. 375 (1/2), 153 1996; and references therein.Author Institution: Department of Chemistry, Idaho State University; Department of Chemistry, Pacific Northwest National LaboratoryThe infrared spectrum of gas phase methyl nitrite $(CH_{3}ONO)$ has been recorded at high resolution between 600 and $4000 cm^{-1}$. The conformational doublets due to the cis and trans conformers are clearly separated in a number of the fundamentals. Previous work in the microwave has established that the barrier to rotation of the methyl group in the trans form is very $low^{a}$ and the infrared bands observed in this study are very congested. The barrier in the cis conformer is much $higher^{b}$. The $\nu_{8}$ at $841 cm^{-1}$ was assigned by previous workers to the N-O stretch of the cis $conformer^{c}$ and is partially overlapped by the $\nu_{8}$ of the trans conformer. In this study, spectra taken at $0.0015 cm^{-1}$ resolution on the PNNL IFS120/HR in a 20 cm cell were used to assign more than 800 A-type rovibrational lines of the cis $\nu_{8}$ between 815 and $865 cm^{-1}$