Infrared spectra of the methyl halides. Methyl fluoridenear 4100 Cm −11

Abstract

High resolution infrared spectra of methyl fluoride between 3900 and 4500 cm −1 have been obtained and analyzed. The parallel band near 4011 cm −1 has been assigned to ν 1 + ν 3 , and the perpendicular band near 4060 cm −1 has been assigned to ν 3 + ν 4. Several perturbations were observed in ν 3 + ν 4 , and one of them has been interpreted as a combination of a first-order Coriolis effect with ν 1 + va and ℓ-type doubling in the K = ℓ = ± 1 upper states of ν 3 + ν 4. A set of molecular constants which reproduce the transition frequencies of the nonmeasurably perturbed transitions has been obtained together with a value for 14 X and the ℓ-type doubling constant for ν 3 + ν 4.