The infrared bands ν2 and ν5 of CH3Br with Coriolis interaction

The infrared bands ν₂ and ν₅ of CH₃Br have been measured at a resolution of 0.015 cm^?1. The lines due to the isotopic species CH₃⁷⁹Br and CH₃⁸¹Br were resolved and altogether about 3000 lines were assigned. The bands were analyzed simultaneously by taking into account the xy-Coriolis resonance between the states v₂ = 1 and v₅ = 1. A local perturbation observed in ν₅ could be explained in terms of a (1,?2) resonance between v₂ = 1 and v₅ = 1. Some perturbation allowed transitions could be assigned and they give an equation between A₀ and D₀^K.