High Resolution Infrared Spectra of the ν₂ and 2ν₁ Bands of ¹⁴N¹⁶O₂

The infrared spectra of two B type bands, ν 2 and 2ν 1 , of 14 N 16 O 2 have been recorded under high resolution. Ground state combination differences from these bands have been combined with combination differences obtained in previous studies and eight pure rotational microwave transitions to yield improved ground state rotational constants. Upper state constants and band centers for the ν 2 and 2ν 1 bands are also reported. The 2ν 1 band contains internal intensity anomalies believed to arise from a weak Coriolis interaction with the much stronger ν 1 + ν 3 band. Equilibrium rotational constants have been calculated. The equilibrium structure of the molecule is: r c = 1.1945 ± 0.0005 Å and Θ c = 133.85 ± 0.10°. For the sake of comparison, effective, substitution, and average structures are also reported.