12C16O2: Σ and Π Fermi dyads in the 4.5-μm region: Wavenumbers and spectroscopic constants

Emission spectra of CO₂ vibrationally excited by a dc electric discharge were recorded under Doppler-limited resolution, using the high information interferometer of Laboratoire d'Infrarouge Orsay, France, in the spectral region 4–5 μm. Sixteen bands with Δv₃ = 1 of ¹²C¹⁶O₂ involving the Fermi dyads (10⁰v₃, 02⁰v₃)_{I and II} and (11¹v₃, 03¹v₃)_{I and II} have been studied. The band centers and the spectroscopic constants for all the vibrational levels involved are given. They reproduce the experimental wavenumbers with a rms of the order of 4 × 10^?5 cm^?1 for the best vibrational transition and always less than 3 × 10^?4 cm^?1 for the others. These results are compared with laser measurements for the (10⁰0, 02⁰0) dyad.