High sensitivity CW-Cavity Ring Down Spectroscopy of N2O between 6950 and 7653 cm−1 (1.44-1.31 μm): I. Line positions

The absorption spectrum of nitrous oxide, N2O, has been recorded by CW-Cavity Ring Down Spectroscopy between 6950 and 7653 cm−1. The spectra were obtained at Doppler limited resolution using a CW-CRDS spectrometer based on a series of fibered DFB laser diodes. The typical noise equivalent absorption, in the order of αmin≈1×10−10 cm−1, allowed for the detection of lines with intensity as small as 1×10-29 cm/molecule.The positions of 7203 lines of four isotopologues (14N216O, 14N15N16O, 15N14N16O and 14N218O) were measured with a typical accuracy of 1.0×10−3 cm−1. The transitions were rovibrationally assigned on the basis of the global effective Hamiltonian models developed for each isotopologue. The band by band analysis allowed for the determination of the rovibrational parameters of more than 95 bands, most of them being newly reported while new rotational transitions are measured for the others. The measured line positions of the main isotopologue are found to be in good agreement with the predictions of the effective Hamiltonian model but a few deviations up to 0.20 cm−1 are observed. Local rovibrational perturbations were evidenced for several bands. The interaction mechanisms and the perturbers were univocally assigned on the basis of the effective Hamiltonian models.

► High sensitivity Cavity Ring Down Spectroscopy of N2O, between 6950 and 7653 cm−1. ► 7203 lines of four isotopologues: 14N216O, 15N14N16O, 14N15N16O and 14N218O. ► A total of 95 bands analyzed, 61 of them being newly reported. ► Intra- and interpolyad perturbations identified for eleven bands. ► Good agreement with the predictions of the effective Hamiltonian models.