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

Abstract The room temperature absorption spectra of nitrous oxide, N 2 O, have been recorded in the 6950–7653  cm −1 spectral region at 2 and 10 Torr using a CW-CRDS spectrometer based on 24 fibered DFB lasers. The achieved sensitivity (noise equivalent absorption α min ≈5×10 –11  cm −1 ) allowed detecting lines with intensities as low as 1×10 –29  cm/molecule. In the preceding contribution (Lu Y, Mondelain D, Liu AW, Perevalov VI, Kassi S, Campargue A, J Quant Spectros and Radiat Transfer 2012;113:749–62), we reported the assignment of more than 7200 N 2 O lines in the region and the derivation of the corresponding spectroscopic parameters G v , B v , D v and H v . In the present work, more than 1300 14 N 2 16 O absolute line intensities of cold and hot bands belonging to the Δ P =12, 13 and 14 series of transitions have been measured ( P =2 V 1 + V 2 +4 V 3 is the polyad number). The uncertainty of the obtained line intensity values varies from 4 to 7% for the majority of the lines. The obtained dataset extends importantly the set of measurements available in the literature, in particular for the Δ P =13 series for which previous data were very limited. The Δ P =12–14 effective dipole moment parameters were fitted to the intensity values measured in this work and available in the literature. The obtained sets of the dipole moment parameters allow reproducing the observed line intensities within their experimental uncertainties. The calculated intensities of the Δ P =12, 13 and 14 bands of 14 N 2 16 O assigned by CRDS in the 6950–7653  cm −1 region are provided as supplementary material.