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, N2O, have been recorded in the 6950–7653 cm−1 spectral region at 2 and 10Torr using a CW-CRDS spectrometer based on 24 fibered DFB lasers. The achieved sensitivity (noise equivalent absorption αmin≈5×10–11cm−1) allowed detecting lines with intensities as low as 1×10–29cm/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 N2O lines in the region and the derivation of the corresponding spectroscopic parameters Gv, Bv, Dv and Hv. In the present work, more than 1300 14N216O absolute line intensities of cold and hot bands belonging to the ΔP=12, 13 and 14 series of transitions have been measured (P=2V1+V2+4V3 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 ΔP =13 series for which previous data were very limited. The ΔP=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 ΔP=12, 13 and 14 bands of 14N216O assigned by CRDS in the 6950–7653 cm−1 region are provided as supplementary material.