High sensitivity CW-cavity ring down spectroscopy of N 2O near 1.5 μm (III)

Abstract

We present the third part of the investigation of the high sensitivity absorption spectrum of nitrous oxide by CW-Cavity Ring Down Spectroscopy near 1.5 μm. In the two first contributions (A. Liu, et al., J. Mol. Spectrosc. 244 (2007) 33–47 and A. Liu, et al., J. Mol. Spectrosc. 244 (2007) 48–62) devoted to the 5905–6833 cm −1 region, more than 9000 line positions of five isotopologues ( 14N 2 16O, 15N 14N 16O, 14N 15N 16O, 14N 2 17O and 14N 2 18O), were rovibrationally assigned to a total of 115 bands, most of them being newly detected. The achieved sensitivity ( α min∼3 × 10 −10 cm −1) allowed for the detection of lines with intensity weaker than 2 × 10 −29 cm/molecule. In this contribution, the investigated region was extended up to 7066 cm −1. The analysis based on the predictions of the effective Hamiltonian model has allowed assigning about 1500 transitions to 17, 1, 2 and 1 bands of the 14N 2 16O, 14N 15N 16O, 15N 14N 16O and 14N 2 18O isotopologues, respectively. Eleven of these 21 bands are newly reported, while the observations of the transitions are extended to higher J values for most of the others. The band by band analysis has allowed reproducing the measured line positions within the experimental uncertainty (about 1 × 10 −3 cm −1) and determining the corresponding spectroscopic parameters. A detailed analysis of the rovibrational perturbations affecting three bands of 14N 2 16O is presented.