High sensitivity CW-Cavity Ring Down Spectroscopy of N2O near 1.5μm (II)

Abstract

We present the second part of the investigation of the high sensitivity absorption spectrum of nitrous oxide by CW-Cavity Ring Down Spectroscopy near 1.5 lm. In a first paper [A.. 244 (2007) 33-47] devoted to the 6000-6833 cm À1 region, more than 6000 line positions of five isotopologues ( 14 N 2 16 O, 15 N 14 N 16 O, 14 N 15 N 16 O, 14 N 2 17O, and 14 N 2 18 O), were rovibrationally assigned to a total of 68 bands. The achieved noise equivalent absorption (a min $ 2 · 10 À10 cm À1 ) allowed for the detection of lines with intensity weaker than 2 · 10 À29 cm/molecule. In this contribution, the investigated region was extended down to 5905 cm À1 and additional recordings allowed accessing small spectral sections uncovered in our preceding recordings. A deeper analysis based on the predictions of the effective Hamiltonian model has allowed assigning a total of 3149 transitions and lowering the percentage of lines left unassigned from 51% to 28%. It led to the analysis of 35, 6, 7, and 6 bands for the 14 N 2 16 O, 15 N 14 N 16 O, 14 N 15 N 16 O, and 14 N 2 18 O isotopologues, respectively. Forty-two of these 54 bands are newly observed, while the rotational analysis of the twelve others is significantly extended and improved. Most of the bands were found unperturbed and their line positions could be reproduced within the experimental uncertainty (about 1 · 10 À3 cm À1 ). The corresponding spectroscopic parameters are reported. Local rovibrational perturbations induced by either intrapolyad or interpolyad couplings were found to affect five hot bands of 14 N 2 16 O. Their detailed analysis is presented.

High sensitivity CW-cavity ring down spectroscopy of N2O near 1.5μm (III)

“…This work is a continuation of our previous studies of the absorption spectrum of nitrous oxide by high sensitivity CW-Cavity Ring Down Spectroscopy (CW-CRDS) [1,2] near 1.5 lm. We have developed a fibered CW-CRDS spectrometer using Distributed Feed-Back (DFB) diode lasers dedicated to the characterization of this important atmospheric window of transparency.…”

Fourier-transform spectroscopy of 14N15N16O in the 3800–9000cm−1 region and global modeling of its absorption spectrum

“…For 27 bands reported in Refs. [5][6][7][8][9][10][11][12][13], our work extends to higher J value transitions and allows a refinement of the spectroscopic constants. They are reviewed and included in Table 3.…”

“…The uncertainties are given in parenthesis in the unit of the last quoted digit. When a given band has been previously analyzed, the corresponding spectroscopic parameters are given in italics for comparison: T Toth [9], A Amiot [5], H Herbin [11] L Liu et al [12,13], W Wang [10]. The cold and hot bands are listed successively and ordered according to their DG v values.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13]22]. The measurements include microwave, Fourier-transform, ICLAS and CRDS.…”

“…As a consequence, the high-resolution spectra of this molecule are widely used for the monitoring of its concentration in atmosphere and in the combustion exhaust. 15 [1][2][3], Fourier-transform infrared spectrometers (FTS) [4][5][6][7][8][9][10], intra-cavity laser absorption spectrometer (ICLAS) [11], and cavity ringdown spectrometer (CRDS) [12,13]. All the above listed measurements were carried out with natural nitrous oxide samples.…”