Analysis and theoretical modeling of the ¹⁸O enriched carbon dioxide spectrum by CRDS near 1.35 μm: (I) ¹⁶O¹²C¹⁸O, ¹⁶O¹²C¹⁷O, ¹²C¹⁶O₂ and ¹³C¹⁶O₂

The room temperature absorption spectrum of ¹⁸O enriched carbon dioxide has been recorded by very high-sensitivity Cavity Ring Down spectroscopy between 6977 and 7918 cm⁻¹ (1.43−1.26 μm). The achieved sensitivity (noise equivalent absorption α_min ~8×10⁻¹¹ cm⁻¹) has allowed for the detection of more than 8600 lines belonging to 166 bands of eleven carbon dioxide isotopologues. Line intensities of the weakest observed transitions are on the order of 2×10⁻³⁰ cm/molecule. In this first part, we present the results relative to the ¹⁶O¹²C¹⁸O, ¹⁶O¹²C¹⁷O, ¹²C¹⁶O₂ and ¹³C¹⁶O₂ isotopologues. Their absorption lines were rovibrationally assigned on the basis of the predictions of their respective effective Hamiltonian model. Overall 5476 lines were measured and assigned to 93 bands. Forty nine of them, all belonging to ¹⁶O¹²C¹⁸O and ¹⁶O¹²C¹⁷O, are reported for the first time. The studied spectral region is formed by ΔP=10–12 series of transitions, where P=2V₁+V₂+3V₃ is the polyad number (V_i are vibrational quantum numbers). The spectroscopic parameters of 58 bands of ¹⁶O¹²C¹⁸O and ¹⁶O¹²C¹⁷O were determined from a fit of the measured line positions. An inter- and an intrapolyad resonance perturbation were identified and analyzed in the ¹⁶O¹²C¹⁸O spectrum. The comparison with the line positions and line intensities included in the AMES line list is discussed. Global fits of the line intensities were performed in order to (i) improve the ΔP=10 and 11 sets of the effective dipole moment parameters of ¹⁶O¹²C¹⁸O and the ΔP=11 set of parameters of ¹⁶O¹²C¹⁷O and (ii) derive for the first time the ΔP=10 and 12 parameters of ¹⁶O¹²C¹⁷O and ¹⁶O¹²C¹⁸O, respectively. - Highlights: • Cavity Ring Down spectroscopy of ¹⁸O enriched CO₂ between 6977 and 7918 cm⁻¹. • 4243 transitions belonging to 59 bands of ¹⁶O¹²C¹⁸O and ¹⁶O¹²C¹⁷O are assigned. • Thirty seven ¹⁶O¹²C¹⁸O and twelve ¹⁶O¹²C¹⁷O bands are newly assigned. • Improved or new effective dipole moment parameters for ΔP=10–12 series of bands.