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A continuous-wave cavity ring-down spectrometer was employed to record the spectrum of the acetylene molecule spanning the 12350 - 12790 cm−1 region. A total of 747 lines from the principal isotopologue and 68 lines from 12C13CH 2 were identified, with nearly all line intensities retrieved from the spectra. These lines belong to eighteen vibrational bands of 12C 2 H 2 and two vibrational bands of 12C13CH 2 , among which five vibrational bands are reported here for the first time. Spectroscopic constants were deduced for all the identified bands, and the vibrational dipole moment squared along with Herman–Wallis coefficients were determined for the majority of these bands. Additionally, several resonance interactions were thoroughly explored. [Display omitted] • CRDS spectrum of acetylene in the 800 nm region. • Eighteen observed bands of 12C 2 H 2 and two observed bands of 12C13CH 2 • Five newly observed bands. • The experimental line intensities for nineteen bands of acetylene in the 800 nm region. [ABSTRACT FROM AUTHOR]

• More than 2900 transitions of 14N15N16O and 15N14N16O isotopologues were obtained with CW-CRDS spectroscopy in the range of 6277 – 6512 cm−1. • Six bands of 14N15N18O, 14N15N17O, 15N14N18O, 15N14N17O minor nitrous oxide isotopologues were found for the first time in the near infrared region. • New sets of the effective Hamiltonian parameters are determined for the 14N15N16O and 15N14N16O isotopologues. The absorption spectrum of nitrous oxide around 1.56 µm has been recorded with Doppler limited resolution by a continuous-wave cavity ring-down spectrometer at room temperature using 15N-enriched samples. The typical sensitivity was at the level of 2 × 10−10 cm−1. In total, 3389 transitions were observed and ro-vibrationally assigned on the basis of the global effective Hamiltonian model for six nitrous oxide isotopologues (14N15N16O, 15N14N16O, 14N15N18O, 15N14N18O, 14N15N17O and 15N14N17O). The band-by-band analysis led to the determination of ro-vibrational parameters of 47 bands, 36 of them were newly observed, and the rotational analysis of 11 others were significantly extended and improved. New sets of the effective Hamiltonian parameters were determined for the 14N15N16O and 15N14N16O isotopic species. [ABSTRACT FROM AUTHOR]

• The spectrum of 00°3 – 00°0 band of 14N 2 16O is studied with a laser-locked cavity ring-down spectrometer referenced to an optical frequency comb. • 88 line positions are determined with an uncertainty below 1.0 MHz. • N 2 -induced broadening and shift coefficients of 20 isolated lines were retrieved with the voigt and quadratic speed-dependence voigt profiles. • Comparisons of line parameters determined in this work with those given in literatures are discussed. Ro-vibrational transitions of the 00°3–00°0 band around 1.52 µm with line intensities in the order of 10−24 to 10−23 cm−1/(molecule·cm−2) have been recorded using a comb-assisted laser-locked cavity ring-down spectrometer with high sensitivity as well as high precision. In total, 88 line positions were determined with a sub-MHz uncertainty (1-σ), better than previous experimental results by 1–2 order of magnitude. N 2 -induced line shape parameters of 20 isolated transitions were derived by using the Voigt profile and the quadratic Speed-Dependent Voigt profile with relative uncertainties of 1–2% (1-σ). Comparisons of the line parameters determined in this work with literature experimental values are given. [ABSTRACT FROM AUTHOR]

Thirty well isolated ro-vibrational transitions of the 30011e – 00001e band of 12 C 16 O 2 at 1.54 μm have been recorded with a laser-locked cavity ring-down spectrometer. The line intensities were obtained with accuracies better than 0.85%. Comparisons of the line intensities determined in this work with literature experimental values and those from HITRAN2016, AMES, UCL-IAO and CDSD-296 line lists are given. [ABSTRACT FROM AUTHOR]

The extremely weak 6–0 absorption band of the 12 C 16 O molecule was recorded for the first time using a very sensitive cavity ring-down spectrometer. Frequencies of a few atomic transitions in the 0.8 μm region, transferred to the passive modes of a thermally stabilized Fabry-Pérot interferometer, are used to calibrate the observed spectra with an absolute accuracy of 3×10 −4 cm −1 . Line parameters, including line positions, intensities, self-broadening and -shifting coefficients were derived by fitting the observed spectra with the Voigt profile. [ABSTRACT FROM AUTHOR]

Highlights: [•] Eight electric quadrupole lines in the (3–0) band of were recorded by CRDS. [•] Extremely weak (5) line (I =9.2E−31cm/molecule) was detected for the first time. [•] Positions of six lines were determined with an accuracy of . [•] Results agree with the calculations including high-level QED effects. [Copyright &y& Elsevier]

• The Doppler free saturated absorption spectrum of sixty-one transitions were measured with a comb-locked cavity ring-down spectrometer around 1.57 μm for carbon monoxide. • The line positions were determined with an accuracy of a few kHz for the transitions with a wide intensity range of three orders of magnitude. • An independent set of rotational spectroscopic parameters was derived with 30 ground combination difference for the ground vibrational state with a standard deviation of 4.5 kHz. • The pure rotational line lists of the υ = 0 ← 0 and υ = 3 ← 3 were constructed in the 112 GHz – 3.89 THz regions. Molecular transitions provide natural frequency standards for spectroscopy, telecommunication, and astrophysics. The frequency accuracy is also crucial in various tests of fundamental physics. A comb-locked cavity ring-down spectrometer measured lamb dips of sixty-one 12C16O transitions around 1.57 μm in the second overtone band. The positions were determined with an accuracy of a few kHz. A new set of rotational spectroscopic parameters was derived with 30 ground state combination difference for the ground vibrational state with a standard deviation of 4.5 kHz. It results in a refinement of the ro-vibrational spectroscopic constants for the v =3 vibrational state. These parameters allow the pure rotational line lists of the υ = 0 ← 0 and υ = 3 ← 3 in the 112 GHz – 3.89 THz regions. [ABSTRACT FROM AUTHOR]

• More than 500 transitions assigned to 13 vibrational bands of H 2 17O. • About 110 vibration-rotational energies of H 2 17O are newly obtained. • The line positions were found to have significant discrepancies for more than 90 transitions of H 2 16O and H 2 17O in HITRAN2016 database. The absorption spectrum of oxygen-17-enriched water vapor in the 12,055–12,260 cm−1 region was recorded with a continuous-wave cavity ring-down spectrometer (CW-CRDS) at room temperature. In total, 1342 lines were observed in this region, while more than 1400 absorption transitions were assigned based on previously published experimental energies and the variational calculations based on the results of Partridge and Schwenke. The typical frequency accuracy of 0.002 cm−1 was achieved in this work. Three hundred and fifty-eight ro-vibrational energy levels of H 2 17O water isotopologue were retrieved, which belong to the ν 1 + 1 2 ν 2 + ν 3 =3.5 and 4 polyads: (0 1 3), (0 3 2), (1 1 2), (1 3 1), (2 1 1), (2 2 1), (2 3 0), (3 0 1), and (3 1 0) states. One hundred and ten of them were reported for the first time. Comparisons of experimental line positions with those in the HITRAN database were given for H 2 16O and H 2 17O isotopologues. The obtained vibration-rotation energy levels were also compared with MARVEL values. [ABSTRACT FROM AUTHOR]