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The ammonia spectrum is revisited in the important 1.6 µm atmospheric transparency window between 5650 and 6350 cm $ ^{-1} $ − 1 on the basis of recently recorded high-resolution Fourier transform spectra. These spectra offer an improved frequency sampling and better traceability of the measurement conditions compared to previously studied Kitt Peak spectra (Cacciani et al. J. Quant Spectrosc Radiat Transf 2021; 258:107334. https://doi.org/10.1016/j.jqsrt.2020.107334). Overall, 4812 $ ^{14} $ 14 NH $ _3 $ 3 lines were measured in the 5650–6350 cm $ ^{-1} $ − 1 region corresponding to 4866 transitions including 2066 new ones compared with our previous study, included in the HITRAN2020 database. The energy of 1023 upper state levels (including 107 new ones) was derived from 2608 assigned transitions. Independently, ammonia spectra recorded in a supersonic jet expansion using a tunable extended cavity diode laser allow us to check the absolute transition energies in the 5980–6080 cm $ ^{-1} $ − 1 range. Accurate jet spectra calibration was achieved using CH $ _4 $ 4 reference line positions known with kHz accuracy. The position agreement with the FTS data is within the $ 4\times 10^{-4} $ 4 × 10 − 4 cm $ ^{-1} $ − 1 uncertainty of the positions measured in the jet expansion. A recommended line list of 5620 transitions is provided for $ ^{14} $ 14 NH $ _3 $ 3 in the considered 5650–6350 cm $ ^{-1} $ − 1 region. [ABSTRACT FROM AUTHOR]

The absorption spectrum of dideuteroacetylene has been recorded by intracavity laser absorption spectroscopy (ICLAS) in the 10 200-12 500 cm 1 spectral region. Among 25 absorption bands of [sup 12]C[sub 2]D[sub 2] rotationally analysed in this spectral region, 17 are newly observed. They include one Πu-Σg+and thirteen Σu+-Σg+bands starting from the vibrational ground state and eleven hot bands from the V[sub 4] = 1 and V[sub 5] = 1 lower states. The rotational structure of two excited levels is affected by a strongly J-dependent interaction with a perturber which induces intensity transfer to extra lines. The coupling is identified as a l-resonance interaction with Δu dark states and the vibrational assignment of the perturbers is discussed. Two Σ-Σ bands of the [sup 12]C[sup 13]CD[sub 2] species, present in natural abundance in the sample, could also be identified and rotationally analysed. Most of the corresponding excited vibrational levels of [sup 12]C[sup 2]D[sup 2] were unambiguously assigned using the polyad model \[HERMAN, M., EL IDRISSI, M. I., PISARCHIK, A., CAMPARGUE, A., GAILLOT, A.-C., BIENNIER, L., DI LONARDO, G. and FUSINA, L., 1998, J. chem. Phys., 108, 1377] which allows vibrational energies and BV rotational constants to be predicted. In particular the previously highlighted 1/244 anharmonic resonance is confirmed by energy and intensity features in several {( V 1, V 2, V 3, V 4 = 0, V 5 = 0), (V[sub 1]-1, V[sub 2] + 1, V[sub 3], V[sub 4] = 2, V[sub 5] = 0)} dyads. Significant deviations between predicted and experimental energy levels are observed for a few levels and discussed. [ABSTRACT FROM AUTHOR]

The absorption spectrum of 12C H has been recorded at high resolution by intracavity laser 2 2- absorption spectroscopy between 14 500 cm 1 and 17 000 cm 1. Among the 32 bands which have been rotationally analysed 15 are newly observed, and improved rovibrational parameters are obtained for the others. The new resulting set of 26 vibrational levels is assigned by extrapolating the cluster model built from lower energy data (Abbouti Temsamani, M., and Herman, M., 1995, J. chem. Phys. , 102, 6371) which allows vibrational energies and B rotational constants to be predicted. Intensity features are also discussed. V. [ABSTRACT FROM AUTHOR]

The rotational structure of the vibrational bands of 12C2H2 is investigated in three spect- ra 1l energy regions not previously systematically explored at high resolution, 12 800-13 500 cm , 14000-15 200 cm- 1 and 16 500-18 360 cm- 1, on the basis of new spectral data recorded by intracavity laser absorption spectroscopy. The + rota+ tional analysis of 17 + new absorption bands arising from the ground state is reported (11 u- g bands and 6 u- g bands). Four bands in the range studied show strong perturbations affecting both the line positions and intensities. Their detailed analysis is performed in order to determine the nature of the coupling schemes, the vibrational species and the rotational constants of the perturber states. Altogether, the vibration-rotation parameters of 21 newly observed vibrational states are derived. [ABSTRACT FROM AUTHOR]

The ammonia spectrum is revisited in the important 1.6 µm atmospheric transparency window between 5650 and 6350 cm $ ^{-1} $ − 1 on the basis of recently recorded high-resolution Fourier transform spectra. These spectra offer an improved frequency sampling and better traceability of the measurement conditions compared to previously studied Kitt Peak spectra (Cacciani et al. J. Quant Spectrosc Radiat Transf 2021; 258:107334. https://doi.org/10.1016/j.jqsrt.2020.107334). Overall, 4812 $ ^{14} $ 14 NH $ _3 $ 3 lines were measured in the 5650–6350 cm $ ^{-1} $ − 1 region corresponding to 4866 transitions including 2066 new ones compared with our previous study, included in the HITRAN2020 database. The energy of 1023 upper state levels (including 107 new ones) was derived from 2608 assigned transitions. Independently, ammonia spectra recorded in a supersonic jet expansion using a tunable extended cavity diode laser allow us to check the absolute transition energies in the 5980–6080 cm $ ^{-1} $ − 1 range. Accurate jet spectra calibration was achieved using CH $ _4 $ 4 reference line positions known with kHz accuracy. The position agreement with the FTS data is within the $ 4\times 10^{-4} $ 4 × 10 − 4 cm $ ^{-1} $ − 1 uncertainty of the positions measured in the jet expansion. A recommended line list of 5620 transitions is provided for $ ^{14} $ 14 NH $ _3 $ 3 in the considered 5650–6350 cm $ ^{-1} $ − 1 region. [ABSTRACT FROM AUTHOR]

The absorption spectrum of [sup 12] C[sub 2] H[sub 2] has been recorded by intracavity laser absorption spectroscopy (ICLAS) in the 10600-11500cm[sup -1] spectral region, where no absorption bands were previously reported. Fifteen bands starting from the vibrational ground state are observed and rotationally analysed. All corresponding excited vibrational levels were assigned using the polyad model, the so-called cluster model (El Idrissi, M.I., Liévin, J., Campargue, A., and Herman, M., 1999, J. chem. Phys. , 110, 2074) which allows vibrational energies, rotational B[sub V] constants and, to some respect, relative band intensities to be predicted. Additional data and constants are also provided in the range 7600-9200cm[sub -1] , whenever improving the literature results, from spectra recorded previously at ULB using Fourier transform spectroscopy. The assignment procedure in the range recorded by ICLAS is detailed, leading to a deeper understanding of vibration-rotation and intensity features of the absorption bands within the frame of the cluster model. [ABSTRACT FROM AUTHOR]