New acetylene line list near 5μm - Part I: 12C2H2

The spectroscopic knowledge of the 5-µm spectral region of acetylene has been improved from the analysis of Fourier Transform spectra using high optical path length (up to 1 km). In the present work line positions and intensities were investigated for around 4300 transitions belonging to 60 bands of ¹²C₂H₂ including 15 bands already present in the HITRAN and GEISA databases. The band centers and the upper level spectroscopic constants were retrieved for all bands. Comparisons of measured line positions and calculated ones (with spectroscopic constants or effective Hamiltonian model) were performed for each band in order to select the best model to retain. The effective dipole moment operator parameters describing intensities observed in the ΔP = 3 spectral region were refined. The measured line positions and intensities have also been compared to the literature data included in the HITRAN and GEISA databases showing a good consistency for most of the bands, except for some bands for which only a few transitions were measured. A complete list of calculated line parameters for 6200 transitions has been generated for 60 bands between 1767 cm⁻¹ and 2267 cm⁻¹ and is available in the HITRAN format as supplementary material of this work.