The bending vibrations in 12C2H2 : Global vibration-rotation analysis

International audience; A total of 3155 vibration-rotation line positions providing accurate information on all known vibration-rotation states up to 3000 cm-1 in 12C2H2 were gathered from the literature. Additional 966 lines were assigned on new spectra. The full data set was simultaneously fitted using an appropriate Hamiltonian, with 85 refined parameters. A dimensionless standard deviation equal to 0.86, accounting for 92 % of the lines, was achieved. The vibrational transition dipole moment of the v5 = 1 ← v4 = 1 band observed in the far-infrared was estimated to be │μ5←4│ = 0.55 D with 20 % accuracy, from absolute intensity measurements for a few Q-branch lines.