Temperature-dependent line parameter study of acetylene transitions near 3 µm

Knowledge of the acetylene spectrum is important for astrophysics, atmospheric, and combustion chemistry research. Twelve acetylene transitions across eleven bands have been studied between 3335.0 and 3336.5 cm−1 with a tunable interband cascade laser. Linestrengths and temperature-dependent lineshape parameters, including collisional broadening and narrowing, are reported through Voigt, Rautian, and Galatry lineshape fits to two strong cold band transitions. Measurements were made in pure acetylene, as well as with diluents argon, nitrogen, and methane, over a temperature range of 296-637 K and pressures of 5-90 Torr. Linestrengths and temperature-dependent self-broadening coefficients are also reported for ten weak hot band transitions through Voigt lineshape fits, measured between 296-513 K and 5-20 Torr. Line parameter measurements are found to be in good agreement with the literature and extend experimental lineshape studies of acetylene into new rovibrational bands, a sparsely-studied temperature regime, and a new perturber: methane.