Broadening, shift and narrowing coefficients in the 2ν4 band of NH3 perturbed by O2, N2 and air

Abstract

Collisional broadening and shift coefficients as well as Dicke narrowing parameters have been measured at room temperature in the 2ν4 band of NH3 perturbed by O2 and N2 for 310 rovibrational lines with rotational quantum numbers 1 ≤ J ≤ 11 and 0 ≤ K ≤ 11.The experiments were performed at room temperature with ammonia mixtures in nitrogen and oxygen at different pressures using a high-resolution Fourier transform spectrometer and a mono-spectrum non-linear least squares fitting of Voigt and soft-collision Galatry profiles. Because of Dicke narrowing effect, departure from the Voigt profile is observed that allowed measurement of narrowing parameters for about 100 transitions of the 2ν4 band. The collisional broadening coefficients obtained with Galatry profile are larger by about 5% than those derived from Voigt profile. Average absolute accuracies of the measurements are estimated to be 5%, 10% and 14% for broadening, shift and narrowing coefficients, respectively.Air-broadening coefficients were retrieved from the linear combination of O2- and N2-broadening coefficients. The results are in good agreement with previous experimental data available in the literature. The whole set of results is given as supplementary material for a possible use in spectroscopic databases.