Self and N2 broadening coefficients of H2S probed by submillimeter spectroscopy: Comparison with IR measurements and semi-classical calculations

High-resolution lines of H2S self-perturbed and perturbed by N-2 have been recorded at room temperature using a frequency modulated THz spectrometer at pressures of H2S ranging from 0.1 to 1.0 mbar. A non-linear least squares fitting of these spectra has been performed to retrieve self- and N-2-broadening coefficients of pure rotational transitions (mainly in the (R)Q sub-branch) of H2S in the submillimeter region. We show that the lineshapes are well reproduced by the Speed-Dependent Voigt profile accounting for the speed dependence of relaxation rates which display linear pressure dependencies. Using the Robert and Bonamy formalism, these coefficients were calculated, showing the need to account for all contributions of the intermolecular interaction for N-2-broadening. The calculated coefficients are consistent with the measured data and the average accuracy of the line parameters has been estimated to be about 5%. The observed J '' and K-a '' rotational dependences have been analyzed using an empirical model and compared to previous rovibrational studies in the nu(2) fundamental band. In our study the self- and the N-2-broadening coefficients decreases monotonically with K-a '' and J '', respectively. (C) 2020 Elsevier Ltd. All rights reserved.