Collision induced broadening of ν1band and ground state spectral lines of sulfur dioxide perturbed by N2and O2

To monitor the constituents and trace pollutants of Earth atmosphere and understand its evolution, accurate spectroscopic parameters are fundamental information. SO2is produced by both natural and anthropogenic sources and it is one of the principal causes of acid rains as well as an important component of fine aerosol particles, once oxidized to sulfate. The present work aims at determining SO2broadening parameters using N2and O2as atmospherically relevant damping gases. Measurements are carried out in the infrared (IR) and mm-/sub-mm wave regions, around 8.8 µm and in the 104 GHz–1.1 THz interval, respectively. IR ro-vibrational transitions are recorded by using a tunable diode laser spectrometer, whereas the microwave spectra are recorded by using a frequency-modulated millimeter-/submillimeter-wave spectrometer. SO2-N2and SO2-O2collisional cross sections are retrieved for several ν1band ro-vibrational transitions of32S16O2, for some transitions belonging to either ν1 + ν2 − ν2of32S16O2or ν1of34S16O2as well as for about 20 pure rotational transitions in the vibrational ground state of the main isotopic species. From N2- and O2- broadening coefficients the broadening parameters of SO2in air are derived. The work is completed with the study of the dependence of foreign broadening coefficients on the rotational quantum numbers.