Collision induced broadening of ν1 band and ground state spectral lines of sulfur dioxide perturbed by N2 and O2

To monitor the constituents and trace pollutants of Earth atmosphere and understand its evolution, ac- curate spectroscopic parameters are fundamental information. SO 2 is produced by both natural and an- thropogenic 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 SO 2 broaden- ing parameters using N 2 and O 2 as 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 in- terval, 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. SO 2 -N 2 and SO 2 -O 2 collisional cross sections are retrieved for several ν1 band ro- vibrational transitions of 32 S 16 O 2 , for some transitions belonging to either ν1 + ν2 −ν2 of 32 S 16 O 2 or ν1 of 34 S 16 O 2 as well as for about 20 pure rotational transitions in the vibrational ground state of the main isotopic species. From N 2 - and O 2 - broadening coefficients the broadening parameters of SO 2 in air are derived. The work is completed with the study of the dependence of foreign broadening coefficients on the rotational quantum numbers.