Molecular Interaction and Linewidth of Asymmetric Molecule SO2. I. SO2–N2 Collisions

Abstract

The linewidth of the 9_1,9→8_2,6 transition of sulfur dioxide broadened by nitrogen has been measured at different pressures using a double modulation video spectrograph. The measured linewidth for the SO₂–N₂ collision is 4.19 Mc/mm. The hard‐sphere collision diameter corresponding to this is 5.68 Å as compared to the kinetic collision diameter of 4.0 Å. The result has been interpreted on the basis of Anderson's theory assuming a dipole—quadrupole interaction to be responsible for the width. The quadrupole moment of nitrogen so evaluated is equal to 2.79×10^—26 esu. The temperature dependence of the linewidth parameter has also been calculated and it has been found that for the temperature range 340°—600°K, Δν varies as T^—0·78 and for the temperature range 195°—340°K, Δν varies as T^—0·86.