Fluorescence yields from photodissociation of SO₂ at 1060-1330 AA

The photoabsorption and fluorescence cross sections of SO₂ were measured using synchrotron radiation in the 1060-1330 AA region. Fluorescence in the 1900-8000 AA region starts to appear around 1300 AA. The quantum yields for the production of fluorescence increase with decreasing wavelength and reach plateau at wavelengths shorter than 1150 AA, where the yields are about 4 and 9.5% for the fluorescence in the 3000-8000 and 1900-8000 AA regions, respectively. The fluorescence results mainly from the SO (A ³ Pi and B ³ Sigma ^- to X³ Sigma ^-) systems. The dissociation threshold energy of SO₂ is reevaluated and found to be 5.52 eV, which makes the observed fluorescence yields correlate well with various photodissociation processes of SO₂. The structures shown in the absorption spectrum are well correlated with the photoelectron spectrum, and are assigned to various Rydberg states that converge to ion states of similar structures.