Photodissociation Dynamics of SO₂ from the Electronically Excited C State

The early earth rock record shows unusual sulfur mass independent fractionation that is potentially caused by the UV photodissociation of SO₂. We investigate the dynamics of SO₂ photodissociation from the electronically excited C state, using tunable, pulsed UV light (λ = 210-220 nm) to initiate the dissociation and state-resolved high-resolution transient IR spectroscopy to measure the appearance of SO(v=0) product state. Individual ro-vibrational states of nascent SO products are measured along with the fluorescence excitation spectrum to determine anisotropy parameters and the dissociation quantum yield. UV wavelength dependent studies were used to obtain rotational energy distributions. The measurements near the photodissociation threshold at λ = 220 nm provide insight into the dissociation dynamics of SO₂ from the C state.