The 157 nm photodissociation of OCS

The photodissociation of OCS at 157 nm has been investigated by using tunable vacuum ultraviolet radiation to probe the CO and S photoproducts. Sulfur is produced almost entirely in the ¹S state, while CO is produced in its ground electronic state and in vibrational levels from v = 0-3 in the approximate ratio (v = 0):(v = 1):(v = 2):(v = 3) = (1.0):(1.0):(0.5) :(0.3). The rotational distribution for each vibrational level is found to be near Boltzmann, with temperatures that decrease from 1350 K for v = 0 to 780 K for v = 3. Measurements of the CO Doppler profiles demonstrate that the dissociation takes place from a transition of predominantly parallel character (β = 1.8 ± 0.2) and that the CO velocity and angular momentum vectors are perpendicular to one another.