Kinetic spectroscopic measurements in the vacuum ultra-violet on the decay of electronically excited iodine atoms (I(52P½)) generated from the flash photolysis of gaseous CF3I have been carried out in the presence of the gases Xe, NO, O2, H2O, D2O, CH4, CF3H, CF4, SF6, CO and CO2. The decay in xenon of I(52P½) to the ground state (52P⅓) is primarily controlled by diffusion to the walls of the vessel. The probability of spin orbit relaxation on collision for the gases NO to CO2 listed in the above order are 6.7 × 10–2, 5.6 × 10–2, 5.9 × 10–3, 4.0 × 10–4, 2.4 × 10–4, 2.3 × 10–4, 2.5 × 10–5, 1.8 × 10–5, 6.7 × 10–6 and 7.7 × 10–7, respectively. The probability of collisional deactivation by the paramagnetic species NO and O2 is particularly high and comparable with that of I2(7.1 × 10–2). The deactivation of I(52P½) by the gases studied to date are discussed.