The recombination reaction Na + S02 + Ar was investigated at 787 16 K and at pressures from 1.7 to 80 kPa. NaI vapor was photolyzed by an excimer laser at 308 nm to create Na atoms, whose concentration was monitored by time-resolved resonance absorption at 589 nm. The rate constant at the low pressure limit is ko = (2.7 0.2) x 10-21 cm6 molecule-2 s~1. The Na-SO 2 dissociation energy E0 = 170 35 kJ mol1 was calculated with RRKM theory. The equilibrium constant gave a lower limit E0 > 172 kJ mol~ 1. By combination of these two results, E0 = 190 15 kJ mol~ 1 is obtained. The high pressure limit is k, = (1 - 3) x 10-10 cm3 molecule 1 s~1, depending on the extrapolation method used. Two versions of collision theory were employed to estimate k,.. The 'harpoon' model shows the best agreement with experiment.