The recombination of atomic potassium, K(4(2)S), With SO2 has been inv
estigated at about 863 K, in a bath of Ar at pressures from 20 to 690
mbar. K was generated by flash photolysis of KI vapor and monitored by
time-resolved resonance absorption of a D-line at 766 nm under pseudo
-first-order conditions. The measured pseudo-second-order rate constan
ts lie in the low-pressure and falloff regions and were fitted with an
empirical RRKM expression to yield k0 = 5.9 X 10(-29) cm6 s-1 and k(i
nfinity) = 6.2 X 10(-10) cm3 s-1. Error limits are discussed in the te
xt. The KSO2 adduct was characterized by ab initio methods. An RRKM an
alysis of k0, together with a lower limit to the equilibrium constant,
yielded a K-SO2 bond strength of 190 +/- 10 kJ mol-1. k(infinity) was
shown to be consistent with a simple harpoon model for electron trans
fer.