Rate coefficients for the reaction of chlorine atoms with FS(O2)O and FS(O2)OCl at 298 K.

MARIA EUGENIA TUCCERI; CASTELLANO, E.; CROCE, A. E.; COBOS, C. J.

Journal of the Argentine Chemical Society

Año: 2005 p. 29 - 41

The kinetics of the Cl + FS(O2)O --> FS(O2)OCl recombination reaction has been studied by using an ArF excimer laser flash photolysis technique over the 25-950 mbar total pressure range of the bath gases He, N2 and CF4 at 298 K. The reaction was found to be essentially in the second-order regime. The derived limiting high-pressure rate coefficient is (1.3±0.3)x10-10 cm3 molecule-1 s-1. For the Cl + FS(O2)OCl ® FS(O2)O + Cl2 reaction a rate coefficient of (2.0±0.8)x10-11 cm3 molecule-1 s-1 was measured. The ratio between both rate coefficients of 0.15 agrees very well with the determined by Vasini and Schumacher. Quantum chemical calculations carried out at the B3MP2//B3LYP/6-311+G(3df) level of theory allow to determine an standard heat of formation of -136.5 kcal mol-1 for FS(O2)OCl. Rate coefficient calculations in the framework of the phase space theory, performed on a G3MP2B3 electronic potential, indicate that central forces mainly dominate the present recombination reaction.