Experimental and theoretical study of the recombination reaction of FS(O2)O with FC(O)O and CO.

MARIA EUGENIA TUCCERI; BADENES, M. P.; CROCE, A. E.; COBOS, C. J.

Physical Chemistry Chemical Physics

Año: 2001 vol. 3 p. 1832 - 1839

1463-9076

The laser flash photolysis technique has been used to study the kinetics of the reactions of FS(O2)O with FC(O)O and CO at 296 K. Both reactions were found to be essentially at the second-order regime at total pressures ranging from 160 to 1020 mbar of the radical precursors FS(O2)OF, CO and O2 and the bath gas SF6. FS(O2)O and FC(O)O radicals were monitored by absorption spectroscopy at 450 and 545 nm. The determined limiting high pressure rate coefficients for the FC(O)O+FS(O2)O-->FC(O)OO(O2)SF and FS(O2)O+CO-->FS(O2)OCO reactions are (1.0±0.1)x10-12 and (4.3±0.9)x10-17 cm3 molecule-1 s-1. Employing isodesmic reaction schemes with total energies calculated at the B3LYP/6-311++G(3df,p)//B3LYP/6-311++G(d,p) level of theory, enthalpies of formation for FS(O2)O, FS(O2)O2, FS(O2)OF, FS(O2)OCO, FS(O2)OC(O)CO, FS(O2)OC(O)O2, FC(O)OO(O­2)SF, FCO, FC(O)O and FC(O)O2 molecules were derived. An analysis of the rate coefficients in terms of the statistical adiabatic channel model and the transition state theory on potential energy surfaces derived from density functional theory calculations has been carried out.