Articulo
A theoretical study of the thermal stability of the FS(O<SUB>2</SUB>)OSO<SUB>2</SUB> radical and the recombination kinetics with the FSO<SUB>3</SUB> radical
Autor
Badenes, María Paula
Cobos, Carlos Jorge
Croce, Adela Ester
Institución
Resumen
The kinetics of the thermal reaction of FS(O2)OO(O2)SF with SO2 have been theoretically studied. Experimental investigations performed at 293–323 K indicate that the FSO3 radical, in equilibrium with the peroxide FS(O2)OO(O2)SF ¢ 2 FSO3 (1, -1), initially attacks the SO2 forming the FS(O2)OSO2 radical which afterwards may dissociate back, FSO3 + SO2 ¢FS(O2)OSO2 (2, -2), or recombinewith FSO3 generating the final product, FSO3 + FS(O2)OSO2? (FS(O2)O)2SO2 (3). Several DFT formulations and composite ab initio models were employed to characterize FS(O2)OSO2 molecular properties and to determine relevant potential energy surfaces features of reactions (2), (-2) and (3). Transition state theory calculations lead to the high pressure rate coefficients k1;2 ¼ 9:1 10 14 expð 5:2 kcal mol 1 = RTÞ cm3 molecule 1 s 1 and k1; 2 ¼ 4:9 1015 expð 13:9 kcal mol 1 =RTÞ s 1 while statistical adiabatic channel model (SACM/CT) calculations predict for the barrierless reaction (3) the expression k1;3 ¼ 2:9 10 11ðT=300Þ0:4 cm3 molecule 1 s 1. The experimental phenomenological rate coefficients are very well reproduced by these rate coefficients. Facultad de Ciencias Exactas