UNIMOLECULAR DECOMPOSITION OF THE FCO RADICAL

The kinetics of the unimolecular decomposition of the FCO radical has been studied experimentally in a heated tubular flow reactor coupled t o a photoionization mass spectrometer. Rate constants for the decompos ition were determined in time-resolved experiments as a function of te mperature (951-1051 K) and bath gas density ((6-12) x 10(16) molecules cm(-3)) in two bath gases-He and N-2. The rate constants are in the l ow-pressure limit under the conditions of the experiments and can be d escribed by the following expressions: k(l)(o)(He) 10(-8.74+/-0.28) ex p(-(14169 +/- 653 K)/T) cm(3) molecule(-1) s(-1) (from the fitting of experimental data) and k(l)(o)(N-2) = 10(-8.71) exp(-14154 K)/T) cm(3) molecule(-1) s(-1) (evaluated from comparison of data obtained in nit rogen and helium bath gases). The thermochemistry of the reaction was analyzed on the basis of the data available in the literature and thos e obtained in the current study. An upper Limit estimate was obtained for the rate constant of the reaction of FCO radicals with Oz at the t emperature of 800 K: k(FCO+O-2-->products) less than or equal to 4 x 1 0(-16) cm(3) molecule(-1) s(-1).