Unimolecular Decomposition of the FCO Radical

Abstract

The kinetics of the unimolecular decomposition of the FCO radical has been studied experimentally in a heated tubular flow reactor coupled to a photoionization mass spectrometer. Rate constants for the decomposition were determined in time-resolved experiments as a function of temperature (951−1051 K) and bath gas density ((6−12) × 1016 molecules cm-3) in two bath gasesHe and N2. The rate constants are in the low-pressure limit under the conditions of the experiments and can be described by the following expressions: k°1(He) = 10-8.74±0.28 exp(−(14169 ± 653 K)/T) cm3 molecule-1 s-1 (from the fitting of experimental data) and k°1(N2) = 10-8.71 exp(−14154 K)/T) cm3 molecule-1 s-1 (evaluated from comparison of data obtained in nitrogen and helium bath gases). The thermochemistry of the reaction was analyzed on the basis of the data available in the literature and those obtained in the current study. An upper limit estimate was obtained for the rate constant of the reaction of FCO radicals with O2 at the temperature of 800 K: k(FCO+O2→products) ≤ 4 × 10-16 cm3 molecule-1 s-1.