KINETICS OF FO2 WITH NO, NO2, O-3, CH4, AND C2H6

The kinetics of the reactions FO2 + NO --> products (11) and FO2 + NO2 --> products (12) have been studied as functions of temperature at 1 Torr total pressure using a discharge-flow mass spectrometric techniqu e. The measured rate coefficients, expressed in Arrhenius form, are k( 11) (7.5 +/- 0.5) x 10(-12) exp[(-688 +/- 377)/T] cm(3) molecule(-1) s (-1) for 190 K < T < 298 K and k(12) = (3.8 +/- 0.8) x 10(-11) exp[(-2 042 +/- 456)/T] cm(3) molecule(-1) s(-1) for 260 K < T < 315 K. The ob served temperature dependencies of the rate coefficients indicate that the reactions occur primarily by simple bimolecular, rather than term olecular, mechanisms. Mass spectral product studies are consistent wit h bimolecular processes involving F atom extraction from FO2. Upper li mits for the rate coefficients of FO2 + O-3 --> products (13), FO2 + C H4 --> products (14), and FO2 + C2H6 --> products (15) have also been determined with the same experimental system at room temperature: k(13 ) < 3 X 10(-15) cm(3) molecule(-1) s(-1), k(14) < 2 x 10(-16) cm(3) mo lecule(-1) s-(1,) and k(15) < 4 x 10(-16) cm(3) molecule(-1) s(-1). As part of the FO2 + O-3 study, an investigation of the reaction FO + O- 3 --> FO2 + O-2 (6) was conducted. An upper limit of k(6) < 1 x 10(-14 ) cm(3) molecule(-1) s(-1) has been obtained for the FO reaction. The implications of these results for fluorine oxide chemistry in the atmo sphere are discussed.