Kinetics of the Sn(P-3(0)) reactions with CO2 and O-2 over wide temperature ranges

Rate coefficients for the title reactions have been measured by the high-temperature fast-flow reactor (HTFFR) technique. The relative concentrations of Sn ground-state atoms were monitored by laser-induced fluorescence (LIF) for Sn + CO2 --> SnO + CO and by either LIF or atomic resonance absorption for the Sn + O-2 --> SnO + O reaction. Results from these two diagnostic methods agree very well. We obtained, in units of cm(3) molecule(-1) s(-1), k(1)(690-1600 K) = 2.3 x 10(-10) exp(-9100 K/T) and k(2)(380-1840 K) = (5.1 x 10(-13))(T/K)(0.79) exp(-437 K/T), with 2 sigma accuracy limits of about +/-25%. The results are compared to other metal atom reactions with these oxidants. All have similarly large preexponentials. The magnitudes of the exponential terms are shown to be typical for a spin-forbidden and a spin-allowed reaction, respectively.