KINETICS OF NEUTRAL TRANSITION-METAL ATOMS IN THE GAS-PHASE - OXIDATION REACTIONS OF TI(A(3)F) FROM 300-K TO 600-K

Gas-phase kinetics are reported for the reactions of Ti(a3F) with O2, N2O, NO, CO2, SO2, and NO2 from 300 to 600 K. Titanium atoms were produced by the photolysis of TiCl4 at 248 nm and were detected by laser-induced fluorescence. Arrhenius expressions obtained for these reactions at a buffer gas pressure of 20 Torr are k(O2) = (1.69 +/- 0.41) x 10(-10) exp(-(11.6 +/- 0.8 kJ/mol)/RT) cm3 s-1, k(N2O) = (1.74 +/- 0.44) X 10(-10) exp(-(14.3 +/- 0.9 kJ/mol)/RT cm3 s-1, k(NO) = 3.28 +/- 0.69) x 10(-11) exp(-(3.62 +/- 0.71 kJ/mol)/RT) cm3 s-1, k(CO2) = (7.0 +/- 1.6) x 10(-11) exp(-(14.9 +/- 0.8 kJ/mol)/RT) cm3 s-1, and k(SO2) = (1.70 +/- 0.33) X 10(-10) exp(-(2.66 +/- 0.64 kJ/mol)/RT) cm3 s-1. The rate constant of Ti with NO2 was found to be temperature independent from 300 to 500 K with a value of (9 +/- 4) x 10(-11) cm3 s-1. Quoted uncertainities are +/- 2sigma. With the exception of Ti + O2, all reactions were investigated as a function of pressure. Only the reactions of Ti with NO and CO2 were found to depend on the argon buffer gas pressure. Termolecular rate constants at 300 K were determined to be (5.8 +/- 2.6) x 10(-31) cm6 s-1 and (3.5 +/- 1.0) X 10(-32) cm6 s-1 for NO and CO2, respectively.