Temperature dependent study of the kinetics of Sc(a(2)D(3/2)) with O-2, N2O, CO2, NO and SO2

The gas phase reactivity of Sc(a(2)D(3/2)) with O-2, N2O, CO2, NO and SO2 in the temperature range 298-523 K is reported. The bimolecular rate constants are described in Arrhenius form by k(O-2) = (1.7 +/- 0.4) x 10(-10) exp(-7.9 +/- 0.7 kJ/mol/RT) cm(3) s(-1), k(N2O) = (1.7 +/- 0.3) x 10(-10) exp(-12.0 +/- 0.6 kJ/mol/RT) cm(3) s(-1), k(CO2) = (7.3 +/- 1.3) x 10(-11) exp(-12.3 +/- 0.6 kJ/mol/RT) cm(3) s(-1) where the uncertainties are +/- 2 sigma. The rate constants with NO and SO2 were temperature insensitive with room temperature rate constants of 1.5 x 10(-11) and 2.0 x 10(-10) cm(3) s(-1), respectively. The disappearance rates for all the reactants are independent of total pressure indicating a bimolecular abstraction mechanism. (C) 1997 Elsevier Science B.V.