KINETIC-STUDY OF THE REACTION OF RE(A(6)S(5 2)) WITH O-2, NO, N2O, AND CH4/

The gas-phase reactivity of ground-state Re(a(6)S(5/2)) with O-2, NO, N2O, and CH4 is reported. Rhenium atoms were produced by the photodiss ociation of Re(CO)(5)Cl and detected by laser-induced fluorescence. Th e reaction rate of the a(6)S(5/2) state with O-2 is slow and temperatu re-dependent. The reaction is pressure-independent, indicating a bimol ecular abstraction reaction. The bimolecular rate constant from 296 to 548 K is described in Arrhenius form by (2.1 +/- 0.3) x 10(-11) exp(- 11.6 +/- 0.6 kJ/mol/RT) where the uncertainties represent +/- 2 sigma. The reaction rate of the a(6)S(5/2) state-with NO is pressure-depende nt, indicating adduct formation. The limiting low-pressure third-order , k(0), and limiting high-pressure second-order, k(infinity), room-tem perature rate constants with NO in nitrogen buffer are (3.7 +/- 0.8) x 10(-30) cm(6) s(-1) and (7.0 +/- 0.8) x 10(-12) cm(3) s(-1), respecti vely. There is no evidence of chemical reaction for the ground state o f rhenium with N2O or CH4 up to a temperature of 548 K.