Time-resolved laser-induced fluorescence spectroscopic studies of [formula omitted] with N 2O at elevated temperatures

Abstract

We present a kinetic study of the oxidation reaction of Rb(5 2 S 1 2 ) with N 2O at elevated temperatures by the technique of pulsed photolysis of a Rb atom precursor, RbCl, followed by time-resolved laser-induced fluorescence spectroscopy of Rb atoms using the resolved Rydberg transition at λ = 420.2 nm ( Rb(6 2 P 3 2 ) → Rb(5 2 S 1 2 ). A value of the absolute second-order rate constant of (2.1 ± 0.4) × 10 −11 cm 3 molecule −1 s −1 has been obtained at 830 K. This result is compared with the previously reported result obtained by atomic resonance absorption spectroscopy. An estimate of the diffusion coefficient for rubidium in helium of D 12(RbHe) = (0.27 ± 0.03) cm 2 s −1 at s.t.p. is reported. Finally, the result is considered briefly in terms of the potential surfaces involved in the reaction. Rb(5 2 S 1 2 ) + N 2 O(X 1Σ +) correlates directly with the ground state products RbO(X 2 Σ +) + N 2(X 1 Σ +g) via a 2A′ surface. We believe the present type of investigation to constitute the first study of the present process by flash photolysis with laser-induced fluorescence (LIF).