Kinetics of atomic nitrogen photofragment produced by laser photodissociation of N2O

The kinetics of ground-state atomic nitrogen photofragments produced by laser photodissociation of nitrous oxide have been investigated using two-photon LIF. A single 207 nm laser pulse was used for both N2O photolysis and N atom two-photon LIF. The dependency of the LIF signal with laser power indicated that the observed N atom fragment was produced by N2O dissociation via single-photon absorption. Effects of translational energy of the N atom fragment were detected in collisional quenching rates of the two-photon excited N atom (3p)S-4 state as observed in the decay lifetime of the induced fluorescence. The mean translational kinetic energy of the N atom fragment was determined to be 0.6 +/- 0.2 eV from the quenching data. An analysis of the Doppler broadened absorption line shape of the recoiling atomic nitrogen confirmed the mean kinetic energy and further presented a model speed distribution and anisotropy parameter that was consistent with the line shape data. The NO translational and internal energies of 0.3 +/- 0.1 eV and 0.2 +/- 0.1 eV, respectively, were also assigned by momentum and energy conservation.