Direct Dissociation of N₂O⁺(X²II_i) in the Narrow Energy Regime of 14.8-15.5 eV

Abstract

Fragmentation of N₂O⁺ in the narrow energy regime of 14.8 to 15.5 eV, where electronic predissociation occurs involving a state transition between N₂O⁺ (X₂II_i) and N₂O⁺ (2⁴Σ^-), has been studied by threshold photoelectron-photoion coincidence (TPEPICO) mass spectrometry using a non-pulsed ion-extraction field. Detailed breakdown curves and kinetic energy releases accompanied by fragmentation were obtained. Kinetic energy releases observed for both the NO⁺ and O⁺ formations were consistent with the predictions based on the spectator model of direct dissociation. Results obtained have thus suggested that the fragmentations on the N₂O⁺ (2⁴Σ^-) state occur considerably faster than the rate with which the system jumps from X²II_i to 2⁴Σ^-, and therefore this transition probability has been given approximately by the summation of both the NO⁺ and O⁺ breakdown curves with a most probable energy of ca. 15.2 eV in the curve-crossing.