Photodissociation of positive ions. I. Photodissociation spectra of D+2, HD+, and N2O+

Abstract

The operation of an apparatus constructed to measure absolute photodissociation spectra of ions and to determine the kinetic energy spectrum of the photoproducts by time‐of‐flight analysis is described. Photodissociation spectra for the processes D⁺₂+hν→D⁺+D and N₂O⁺→NO⁺+N have been obtained, and the photodissociation cross sections for HD⁺+hν→H⁺+D and HD⁺+hν→D⁺+H have been measured. The photodissociation spectrum of D⁺₂, using an irradiation bandwidth of + were observed to have the same cross sections 2×10⁻¹⁹ cm² at 589 nm. The photodissociation spectrum of N₂O⁺ over the range 295–342 nm was found to be very sharply structured, with σ_{NO⁺ =2.6×10}⁻¹⁸ cm² for the largest peak, at 338.5 nm. Fifteen peaks in the N₂O⁺ spectrum were assigned to vibrational progressions in the ? ²Σ←? ²Π_1/2,3/2 transition. In making the assignments it was necessary to assume the ions possess from 0 to 2 quanta in the degenerate bending mode, leading to Renner effect splitting in the ²Π state.