Direct Coulomb explosion of N₂O²⁺ induced by monochromatic extreme ultraviolet photons at 38.5 eV

The direct Coulomb explosion of N₂O²⁺ has been investigated experimentally after double-ionization by a single extreme ultraviolet (EUV) photon with an energy of ～38.5 eV. From the ion-ion time-of-flight coincidence spectrum, the de-nitrogenation (N₂O²⁺→N⁺+NO⁺) and de-oxygenation (N₂O²⁺→O⁺+N₂⁺) photodissociation channels of N₂O²⁺ are unequivocally identified. The measured kinetic energy release (KER) distribution of the de-nitrogenation channel presents a major peak accompanied by a shoulder structure. We find that the major peak can be attributed to the direct photodissociation of the 1¹Δ and 1¹Σ⁺ states, while the shoulder structure should be ascribed to the predissociation of the 1¹Δ and 1¹Σ⁺ states via 1³Π state.