Determination of structural parameters from advanced molecular electronic spectroscopy: The double ionization of nitrous oxide by synchrotron radiation

The double photoionization of N₂O molecules, in the 30–50 eV energy range, has been studied by synchrotron radiation. In the whole energy range, dissociative ionization producing N⁺ + NO⁺ or N₂⁺ + O⁺ has been observed. These two processes appear to occur also below the vertical thresh-old of 35.8 eV, where the double ionization should be indirect. In the range between 35.8 and 38.5 eV. The two processes occur instead by direct coulomb explosion of the N₂O²⁺ dication. Above 38.5 eV, the dissociation leading to NO⁺ + N⁺ is also promoted by the formation of a dication metastable state, which decays by fluorescence to the ground state and then dissociates.