Photodissociation and photodetachment of molecular negative ions. VIII. Nitrogen oxides and hydrates, 3500–8250 Å

Abstract

Total photodestruction cross sections for the ions, NO2−, NO2−⋅H2O, NO3−, NO3−⋅H2O, and the peroxy isomers, O2−⋅NO and O2−⋅NO⋅H2O have been measured at wavelengths between 3500 and 8250 Å, using Ar+, Kr, and dye lasers and a drift tube mass spectrometer. A threshold of ∼2.5 eV was observed for the photodetachment of thermalized NO2−. Upper limits were set for the photodestruction cross sections of NO2−⋅H2O, NO3−, and NO3−⋅H2O over this wavelength range. The NO3− isomer O2−⋅NO and its hydrate, formed in N2O, have large photodissociation cross sections at wavelengths shorter than 5500 Å. Observations of collisional dissociation of cluster ions such as NO2−⋅H2O by laser-excited NO2 in the drift tube are also discussed.