Dissociative photoionisation of NO2 up to 26 eV Original Research Article

The dissociations of NO2+ from the states populated in photoionisation at 30.4 and 58.4 nm have been examined by photoelectron–photoion coincidence spectroscopy. Ions in the a 3B2 state with v=1,2,3 and in the a 1A2 state with v=0 are found to be metastable on a microsecond time scale; estimates of their lifetimes are given. Ions in the b 3A2 state dissociate rapidly, with an anisotropic distribution of the product ions relative to the photoelectrons. The kinetic energy releases show little excitation of the diatomic products in dissociations of the low-lying NO2+ states. Relevance of the results to atmospheric ion–molecule reactions is discussed.