STUDY OF N2O2 BY PHOTOELECTRON-SPECTROSCOPY OF N2O2-

Photoelectron spectra of the N2O2- anion, collected at hv=4.657 and 5.822 eV, are presented. The spectra originate from the C2v isomer of the anion. Vibrationally resolved progressions corresponding to transitions to several electronic states of the previously unobserved N2O2 molecule are observed. All of the observed transitions lie above the dissociation asymptotes for N+NO2, NO+NO, and O+N2O, and several lie above the N+NO2 and N 2+O+O asymptotes. Ab initio calculations have been carried out for the anion ground state and several singlet and triplet states of neutral N 2O2. By comparing the observed spectra with Franck-Condon simulations based on these calculations, the lowest bands observed in our spectra were assigned to transitions to the 3A2 and 3A1 states (C2v symmetry) of N2O2. These spectra thus represent the first experimental characterization of metastable, high energy forms of N2O2. Both the N 2O2- and the N2O2 species are considered in terms of their roles as reactive intermediates in the O -+N2O and N+NO2 chemical reactions. © 1995 American Institute of Physics.