Complete double photoionisation spectrum of NO

A new time-of-flight photoelectron-photoelectron coincidence technique, which gives complete two-dimensional e(-)-e(-) spectra in single-photon double photoionisation, is applied to nitric oxide. Direct double photoionisation is the major process at photon energies of 40.8, 48.4 and 50 eV, but dissociative ionisation with autoionisation of atomic fragments is also significant at these wavelengths and is dominant at 38.7 eV photon energy. The energy of the v = 0 level of the A(2)pi state of NO2+ is corrected, leading to a new prediction of the wavelength of optical emission. The electron energy distributions in formation of the bound states of NO2+ are smooth, lacking sharp autoionisation features. Broad peaks found in the photoelectron distributions coincident with autoionisations of atomic oxygen are at different energies for each different O state, indicating the involvement of several distinct dissociative superexcited states of NOdivided by. (C) 2003 Elsevier Science B.V. All rights reserved.