DEEXCITATION ELECTRON-SPECTROSCOPY OF CORE-EXCITED NO AS A FUNCTION OF EXCITATION-ENERGY

Deexcitation electron spectra of core-excited NO have been measured at several excitation energies in the N 1s --> 2 pi and O 1s --> 2 pi resonances. The nitrogen spectra exhibit significant variation with excitation energy; the, oxygen spectra vary only slightly. Sensitivity to excitation energy occurs because each resonance represents the overlap of three transitions to (2) Sigma(+), (2) Delta, and (2) Sigma(-) states, and each of these excited states decays to a unique set of levels in the final-state ion. We have analyzed all spectra by taking into account excitation energy, lifetime-vibrational interference, and the ordering and splitting of the core-excited levels. Good agreement between calculated line shapes and experiment occurs if it assumed that the level ordering is (2) Delta, (2) Sigma(-), (2) Sigma(+) for core-excited nitrogen and (2) Sigma(-), (2) Delta, (2) Sigma(+) for core-excited oxygen. Photoexcitation data for oxygen have been analyzed to determine the energies of these states 531.7, 532.7, and 533.7 eV. The deexcitation spectrum from the (2) Delta State of nitrogen core-excited NO to the ground state of NO+ has been analyzed using the theory of lifetime-vibrational interference to give a lifetime width for the core-excited state of 146 meV. A similar analysis for the deexcitation of the oxygen core-excited state is less conclusive, but is consistent with a lifetime width of 180 meV.