Vibrational interference in the decay of core-excited nitric oxide

The nitrogen KVV Auger spectrum of nitric oxide contains peaks corresponding to the decay of neutral, core-excited NO to final states of ${\mathrm{NO}}^{+}$. The position and shape of the peak resulting from decay to the ground state cannot be explained by the usual Franck-Condon analysis. Since the lifetime of the core-excited states is comparable to the characteristic vibrational time, it is necessary to include in the analysis the effects of interference between different vibrational states. When these are included, there is excellent agreement between the experimental and theoretical line shapes.