Nuclear motion driven by the Renner-Teller effect as observed in the resonant Auger decay to the (X)over-tilde2Π electronic ground state of N2O+

High-resolution Auger spectroscopy applied under resonant Auger Raman conditions is shown to be a powerful tool for characterizing complex potential energy surfaces in core-excited systems. Using the example of N-t 1s(-1)pi*-->(X) over tilde (2)Pi resonant Auger transition in nitrous oxide we emphasize the interplay between the nuclear motion and the electronic decay. We show how the choice of excitation energy allows selection of core-excited species of different geometries. The nuclear dynamics of these species are mapped by measuring the resonant Auger decay spectra. In addition to the changes in vibrational structure observed for the resonant Auger decay spectra, a strong influence of nuclear motion on the electronic decay is revealed, inducing the so-called "dynamical Auger emission." The experimental results are supported by ab initio quantum chemical calculations restricted to a linear geometry of the core-excited state. (C) 2001 American Institute of Physics.