Nuclear dynamics during the N 1s autoionization of physisorbed N-2

We demonstrate that even for adsorbed molecules, the vibrational fine struc ture of resonant core hole decay channels after narrow-band excitation can show a dependence: on the variation of the primary excitation energy as kno wn from isolated molecules. Despite several adsorption-induced broadening m echanisms, the so-called detuning effect can be observed in the autoionizat ion of a N-2 monolayer physisorbed on Xe/Ru(001) for the 1 pi(u)(-1) final state of participant decay, in good agreement with theoretical predictions and observations for isolated N-2 However, contrary to the corresponding de cay channel of isolated N-2 and to the theoretical predictions for it, the decay into the 3 sigma(g)(-1) final state shows clearly different behavior much closer to that of normal Auger decay. This is partly due to final-stat e broadening. [S0163-1829(99)07947-3].