The effect of the nuclear motion on the electronic decay of core hole excited states in molecules

We have measured the vibrational fine structure in the electronic decay spectrum of the N 1s→1πg core electron excited state in molecular nitrogen. The Franck–Condon analysis of the vibrational substructure shows that within the 10−14 s lifetime of the core hole excited state the molecule adjusts to the excited state configuration, characterized by a change in bond length by 0.071 A. Interference effects due to the short lifetime of the intermediate state play only a minor role.