COHERENT EXCITATION OF VIBRATIONAL WAVE-FUNCTIONS OBSERVED IN-CORE HOLE DECAY SPECTRA OF O2, N2 AND CO

High resolution studies of the electron emission generated in the decay of neutral core to bound state excitations in small molecules, reflect the dynamics of the time evolution of the coherently excited vibronic wavefunctions in the core excited states. This coherent excitation gives rise to interference effects observed in the electronic decay processes. Since the lifetime of the core excited states in O2, N2 and CO is only a few fs, the study of these interference phenomena offers a stringent test of the quantum mechanical description of the time evolution of the excited states. Here we demonstrate that the resulting interference effects are not only observed when the lifetime broadening of the core excited state approaches the vibrational spacing but also for systems where the vibrational levels are clearly resolved in the excitation spectrum.