Nuclear motion of core excited bf₃ probed by high resolution resonant auger spectroscopy

High resolution resonant Auger spectroscopy applied to the core excitation of BF₃ reveals that the kinetic energy of the spectator Auger electrons stays constant when the photon energy is scanned through the B 1s → 2a₂ resonance, whereas the kinetic energy of participator Auger electrons shows a linear photon energy dependence. These nondispersive and dispersive effects are theoretically reproduced using a quasi-Jahn-Teller model and by treating the Auger emission process as a coherent second-order quantum process.