To Be or Not to Be Localized

摘要

In molecules, valence electrons form molecular bonds, whereas the underlying core electrons play a supporting role. If a vacancy, or hole, is created in the core orbitals by an excitation process, a rearrangement process called Auger decay can occur: A valence electron drops to fill the core hole, and energy is released by emitting an Auger electron from another valence orbital. It has long remained unclear whether this shortlived core hole in a homonuclear diatomic molecule such as N_2 is localized on one atomic site, or delocalized over both. On page 920 of this issue, Schoffler et al. (1) show that this question cannot be answered without taking into account how the unstable core hole state relaxes by Auger decay. They show that the photoelectron and the Auger electron that are emitted form an entangled state. Whether one finds the core hole to be localized or delocalized will depend on the experiment used to observe this entangled state.