A Curious Aspect of the Atomic Ionization Process Caused by Nuclear Decay

When the nucleus of an atom decays by emitting an a particle, the surrounding electrons are perturbed and the atom may be ionized. Practically all calculations so far done for this ionization process are based on Migdal’s method in which the a particle is treated as a classical point charge that is emitted by the nucleus at a certain time. Migdal’s method yields the ionization probability that is in reasonable agreement with experiment. We examine a fully quantum mechanical method in which the a particle is represented by a Schrodinger wave that slowly leaks out from the nucleus. This method leads to the ionization probability that is orders of magnitude smaller than the one that follows from Migdal’s method. We emphasize that the ionization process is triggered by a single decay-event. We argue that the failure of our fully quantum mechanical method is a manifestation of the inability of the wave function to describe a single event. Similar aspects of the atomic ionization due to nuclear β decay and of bremsstrahlung in α decay are also discussed.