When do isomeric transitions occur?

Isomeric transitions occur immediately after the formation of the excited nuclear level. In nuclear physics, when a nucleus is excited to a higher energy state, it can remain in that state for a brief period before returning to a more stable configuration. This return to stability is often accompanied by the emission of gamma radiation, which is characteristic of these transitions.

The process typically involves the nucleus releasing energy in the form of gamma rays as it transitions from the excited state to a lower energy state. This is distinct from other nuclear processes such as beta decay or nuclear fission, which involve more significant changes to the nucleus's structure or composition. Isomeric transitions are often associated with specific excited states of nuclei that have a longer half-life than other decay processes, but they still take place shortly after the excitation occurs.

In summary, isomeric transitions are instantaneous responses to the excitation of a nuclear state, reflecting the inherent behavior of nuclei as they seek a more stable configuration by releasing energy in the form of radiation.