isomeric transition

physics

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June 29, 2026

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An isomeric transition is a type of radioactivity where an unstable atomic nucleus releases excess energy. This typically occurs through gamma decay, where gamma rays are emitted. If a nucleus remains in an excited, or metastable, state for a measurable period (longer than about a nanosecond) before emitting a gamma ray, this decay process is called an isomeric transition.1

Nuclear isomers are nuclides with the same number of protons and neutrons but different energy levels and decay modes. The half-life of an isomer can range from fractions of a second to years. These isomers are formed either as a result of nuclear reactions or as intermediate products in the decay of other radioactive nuclei.2

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radioactivity
Isomeric transitions
) There is a wide range of rates of half-lives for the gamma-emission process. Usually dipole transitions (see below Gamma transition), in which the gamma ray carries off one ℏ unit of angular momentum, are fast, less than nanoseconds (one nanosecond equals 10⁻⁹ second).…
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) There is a wide range of rates of half-lives for the gamma-emission process. Usually dipole transitions (see below Gamma transition), in which the gamma ray carries off one ℏ unit of angular momentum, are fast, less than nanoseconds (one nanosecond equals 10⁻⁹ second).…
Read More