A nuclear process where an atomic nucleus absorbs a high-energy gamma ray, enters an excited state, and immediately decays by emitting one or more nucleons (neutrons or protons), or an alpha particle from the nucleus. (The reactions are called $\left( \gamma, \, n \right)$, $\left( \gamma, \, p \right)$, and $\left( \gamma, \, \alpha \right)$.) **Important Notes:** - Photodisintegration is endothermic (energy absorbing) for atomic nuclei lighter than iron - Photodisintegration is exothermic (energy releasing) for atomic nuclei heavier than iron - It is responsible for the nucleosynthesis of at least some heavy, proton-rich elements via the [[Proton Capture|p-process]]