What is proton emission radioactive decay?

Proton emission is a rare form of radioactive decay where an unstable atomic nucleus ejects a single proton. It typically occurs in very proton-rich nuclei or from high-lying excited states following beta decay. Because the proton is unbound, it tunnels out of the nucleus in a finite time through a process governed by nuclear, Coulomb, and centrifugal potentials.

What we know

• Proton emission is a rare type of radioactive decay in which a proton is ejected from an atomic nucleus. [1, 2]
• For a proton to escape the nucleus, the proton separation energy must be negative, meaning the proton is unbound and tunnels out in a finite time. [2]
• Proton emission can occur either from the ground state of very proton-rich nuclei or from high-lying excited states following a beta decay. [2]
• More than 25 isotopes have been found to exhibit proton emission, and the phenomenon has even extended to the observation of double and triple proton decay in specific light elements. [2]

Where to go next

• how it workedHow does quantum tunneling enable radioactive decay?
• compared withWhat is alpha decay?
• what followedHow does positron emission alter the neutron-proton ratio?
• the bigger pictureWhat is the neutron-proton ratio in atomic nuclei?
• whenWhen was proton radioactivity first observed experimentally?
• an unexpected connectionHow can an aluminum isotope decay by emitting three protons?Aluminum-20 undergoes triple proton decay sequentially rather than all at once, first ejecting a single proton to become magnesium-19 before subsequently releasing two more.

Sources

• [1]proton emission (Wikidata Q902157) · CC0 1.0
• [2]Proton emission · CC BY-SA 4.0
• [3]Positron emission · CC BY-SA 4.0
• [4]Alpha decay · CC BY-SA 4.0
• [5]Neutron–proton ratio · CC BY-SA 4.0