electron capture

A radioactive decay in which an atomic electron combines with a proton in the nucleus to form a neutron (which remains in the nucleus) and a neutrino. Nucleon number remains unchanged; proton number is reduced by one. For example, the decay of fluorine to oxygen, ₉F¹⁷+e^? gives ₈O¹⁷ +?.

Nuclear processes
Radioactive decay processes Alpha decay Beta decay Cluster decay Double beta decay Double electron capture Electron capture Gamma radiation Internal conversion Isomeric transition Neutron emission Positron emission Proton emission Spontaneous fission Nucleosynthesis Neutron Capture The R-process The S-process Proton capture: The P-process The Rp-process Spallation

Electron capture ( sometimes called Inverse Beta Decay) is a decay mode for isotopes that will occur when there are too many protons in the nucleus of an atom and insufficient energy to emit a positron; If the energy difference between the parent atom and the daughter atom is less than 1.022 MeV, positron emission is forbidden and electron capture is the sole decay mode.

In this case, one of the orbital electrons, usually from the K or L electron shell (K-electron capture, also K-capture, or L-electron capture, L-capture), is captured by a proton in the nucleus, forming a neutron and a neutrino.

examples:

Note that radioactive isotopes which go by pure electron capture can, in theory, be inhibited from radioactive decay if they are fully ionized ("stripped" is sometimes used to describe such ions).

Chemical bonds can also affect the rate of electron capture to a small degree (generally less than 1%) depending on the proximity of electrons to the nucleus.