electron capture

Scheme of two types of electron capture. Top: The nucleus absorbs an electron. Lower left: An outer electron replaces the "missing" electron. Electromagnetic radiation equal in energy to the difference between the two electron shells is emitted. Lower right: In the Auger effect, the energy absorbed when the outer electron replaces the inner electron is transferred to an outer electron. The outer electron is ejected from the atom, leaving a positive ion.

Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shells. This process thereby changes a nuclear proton to a neutron and simultaneously causes the emission of an electron neutrino.