Electron capture ionization

Electron capture ionization is the ionization of a gas phase atom or molecule by attachment of an electron to create an ion of the form A − {\displaystyle {\ce {A^-}}} . The reaction is A + e − → M A − {\displaystyle {\ce {A + e^- ->[M]A^-}}} where the M over the arrow denotes that to conserve energy and momentum a third body is required (the molecularity of the reaction is three).