association reaction (associative combination)

in mass spectrometry
The reaction of a (slow moving) ion with a neutral species wherein the reactants combine to form a single ionized species.
PAC, 1991, 63, 1541. (Recommendations for nomenclature and symbolism for mass spectroscopy (including an appendix of terms used in vacuum technology). (Recommendations 1991)) on page 1555 [Terms] [Paper]