ion/molecule reaction

in mass spectrometry
An ion/neutral species reaction in which the neutral species is a molecule. The use of ion-molecule reaction is not recommended; the hyphen suggests a reaction of a species that is both an ion and a molecule and is not the intended meaning.
Orange Book, 2nd ed., p. 206 (
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 1556 (