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.
Source:
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