ion/neutral species reaction

in mass spectrometry
A process wherein a charged species interacts with a neutral reactant to produce either chemically different species or changes in the @I03103@ of one or both of the reactants. The contrasting expression ion/neutral reaction is not ideal, simply because the word neutral is not a noun. However, any alternatives such as ion/neutral species reaction are so clumsy as to mitigate against their general acceptance
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 [Terms] [Paper]