This is the term used to describe @[email protected] of any species by electrons. The process may, for example, be written:
  • for atoms or molecules: \[\text{M} + e \rightarrow \text{M}^{+\cdot } + 2e\]
  • for radicals: \[\text{M}^{\cdot}  + e \rightarrow \text{M}^{+} + 2e\]
The term 'electron impact' should not be used.
radical ion
See also:
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 1547 [Terms] [Paper]