The negative of the @[email protected] change in the gas phase reaction (real or hypothetical) between a @[email protected] (more appropriately @[email protected]) and the @[email protected] concerned, usually an electrically neutral species to give the @[email protected] of that species. @[email protected] affinity is often, but unofficially, abbreviated as PA.
See also:
gas-phase basicity
PAC, 1994, 66, 1077. (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1153 [Terms] [Paper]