Defined by the equation \[a = e^{\frac{\mu - \mu^{o}}{R\,T}}\] where \(R\) is the @G02579@, \(T\) the @T06321@, \(\mu\) the @C01032@ and \(\mu^{o}\) the @S05908@ the definition of which depends on the choice of the @S05925@.
See also:
absolute activity
Green Book, 2nd ed., p. 49 [Terms] [Book]
PAC, 1996, 68, 957. (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 989 [Terms] [Paper]