Coefficient in front of the exponential factor expressing the empirical temperature dependence of the rate coefficient, , on temperature, ,, where is the activation energy.
Sources: Green Book, 2nd ed., p. 56 [Terms] [Book] PAC, 1996, 68, 149. (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 177 [Terms] [Paper]