## kinetic activity factor

https://doi.org/10.1351/goldbook.K03396
A factor involving activity coefficients that appears as a multiplier in the rate equation. For a @M03989-1@ reaction the factor is $\frac{y_{\text{A}}\ y_{\text{B}}}{y_{\ddagger}}$ where $$y_{\text{A}}$$, $$y_{\text{B}}$$ and $$y_{\ddagger }$$ are the activity coefficients for the reactants A and B and the @A00092@, respectively. For a @M03989-2@ reaction the factor is $\frac{y_{\text{A}}}{y_{\ddagger}}$ and for a trimolecular reaction it is $\frac{y_{\text{A}}\ y_{\text{B}}\ y_{\text{C}}}{y_{\ddagger}}$
Source:
PAC, 1996, 68, 149. (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 171 [Terms] [Paper]