## Wikipedia - Transition state theory transition state theory

https://doi.org/10.1351/goldbook.T06470
A theory of the rates of @E02035@ which assumes a special type of equilibrium, having an @E02177@ $$K^{\ddagger }$$, to exist between reactants and activated complexes. According to this theory the @O04322@ is given by: $k=\frac{k_{\text{B}}\ T}{h}\ K^{\ddagger }$ where $$k_{B}$$ is the @B00695@ and $$h$$ is the @P04685@. The @O04322@ can also be expressed as: $k=\frac{k_{\text{B}}\ T}{h}\ \exp (\frac{\Delta ^{\ddagger }S^{\,\unicode{x26ac}}}{R})\ \exp (- \frac{\Delta ^{\ddagger }H^{\,\unicode{x26ac}}}{R\ T})$ where $$\Delta ^{\ddagger}S^{\,\unicode{x26ac}}$$, the @E02150@, is the standard molar change of @E02149@ when the @A00092@ is formed from reactants and $$\Delta ^{\ddagger}H^{\,\unicode{x26ac}}$$, the @E02142@, is the corresponding standard molar change of @E02141@. The quantities $$E_{a}$$ (the @E02108@) and $$\Delta ^{\ddagger}H^{\,\unicode{x26ac}}$$ are not quite the same, the relationship between them depending on the type of reaction. Also: $k=\frac{k_{\text{B}}\ T}{h}\ \exp (- \frac{\Delta ^{\ddagger }G^{\,\unicode{x26ac}}}{R\ T})$ where $$\Delta ^{\ddagger}G^{\,\unicode{x26ac}}$$, known as the @G02631@, is the standard molar Gibbs energy change for the conversion of reactants into @A00092@. A plot of standard molar Gibbs energy against a @R05168@ is known as a Gibbs-@E02112@; such plots, unlike @P04779@, are temperature-dependent. In principle the equations above must be multiplied by a @T06479@, $$\kappa$$, which is the @P04855@ that an @A00092@ forms a particular set of products rather than reverting to reactants or forming alternative products. It is to be emphasized that $$\Delta ^{\ddagger}S^{\,\unicode{x26ac}}$$, $$\Delta ^{\ddagger}H^{\,\unicode{x26ac}}$$ and $$\Delta ^{\ddagger}G^{\,\unicode{x26ac}}$$ occurring in the former three equations are not ordinary thermodynamic quantities, since one degree of freedom in the @A00092@ is ignored. Transition-state theory has also been known as absolute rate theory, and as activated-complex theory, but these terms are no longer recommended.
Source:
PAC, 1996, 68, 149. (A glossary of terms used in chemical kinetics, including reaction dynamics (IUPAC Recommendations 1996)) on page 190 [Terms] [Paper]